WorldWideScience

Sample records for charged gas-phase ions

  1. Gas phase ion chemistry

    CERN Document Server

    Bowers, Michael T

    1979-01-01

    Gas Phase Ion Chemistry, Volume 2 covers the advances in gas phase ion chemistry. The book discusses the stabilities of positive ions from equilibrium gas-phase basicity measurements; the experimental methods used to determine molecular electron affinities, specifically photoelectron spectroscopy, photodetachment spectroscopy, charge transfer, and collisional ionization; and the gas-phase acidity scale. The text also describes the basis of the technique of chemical ionization mass spectrometry; the energetics and mechanisms of unimolecular reactions of positive ions; and the photodissociation

  2. Gas phase ion chemistry

    CERN Document Server

    Bowers, Michael T

    1979-01-01

    Gas Phase Ion Chemistry, Volume 1 covers papers on the advances of gas phase ion chemistry. The book discusses the advances in flow tubes and the measurement of ion-molecule rate coefficients and product distributions; the ion chemistry of the earth's atmosphere; and the classical ion-molecule collision theory. The text also describes statistical methods in reaction dynamics; the state selection by photoion-photoelectron coincidence; and the effects of temperature and pressure in the kinetics of ion-molecule reactions. The energy distribution in the unimolecular decomposition of ions, as well

  3. Ab initio treatment of gas phase GeO{sup 2+} doubly charged ion

    Energy Technology Data Exchange (ETDEWEB)

    Mogren Al Mogren, M. [Chemistry Department, Faculty of Science, King Saud University, PO Box 2455, Riyadh 11451 (Saudi Arabia); Ben Abdallah, D. [Laboratoire de Spectroscopie Atomique, Moléculaire et Applications – LSAMA, Université de Tunis, Tunis (Tunisia); Department of General Studies, Riyadh Corporation of Technology, Technical and Vocational Training Corporation, PO Box 42826, Riyadh 11551 (Saudi Arabia); Hochlaf, M., E-mail: hochlaf@univ-mlv.fr [Université Paris-Est, Laboratoire Modélisation et Simulation Multi Echelle, MSME UMR 8208 CNRS, 5 bd Descartes, 77454 Marne-la-Vallée (France)

    2015-01-13

    Highlights: • Theoretical investigation of the novel gas-phase molecular species GeO{sup 2+}. • Spectroscopic parameters of this dication in its electronic ground and exited states. • Theoretical double ionization spectrum of GeO. - Abstract: Using multi reference configuration interaction methodology in connection with a large basis set, we show that GeO{sup 2+} is a metastable species either in the ground or in the electronically excited states. This confirms the observation of this dication in gas phase by mass spectrometry. In addition, we derived a set of accurate spectroscopic terms for GeO{sup 2+} bound states. At the MRCI/aug-cc-pV5Z level of theory, the adiabatic double ionization energy of GeO is computed to be ∼28.93 eV.

  4. Ab initio treatment of gas phase GeO2+ doubly charged ion

    Science.gov (United States)

    Mogren Al Mogren, M.; Ben Abdallah, D.; Hochlaf, M.

    2015-01-01

    Using multi reference configuration interaction methodology in connection with a large basis set, we show that GeO2+ is a metastable species either in the ground or in the electronically excited states. This confirms the observation of this dication in gas phase by mass spectrometry. In addition, we derived a set of accurate spectroscopic terms for GeO2+ bound states. At the MRCI/aug-cc-pV5Z level of theory, the adiabatic double ionization energy of GeO is computed to be ∼28.93 eV.

  5. Gas-Phase Covalent And Non-Covalent Ion/ion Chemistry Of Biological Macromolecules

    OpenAIRE

    Stutzman, John Robert

    2013-01-01

    Gas-phase ion/ion chemistry involves the interaction of oppositely charged ions inside of the mass spectrometer. During this gas-phase chemistry, particle transfer (i.e., proton and electron) or synthesis can occur at rapid reaction rates. Particle transfer represents a mature area of ion/ion chemistry, while selective covalent modification represents a fairly new area of gas-phase chemistry. Gas-phase covalent chemistry is based on traditional solution phase organic chemistry. The work de...

  6. Hydrocarbon radical thermochemistry: Gas-phase ion chemistry techniques

    Energy Technology Data Exchange (ETDEWEB)

    Ervin, Kent M. [Univ. of Nevada, Reno, NV (United States)

    2014-03-21

    Final Scientific/Technical Report for the project "Hydrocarbon Radical Thermochemistry: Gas-Phase Ion Chemistry Techniques." The objective of this project is to exploit gas-phase ion chemistry techniques for determination of thermochemical values for neutral hydrocarbon radicals of importance in combustion kinetics.

  7. Flourescence from Gas-Phase Biomolecular Ions

    DEFF Research Database (Denmark)

    2013-01-01

    difficulties, of fluorescence spectroscopy compared to absorption spectroscopy are discussed. Extensive work has been done on the isolated dyes in characterising them with respect to their dispersed fluorescence spectra, excited-state lifetimes, and gas-phase Stokes shifts. After a brief introduction, results...

  8. Laserspray ionization, a new atmospheric pressure MALDI method for producing highly charged gas-phase ions of peptides and proteins directly from solid solutions.

    Science.gov (United States)

    Trimpin, Sarah; Inutan, Ellen D; Herath, Thushani N; McEwen, Charles N

    2010-02-01

    The first example of a matrix-assisted laser desorption/ionization (MALDI) process producing multiply charged mass spectra nearly identical to those observed with electrospray ionization (ESI) is presented. MALDI is noted for its ability to produce singly charged ions, but in the experiments described here multiply charged ions are produced by laser ablation of analyte incorporated into a common MALDI matrix, 2,5-dihydroxybenzoic acid, using standard solvent-based sample preparation protocols. Laser ablation is known to produce matrix clusters in MALDI provided a threshold energy is achieved. We propose that these clusters (liquid droplets) are highly charged, and under conditions that produce sufficient matrix evaporation, ions are field-evaporated from the droplets similarly to ESI. Because of the multiple charging, advanced mass spectrometers with limited mass-to-charge range can be used for protein characterization. Thus, using an Orbitrap mass spectrometer, low femtomole quantities of proteins produce full-range mass spectra at 100,000 mass resolution with <5-ppm mass accuracy and with 1-s acquisition. Furthermore, the first example of protein fragmentation using electron transfer dissociation with MALDI is presented.

  9. Oxidation of methionine residues in polypeptide ions via gas-phase ion/ion chemistry.

    Science.gov (United States)

    Pilo, Alice L; McLuckey, Scott A

    2014-06-01

    The gas-phase oxidation of methionine residues is demonstrated here using ion/ion reactions with periodate anions. Periodate anions are observed to attach in varying degrees to all polypeptide ions irrespective of amino acid composition. Direct proton transfer yielding a charge-reduced peptide ion is also observed. In the case of methionine and, to a much lesser degree, tryptophan-containing peptide ions, collisional activation of the complex ion generated by periodate attachment yields an oxidized peptide product (i.e., [M + H + O](+)), in addition to periodic acid detachment. Detachment of periodic acid takes place exclusively for peptides that do not contain either a methionine or tryptophan side chain. In the case of methionine-containing peptides, the [M + H + O](+) product is observed at a much greater abundance than the proton transfer product (viz., [M + H](+)). Collisional activation of oxidized Met-containing peptides yields a signature loss of 64 Da from the precursor and/or product ions. This unique loss corresponds to the ejection of methanesulfenic acid from the oxidized methionine side chain and is commonly used in solution-phase proteomics studies to determine the presence of oxidized methionine residues. The present work shows that periodate anions can be used to 'label' methionine residues in polypeptides in the gas phase. The selectivity of the periodate anion for the methionine side chain suggests several applications including identification and location of methionine residues in sequencing applications.

  10. Negative ion gas-phase chemistry of arenes.

    Science.gov (United States)

    Danikiewicz, Witold; Zimnicka, Magdalena

    2016-01-01

    Reactions of aromatic and heteroaromatic compounds involving anions are of great importance in organic synthesis. Some of these reactions have been studied in the gas phase and are occasionally mentioned in reviews devoted to gas-phase negative ion chemistry, but no reviews exist that collect all existing information about these reactions. This work is intended to fill this gap. In the first part of this review, methods for generating arene anions in the gas phase and studying their physicochemical properties and fragmentation reactions are presented. The main topics in this part are as follows: processes in which gas-phase arene anions are formed, measurements and calculations of the proton affinities of arene anions, proton exchange reactions, and fragmentation processes of substituted arene anions, especially phenide ions. The second part is devoted to gas-phase reactions of arene anions. The most important of these are reactions with electrophiles such as carbonyl compounds and α,β-unsaturated carbonyl and related compounds (Michael acceptors). Other reactions including oxidation of arene anions and halogenophilic reactions are also presented. In the last part of the review, reactions of electrophilic arenes with nucleophiles are discussed. The best known of these is the aromatic nucleophilic substitution (SN Ar) reaction; however, other processes that lead to the substitution of a hydrogen atom in the aromatic ring are also very important. Aromatic substrates in these reactions are usually but not always nitroarenes bearing other substituents in the ring. The first step in these reactions is the formation of an anionic σ-adduct, which, depending on the substituents in the aromatic ring and the structure of the attacking nucleophile, is either an intermediate or a transition state in the reaction path. In the present review, we attempted to collect the results of both experimental and computational studies of the aforementioned reactions conducted since the

  11. Alteration of gas phase ion polarizabilities upon hydration in high dielectric liquids

    OpenAIRE

    2013-01-01

    We investigate the modification of gas phase ion polarizabilities upon solvation in polar solvents and ionic liquids. To this aim, we develop a classical electrostatic theory of charged liquids composed of solvent molecules modeled as finite size dipoles, and embedding polarizable ions that consist of Drude oscillators. In qualitative agreement with ab-initio calculations of polar solvents and ionic liquids, the hydration energy of a polarizable ion in both type of dielectric liquid is shown ...

  12. Alteration of gas phase ion polarizabilities upon hydration in high dielectric liquids.

    Science.gov (United States)

    Buyukdagli, Sahin; Ala-Nissila, T

    2013-07-28

    We investigate the modification of gas phase ion polarizabilities upon solvation in polar solvents and ionic liquids. To this aim, we develop a classical electrostatic theory of charged liquids composed of solvent molecules modeled as finite size dipoles, and embedding polarizable ions that consist of Drude oscillators. In qualitative agreement with ab initio calculations of polar solvents and ionic liquids, the hydration energy of a polarizable ion in both types of dielectric liquid is shown to favor the expansion of its electronic cloud. Namely, the ion carrying no dipole moment in the gas phase acquires a dipole moment in the liquid environment, but its electron cloud also reaches an enhanced rigidity. We find that the overall effect is an increase of the gas phase polarizability upon hydration. In the specific case of ionic liquids, it is shown that this hydration process is driven by a collective solvation mechanism where the dipole moment of a polarizable ion induced by its interaction with surrounding ions self-consistently adds to the polarization of the liquid, thereby amplifying the dielectric permittivity of the medium in a substantial way. We propose this self-consistent hydration as the underlying mechanism behind the high dielectric permittivities of ionic liquids composed of small charges with negligible gas phase dipole moment. Hydration being a correlation effect, the emerging picture indicates that electrostatic correlations cannot be neglected in polarizable liquids.

  13. Distinct Fragmentation Pathways of Anticancer Drugs Induced by Charge-Carrying Cations in the Gas Phase

    Science.gov (United States)

    Hong, Areum; Lee, Hong Hee; Heo, Chae Eun; Cho, Yunju; Kim, Sunghwan; Kang, Dukjin; Kim, Hugh I.

    2016-12-01

    With the growth of the pharmaceutical industry, structural elucidation of drugs and derivatives using tandem mass spectrometry (MS2) has become essential for drug development and pharmacokinetics studies because of its high sensitivity and low sample requirement. Thus, research seeking to understand fundamental relationships between fragmentation patterns and precursor ion structures in the gas phase has gained attention. In this study, we investigate the fragmentation of the widely used anticancer drugs, doxorubicin (DOX), vinblastine (VBL), and vinorelbine (VRL), complexed by a singly charged proton or alkali metal ion (Li+, Na+, K+) in the gas phase. The drug-cation complexes exhibit distinct fragmentation patterns in tandem mass spectra as a function of cation size. The trends in fragmentation patterns are explicable in terms of structures derived from ion mobility mass spectrometry (IM-MS) and theoretical calculations.

  14. Gas-phase energetics of thorium fluorides and their ions.

    Science.gov (United States)

    Irikura, Karl K

    2013-02-14

    Gas-phase thermochemistry for neutral ThF(n) and cations ThF(n)(+) (n = 1-4) is obtained from large-basis CCSD(T) calculations, with a small-core pseudopotential on thorium. Electronic partition functions are computed with the help of relativistic MRCI calculations. Geometries, vibrational spectra, electronic fine structure, and ion appearance energies are tabulated. These results support the experimental results by Lau, Brittain, and Hildenbrand for the neutral species, except for ThF. The ion thermochemistry is presented here for the first time.

  15. Spectroscopic studies of cold, gas-phase biomolecular ions

    Science.gov (United States)

    Rizzo, Thomas R.; Stearns, Jaime A.; Boyarkin, Oleg V.

    While the marriage of mass spectrometry and laser spectroscopy is not new, developments over the last few years in this relationship have opened up new horizons for the spectroscopic study of biological molecules. The combination of electrospray ionisation for producing large biological molecules in the gas phase together with cooled ion traps and multiple-resonance laser schemes are allowing spectroscopic investigation of individual conformations of peptides with more than a dozen amino acids. Highly resolved infrared spectra of single conformations of such species provide important benchmarks for testing the accuracy of theoretical calculations. This review presents a number of techniques employed in our laboratory and in others for measuring the spectroscopy of cold, gas-phase protonated peptides. We show examples that demonstrate the power of these techniques and evaluate their extension to still larger biological molecules.

  16. Review: gas-phase ion chemistry of the noble gases: recent advances and future perspectives.

    Science.gov (United States)

    Grandinetti, Felice

    2011-01-01

    This review article surveys recent experimental and theoretical advances in the gas-phase ion chemistry of the noble gases. Covered issues include the interaction of the noble gases with metal and non-metal cations, the conceivable existence of covalent noble-gas anions, the occurrence of ion-molecule reactions involving singly-charged xenon cations, and the occurrence of bond-forming reactions involving doubly-charged cations. Research themes are also highlighted, that are expected to attract further interest in the future.

  17. Molecular ions of ionic liquids in the gas phase.

    Science.gov (United States)

    Gross, Jürgen H

    2008-09-01

    Ionic liquids form neutral ion pairs (CA) upon evaporation. The softness of the gas-phase ionization of field ionization has been used to generate "molecular ions," CA(+*), of ionic liquids, most probably by neutralization of the anion. In detail, 1-ethyl-3-methylimidazolium-thiocyanate, [C(6)H(11)N(2)](+) [SCN](-), 1-butyl-3-methylimidazolium-tricyanomethide, [C(8)H(15)N(2)](+) [C(4)N(3)](-), N-butyl-3-methylpyridinium-dicyanamide, [C(10)H(16)N](+) [C(2)N(3)](-), and 1-butyl-1-methylpyrrolidinium-bis[(trifluormethyl)sulfonyl]amide, [C(9)H(20)N](+) [C(2)F(6)NO(4)S(2)](-) were used. The assignment as CA(+*) ions, which has been confirmed by accurate mass measurements and misassignments due to thermal decomposition of the ionic liquids, has been ruled out by field desorption and electrospray ionization mass spectrometry of the residues.

  18. Gas-Phase Intramolecular Protein Crosslinking via Ion/Ion Reactions: Ubiquitin and a Homobifunctional sulfo-NHS Ester

    Science.gov (United States)

    Webb, Ian K.; Mentinova, Marija; McGee, William M.; McLuckey, Scott A.

    2013-05-01

    Gas-phase intra-molecular crosslinking of protein ubiquitin cations has been demonstrated via ion/ion reactions with anions of a homobifunctional N-hydroxysulfosuccinimide (sulfo-NHS) ester reagent. The ion/ion reaction between multiply-protonated ubiquitin and crosslinker monoanions produces a stable, charge-reduced complex. Covalent crosslinking is indicated by the consecutive loss of 2 molecules of sulfo-NHS under ion trap collisional activation conditions. Covalent modification is verified by the presence of covalently crosslinked sequence ions produced by ion-trap collision-induced dissociation of the ion generated from the losses of sulfo-NHS. Analysis of the crosslinked sequence fragments allows for the localization of crosslinked primary amines, enabling proximity mapping of the gas-phase 3-D structures. The presence of two unprotonated reactive sites within the distance constraint of the crosslinker is required for successful crosslinking. The ability to covalently crosslink is, therefore, sensitive to protein charge state. As the charge state increases, fewer reactive sites are available and protein structure is more likely to become extended because of intramolecular electrostatic repulsion. At high charge states, the reagent shows little evidence for covalent crosslinking but does show evidence for `electrostatic crosslinking' in that the binding of the sulfonate groups to the protein is sufficiently strong that backbone cleavages are favored over reagent detachment under ion trap collisional activation conditions.

  19. Substituent effects on the gas-phase fragmentation reactions of sulfonium ion containing peptides.

    Science.gov (United States)

    Sierakowski, James; Amunugama, Mahasilu; Roberts, Kade D; Reid, Gavin E

    2007-01-01

    The multistage mass spectrometric (MS/MS and MS3) gas-phase fragmentation reactions of methionine side-chain sulfonium ion containing peptides formed by reaction with a series of para-substituted phenacyl bromide (XBr where X=CH2COC6H4R, and R=--COOH, --COOCH3, --H, --CH3 and --CH2CH3) alkylating reagents have been examined in a linear quadrupole ion trap mass spectrometer. MS/MS of the singly (M+) and multiply ([M++nH](n+1)+) charged precursor ions results in exclusive dissociation at the fixed charge containing side chain, independently of the amino acid composition and precursor ion charge state (i.e., proton mobility). However, loss of the methylphenacyl sulfide side-chain fragment as a neutral versus charged (protonated) species was observed to be highly dependent on the proton mobility of the precursor ion, and the identity of the phenacyl group para-substituent. Molecular orbital calculations were performed at the B3LYP/6-31+G** level of theory to calculate the theoretical proton affinities of the neutral side-chain fragments. The log of the ratio of neutral versus protonated side-chain fragment losses from the derivatized side chain were found to exhibit a linear dependence on the proton affinity of the side-chain fragmentation product, as well as the proton affinities of the peptide product ions. Finally, MS3 dissociation of the nominally identical neutral and protonated loss product ions formed by MS/MS of the [M++H]2+ and [M++2H]3+ precursor ions, respectively, from the peptide GAILM(X)GAILK revealed significant differences in the abundances of the resultant product ions. These results suggest that the protonated peptide product ions formed by gas-phase fragmentation of sulfonium ion containing precursors in an ion trap mass spectrometer do not necessarily undergo intramolecular proton 'scrambling' prior to their further dissociation, in contrast to that previously demonstrated for peptide ions introduced by external ionization sources.

  20. Unusual hydrogen and hydroxyl migration in the fragmentation of excited doubly-positively-charged amino acids in the gas phase

    OpenAIRE

    Díaz-Tendero, Sergio; Piekarski, Dariusz G.; Alcamí, Manuel; Martín, Fernando; Maclot, Sylvain; Delaunay, Rudy; Domaracka, Alicja; Rousseau, Patrick; Adoui, Lamri; Huber, Bernd A.

    2015-01-01

    We present a combined experimental and theoretical study of the fragmentation of doubly-positively- charged amino acids in the gas phase. The combination of ab initio molecular dynamics simulations with ion- molecule collisions followed by multiple-coincidence mass spectrometric techniques, allows us to obtain a complete picture of the fragmentation dynamics. In addition to the expected Coulomb explosion, we have found evidence of hydrogen and hydroxyl-group migration processes, which leads t...

  1. Ion chemistry and gas-phase basicity of nickelocene by ion cyclotron resonance spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Corderman, R.R.; Beauchamp, J.L.

    1976-01-01

    The gas-phase ion chemistry of bis(eta/sup 5/-cyclopentadienyl)nickel(nickelocene) is studied using the techniques of ion cyclotron resonance spectroscopy. Total rate constants for the reactions of the primary fragment ions at 70 eV are determined using trapped-ion methods. The long-lived nickelocene anion, Ni(C/sub 5/H/sub 5/)/sub 2//sup -/, is formed directly by electron attachment and is unreactive with a variety of simple molecules. Nickelocene is observed to be an exceptionally strong base in the gas phase. Equilibrium proton-transfer reactions are observed in mixtures of nickelocene with (CH/sub 3/)/sub 3/N and (C/sub 2/H/sub 5/)/sub 2/NH, from which the gas-phase basicity or proton affinity (PA) is determined to be 218.9 +- 1.0 kcal/mol relative to PA(NH/sub 3/) = 201 +- 1 kcal/mol. Attempts to determine the site of protonation were inconclusive. The ion chemistry and base strength of nickelocene and ferrocene are compared. 39 references, 2 figures, 3 tables.

  2. Ion chemistry and gas-phase basicity of nickelocene by ion cyclotron resonance spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Corderman, R.D.; Beauchamp, J.L.

    1976-03-01

    The gas-phase ion chemistry of bis(eta/sup 5/-cyclopentadienyl)nickel (nickelocene) is studied using the techniques of ion cyclotron resonance spectroscopy. Total rate constants for the reactions of the primary fragment ions at 70 eV are determined using trapped-ion methods. The long-lived nickelocene anion, Ni(C/sub 5/H/sub 5/)/sub 2//sup -/, is formed directly by electron attachment and is unreactive with a variety of simple molecules. Nickelocene is observed to be an exceptionally strong base in the gas phase. Equilibrium proton-transfer reactions are observed in mixtures of nickelocene with (CH/sub 3/)/sub 3/N and (C/sub 2/H/sub 5/)/sub 2/NH, from which the gas-phase basicity or proton affinity (PA) is determined to be 218.9 +- 1.0 kcal/mol relative to PA(NH/sub 3/) = 201 +- 1 kcal/mol. Attempts to determine the site of protonation were inconclusive. The ion chemistry and base strength of nickelocene and ferrocene are compared. (auth)

  3. Fixed-charge phosphine ligands to explore gas-phase coinage metal-mediated decarboxylation reactions.

    Science.gov (United States)

    Vikse, Krista; Khairallah, George N; McIndoe, J Scott; O'Hair, Richard A J

    2013-05-14

    A combination of multistage mass spectrometry experiments and density functional theory (DFT) calculations were used to examine the decarboxylation reactions of a series of metal carboxylate complexes bearing a fixed-charge phosphine ligand, [(O3SC6H4)(C6H5)2PM(I)O2CR](-) (M = Cu, Ag, Au; R = Me, Et, benzyl, Ph). Collision-induced dissociation (CID) of these complexes using an LTQ linear ion mass spectrometer results in three main classes of reactions being observed: (1) decarboxylation; (2) loss of the phosphine ligand; (3) loss of carboxylic acid. The gas-phase unimolecular chemistry of the resultant decarboxylated organometallic ions, [(O3SC6H4)(C6H5)2PM(I)R](-), were also explored using CID experiments, and fragment primarily via loss of the phosphine ligand. Energy-resolved CID experiments on [(O3SC6H4)(C6H5)2PM(I)O2CR](-) (M = Cu, Ag, Au; R = Me, Et, benzyl, Ph) using a Q-TOF mass spectrometer were performed to gain a more detailed understanding of the factors influencing coinage metal-catalyzed decarboxylation and DFT calculations on the major fragmentation pathways aided in interpretation of the experimental results. Key findings are that: (1) the energy required for loss of the phosphine ligand follows the order Ag phosphine ligand on decarboxylation is also considered in comparison with previous studies on metal carboxylates that do not contain a phosphine ligand.

  4. Device for two-dimensional gas-phase separation and characterization of ion mixtures

    Science.gov (United States)

    Tang, Keqi; Shvartsburg, Alexandre A.; Smith, Richard D.

    2006-12-12

    The present invention relates to a device for separation and characterization of gas-phase ions. The device incorporates an ion source, a field asymmetric waveform ion mobility spectrometry (FAIMS) analyzer, an ion mobility spectrometry (IMS) drift tube, and an ion detector. In one aspect of the invention, FAIMS operating voltages are electrically floated on top of the IMS drift voltage. In the other aspect, the FAIMS/IMS interface is implemented employing an electrodynamic ion funnel, including in particular an hourglass ion funnel. The present invention improves the efficiency (peak capacity) and sensitivity of gas-phase separations; the online FAIMS/IMS coupling creates a fundamentally novel two-dimensional gas-phase separation technology with high peak capacity, specificity, and exceptional throughput.

  5. Toward a Rational Design of Highly Folded Peptide Cation Conformations. 3D Gas-Phase Ion Structures and Ion Mobility Characterization

    Science.gov (United States)

    Pepin, Robert; Laszlo, Kenneth J.; Marek, Aleš; Peng, Bo; Bush, Matthew F.; Lavanant, Helène; Afonso, Carlos; Tureček, František

    2016-10-01

    Heptapeptide ions containing combinations of polar Lys, Arg, and Asp residues with non-polar Leu, Pro, Ala, and Gly residues were designed to study polar effects on gas-phase ion conformations. Doubly and triply charged ions were studied by ion mobility mass spectrometry and electron structure theory using correlated ab initio and density functional theory methods and found to exhibit tightly folded 3D structures in the gas phase. Manipulation of the basic residue positions in LKGPADR, LRGPADK, KLGPADR, and RLGPADK resulted in only minor changes in the ion collision cross sections in helium. Replacement of the Pro residue with Leu resulted in only marginally larger collision cross sections for the doubly and triply charged ions. Disruption of zwitterionic interactions in doubly charged ions was performed by converting the C-terminal and Asp carboxyl groups to methyl esters. This resulted in very minor changes in the collision cross sections of doubly charged ions and even slightly diminished collision cross sections in most triply charged ions. The experimental collision cross sections were related to those calculated for structures of lowest free energy ion conformers that were obtained by extensive search of the conformational space and fully optimized by density functional theory calculations. The predominant factors that affected ion structures and collision cross sections were due to attractive hydrogen bonding interactions and internal solvation of the charged groups that overcompensated their Coulomb repulsion. Structure features typically assigned to the Pro residue and zwitterionic COO-charged group interactions were only secondary in affecting the structures and collision cross sections of these gas-phase peptide ions.

  6. Toward a Rational Design of Highly Folded Peptide Cation Conformations. 3D Gas-Phase Ion Structures and Ion Mobility Characterization.

    Science.gov (United States)

    Pepin, Robert; Laszlo, Kenneth J; Marek, Aleš; Peng, Bo; Bush, Matthew F; Lavanant, Helène; Afonso, Carlos; Tureček, František

    2016-10-01

    Heptapeptide ions containing combinations of polar Lys, Arg, and Asp residues with non-polar Leu, Pro, Ala, and Gly residues were designed to study polar effects on gas-phase ion conformations. Doubly and triply charged ions were studied by ion mobility mass spectrometry and electron structure theory using correlated ab initio and density functional theory methods and found to exhibit tightly folded 3D structures in the gas phase. Manipulation of the basic residue positions in LKGPADR, LRGPADK, KLGPADR, and RLGPADK resulted in only minor changes in the ion collision cross sections in helium. Replacement of the Pro residue with Leu resulted in only marginally larger collision cross sections for the doubly and triply charged ions. Disruption of zwitterionic interactions in doubly charged ions was performed by converting the C-terminal and Asp carboxyl groups to methyl esters. This resulted in very minor changes in the collision cross sections of doubly charged ions and even slightly diminished collision cross sections in most triply charged ions. The experimental collision cross sections were related to those calculated for structures of lowest free energy ion conformers that were obtained by extensive search of the conformational space and fully optimized by density functional theory calculations. The predominant factors that affected ion structures and collision cross sections were due to attractive hydrogen bonding interactions and internal solvation of the charged groups that overcompensated their Coulomb repulsion. Structure features typically assigned to the Pro residue and zwitterionic COO-charged group interactions were only secondary in affecting the structures and collision cross sections of these gas-phase peptide ions. Graphical Abstract ᅟ.

  7. Evolution of Instrumentation for the Study of Gas-Phase Ion/Ion Chemistry via Mass Spectrometry

    OpenAIRE

    Xia, Yu; McLuckey, Scott A.

    2007-01-01

    The scope of gas phase ion/ion chemistry accessible to mass spectrometry is largely defined by the available tools. Due to the development of novel instrumentation, a wide range of reaction phenomenologies have been noted, many of which have been studied extensively and exploited for analytical applications. This perspective presents the development of mass spectrometry-based instrumentation for the study of the gas phase ion/ion chemistry in which at least one of the reactants is multiply-ch...

  8. Preparative soft and reactive landing of gas-phase ions on plasma-treated metal surfaces.

    Science.gov (United States)

    Volný, Michael; Elam, W Timothy; Ratner, Buddy D; Turecek, Frantisek

    2005-08-01

    Soft landing of singly charged gas-phase ions on dry metal surfaces that were pretreated in situ by oxygen plasma results in 0.1-2% total yields of recovered intact compounds. Lysine, peptides, crystal violet dye, and a biotin conjugate are found to survive soft landing of hyperthermal ions of up to 50-eV kinetic energy. Soft landing at 40-50-eV ion kinetic energies of a fluorescence-labeled biotin conjugate results in an immobilized fraction that cannot be washed from the surface and is found to contain an intact biotin moiety. The present results represent an approximately 10(4) fold improvement in soft-landing efficiency and indicate that plasma-treated metal surfaces can be useful for preparative separation of organic and biological molecules by mass spectrometry. The substantial improvement in soft-landing yields results from a high transmission of electrosprayed ions into the vacuum system, efficient and nondestructive discharge of ions on the metal oxide surface, and facile analyte recovery in the absence of a matrix.

  9. Formation of Carbamate Anions by the Gas-phase Reaction of Anilide Ions with CO2.

    Science.gov (United States)

    Liu, Chongming; Nishshanka, Upul; Attygalle, Athula B

    2016-05-01

    The anilide anion (m/z 92) generated directly from aniline, or indirectly as a fragmentation product of deprotonated acetanilide, captures CO2 readily to form the carbamate anion (m/z 136) in the collision cell, when CO2 is used as the collision gas in a tandem-quadrupole mass spectrometer. The gas-phase affinity of the anilide ion to CO2 is significantly higher than that of the phenoxide anion (m/z 93), which adds to CO2 only very sluggishly. Our results suggest that the efficacy of CO2 capture depends on the natural charge density on the nitrogen atom, and relative nucleophilicity of the anilide anion. Generally, conjugate bases generated from aniline derivatives with proton affinities (PA) less than 350 kcal/mol do not tend to add CO2 to form gaseous carbamate ions. For example, the anion generated from p-methoxyaniline (PA = 367 kcal/mol) reacts significantly faster than that obtained from p-nitroaniline (PA = 343 kcal/mol). Although deprotonated p-aminobenzoic acid adds very poorly because the negative charge is now located primarily on the carboxylate group, it reacts more efficiently with CO2 if the carboxyl group is esterified. Moreover, mixture of CO2 and He as the collision gas was found to afford more efficient adduct formation than CO2 alone, or as mixtures made with nitrogen or argon, because helium acts as an effective "cooling" gas and reduces the internal energy of reactant ions.

  10. A cylindrical quadrupole ion trap in combination with an electrospray ion source for gas-phase luminescence and absorption spectroscopy

    Science.gov (United States)

    Stockett, Mark H.; Houmøller, Jørgen; Støchkel, Kristian; Svendsen, Annette; Brøndsted Nielsen, Steen

    2016-05-01

    A relatively simple setup for collection and detection of light emitted from isolated photo-excited molecular ions has been constructed. It benefits from a high collection efficiency of photons, which is accomplished by using a cylindrical ion trap where one end-cap electrode is a mesh grid combined with an aspheric condenser lens. The geometry permits nearly 10% of the emitted light to be collected and, after transmission losses, approximately 5% to be delivered to the entrance of a grating spectrometer equipped with a detector array. The high collection efficiency enables the use of pulsed tunable lasers with low repetition rates (e.g., 20 Hz) instead of continuous wave (cw) lasers or very high repetition rate (e.g., MHz) lasers that are typically used as light sources for gas-phase fluorescence experiments on molecular ions. A hole has been drilled in the cylinder electrode so that a light pulse can interact with the ion cloud in the center of the trap. Simulations indicate that these modifications to the trap do not significantly affect the storage capability and the overall shape of the ion cloud. The overlap between the ion cloud and the laser light is basically 100%, and experimentally >50% of negatively charged chromophore ions are routinely photodepleted. The performance of the setup is illustrated based on fluorescence spectra of several laser dyes, and the quality of these spectra is comparable to those reported by other groups. Finally, by replacing the optical system with a channeltron detector, we demonstrate that the setup can also be used for gas-phase action spectroscopy where either depletion or fragmentation is monitored to provide an indirect measurement on the absorption spectrum of the ion.

  11. Conformation Switching in Gas-Phase Complexes of Histidine with Alkaline Earth Ions

    NARCIS (Netherlands)

    Dunbar, R. C.; Hopkinson, A. C.; Oomens, J.; Siu, C. K.; Siu, K. W. M.; Steill, J. D.; Verkerk, U. H.; Zhao, J. F.

    2009-01-01

    Infrared multiple photon dissociation spectroscopy of gas-phase doubly charged alkaline earth complexes of histidine reveals a transition from dominance of the zwitterion (salt bridge, SB) conformation with Ba2+ to substantial presence of the canonical (charge-solvated, CS) conformation with Ca2+. T

  12. Fluorescence resonance energy transfer of gas-phase ions under ultra high vacuum and ambient conditions.

    Science.gov (United States)

    Frankevich, Vladimir; Chagovets, Vitaliy; Widjaja, Fanny; Barylyuk, Konstantin; Yang, Zhiyi; Zenobi, Renato

    2014-05-21

    We report evidence for fluorescence resonance energy transfer (FRET) of gas-phase ions under ultra high vacuum conditions (10(-9) mbar) inside a mass spectrometer as well as under ambient conditions inside an electrospray plume. Two different FRET pairs based on carboxyrhodamine 6G (donor) and ATTO590 or Bodipy TR (acceptor) dyes were examined and their gas-phase optical properties were studied. Our measurements indicate a different behavior for the two FRET pairs, which can be attributed to their different conformations in the gas phase. Upon desolvation via electrospray ionization, one of the FRET pairs undergoes a conformational change that leads to disappearance of FRET. This study shows the promise of FRET to obtain a direct correlation between solution and gas-phase structures.

  13. Characterization of a DAPI-RIT-DAPI system for gas-phase ion/molecule and ion/ion reactions.

    Science.gov (United States)

    Lin, Ziqing; Tan, Lei; Garimella, Sandilya; Li, Linfan; Chen, Tsung-Chi; Xu, Wei; Xia, Yu; Ouyang, Zheng

    2014-01-01

    The discontinuous atmospheric pressure interface (DAPI) has been developed as a facile means for efficiently introducing ions generated at atmospheric pressure to an ion trap in vacuum [e.g., a rectilinear ion trap (RIT)] for mass analysis. Introduction of multiple beams of ions or neutral species through two DAPIs into a single RIT has been previously demonstrated. In this study, a home-built instrument with a DAPI-RIT-DAPI configuration has been characterized for the study of gas-phase ion/molecule and ion/ion reactions. The reaction species, including ions or neutrals, can be introduced from both ends of the RIT through the two DAPIs without complicated ion optics or differential pumping stages. The primary reactant ions were isolated prior to reaction and the product ions were mass analyzed after controlled reaction time period. Ion/molecule reactions involving peptide radical ions and proton-transfer ion/ion reactions have been carried out using this instrument. The gas dynamic effect due to the DAPI operation on internal energy deposition and the reactivity of peptide radical ions has been characterized. The DAPI-RIT-DAPI system also has a unique feature for allowing the ion reactions to be carried out at significantly elevated pressures (in 10(-1) Torr range), which has been found to be helpful to speed up the reactions. The viability and flexibility of the DAPI-RIT-DAPI system for the study of gas-phase ion reactions have been demonstrated.

  14. Characterization of a DAPI-RIT-DAPI System for Gas-Phase Ion/Molecule and Ion/Ion Reactions

    Science.gov (United States)

    Lin, Ziqing; Tan, Lei; Garimella, Sandilya; Li, Linfan; Chen, Tsung-Chi; Xu, Wei; Xia, Yu; Ouyang, Zheng

    2014-01-01

    The discontinuous atmospheric pressure interface (DAPI) has been developed as a facile means for efficiently introducing ions generated at atmospheric pressure to an ion trap in vacuum [e.g., a rectilinear ion trap (RIT)] for mass analysis. Introduction of multiple beams of ions or neutral species through two DAPIs into a single RIT has been previously demonstrated. In this study, a home-built instrument with a DAPI-RIT-DAPI configuration has been characterized for the study of gas-phase ion/molecule and ion/ion reactions. The reaction species, including ions or neutrals, can be introduced from both ends of the RIT through the two DAPIs without complicated ion optics or differential pumping stages. The primary reactant ions were isolated prior to reaction and the product ions were mass analyzed after controlled reaction time period. Ion/molecule reactions involving peptide radical ions and proton-transfer ion/ion reactions have been carried out using this instrument. The gas dynamic effect due to the DAPI operation on internal energy deposition and the reactivity of peptide radical ions has been characterized. The DAPI-RIT-DAPI system also has a unique feature for allowing the ion reactions to be carried out at significantly elevated pressures (in 10-1 Torr range), which has been found to be helpful to speed up the reactions. The viability and flexibility of the DAPI-RIT-DAPI system for the study of gas-phase ion reactions have been demonstrated.

  15. Multidimensional separations of ubiquitin conformers in the gas phase: relating ion cross sections to H/D exchange measurements.

    Science.gov (United States)

    Robinson, Errol W; Williams, Evan R

    2005-09-01

    Investigating gas-phase structures of protein ions can lead to an improved understanding of intramolecular forces that play an important role in protein folding. Both hydrogen/deuterium (H/D) exchange and ion mobility spectrometry provide insight into the structures and stabilities of different gas-phase conformers, but how best to relate the results from these two methods has been hotly debated. Here, high-field asymmetric waveform ion mobility spectrometry (FAIMS) is combined with Fourier-transform ion cyclotron resonance mass spectrometry (FT/ICR MS) and is used to directly relate ubiquitin ion cross sections and H/D exchange extents. Multiple conformers can be identified using both methods. For the 9+ charge state of ubiquitin, two conformers (or unresolved populations of conformers) that have cross sections differing by 10% are resolved by FAIMS, but only one conformer is apparent using H/D exchange at short times. For the 12+ charge state, two conformers (or conformer populations) have cross sections differing by ion collisional cross sections and H/D exchange distributions are not strongly correlated and that factors other than surface accessibility appear to play a significant role in determining rates and extents of H/D exchange. Conformers that are not resolved by one method could be resolved by the other, indicating that these two methods are highly complementary and that more conformations can be resolved with this combination of methods than by either method alone.

  16. Gas-phase conformations of small polyprolines and their fragment ions by IRMPD spectroscopy

    NARCIS (Netherlands)

    Martens, J.K.; Grzetic, J.; Berden, G.; Oomens, J.

    2015-01-01

    Infrared multiple-photon dissociation (IRMPD) spectroscopy has been used to examine the gas-phase conformations of a series of short protonated polyproline ions (Pro(3)-Pro(6)), their CID/IRMPD fragmentation pathways, and the associated fragment identities. Consistent with previous findings, and in

  17. Effects of metal ion adduction on the gas-phase conformations of protein ions.

    Science.gov (United States)

    Flick, Tawnya G; Merenbloom, Samuel I; Williams, Evan R

    2013-11-01

    Changes in protein ion conformation as a result of nonspecific adduction of metal ions to the protein during electrospray ionization (ESI) from aqueous solutions were investigated using traveling wave ion mobility spectrometry (TWIMS). For all proteins examined, protein cations (and in most cases anions) with nonspecific metal ion adducts are more compact than the fully protonated (or deprotonated) ions with the same charge state. Compaction of protein cations upon nonspecific metal ion binding is most significant for intermediate charge state ions, and there is a greater reduction in collisional cross section with increasing number of metal ion adducts and increasing ion valency, consistent with an electrostatic interaction between the ions and the protein. Protein cations with the greatest number of adducted metal ions are no more compact than the lowest protonated ions formed from aqueous solutions. These results show that smaller collisional cross sections for metal-attached protein ions are not a good indicator of a specific metal-protein interaction in solution because nonspecific metal ion adduction also results in smaller gaseous protein cation cross sections. In contrast, the collisional cross section of α-lactalbumin, which specifically binds one Ca(2+), is larger for the holo-form compared with the apo-form, in agreement with solution-phase measurements. Because compaction of protein cations occurs when metal ion adduction is nonspecific, elongation of a protein cation may be a more reliable indicator that a specific metal ion-protein interaction occurs in solution.

  18. From Compact to String—The Role of Secondary and Tertiary Structure in Charge-Induced Unzipping of Gas-Phase Proteins

    Science.gov (United States)

    Warnke, Stephan; Hoffmann, Waldemar; Seo, Jongcheol; De Genst, Erwin; von Helden, Gert; Pagel, Kevin

    2016-12-01

    In the gas phase, protein ions can adopt a broad range of structures, which have been investigated extensively in the past using ion mobility-mass spectrometry (IM-MS)-based methods. Compact ions with low number of charges undergo a Coulomb-driven transition to partially folded species when the charge increases, and finally form extended structures with presumably little or no defined structure when the charge state is high. However, with respect to the secondary structure, IM-MS methods are essentially blind. Infrared (IR) spectroscopy, on the other hand, is sensitive to such structural details and there is increasing evidence that helices as well as β-sheet-like structures can exist in the gas phase, especially for ions in low charge states. Very recently, we showed that also the fully extended form of highly charged protein ions can adopt a distinct type of secondary structure that features a characteristic C5-type hydrogen bond pattern. Here we use a combination of IM-MS and IR spectroscopy to further investigate the influence of the initial, native conformation on the formation of these structures. Our results indicate that when intramolecular Coulomb-repulsion is large enough to overcome the stabilization energies of the genuine secondary structure, all proteins, regardless of their sequence or native conformation, form C5-type hydrogen bond structures. Furthermore, our results suggest that in highly charged proteins the positioning of charges along the sequence is only marginally influenced by the basicity of individual residues.

  19. Ion sponge: a 3-dimentional array of quadrupole ion traps for trapping and mass-selectively processing ions in gas phase.

    Science.gov (United States)

    Xu, Wei; Li, Linfan; Zhou, Xiaoyu; Ouyang, Zheng

    2014-05-01

    In this study, the concept of ion sponge has been explored for developing 3D arrays of large numbers of ion traps but with simple configurations. An ion sponge device with 484 trapping units in a volume of 10 × 10 × 3.2 cm has been constructed by simply stacking 9 meshes together. A single rf was used for trapping ions and mass-selective ion processing. The ion sponge provides a large trapping capacity and is highly transparent for transfer of ions, neutrals, and photons for gas phase ion processing. Multiple layers of quadrupole ion traps, with 121 trapping units in each layer, can operate as a single device for MS or MS/MS analysis, or as a series of mass-selective trapping devices with interlayer ion transfers facilitated by AC and DC voltages. Automatic sorting of ions to different trapping layers based on their mass-to-charge (m/z) ratios was achieved with traps of different sizes. Tandem-in-space MS/MS has also been demonstrated with precursor ions and fragment ions trapped in separate locations.

  20. Conformations of gas-phase ions of ubiquitin, cytochrome c, apomyoglobin, and beta-lactoglobulin produced from two different solution conformations.

    Science.gov (United States)

    Wright, P John; Zhang, Jianmin; Douglas, D J

    2008-12-01

    At low pH in solutions of 50% methanol, proteins form expanded denatured states (the "H" state). In 90% methanol, proteins form expanded helical denatured states with artificial alpha-helices (the "H(c)" state). Gas-phase ions of ubiquitin, cytochrome c, apomyoglobin, and native and disulfide-reduced beta-lactoglobulin were formed by electrospray ionization (ESI) of the proteins from the H and H(c) states in solution. Both states in solution produce the same charge states in ESI. The conformations of the ions were studied with cross section measurements and gas-phase H/D exchange experiments. The cross sections show that the ions retain considerable folded structure. For a given protein and given charge state, ions produced from the H and H(c) states showed the same cross sections (within approximately 1%). Ions of cytochrome c, apomyoglobin, and native and reduced beta-lactoglobulin of a given charge state showed no differences in H/D exchange level when produced from the H or H(c) state. However, ubiquitin ions produced from the H(c) state consistently exchange fewer ( approximately 13%) hydrogens than ions produced from the H state, suggesting that in this case the gas-phase protein ions retain some memory of their solution conformations.

  1. Gas-phase metalloprotein complexes interrogated by ion mobility-mass spectrometry

    Science.gov (United States)

    Faull, Peter A.; Korkeila, Karoliina E.; Kalapothakis, Jason M.; Gray, Andrew; McCullough, Bryan J.; Barran, Perdita E.

    2009-06-01

    Gas-phase biomolecular structure may be explored through a number of analytical techniques. Ion mobility-mass spectrometry (IM-MS) continues to prove itself as a sensitive and reliable bioanalytical tool for gas-phase structure determination due to intense study and development over the past 15 years. A vast amount of research interest, especially in protein and peptide conformational studies has generated a wealth of structural information for biological systems from small peptides to megadalton-sized biomolecules. In this work, linear low field IM-MS has been used to study gas-phase conformations and determine rotationally averaged collision cross-sections of three metalloproteins--cytochrome c, haemoglobin and calmodulin. Measurements have been performed on the MoQToF, a modified QToF 1 instrument (Micromass UK Ltd., Manchester, UK) modified in house. Gas-phase conformations and cross-sections of multimeric cytochrome c ions of the form [xM + nH+]n+ for x = 1-3 (monomer to trimer) have been successfully characterised and measured. We believe these to be the first reported collision cross-sections of higher order multimeric cytochrome c. Haemoglobin is investigated to obtain structural information on the associative mechanism of tetramer formation. Haemoglobin molecules, comprising apo- and holo-monomer chains, dimer and tetramer are transferred to the gas phase under a range of solution conditions. Structural information on the proposed critical intermediate, semi-haemoglobin, is reported. Cross-sections of the calcium binding protein calmodulin have been obtained under a range of calcium-bound conditions. Metalloprotein collision cross-sections from ion mobility measurements are compared with computationally derived values from published NMR and X-ray crystallography structural data. Finally we consider the change in the density of the experimentally measured rotationally averaged collision cross-section for compact geometries of the electrosprayed proteins.

  2. Effects of ion/ion proton transfer reactions on conformation of gas-phase cytochrome c ions.

    Science.gov (United States)

    Zhao, Qin; Schieffer, Gregg M; Soyk, Matthew W; Anderson, Timothy J; Houk, R S; Badman, Ethan R

    2010-07-01

    Positive ions from cytochrome c are studied in a 3-D ion trap/ion mobility (IM)/quadrupole-time-of-flight (TOF) instrument with three independent ion sources. The IM separation allows measurement of the cross section of the ions. Ion/ion reactions in the 3-D ion trap that remove protons cause the cytochrome c ions to refold gently without other degradation of protein structure, i.e., fragmentation or loss of heme group or metal ion. The conformation(s) of the product ions generated by ion/ion reactions in a given charge state are similar regardless of whether the cytochrome c ions are originally in +8 or +9 charge states. In the lower charge states (+1 to +5) cytochrome c ions made by the ion/ion reaction yield a single IM peak with cross section of approximately 1110 to 1180 A(2), even if the original +8 ion started with multiple conformations. The conformation expands slightly when the charge state is reduced from +5 to +1. For product ions in the +6 to +8 charge states, ions created from higher charge states (+9 to +16) by ion/ion reaction produce more compact conformation(s) in somewhat higher abundances compared with those produced directly by the electrospray ionization (ESI) source. For ions in intermediate charge states that have a variety of resolvable conformers, the voltage used to inject the ions into the drift tube, and the voltage and duration of the pulse that extracts ions from the ion trap, can affect the observed abundances of various conformers.

  3. Tuning a High Transmission Ion Guide to Prevent Gas-Phase Proton Exchange During H/D Exchange MS Analysis.

    Science.gov (United States)

    Guttman, Miklos; Wales, Thomas E; Whittington, Dale; Engen, John R; Brown, Jeffery M; Lee, Kelly K

    2016-04-01

    Hydrogen/deuterium exchange (HDX) mass spectrometry (MS) for protein structural analysis has been adopted for many purposes, including biopharmaceutical development. One of the benefits of examining amide proton exchange by mass spectrometry is that it can readily resolve different exchange regimes, as evidenced by either binomial or bimodal isotope patterns. By careful analysis of the isotope pattern during exchange, more insight can be obtained on protein behavior in solution. However, one must be sure that any observed bimodal isotope patterns are not artifacts of analysis and are reflective of the true behavior in solution. Sample carryover and certain stationary phases are known as potential sources of bimodal artifacts. Here, we describe an additional undocumented source of deuterium loss resulting in artificial bimodal patterns for certain highly charged peptides. We demonstrate that this phenomenon is predominantly due to gas-phase proton exchange between peptides and bulk solvent within the initial stages of high-transmission conjoined ion guides. Minor adjustments of the ion guide settings, as reported here, eliminate the phenomenon without sacrificing signal intensity. Such gas-phase deuterium loss should be appreciated for all HDX-MS studies using such ion optics, even for routine studies not focused on interpreting bimodal spectra. Graphical Abstract ᅟ.

  4. Gas phase studies of the Pesci decarboxylation reaction: synthesis, structure, and unimolecular and bimolecular reactivity of organometallic ions.

    Science.gov (United States)

    O'Hair, Richard A J; Rijs, Nicole J

    2015-02-17

    CONSPECTUS: Decarboxylation chemistry has a rich history, and in more recent times, it has been recruited in the quest to develop cheaper, cleaner, and more efficient bond-coupling reactions. Thus, over the past two decades, there has been intense investigation into new metal-catalyzed reactions of carboxylic substrates. Understanding the elementary steps of metal-mediated transformations is at the heart of inventing new reactions and improving the performance of existing ones. Fortunately, during the same time period, there has been a convergence in mass spectrometry (MS) techniques, which allows these catalytic processes to be examined efficiently in the gas phase. Thus, electrospray ionization (ESI) sources have been combined with ion-trap mass spectrometers, which in turn have been modified to either accept radiation from tunable OPO lasers for spectroscopy based structural assignment of ions or to allow the study of ion-molecule reactions (IMR). The resultant "complete" gas-phase chemical laboratories provide a platform to study the elementary steps of metal-catalyzed decarboxylation reactions in exquisite detail. In this Account, we illustrate how the powerful combination of ion trap mass spectrometry experiments and DFT calculations can be systematically used to examine the formation of organometallic ions and their chemical transformations. Specifically, ESI-MS allows the transfer of inorganic carboxylate complexes, [RCO2M(L)n](x), (x = charge) from the condensed to the gas phase. These mass selected ions serve as precursors to organometallic ions [RM(L)n](x) via neutral extrusion of CO2, accessible by slow heating in the ion trap using collision induced dissociation (CID). This approach provides access to an array of organometallic ions with well-defined stoichiometry. In terms of understanding the decarboxylation process, we highlight the role of the metal center (M), the organic group (R), and the auxiliary ligand (L), along with cluster nuclearity, in

  5. Gas Phase Reactions of Ions Derived from Anionic Uranyl Formate and Uranyl Acetate Complexes

    Science.gov (United States)

    Perez, Evan; Hanley, Cassandra; Koehler, Stephen; Pestok, Jordan; Polonsky, Nevo; Van Stipdonk, Michael

    2016-09-01

    The gas-phase oxidation of doubly protonated peptides containing neutral basic residues to various products, including [M + H + O]+, [M - H]+, and [M - H - NH3]+, is demonstrated here via ion/ion reactions with periodate. It was previously demonstrated that periodate anions are capable of oxidizing disulfide bonds and methionine, tryptophan, and S-alkyl cysteine residues. However, in the absence of these easily oxidized sites, we show here that systems containing neutral basic residues can undergo oxidation. Furthermore, we show that these neutral basic residues primarily undergo different types of oxidation (e.g., hydrogen abstraction) reactions than those observed previously (i.e., oxygen transfer to yield the [M + H + O]+ species) upon gas-phase ion/ion reactions with periodate anions. This chemistry is illustrated with a variety of systems, including a series of model peptides, a cell-penetrating peptide containing a large number of unprotonated basic sites, and ubiquitin, a roughly 8.6 kDa protein.

  6. Selective Gas-Phase Oxidation and Localization of Alkylated Cysteine Residues in Polypeptide Ions via Ion/Ion Chemistry.

    Science.gov (United States)

    Pilo, Alice L; Zhao, Feifei; McLuckey, Scott A

    2016-09-01

    The thiol group in cysteine residues is susceptible to several post-translational modifications (PTMs), including prenylation, nitrosylation, palmitoylation, and the formation of disulfide bonds. Additionally, cysteine residues involved in disulfide bonds are commonly reduced and alkylated prior to mass spectrometric analysis. Several of these cysteine modifications, specifically S-alkyl modifications, are susceptible to gas-phase oxidation via selective ion/ion reactions with periodate anions. Multiply protonated peptides containing modified cysteine residues undergo complex formation upon ion/ion reaction with periodate anions. Activation of the ion/ion complexes results in oxygen transfer from the reagent to the modified sulfur residue to create a sulfoxide functionality. Further activation of the sulfoxide derivative yields abundant losses of the modification with the oxidized sulfur as a sulfenic acid (namely, XSOH) to generate a dehydroalanine residue. This loss immediately indicates the presence of an S-alkyl cysteine residue, and the mass of the loss can be used to easily deduce the type of modification. An additional step of activation can be used to localize the modification to a specific residue within the peptide. Selective cleavage to create c- and z-ions N-terminal to the dehydroalanine residue is often noted. As these types of ions are not typically observed upon collision-induced dissociation (CID), they can be used to immediately indicate where in the peptide the PTM was originally located.

  7. Ion yields for some salts in MALDI: mechanism for the gas-phase ion formation from preformed ions.

    Science.gov (United States)

    Moon, Jeong Hee; Shin, Young Sik; Bae, Yong Jin; Kim, Myung Soo

    2012-01-01

    Preformed ion emission is the main assumption in one of the prevailing theories for peptide and protein ion formation in matrix-assisted laser desorption ionization (MALDI). Since salts are in preformed ion forms in the matrix-analyte mixture, they are ideal systems to study the characteristics of preformed ion emission. In this work, a reliable method to measure the ion yield (IY) in MALDI was developed and used for a solid salt benzyltriphenylphosphonium chloride and two room-temperature ionic liquids 1-butyl-3-methylimidazolium hexafluorophosphate and trihexyltetradecylphosphonium bis(2,4,4-trimethylpentyl)phosphinate. IY for the matrix (α-cyano-4-hydroxycinnamic acid, CHCA) was also measured. Taking 1 pmol salts in 25 nmol CHCA as examples, IYs for three salts were similar, (4-8) × 10(-4), and those for CHCA were (0.8-1.2) × 10(-7). Even though IYs for the salts and CHCA remained virtually constant at low analyte concentration, they decreased as the salt concentrations increased. Two models, Model 1 and Model 2, were proposed to explain low IYs for the salts and the concentration dependences. Both models are based on the fact that the ion-pair formation equilibrium is highly shifted toward the neutral ion pair. In Model 1, the gas-phase analyte cations were proposed to originate from the same cations in the solid that were dielectrically screened from counter anions by matrix neutrals. In Model 2, preformed ions were assumed to be released from the solid sample in the form of neutral ion pairs and the anions in the ion pairs were assumed to be eliminated via reactions with matrix-derived cations.

  8. Development of Monopole Interaction Models for Ionic Compounds. Part I: Estimation of Aqueous Henry's Law Constants for Ions and Gas Phase pKa Values for Acidic Compounds.

    Science.gov (United States)

    Hilal, S H; Saravanaraj, A N; Carreira, L A

    2014-02-01

    The SPARC (SPARC Performs Automated Reasoning in Chemistry) physicochemical mechanistic models for neutral compounds have been extended to estimate Henry's Law Constant (HLC) for charged species by incorporating ionic electrostatic interaction models. Combinations of absolute aqueous pKa values, relative pKa values in the gas phase, and aqueous HLC for neutral compounds have been used to develop monopole interaction models that quantify the energy differences upon moving an ionic solute molecule from the gas phase to the liquid phase. Inter-molecular interaction energies were factored into mechanistic contributions of monopoles with polarizability, dipole, H-bonding, and resonance. The monopole ionic models were validated by a wide range of measured gas phase pKa data for 450 acidic compounds. The RMS deviation error and R(2) for the OH, SH, CO2 H, CH3 and NR2 acidic reaction centers (C) were 16.9 kcal/mol and 0.87, respectively. The calculated HLCs of ions were compared to the HLCs of 142 ions calculated by quantum mechanics. Effects of inter-molecular interaction of the monopoles with polarizability, dipole, H-bonding, and resonance on acidity of the solutes in the gas phase are discussed.

  9. Gas Phase Reactions of Ions Derived from Anionic Uranyl Formate and Uranyl Acetate Complexes

    Science.gov (United States)

    Perez, Evan; Hanley, Cassandra; Koehler, Stephen; Pestok, Jordan; Polonsky, Nevo; Van Stipdonk, Michael

    2016-12-01

    The speciation and reactivity of uranium are topics of sustained interest because of their importance to the development of nuclear fuel processing methods, and a more complete understanding of the factors that govern the mobility and fate of the element in the environment. Tandem mass spectrometry can be used to examine the intrinsic reactivity (i.e., free from influence of solvent and other condensed phase effects) of a wide range of metal ion complexes in a species-specific fashion. Here, electrospray ionization, collision-induced dissociation, and gas-phase ion-molecule reactions were used to create and characterize ions derived from precursors composed of uranyl cation (UVIO2 2+) coordinated by formate or acetate ligands. Anionic complexes containing UVIO2 2+ and formate ligands fragment by decarboxylation and elimination of CH2=O, ultimately to produce an oxo-hydride species [UVIO2(O)(H)]-. Cationic species ultimately dissociate to make [UVIO2(OH)]+. Anionic complexes containing acetate ligands exhibit an initial loss of acetyloxyl radical, CH3CO2•, with associated reduction of uranyl to UVO2 +. Subsequent CID steps cause elimination of CO2 and CH4, ultimately to produce [UVO2(O)]-. Loss of CH4 occurs by an intra-complex H+ transfer process that leaves UVO2 + coordinated by acetate and acetate enolate ligands. A subsequent dissociation step causes elimination of CH2=C=O to leave [UVO2(O)]-. Elimination of CH4 is also observed as a result of hydrolysis caused by ion-molecule reaction with H2O. The reactions of other anionic species with gas-phase H2O create hydroxyl products, presumably through the elimination of H2.

  10. Infrared Spectroscopy of Gas-Phase M(+)(CO2)n (M = Co, Rh, Ir) Ion-Molecule Complexes.

    Science.gov (United States)

    Iskra, Andreas; Gentleman, Alexander S; Kartouzian, Aras; Kent, Michael J; Sharp, Alastair P; Mackenzie, Stuart R

    2017-01-12

    The structures of gas-phase M(+)(CO2)n (M = Co, Rh, Ir; n = 2-15) ion-molecule complexes have been investigated using a combination of infrared resonance-enhanced photodissociation (IR-REPD) spectroscopy and density functional theory. The results provide insight into fundamental metal ion-CO2 interactions, highlighting the trends with increasing ligand number and with different group 9 ions. Spectra have been recorded in the region of the CO2 asymmetric stretch around 2350 cm(-1) using the inert messenger technique and their interpretation has been aided by comparison with simulated infrared spectra of calculated low-energy isomeric structures. All vibrational bands in the smaller complexes are blue-shifted relative to the asymmetric stretch in free CO2, consistent with direct binding to the metal center dominated by charge-quadrupole interactions. For all three metal ions, a core [M(+)(CO2)2] structure is identified to which subsequent ligands are less strongly bound. No evidence is observed in this size regime for complete activation or insertion reactions.

  11. Preparation of cold ions in strong magnetic field and its application to gas-phase NMR spectroscopy

    Science.gov (United States)

    Fuke, K.; Ohshima, Y.; Tona, M.

    2015-11-01

    Nuclear Magnetic Resonance (NMR) technique is widely used as a powerful tool to study the physical and chemical properties of materials. However, this technique is limited to the materials in condensed phases. To extend this technique to the gas-phase molecular ions, we are developing a gas-phase NMR apparatus. In this note, we describe the basic principle of the NMR detection for molecular ions in the gas phase based on a Stern-Gerlach type experiment in a Penning trap and outline the apparatus under development. We also present the experimental procedures and the results on the formation and the manipulation of cold ions under a strong magnetic field, which are the key techniques to detect the NMR by the present method.

  12. Preparation of cold ions in strong magnetic field and its application to gas-phase NMR spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Fuke, K., E-mail: fuke@kobe-u.ac.jp [Institute for Molecular Science (Japan); Ohshima, Y. [Tokyo Institute of Technology, Department of Chemistry (Japan); Tona, M. [Ayabo Co. Fukukama (Japan)

    2015-11-15

    Nuclear Magnetic Resonance (NMR) technique is widely used as a powerful tool to study the physical and chemical properties of materials. However, this technique is limited to the materials in condensed phases. To extend this technique to the gas-phase molecular ions, we are developing a gas-phase NMR apparatus. In this note, we describe the basic principle of the NMR detection for molecular ions in the gas phase based on a Stern-Gerlach type experiment in a Penning trap and outline the apparatus under development. We also present the experimental procedures and the results on the formation and the manipulation of cold ions under a strong magnetic field, which are the key techniques to detect the NMR by the present method.

  13. Gas phase ion-molecule reactions of buckminsterfullerene C60 with some small organic compounds in mass spectrometer

    Institute of Scientific and Technical Information of China (English)

    刘淑莹; 郭兴华; 刘子阳; 倪嘉缵

    1995-01-01

    In chemical ionization mass spectrometry (CIMS) gas phase C60+ or C60can react with fragment ions from three chloromethane and four multichloroethane molecular ions via ion-molecule reactions A dozen of gas-phase adduct ions of C60 are observed, and most of them contain chlorine atoms The results of the comparison and analysis show that the relative intensities of adduct ions are not directly proportional to the corresponding fragment ions in the MS of reagents,which implies that some fragment ions containing radicals are more reactive with C60+ or C60. This indicates that the alkene-like C60+ or C60 can act as a radical sponge in addition reactions.

  14. Metal Cation Binding to Gas-Phase Pentaalanine: Divalent Ions Restructure the Complex

    NARCIS (Netherlands)

    Dunbar, R. C.; Steill, J. D.; Polfer, N. C.; Oomens, J.

    2013-01-01

    Ion-neutral complexes of pentaalalanine with several singly- and doubly charged metal ions are examined using conformation analysis by infrared multiple photon dissociation (IRMPD) spectroscopy and density functional theory (DFT) computations. The infrared spectroscopy in the 1500-1800 cm(-1) region

  15. Gas-phase hydrogen/deuterium exchange in a traveling wave ion guide for the examination of protein conformations.

    Science.gov (United States)

    Rand, Kasper D; Pringle, Steven D; Murphy, James P; Fadgen, Keith E; Brown, Jeff; Engen, John R

    2009-12-15

    Accumulating evidence suggests that solution-phase conformations of small globular proteins and large molecular protein assemblies can be preserved for milliseconds after electrospray ionization. Thus, the study of proteins in the gas phase on this time scale is highly desirable. Here we demonstrate that a traveling wave ion guide (TWIG) of a Synapt mass spectrometer offers a highly suitable environment for rapid and efficient gas-phase hydrogen/deuterium exchange (HDX). Gaseous ND(3) was introduced into either the source TWIG or the TWIG located just after the ion mobility cell, such that ions underwent HDX as they passed through the ND(3) on the way to the time-of-flight analyzer. The extent of deuterium labeling could be controlled by varying the quantity of ND(3) or the speed of the traveling wave. The gas-phase HDX of model peptides corresponded to labeling of primarily fast exchanging sites due to the short labeling times (ranging from 0.1 to 10 ms). In addition to peptides, gas-phase HDX of ubiquitin, cytochrome c, lysozyme, and apomyoglobin were examined. We conclude that HDX of protein ions in a TWIG is highly sensitive to protein conformation, enables the detection of conformers present on submilliseconds time scales, and can readily be combined with ion mobility spectrometry.

  16. Structure of alcohol cluster ions in the gas phase, according to spectrometry and ab initio calculations

    Science.gov (United States)

    Krisilov, A. V.; Lantsuzskaya, E. V.; Levina, A. M.

    2017-01-01

    Reduced ion mobility and scattering cross sections are calculated from experimentally obtained spectra of the ion mobility of linear aliphatic alcohols with carbon atom numbers from 2 to 9. A linear increase in the scattering cross sections as the molecular weight grows is found. According to the results from experiments and quantum chemical calculations, alcohol cluster ions do not form a compact structure. Neither are dipole moments compensated for during dimerization, in contrast to the aldehydes and ketones described earlier. It was concluded from ab initio calculations that charge delocalization in monomeric and dimeric ions of alcohols increases the dipole moment many times over.

  17. A new approach for the study of gas-phase ion-ion reactions using electrospray ionization.

    Science.gov (United States)

    Ogorzalek Loo, R R; Udseth, H R; Smith, R D

    1992-10-01

    A simple flow reactor which facilitates the study and application of ion-ion and ion-molecule reactions at near atmospheric pressures is reported. Reactant ions were generated by electrospray ionization and discharge ionization methods, although any ionization sources amenable to atmospheric pressure may be used. Ions of opposite charge are generated in spatially separate ion sources and are swept into capillary inlets where the flows are merged and where reaction(s) can occur. Among the reactions investigated were the partial neutralization of multiply protonated polypeptides and proteins such as melittin, bradykinin, cytochrome c, and myoglobin by reaction with discharge-generated anions, the partial neutralization of multiply charged anions of oligodeoxyadenylic acid (d(pA)3) by reaction with discharge-generated cations, the partial neutralization of bovine A-chain insulin anions by reaction with myoglobin [M+nH](n+) ions, and the reaction of multiply protonated melittin with discharge-generated cations. The cation-anion reactions generally resulted in a shift to lower charge (higher mass-to-charge ratio) in the products' charge state distributions and the transfer of solvent molecules to the macromolecule products. Multiply protonated melittin was detected in a less highly solvated state with the positive discharge in operation.

  18. Gas-Phase Ion-Molecule Reactions in Selected Cyclohexanes (PREPRINT)

    Science.gov (United States)

    2012-12-01

    Varian variable leak valve) into the FTMS system. The hydrocarbon ions were formed by electron impact on C6H12 or C7H14 in the trapping cell at a total...would become overpopulated during electron ionization, resulting in a significant space charge effect. To eliminate this effect, an rf waveform with the...H- transfer proceeding via large impact parameter collisions, favoring no H/D shuffling. Direct H- transfer vs. H- transfer via long-lived complex

  19. How useful is ion mobility mass spectrometry for structural biology? The relationship between protein crystal structures and their collision cross sections in the gas phase.

    Science.gov (United States)

    Jurneczko, Ewa; Barran, Perdita E

    2011-01-07

    The technique of ion mobility mass spectrometry (IM-MS) has become of increasing interest for rapid analysis of the conformations adopted by biological macromolecules. It is currently used routinely for analysis of explosives and illegal substances in airport and military security. In biophysical research, it can be used to determine the temperature dependent rotationally averaged collision cross section of gas-phase ions of proteins and nucleic acids along with their mass to charge ratios. Nanoelectrospray ionisation allows the gentle transfer of intact biomolecules from solutions in which the native form(s) are present, into the solvent free environment of a mass spectrometer. It is believed by many researchers that the experimental collision cross sections of these molecules should have some relationship to crystal structure coordinates. In this review we outline the different experimental methods that can be used to measure ion mobility; we also describe methods used to calculate collision cross sections from input coordinates. Following this survey of the methodological approaches to IM-MS, we then summarise IM-MS data published to date for some monomeric peptides and small soluble proteins, along with collision cross sections calculated from their crystal structure coordinates. Finally we consider the relationship between experimental gas-phase conformations and those adopted in crystals and give an outlook on the application of IM-MS as a tool for structural biology.

  20. Zwitterionic states in gas-phase polypeptide ions revealed by 157-nm ultra-violet photodissociation

    DEFF Research Database (Denmark)

    Kjeldsen, Frank; Silivra, Oleg A; Zubarev, Roman A

    2006-01-01

    carboxylic groups relative to competing COOH losses (45 Da) from neutral carboxylic groups. Loss of CO2 is a strong indication of the presence of a zwitterionic [(+)...(-)...(+)] salt bridge in the gas-phase polypeptide cation. This method provides a tool for studying, for example, the nature of binding...

  1. Preparation of Surface Organometallic Catalysts by Gas-Phase Ligand Stripping and Reactive Landing of Mass-Selected Ions

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Grant E.; Laskin, Julia

    2010-12-27

    Organometallic complexes immobilized on surfaces combine the high selectivity of homogeneous catalysts with the ease of separation of catalyst from products of heterogeneous materials. Here we report a novel approach for the highly controlled preparation of surface organometallic catalysts by gas-phase ligand stripping combined with reactive landing of mass-selected ions onto self assembled monolayer surfaces. Collision induced dissociation is used to generate highly reactive undercoordinated metal complexes in the gas-phase for subsequent surface immobilization. Complexes with an open coordination shell around the metal center are demonstrated to show enhanced activity towards reactive landing in comparison to fully ligated species. In situ TOF-SIMS analysis indicates that the immobilized complexes exhibit behaviour consistent with catalytic activity when exposed to gaseous reagents.

  2. Recent Selected Ion Flow Tube (SIFT) Studies Concerning the Formation of Amino Acids in the Gas Phase

    Science.gov (United States)

    Jackson, Douglas M.; Adams, Nigel G.; Babcock, Lucia M.

    2006-01-01

    Recently the simplest amino acid, glycine, has been detected in interstellar clouds, ISC, although this has since been contested. In order to substantiate either of these claims, plausible routes to amino acids need to be investigated. For gas phase synthesis, the SIFT technique has been employed to study simple amino acids via ion-molecule reactions of several ions of interstellar interest with methylamine, ethylamine, formic acid, acetic acid, and methyl formate. Carboxylic acid type ions were considered in the reactions involving the amines. In reactions where the carboxylic acid and methyl formate neutrals were studied, the reactant ions were primarily amine ion fragments. It was observed that the amines and acids preferentially fragment or accept a proton whenever energetically possible. NH3(+), however, uniquely reacted with the neutrals via atom abstraction to form NH4(+). These studies yielded a body of data relevant to astrochemistry, supplementing the available literature. However, the search for gas phase routes to amino acids using conventional molecules has been frustrated. Our most recent research investigates the fragmentation patterns of several amino acids and several possible routes have been suggested for future study.

  3. Competitive homolytic and heterolytic decomposition pathways of gas-phase negative ions generated from aminobenzoate esters.

    Science.gov (United States)

    Xia, Hanxue; Zhang, Yong; Pavlov, Julius; Jariwala, Freneil B; Attygalle, Athula B

    2016-03-01

    An alkyl-radical loss and an alkene loss are two competitive fragmentation pathways that deprotonated aminobenzoate esters undergo upon activation under mass spectrometric conditions. For the meta and para isomers, the alkyl-radical loss by a homolytic cleavage of the alkyl-oxygen bond of the ester moiety is the predominant fragmentation pathway, while the contribution from the alkene elimination by a heterolytic pathway is less significant. In contrast, owing to a pronounced charge-mediated ortho effect, the alkene loss becomes the predominant pathway for the ortho isomers of ethyl and higher esters. Results from isotope-labeled compounds confirmed that the alkene loss proceeds by a specific γ-hydrogen transfer mechanism that resembles the McLafferty rearrangement for radical cations. Even for the para compounds, if the alkoxide moiety bears structural motifs required for the elimination of a more stable alkene molecule, the heterolytic pathway becomes the predominant pathway. For example, in the spectrum of deprotonated 2-phenylethyl 4-aminobenzoate, m/z 136 peak is the base peak because the alkene eliminated is styrene. Owing to the fact that all deprotonated aminobenzoate esters, irrespective of the size of the alkoxy group, upon activation fragment to form an m/z 135 ion, aminobenzoate esters in mixtures can be quantified by precursor ion discovery mass spectrometric experiments.

  4. Proton-driven amide bond-cleavage pathways of gas-phase peptide ions lacking mobile protons.

    Science.gov (United States)

    Bythell, Benjamin J; Suhai, Sándor; Somogyi, Arpád; Paizs, Béla

    2009-10-07

    The mobile proton model (Dongre, A. R., Jones, J. L., Somogyi, A. and Wysocki, V. H. J. Am. Chem. Soc. 1996, 118 , 8365-8374) of peptide fragmentation states that the ionizing protons play a critical role in the gas-phase fragmentation of protonated peptides upon collision-induced dissociation (CID). The model distinguishes two classes of peptide ions, those with or without easily mobilizable protons. For the former class mild excitation leads to proton transfer reactions which populate amide nitrogen protonation sites. This enables facile amide bond cleavage and thus the formation of b and y sequence ions. In contrast, the latter class of peptide ions contains strongly basic functionalities which sequester the ionizing protons, thereby often hindering formation of sequence ions. Here we describe the proton-driven amide bond cleavages necessary to produce b and y ions from peptide ions lacking easily mobilizable protons. We show that this important class of peptide ions fragments by different means from those with easily mobilizable protons. We present three new amide bond cleavage mechanisms which involve salt-bridge, anhydride, and imine enol intermediates, respectively. All three new mechanisms are less energetically demanding than the classical oxazolone b(n)-y(m) pathway. These mechanisms offer an explanation for the formation of b and y ions from peptide ions with sequestered ionizing protons which are routinely fragmented in large-scale proteomics experiments.

  5. Salt bridge stabilization of charged zwitterionic arginine aggregates in the gas phase.

    Science.gov (United States)

    Julian, R R; Hodyss, R; Beauchamp, J L

    2001-04-18

    The discovery of several new unusually stable aggregates of arginine that are intermolecularly bound by salt bridges is reported. Quadrupole ion-trap mass spectrometry provides evidence for the stability of arginine in the zwitterionic state, where the protonated guanidinium group of one arginine interacts strongly with the carboxylate of another to form stable noncovalent complexes, coordinated to either a cation or anion. Clusters of arginine with itself, sodium, potassium, lithium, magnesium, chloride, fluoride, bromide, iodide, and nitrate are observed. DFT calculations at the B3LYP/6-31G level are used to assess the structures and energetics of particularly prominent clusters. An examination of mixtures of D-arginine with isotopically labeled L-arginine indicates that the stability of these clusters does not depend on arginine enantiomeric purity. The cyclic trimers of arginine, capped with either Cl(-) or NO(3)(-), possess exceptional stability.

  6. Charge transfer reactions between gas-phase hydrated electrons, molecular oxygen and carbon dioxide at temperatures of 80-300 K.

    Science.gov (United States)

    Akhgarnusch, Amou; Tang, Wai Kit; Zhang, Han; Siu, Chi-Kit; Beyer, Martin K

    2016-09-14

    The recombination reactions of gas-phase hydrated electrons (H2O)n˙(-) with CO2 and O2, as well as the charge exchange reaction of CO2˙(-)(H2O)n with O2, were studied by Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometry in the temperature range T = 80-300 K. Comparison of the rate constants with collision models shows that CO2 reacts with 50% collision efficiency, while O2 reacts considerably slower. Nanocalorimetry yields internally consistent results for the three reactions. Converted to room temperature condensed phase, this yields hydration enthalpies of CO2˙(-) and O2˙(-), ΔHhyd(CO2˙(-)) = -334 ± 44 kJ mol(-1) and ΔHhyd(O2˙(-)) = -404 ± 28 kJ mol(-1). Quantum chemical calculations show that the charge exchange reaction proceeds via a CO4˙(-) intermediate, which is consistent with a fully ergodic reaction and also with the small efficiency. Ab initio molecular dynamics simulations corroborate this picture and indicate that the CO4˙(-) intermediate has a lifetime significantly above the ps regime.

  7. Charge Breeding of Radioactive Ions

    CERN Document Server

    Wenander, F J C

    2013-01-01

    Charge breeding is a technique to increase the charge state of ions, in many cases radioactive ions. The singly charged radioactive ions, produced in an isotope separator on-line facility, and extracted with a low kinetic energy of some tens of keV, are injected into a charge breeder, where the charge state is increased to Q. The transformed ions are either directed towards a dedicated experiment requiring highly charged ions, or post-accelerated to higher beam energies. In this paper the physics processes involved in the production of highly charged ions will be introduced, and the injection and extraction beam parameters of the charge breeder defined. A description of the three main charge-breeding methods is given, namely: electron stripping in gas jet or foil; external ion injection into an electron-beam ion source/trap (EBIS/T); and external ion injection into an electron cyclotron resonance ion source (ECRIS). In addition, some preparatory devices for charge breeding and practical beam delivery aspects ...

  8. Gas-phase reactivity of peptide thiyl (RS•), perthiyl (RSS•), and sulfinyl (RSO•) radical ions formed from atmospheric pressure ion/radical reactions.

    Science.gov (United States)

    Tan, Lei; Xia, Yu

    2013-04-01

    In this study, we demonstrated the formation of gas-phase peptide perthiyl (RSS•) and thiyl (RS•) radical ions besides sulfinyl radical (RSO•) ions from atmospheric pressure (AP) ion/radical reactions of peptides containing inter-chain disulfide bonds. The identity of perthiyl radical was verified from characteristic 65 Da (•SSH) loss in collision-induced dissociation (CID). This signature loss was further used to assess the purity of peptide perthiyl radical ions formed from AP ion/radical reactions. Ion/molecule reactions combined with CID were carried out to confirm the formation of thiyl radical. Transmission mode ion/molecule reactions in collision cell (q2) were developed as a fast means to estimate the population of peptide thiyl radical ions. The reactivity of peptide thiyl, perthiyl, and sulfinyl radical ions was evaluated based on ion/molecule reactions toward organic disulfides, allyl iodide, organic thiol, and oxygen, which followed in order of thiyl (RS•) > perthiyl (RSS•) > sulfinyl (RSO•). The gas-phase reactivity of these three types of sulfur-based radicals is consistent with literature reports from solution studies.

  9. Photo-fragmentation and electron-detachment studies of gas-phase chromophore ions

    DEFF Research Database (Denmark)

    Rahbek, Dennis Bo

    -physical properties of two important bio-chromophores by investigating the properties of structural isomers of these molecules. The chromophores are the ones found in the green fluorescent protein and the photoactive yellow protein. The photo-physical properties have been studied experimentally in the gas phase...... excitation energy. This results in a competition between de-excitation by internal conversion and electron emission. Both of these processes are of non-adiabatic character as they rely on coupling between electronic energy and energy in nuclear motion. Moreover, it is found that higher-lying states...... in the anionic forms serves as ‘doorway’- states into the continuum of the neutral radical. Regarding the structural isomeric forms of each of the chromophores we find that the degree of electronic coupling between the subunitsmaking up the chromophores is crucial for the tuning the absorption properties, both...

  10. Gas-phase doubly charged complexes of cyclic peptides with copper in +1, +2 and +3 formal oxidation states: formation, structures and electron capture dissociation.

    Science.gov (United States)

    Afonso, Carlos; Tabet, Jean-Claude; Giorgi, Gianluca; Tureček, František

    2012-02-01

    Copper complexes with a cyclic D-His-β-Ala-L-His-L-Lys and all-L-His-β-Ala-His-Lys peptides were generated by electrospray which were doubly charged ions that had different formal oxidation states of Cu(I), Cu(II) and Cu(III) and different protonation states of the peptide ligands. Electron capture dissociation showed no substantial differences between the D-His and L-His complexes. All complexes underwent peptide cross-ring cleavages upon electron capture. The modes of ring cleavage depended on the formal oxidation state of the Cu ion and peptide protonation. Density functional theory (DFT) calculations, using the B3LYP with an effective core potential at Cu and M06-2X functionals, identified several precursor ion structures in which the Cu ion was threecoordinated to pentacoordinated by the His and Lys side-chain groups and the peptide amide or enolimine groups. The electronic structure of the formally Cu(III) complexes pointed to an effective Cu(I) oxidation state with the other charge residing in the peptide ligand. The relative energies of isomeric complexes of the [Cu(c-HAHK + H)](2+) and [Cu(c-HAHK - H)](2+) type with closed electronic shells followed similar orders when treated by the B3LYP and M06-2X functionals. Large differences between relative energies calculated by these methods were obtained for open-shell complexes of the [Cu(c-HAHK)](2+) type. Charge reduction resulted in lowering the coordination numbers for some Cu complexes that depended on the singlet or triplet spin state being formed. For [Cu(c-HAHK - H)](2+) complexes, solution H/D exchange involved only the N-H protons, resulting in the exchange of up to seven protons, as established by ultra-high mass resolution measurements. Contrasting the experiments, DFT calculations found the lowest energy structures for the gas-phase ions that were deprotonated at the peptide C(α) positions.

  11. Negative Hyperconjugation versus Electronegativity: Vibrational Spectra of Free Fluorinated Alkoxide Ions in the Gas Phase

    NARCIS (Netherlands)

    Oomens, J.; Berden, G.; Morton, T.H.

    2015-01-01

    CO stretching frequencies of free, gaseous, fluorinated alkoxide ions shift substantially to the blue, relative to those of corresponding alcohols complexed with ammonia. Free -fluorinated ions, pentafluoroethoxide and heptafluoroisopropoxide anions, display further blue shifts relative to cases wit

  12. Negative Hyperconjugation versus Electronegativity: Vibrational Spectra of Free Fluorinated Alkoxide Ions in the Gas Phase.

    Science.gov (United States)

    Oomens, Jos; Berden, Giel; Morton, Thomas Hellman

    2015-06-22

    CO stretching frequencies of free, gaseous, fluorinated alkoxide ions shift substantially to the blue, relative to those of corresponding alcohols complexed with ammonia. Free α-fluorinated ions, pentafluoroethoxide and heptafluoroisopropoxide anions, display further blue shifts relative to cases with only β-fluorination, providing experimental evidence for fluorine negative hyperconjugation. DFT analysis with the atoms in molecules (AIM) method confirms an increase in CO bond order for the α-fluorinated ions, demonstrating an increase in carbonyl character for the free ions.

  13. Spatial Separation of Charge Carriers in In2O3-x(OH)y Nanocrystal Superstructures for Enhanced Gas-Phase Photocatalytic Activity.

    Science.gov (United States)

    He, Le; Wood, Thomas E; Wu, Bo; Dong, Yuchan; Hoch, Laura B; Reyes, Laura M; Wang, Di; Kübel, Christian; Qian, Chenxi; Jia, Jia; Liao, Kristine; O'Brien, Paul G; Sandhel, Amit; Loh, Joel Y Y; Szymanski, Paul; Kherani, Nazir P; Sum, Tze Chien; Mims, Charles A; Ozin, Geoffrey A

    2016-05-24

    The development of strategies for increasing the lifetime of photoexcited charge carriers in nanostructured metal oxide semiconductors is important for enhancing their photocatalytic activity. Intensive efforts have been made in tailoring the properties of the nanostructured photocatalysts through different ways, mainly including band-structure engineering, doping, catalyst-support interaction, and loading cocatalysts. In liquid-phase photocatalytic dye degradation and water splitting, it was recently found that nanocrystal superstructure based semiconductors exhibited improved spatial separation of photoexcited charge carriers and enhanced photocatalytic performance. Nevertheless, it remains unknown whether this strategy is applicable in gas-phase photocatalysis. Using porous indium oxide nanorods in catalyzing the reverse water-gas shift reaction as a model system, we demonstrate here that assembling semiconductor nanocrystals into superstructures can also promote gas-phase photocatalytic processes. Transient absorption studies prove that the improved activity is a result of prolonged photoexcited charge carrier lifetimes due to the charge transfer within the nanocrystal network comprising the nanorods. Our study reveals that the spatial charge separation within the nanocrystal networks could also benefit gas-phase photocatalysis and sheds light on the design principles of efficient nanocrystal superstructure based photocatalysts.

  14. Examination of the Coordination Sphere of AlIII in Trifluoromethyl-Heteroarylalkenolato Complex Ions by Gas-Phase IRMPD Spectroscopy and Computational Modelling

    NARCIS (Netherlands)

    Bruckmann, L.; Tyrra, W.; Mathur, S.; G. Berden,; Oomens, J.; Meijer, Ajhm; Schafer, M.

    2012-01-01

    A series of aluminium complex ions with trifluoromethyl-heteroarylalkenolato (TMHA) ligands are studied by gas-phase infrared multiphoton-dissociation (IRMPD) spectroscopy and computational modelling. The selected series of aluminium TMHA complex ions are promising species for the initial study of i

  15. Examination of the coordination sphere of AlIII in trifluoromethyl-heteroarylalkenolato complex ions by gas-phase IRMPD spectroscopy and computational modelling

    NARCIS (Netherlands)

    L. Brueckmann; W. Tyrra; S. Mathur; G. Berden; J. Oomens; A.J.H.M. Meijer; M. Schaefer

    2012-01-01

    A series of aluminium complex ions with trifluoromethyl-heteroarylalkenolato (TMHA) ligands are studied by gas-phase infrared multiphoton-dissociation (IRMPD) spectroscopy and computational modelling. The selected series of aluminium TMHA complex ions are promising species for the initial study of i

  16. Structural characterization by infrared multiple photon dissociation spectroscopy of protonated gas-phase ions obtained by electrospray ionization of cysteine and dopamine

    NARCIS (Netherlands)

    Steill, J. D.; Szczepanski, J.; Oomens, J.; Eyler, J. R.; Brajter-Toth, A.

    2011-01-01

    Structural characterization of protonated gas-phase ions of cysteine and dopamine by infrared multiple photon dissociation (IRMPD) spectroscopy using a free electron laser in combination with theory based on DFT calculations reveals the presence of two types of protonated dimer ions in the electrosp

  17. Laserspray ionization imaging of multiply charged ions using a commercial vacuum MALDI ion source.

    Science.gov (United States)

    Inutan, Ellen D; Wager-Miller, James; Mackie, Ken; Trimpin, Sarah

    2012-11-06

    This is the first report of imaging mass spectrometry (MS) from multiply charged ions at vacuum. Laserspray ionization (LSI) was recently extended to applications at vacuum producing electrospray ionization-like multiply charged ions directly from surfaces using a commercial intermediate pressure matrix-assisted laser desorption/ionization ion mobility spectrometry (IMS) MS instrument. Here, we developed a strategy to image multiply charged peptide ions. This is achieved by the use of 2-nitrophloroglucinol as matrix for spray deposition onto the tissue section and implementation of "soft" acquisition conditions including lower laser power and ion accelerating voltages similar to electrospray ionization-like conditions. Sufficient ion abundance is generated by the vacuum LSI method to employ IMS separation in imaging multiply charged ions obtained on a commercial mass spectrometer ion source without physical instrument modifications using the laser in the commercially available reflection geometry alignment. IMS gas-phase separation reduces the complexity of the ion signal from the tissue, especially for multiply charged relative to abundant singly charged ions from tissue lipids. We show examples of LSI tissue imaging from charge state +2 of three endogenous peptides consisting of between 1 and 16 amino acid residues from the acetylated N-terminal end of myelin basic protein: mass-to-charge (m/z) 795.81 (+2) molecular weight (MW) 1589.6, m/z 831.35 (+2) MW 1660.7, and m/z 917.40 (+2) MW 1832.8.

  18. Gas-phase structure of amyloid-β (12-28) peptide investigated by infrared spectroscopy, electron capture dissociation and ion mobility mass spectrometry.

    Science.gov (United States)

    Le, Thi Nga; Poully, Jean Christophe; Lecomte, Frédéric; Nieuwjaer, Nicolas; Manil, Bruno; Desfrançois, Charles; Chirot, Fabien; Lemoine, Jerome; Dugourd, Philippe; van der Rest, Guillaume; Grégoire, Gilles

    2013-12-01

    The gas-phase structures of doubly and triply protonated Amyloid-β12-28 peptides have been investigated through the combination of ion mobility (IM), electron capture dissociation (ECD) mass spectrometry, and infrared multi-photon dissociation (IRMPD) spectroscopy together with theoretical modeling. Replica-exchange molecular dynamics simulations were conducted to explore the conformational space of these protonated peptides, from which several classes of structures were found. Among the low-lying conformers, those with predicted diffusion cross-sections consistent with the ion mobility experiment were further selected and their IR spectra simulated using a hybrid quantum mechanical/semiempirical method at the ONIOM DFT/B3LYP/6-31 g(d)/AM1 level. In ECD mass spectrometry, the c/z product ion abundance (PIA) has been analyzed for the two charge states and revealed drastic differences. For the doubly protonated species, N - Cα bond cleavage occurs only on the N and C terminal parts, while a periodic distribution of PIA is clearly observed for the triply charged peptides. These PIA distributions have been rationalized by comparison with the inverse of the distances from the protonated sites to the carbonyl oxygens for the conformations suggested from IR and IM experiments. Structural assignment for the amyloid peptide is then made possible by the combination of these three experimental techniques that provide complementary information on the possible secondary structure adopted by peptides. Although globular conformations are favored for the doubly protonated peptide, incrementing the charge state leads to a conformational transition towards extended structures with 310- and α-helix motifs.

  19. Gas-phase spectroscopy of protonated adenine, adenosine 5′-monophosphate and monohydrated ions

    DEFF Research Database (Denmark)

    Pedersen, S.O.; Støchkel, K.; Byskov, C.S.

    2013-01-01

    Microsolvation of chromophore ions commonly has large effects on their electronic structure and as a result on their optical absorption spectra. Here spectroscopy of protonated adenine (AdeH+) and its complex with one water molecule isolated in vacuo was done using a home-built mass spectrometer...

  20. The stability of the bifluoride ion (HF - 2) in the gas phase

    Science.gov (United States)

    Heni, Martin; Illenberger, Eugen

    1985-12-01

    The bifluoride ion (HF-2) has been generated by dissociative electron attachment to trans-1,2-difluorethylene and cis-1,2-difluoroethylene. Evaluation of the energetics for these reactions leads to ΔH0f (HF-2) ≤-6.9 eV and E. A. (HF2)≥4.8 eV.

  1. Structures of protonated thymine and uracil and their monohydrated gas-phase ions from ultraviolet action spectroscopy and theory.

    Science.gov (United States)

    Pedersen, Sara Øvad; Byskov, Camilla Skinnerup; Turecek, Frantisek; Brøndsted Nielsen, Steen

    2014-06-19

    The strong UV chromophores thymine (Thy) and uracil (Ura) have identical heteroaromatic rings that only differ by one methyl substituent. While their photophysics has been elucidated in detail, the effect on the excited states of base protonation and single water molecules is less explored. Here we report gas-phase absorption spectra of ThyH(+) and UraH(+) and monohydrated ions and demonstrate that the substituent is not only responsible for spectral shifts but also influences the tautomer distribution, being different for bare and monohydrated ions. Spectra interpretation is aided by calculations of geometrical structures and transition energies. The lowest free-energy tautomer (denoted 178, enol-enol form) accounts for 230-280 nm (ThyH(+)) and 225-270 nm (UraH(+)) bands. ThyH(+) hardly absorbs above 300 nm, whereas a discernible band is measured for UraH(+) (275-320 nm), ascribed to the second lowest free-energy tautomer (138, enol-keto form) comprising a few percent of the UraH(+) population at room temperature. Band widths are similar to those measured of cold ions in support of very short excited-state lifetimes. Attachment of a single water increases the abundance of 138 relative to 178, 138 now clearly present for ThyH(+). 138 resembles more the tautomer present in aqueous solution than 178 does, and 138 may indeed be a relevant transition structure. The band of ThyH(+)(178) is unchanged, that of UraH(+)(178) is nearly unchanged, and that of UraH(+)(138) blue-shifts by about 10 nm. In stark contrast to protonated adenine, more than one solvating water molecule is required to re-establish the absorption of ThyH(+) and UraH(+) in aqueous solution.

  2. Investigation of the gas-phase hydrogen/deuterium exchange behavior of aromatic dicarboxylic acids in a quadrupole ion trap

    Science.gov (United States)

    Chipuk, Joseph E.; Brodbelt, Jennifer S.

    2007-11-01

    Gas-phase hydrogen/deuterium (H/D) exchange reactions of four deprotonated aromatic dicarboxylic acids (phthalic acid, isophthalic acid, terephthalic acid and 2,6-naphthalic acid) with D2O were performed in a quadrupole ion trap mass spectrometer. Experimental results showed significant differences in the rate and extent of exchange when the relative position of the carboxylic acid groups varied. Spontaneous and near complete exchange of one aromatic hydrogen atom occurred when the carboxylic acid groups were in the meta-position, whereas no additional exchange was observed for either the ortho- or para-isomers or for the structurally similar naphthalic acid. Computational investigations support the participation of several possible exchange mechanisms with the contribution of each relying heavily on the relative orientation of the acid moieties. A relay mechanism that bridges the deprotonation site and the labile hydrogen site appears to be responsible for the H/D exchange of not only the labile hydrogen atom of isophthalic acid, but also for the formation of a stable carbanion and corresponding subsequent exchange of one aromatic hydrogen atom. The impact of hydrogen bonding on the relay mechanism is demonstrated by the reaction of phthalic acid as the extent and rate of reaction are greatly retarded by the favorable interaction of the two carboxylic acid groups. Finally, a flip-flop mechanism is likely responsible for the exchange of both terephthalic acid and 2,6-naphthalic acid where the reactive sites are too remote for exchange via relay.

  3. Studies on Ion-molecule Reaction of Disubstituted Benzene with IonSystem of Acetyl Chloride in Gas Phase

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The ion-molecule reactions of disubstituted benzenes with the ion system of acetyl chloride under the chemical ionization condition were examined and the fragmentation reactions of the adduct ions formed by the ion-molecule reactions were studied by using collision-induced dissocia tion technique. It was found that the electron-releasing groups favored the adduct reactions and the electron-withdrawing groups did not. The position and properties of substituting groups had an effect on the relative abundance of the adduct ions. The fragmentation reaction of the adduct ions formed by ortho-benzene diamine with the acetyl ion was similar to the reductive alkylation reaction of amine in condensed phase.

  4. Hydration of highly charged ions.

    Science.gov (United States)

    Hofer, Thomas S; Weiss, Alexander K H; Randolf, Bernhard R; Rode, Bernd M

    2011-08-01

    Based on a series of ab initio quantum mechanical charge field molecular dynamics (QMCF MD) simulations, the broad spectrum of structural and dynamical properties of hydrates of trivalent and tetravalent ions is presented, ranging from extreme inertness to immediate hydrolysis. Main group and transition metal ions representative for different parts of the periodic system are treated, as are 2 threefold negatively charged anions. The results show that simple predictions of the properties of the hydrates appear impossible and that an accurate quantum mechanical simulation in cooperation with sophisticated experimental investigations seems the only way to obtain conclusive results.

  5. Measurement of gas-phase ammonia and amines in air by collection onto an ion exchange resin and analysis by ion chromatography

    Directory of Open Access Journals (Sweden)

    M. L. Dawson

    2014-02-01

    Full Text Available Ammonia and amines are common trace gases in the atmosphere and have a variety of both biogenic and anthropogenic sources, with a major contribution coming from agricultural sites. In addition to their malodorous nature, both ammonia and amines have been shown to enhance particle formation from acids such as nitric, sulfuric and methanesulfonic acids, which has implications for visibility, human health and climate. A key component of quantifying the effects of these species on particle formation is accurate gas-phase measurements in both laboratory and field studies. However, these species are notoriously difficult to measure as they are readily taken up on surfaces, including onto glass surfaces from aqueous solution as established in the present studies. We describe here a novel technique for measuring gas-phase ammonia and amines that involves uptake onto a weak cation exchange resin followed by extraction and analysis using ion chromatography. Two variants, one for ppb concentrations in air and the second with lower (ppt detection limits, are described. The latter involves the use of a custom-designed high-pressure cartridge to hold the resin for in-line extraction. These methods avoid the use of sampling lines, which can lead to significant inlet losses of these compounds. They also have the advantages of being relatively simple and inexpensive. The applicability of this technique to ambient air is demonstrated in measurements made near a cattle farm in Chino, CA.

  6. Measurement of gas-phase ammonia and amines in air by collection onto an ion exchange resin and analysis by ion chromatography

    Science.gov (United States)

    Dawson, M. L.; Perraud, V.; Gomez, A.; Arquero, K. D.; Ezell, M. J.; Finlayson-Pitts, B. J.

    2014-08-01

    Ammonia and amines are common trace gases in the atmosphere and have a variety of both biogenic and anthropogenic sources, with a major contribution coming from agricultural sites. In addition to their malodorous nature, both ammonia and amines have been shown to enhance particle formation from acids such as nitric, sulfuric and methanesulfonic acids, which has implications for visibility, human health and climate. A key component of quantifying the effects of these species on particle formation is accurate gas-phase measurements in both laboratory and field studies. However, these species are notoriously difficult to measure as they are readily taken up on surfaces, including onto glass surfaces from aqueous solution as established in the present studies. We describe here a novel technique for measuring gas-phase ammonia and amines that involves uptake onto a weak cation exchange resin followed by extraction and analysis using ion chromatography. Two variants - one for parts per billion concentrations in air and the second with lower (parts per trillion) detection limits - are described. The latter involves the use of a custom-designed high-pressure cartridge to hold the resin for in-line extraction. These methods avoid the use of sampling lines, which can lead to significant inlet losses of these compounds. They also have the advantages of being relatively simple and inexpensive. The applicability of this technique to ambient air is demonstrated in measurements made near a cattle farm in Chino, CA.

  7. Examination of the coordination sphere of Al(III) in trifluoromethyl-heteroarylalkenolato complex ions by gas-phase IRMPD spectroscopy and computational modelling.

    Science.gov (United States)

    Brückmann, Lisa; Tyrra, Wieland; Mathur, Sanjay; Berden, Giel; Oomens, Jos; Meijer, Anthony J H M; Schäfer, Mathias

    2012-06-01

    A series of aluminium complex ions with trifluoromethyl-heteroarylalkenolato (TMHA) ligands are studied by gas-phase infrared multiphoton-dissociation (IRMPD) spectroscopy and computational modelling. The selected series of aluminium TMHA complex ions are promising species for the initial study of intrinsic binding characteristics of Al(III) cations in the gas phase as corresponding molecular ions. They are readily available for examination by (+) and (-) electrospray ionization mass spectrometry (ESI-MS) by spraying of [Al(3+)⋅(L(-))(3)] solutions. The complex ions under investigation contain trivalent Al(3+) cations with two chelating anionic enolate ligands, [Al(3+)⋅(L(-))(2)](+), providing insights in the nature of the heteroatom-Al bonds. Additionally, the structure of a deprotonated benzimidazole ligand, L(-,) and an anionic complex ion of Al(III) with two doubly deprotonated benzimidazole ligands, [Al(3+)⋅(L(2-))(2)](-), are examined by (-)ESI-IRMPD spectroscopy. Experimental and computational results are highly consistent and allow a reliable identification of the ion structures. In all complex ions examined the planar TMHA ligands are oriented perpendicular to each other around the metal ion, leading to a tetrahedral coordination sphere in which aluminium interacts with the enolate oxygen and heteroaryl nitrogen atoms available in each of the bidentate ligands.

  8. Efficiency of Gas-Phase Ion Formation in Matrix-Assisted Laser Desorption Ionization with 2,5-Dihydroxybenzoic Acid as Matrix

    Energy Technology Data Exchange (ETDEWEB)

    Park, Kyung Man; Ahn, Sung Hee; Bae, Yong Jin; Kim, Myung Soo [Seoul National Univ., Seoul (Korea, Republic of)

    2013-03-15

    Numbers of matrix- and analyte-derived ions and their sum in matrix-assisted laser desorption ionization (MALDI) of a peptide were measured using 2,5-dihydroxybenzoic acid (DHB) as matrix. As for MALDI with α-cyano-4-hydroxy cinnamic acid as matrix, the sum was independent of the peptide concentration in the solid sample, or was the same as that of pure DHB. This suggested that the matrix ion was the primary ion and that the peptide ion was generated by matrix-to-peptide proton transfer. Experimental ionization efficiencies of 10{sup -5}-10{sup -4} for peptides and 10{sup -8}-10{sup -7} for matrices are far smaller than 10.3-10.1 for peptides and 10{sup -5}-10{sup -3} for matrices speculated by Hillenkamp and Karas. Number of gas-phase ions generated by MALDI was unaffected by laser wavelength or pulse energy. This suggests that the main role of photo-absorption in MALDI is not in generating ions via a multi-photon process but in ablating materials in a solid sample to the gas phase.

  9. Photodissociation and charge transfer dynamics of negative ions studied with femtosecond photoelectron spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Zanni, Martin Thomas [Univ. of California, Berkeley, CA (United States)

    1999-12-01

    This dissertation presents studies aimed at understanding the potential energy surfaces and dynamics of isolated negative ions, and the effects of solvent on each. Although negative ions play important roles in atmospheric and solution phase chemistry, to a large extent the ground and excited state potential energy surfaces of gas phase negative ions are poorly characterized, and solvent effects even less well understood. In an effort to fill this gap, the author's coworkers and the author have developed a new technique, anion femtosecond photoelectron spectroscopy, and applied it to gas phase photodissociation and charge transfer processes. Studies are presented that (1) characterize the ground and excited states of isolated and clustered anions, (2) monitor the photodissociation dynamics of isolated and clustered anions, and (3) explore the charge-transfer-to-solvent states of atomic iodide clustered with polar and non-polar solvents.

  10. Photodissociation and charge transfer dynamics of negative ions studied with femtosecond photoelectron spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Zanni, Martin T.

    1999-12-17

    This dissertation presents studies aimed at understanding the potential energy surfaces and dynamics of isolated negative ions, and the effects of solvent on each. Although negative ions play important roles in atmospheric and solution phase chemistry, to a large extent the ground and excited state potential energy surfaces of gas phase negative ions are poorly characterized, and solvent effects even less well understood. In an effort to fill this gap, the author's coworkers and the author have developed a new technique, anion femtosecond photoelectron spectroscopy, and applied it to gas phase photodissociation and charge transfer processes. Studies are presented that (1) characterize the ground and excited states of isolated and clustered anions, (2) monitor the photodissociation dynamics of isolated and clustered anions, and (3) explore the charge-transfer-to-solvent states of atomic iodide clustered with polar and non-polar solvents.

  11. Gas-phase hydrogen/deuterium exchange of 5'- and 3'-mononucleotides in a quadrupole ion trap: exploring the role of conformation and system energy.

    Science.gov (United States)

    Chipuk, Joseph E; Brodbelt, Jennifer S

    2007-04-01

    Gas-phase hydrogen/deuterium (H/D) exchange reactions for deprotonated 2'-deoxy-5'-monophosphate and 2'-deoxy-3'-monophosphate nucleotides with D(2)O were performed in a quadrupole ion trap mass spectrometer. To augment these experiments, molecular modeling was also conducted to identify likely deprotonation sites and potential gas-phase conformations of the anions. A majority of the 5'-monophosphates exchanged extensively with several of the compounds completely incorporating deuterium in place of their labile hydrogen atoms. In contrast, most of the 3'-monophosphate isomers exchanged relatively few hydrogen atoms, even though the rate of the first two exchanges was greater than observed for the 5'-monophosphates. Mononucleotides that failed to incorporate more than two deuterium atoms under default reaction conditions were often found to exchange more extensively when reactions were performed under higher energy conditions. Integration of the experimental and theoretical results supports the use of a relay exchange mechanism and suggests that the exchange behavior depends highly on the identity and orientation of the nucleobase and the position and flexibility of the deprotonated phosphate moiety. These observations also highlight the importance of the distance between the various participating groups in addition to their gas-phase acidity and basicity.

  12. Microhydration of Alanine in Gas Phase Studied by Quantum Chemical Method and ABEEMσπ/MM Fluctuating Charge Model

    Institute of Scientific and Technical Information of China (English)

    LU Li-nan; LIU Cui; GONG Li-dong

    2013-01-01

    A fluctuating charge interaction potential function for alanine-water was constructed in the spirit of newly developed ABEEMσπ/MM(atom-bond electronegativity equalization method at the σπ level fused into molecular mechanics).The properties of gaseous neutral alanine-(H2O)n(n=1-7) clusters were systematically investigated by quantum mechanics(QM) and the constructed ABEEMσπ/MM potential,such as conformations,hydrogen bonds (H-bonds),interaction energies,charge distributions,and so on.The results of ABEEMσπ/MM model are in fair agreement with those of QM and available experimental data.For isolated alanine,compared with those of experi-mental structure,the average absolute deviations(AAD) of bond length and bond angle are 0.002 nm and 1.4°,respectively.For alanine-water clusters,the AAD of interaction energies and H-bond lengths are only 3.77 kJ/mol and 0.012 nm,respectively,compared to the results of MP2/aug-cc-pVDZ//MP2/6-311+G** method.The ABEEMσπ charges fluctuate with the changing conformation of the system,and can accurately and reasonably reflect the interpolarization between water and alanine.The presented alanine-water potential function may provide a basis for further simulations on related aqueous solutions of biomolecules.

  13. Formation of nitrogen-containing polycyclic cations by gas-phase and intracluster reactions of acetylene with the pyridinium and pyrimidinium ions.

    Science.gov (United States)

    Soliman, Abdel-Rahman; Hamid, Ahmed M; Attah, Isaac; Momoh, Paul; El-Shall, M Samy

    2013-01-09

    Here, we present evidence from laboratory experiments for the formation of nitrogen-containing complex organic ions by sequential reactions of acetylene with the pyridinium and pyrimidinium ions in the gas phase and within ionized pyridine-acetylene binary clusters. Additions of five and two acetylene molecules onto the pyridinium and pyrimidinium ions, respectively, at room temperature are observed. Second-order rate coefficients of the overall reaction of acetylene with the pyridinium and pyrimidinium ions are measured as 9.0 × 10(-11) and 1.4 × 10(-9) cm(3) s(-1), respectively, indicating reaction efficiencies of about 6% and 100%, respectively, at room temperature. At high temperatures, only two acetylene molecules are added to the pyridinium and pyrimidinium ions, suggesting covalent bond formation. A combination of ion dissociation and ion mobility experiments with DFT calculations reveals that the addition of acetylene into the pyridinium ion occurs through the N-atom of the pyridinium ion. The relatively high reaction efficiency is consistent with the absence of a barrier in the exothermic N-C bond forming reaction leading to the formation of the C(7)H(7)N(•+) covalent adduct. An exothermic addition/H-elimination reaction of acetylene with the C(7)H(7)N(•+) adduct is observed leading to the formation of a bicyclic quinolizinium cation (C(9)H(8)N(+)). Similar chemistry is observed in the sequential reactions of acetylene with the pyrimidinium ion. The second acetylene addition onto the pyrimidinium ion involves an exclusive addition/H-elimination reaction at room temperature leading to the formation of a bicyclic pyrimidinium cation (C(8)H(7)N(2)(+)). The high reactivity of the pyridinium and pyrimidinium ions toward acetylene is in sharp contrast to the very low reactivity of the benzene cation, which has a reaction efficiency of 10(-4)-10(-5). This indicates that the presence of a nitrogen atom within the aromatic ring enhances the ring growth

  14. Conformational ordering of biomolecules in the gas phase: nitrogen collision cross sections measured on a prototype high resolution drift tube ion mobility-mass spectrometer.

    Science.gov (United States)

    May, Jody C; Goodwin, Cody R; Lareau, Nichole M; Leaptrot, Katrina L; Morris, Caleb B; Kurulugama, Ruwan T; Mordehai, Alex; Klein, Christian; Barry, William; Darland, Ed; Overney, Gregor; Imatani, Kenneth; Stafford, George C; Fjeldsted, John C; McLean, John A

    2014-02-18

    Ion mobility-mass spectrometry measurements which describe the gas-phase scaling of molecular size and mass are of both fundamental and pragmatic utility. Fundamentally, such measurements expand our understanding of intrinsic intramolecular folding forces in the absence of solvent. Practically, reproducible transport properties, such as gas-phase collision cross-section (CCS), are analytically useful metrics for identification and characterization purposes. Here, we report 594 CCS values obtained in nitrogen drift gas on an electrostatic drift tube ion mobility-mass spectrometry (IM-MS) instrument. The instrument platform is a newly developed prototype incorporating a uniform-field drift tube bracketed by electrodynamic ion funnels and coupled to a high resolution quadrupole time-of-flight mass spectrometer. The CCS values reported here are of high experimental precision (±0.5% or better) and represent four chemically distinct classes of molecules (quaternary ammonium salts, lipids, peptides, and carbohydrates), which enables structural comparisons to be made between molecules of different chemical compositions for the rapid "omni-omic" characterization of complex biological samples. Comparisons made between helium and nitrogen-derived CCS measurements demonstrate that nitrogen CCS values are systematically larger than helium values; however, general separation trends between chemical classes are retained regardless of the drift gas. These results underscore that, for the highest CCS accuracy, care must be exercised when utilizing helium-derived CCS values to calibrate measurements obtained in nitrogen, as is the common practice in the field.

  15. Recent progress of nuclear liquid gas phase transition

    Institute of Scientific and Technical Information of China (English)

    MA Yu-Gang; SHEN Wen-Qing

    2004-01-01

    Recent progress on nuclear liquid gas phase transition (LGPT) has been reviewed, especially for the signals of LGPT in heavy ion collisions. These signals include the power-law charge distribution, cluster emission rate, nuclear Zipf law, bimodality, the largest fluctuation of the fragments, △ -scaling, caloric curve, phase coexistence diagram, critical temperature, critical exponent analysis, negative specific heat capacity and spinodal instability etc. The systematic works of the authors on experimental and theoretical LGPT are also introduced.

  16. Characterization of TATP gas phase product ion chemistry via isotope labeling experiments using ion mobility spectrometry interfaced with a triple quadrupole mass spectrometer.

    Science.gov (United States)

    Tomlinson-Phillips, Jill; Wooten, Alfred; Kozole, Joseph; Deline, James; Beresford, Pamela; Stairs, Jason

    2014-09-01

    Identification of the fragment ion species associated with the ion reaction mechanism of triacetone triperoxide (TATP), a homemade peroxide-based explosive, is presented. Ion mobility spectrometry (IMS) has proven to be a key analytical technique in the detection of trace explosive material. Unfortunately, IMS alone does not provide chemical identification of the ions detected; therefore, it is unknown what ion species are actually formed and separated by the IMS. In IMS, ions are primarily characterized by their drift time, which is dependent on the ion׳s mass and molecular cross-section; thus, IMS as a standalone technique does not provide structural signatures, which is in sharp contrast to the chemical and molecular information that is generally obtained from other customary analytical techniques, such as NMR, Raman and IR spectroscopy and mass spectrometry. To help study the ion chemistry that gives rise to the peaks observed in IMS, the hardware of two different commercial IMS instruments has been directly coupled to triple quadrupole (QQQ) mass spectrometers, in order to ascertain each ion׳s corresponding mass/charge (m/z) ratios with different dopants at two temperatures. Isotope labeling was then used to help identify and confirm the molecular identity of the explosive fragment and adduct ions of TATP. The m/z values and isotope labeling experiments were used to help propose probable molecular formulas for the ion fragments. In this report, the fragment and adduct ions m/z 58 and 240 of TATP have been confirmed to be [C3H6NH·H](+) and [TATP·NH4](+), respectively; while the fragment ions m/z 73 and 89 of TATP are identified as having the molecular formulas [C4H9NH2](+) and [C4H9O2](+), respectively. It is anticipated that the work in this area will not only help to facilitate improvements in mobility-based detection (IMS and MS), but also aid in the development and optimization of MS-based detection algorithms for TATP.

  17. Theoretical study of the gas-phase ion pairs SN2 reactions of LiX with CH3SY (X, Y = F, Cl, Br, I)

    Science.gov (United States)

    Gai, Jing-Gang; Ren, Yi

    The gas-phase ion pair SN2 reactions at saturated sulfur LiX + CH3SY ? CH3SX + LiY (X, Y = F, Cl, Br, I) are investigated using the CCSD(T) calculations. The calculated results show that the reactions LiX + CH3SY are exothermic only when the nucleophile is a heavier lithium halide. Central barrier heights are found to depend primarily on the identity of nucleophile LiX, decreasing in the order LiF > LiCl > LiBr > LiI. Another interesting feature of the ion pair reactions at sulfur is the good correlation between the reaction barriers with geometrical looseness of Li bond X and S bond Y bonds in the transition state structures. The data for the reaction barriers show good agreement with the prediction of the Marcus equation and its modification.

  18. Holographic heavy ion collisions with baryon charge

    CERN Document Server

    Casalderrey-Solana, Jorge; van der Schee, Wilke; Triana, Miquel

    2016-01-01

    We numerically simulate collisions of charged shockwaves in Einstein-Maxwell theory in anti-de Sitter space as a toy model of heavy ion collisions with non-zero baryon charge. The stress tensor and the baryon current become well described by charged hydrodynamics at roughly the same time. The effect of the charge density on generic observables is typically no larger than 15\\%. %The rapidity profile of the charge is wider than the profile of the local energy density. We find significant stopping of the baryon charge and compare our results with those in heavy ion collision experiments.

  19. Atmospheric pressure ionization and gas phase ion mobility studies of isomeric dihalogenated benzenes using different ionization techniques

    Science.gov (United States)

    Borsdorf, H.; Nazarov, E. G.; Eiceman, G. A.

    2004-03-01

    Ion mobility spectrometry (IMS) featuring different ionization techniques was used to analyze isomeric ortho-, meta- and para-dihalogenated benzenes in order to assess how structural features affect ion formation and drift behavior. The structure of the product ions formed was investigated by atmospheric pressure chemical ionization (APCI) mass spectrometry (MS) and IMS-MS coupling. Photoionization provided [M]+ ions for chlorinated and fluorinated compounds while bromine was cleaved from isomers of dibromobenzene and bromofluorobenzene. This ionization technique does not permit the different isomers to be distinguished. Comparable ions and additional clustered ions were obtained using 63Ni ionization. Depending on the chemical constitution, different clustered ions were observed in ion mobility spectra for the separate isomers of dichlorobenzene and dibromobenzene. Corona discharge ionization permits the most sensitive detection of dihalogenated compounds. Only clustered product ions were obtained. Corona discharge ionization enables the classification of different structural isomers of dichlorobenzene, dibromobenzene and bromofluorobenzene.

  20. Surface nanostructures by single highly charged ions.

    Science.gov (United States)

    Facsko, S; Heller, R; El-Said, A S; Meissl, W; Aumayr, F

    2009-06-03

    It has recently been demonstrated that the impact of individual, slow but highly charged ions on various surfaces can induce surface modifications with nanometer dimensions. Generally, the size of these surface modifications (blisters, hillocks, craters or pits) increases dramatically with the potential energy of the highly charged ion, while the kinetic energy of the projectile ions seems to be of little importance. This paper presents the currently available experimental evidence and theoretical models and discusses the circumstances and conditions under which nanosized features on different surfaces due to the impact of slow highly charged ions can be produced.

  1. Reactions of 15-crown-5 and bis-15-crown-5 ethers with metal acetylacetonate ions in the gas phase

    Energy Technology Data Exchange (ETDEWEB)

    Timofeev, O.S.; Bogatskii, A.V.; Gren, A.I.; Lobach, A.V.; Nekarsov, Y.S.; Zagorevskii, D.V.

    1985-05-20

    A study was carried out on the ion-molecule reactions of ions arising in the dissociation of ferric, cobaltic, chromic, manganous, neodymium(II), gallium(III), and indium(III) acetylacetonates upon electron impact with 15-crown-5 and bis-15-crown-5. The ratio of the yields of (acac)x-1 /SUP M+L/ ions is determined by the case of reduction of M /SUP x+1+/ to M /SUP x+/ and for (acac)/sub 3/M complexes, this ratio decreases in the series Nd, In, GA > Cr > Fe, Co. The rate constant for the formation of acacCoL/sup +/ ions is greater than for acacFeL/sup +/ ions. The possibility of fixing transition metals in unstable oxidation states by crown ethers is demonstrated in the case of nickel.

  2. Gas Phase Absorption Spectroscopy of C+60 and C+70 in a Cryogenic Ion Trap: Comparison with Astronomical Measurements

    Science.gov (United States)

    Campbell, E. K.; Holz, M.; Maier, J. P.; Gerlich, D.; Walker, G. A. H.; Bohlender, D.

    2016-05-01

    Recent low-temperature laboratory measurements and astronomical observations have proved that the fullerene cation {{{C}}}60+ is responsible for four diffuse interstellar bands (DIBs). These absorptions correspond to the strongest bands of the lowest electronic transition. The gas phase spectrum below 10 {{K}} is reported here for the full wavelength range encompassed by the electronic transition. The absorption spectrum of {{{C}}}70+, with its origin band at 7959.2 {{\\mathringA }}, has been obtained under similar laboratory conditions. Observations made toward the reddened star {HD} 183143 were used in a specific search for the absorption of these fullerene cations in diffuse clouds. In the case of {{{C}}}60+, one further band in the astronomical spectrum at 9348.5 \\mathringA is identified, increasing the total number of assigned DIBs to five. Numerous other {{{C}}}60+ absorptions in the laboratory spectrum are found to lie below the astronomical detection limit. Special emphasis is placed on the laboratory determination of absolute absorption cross-sections. For {{{C}}}60+ this directly yields a column density, N({{{C}}}60+), of 2× {10}13 {{{cm}}}-2 in diffuse clouds, without the need to rely on theoretical oscillator strengths. The intensity of the {{{C}}}70+ electronic transition in the range 7000-8000 Å is spread over many features of similar strength. Absorption cross-section measurements indicate that even for a similar column density, the individual absorption bands of {{{C}}}70+ will be too weak to be detected in the astronomical spectra, which is confirmed giving an upper limit of 2 {{m\\mathringA }} to the equivalent width. Based on observations obtained at the Canada-France-Hawaii Telescope (CFHT) which is operated by the National Research Council of Canada, the Institut National des Sciences de l’Univers of the Centre National de la Recherche Scientifique of France, and the University of Hawaii.

  3. Isomer separation and gas-phase configurations of organoruthenium anticancer complexes: ion mobility mass spectrometry and modeling.

    Science.gov (United States)

    Williams, Jonathan P; Bugarcic, Tijana; Habtemariam, Abraha; Giles, Kevin; Campuzano, Iain; Rodger, P Mark; Sadler, Peter J

    2009-06-01

    We have used ion mobility-mass spectrometry combined with molecular modeling for the separation and configurational analysis of three low-molecular-weight isomeric organoruthenium anticancer complexes containing ortho-, meta-, or para-terphenyl arene ligands. The isomers were separated using ion mobility based on traveling-wave technology and the experimentally determined collision cross sections were compared to theoretical calculations. Excellent agreement was observed between the experimentally and theoretically derived measurements.

  4. Fragmentation of amino acids induced by collisions with low-energy highly charged ions

    Science.gov (United States)

    Piekarski, D. G.; Maclot, S.; Domaracka, A.; Adoui, L.; Alcamí, M.; Rousseau, P.; Díaz-Tendero, S.; Huber, B. A.; Martín, F.

    2014-04-01

    Fragmentation of amino acids NH2-(CH2)n-COOH (n=1 glycine; n=2 β-alanine and n=3 γ-aminobutyric acid GABA) following collisions with slow highly charged ions has been studied in the gas phase by a combined experimental and theoretical approach. In the experiments, a multi-coincidence detection method was used to deduce the charge state of the molecules before fragmentation. Quantum chemistry calculations have been carried out in the basis of the density functional theory and ab initio molecular dynamics. The combination of both methodologies is essential to unambiguously unravel the different fragmentation pathways.

  5. Handbook for highly charged ion spectroscopic research

    CERN Document Server

    Hutton, Roger; Currell, Fred; Martinson, Indrek; Hagmann, Siegbert

    2011-01-01

    Highly charged ions are key research objects in atomic physics. Precision spectroscopy of such ions provides a powerful tool for exploring relativistic and quantum electrodynamics effects. Additionally, the interaction of high-energy heavy-ions with matter is itself a topic of importance in many areas of applied physics, including fusion and plasma physics, accelerator physics, materials science and semiconductor device preparation and behavior. This work provides a complete overview of modern methods of studying highly charged ions. With chapters covering everything from the essential backgro

  6. Selective Covalent Chemistry via Gas-Phase Ion/ion Reactions: An Exploration of the Energy Surfaces Associated with N-Hydroxysuccinimide Ester Reagents and Primary Amines and Guanidine Groups

    Science.gov (United States)

    Bu, Jiexun; Fisher, Christine M.; Gilbert, Joshua D.; Prentice, Boone M.; McLuckey, Scott A.

    2016-06-01

    Selective covalent bond forming reactions (referred to as covalent reactions) can occur in gas-phase ion/ion reactions and take place via the formation of a long-lived chemical complex. The gas-phase ion/ion reactivity between sulfo- N-hydroxysuccinimide (sulfo-NHS) ester reagent anions and peptide cations containing a primary amine or guanidine group has been examined via DFT calculations and complex dissociation rate measurements. The results reveal insights regarding the roles of the barriers of competing processes within the complex. When the covalent reaction is exothermic, two prototypical cases, determined by the nature of the energy surface, are apparent. The product partitioning between covalent reaction and simple proton transfer upon dissociation of the long-lived complex is sensitive to activation conditions when the transition state barrier for covalent reaction is relatively high ( case 1) but is insensitive to activation conditions when the transition state barrier is relatively low ( case 2). Covalent reaction efficiencies are very high in case 2 scenarios, such as when the reactive site is a guanidine and the anion attachment site is a guanidinium ion. Covalent reaction efficiencies are variable, and generally low, in case 1 scenarios, such as when an amine is the reactive site and an ammonium ion is the site of anion attachment. A relatively long slow-heating step prior to the complex dissociation step, however, can dramatically increase covalent reaction yield in case 1 scenarios.

  7. Novel experimental setup for time-of-flight mass spectrometry ion detection in collisions of anionic species with neutral gas-phase molecular targets.

    Science.gov (United States)

    Oller, J C; Ellis-Gibbings, L; da Silva, F Ferreira; Limão-Vieira, P; García, G

    We report a novel experimental setup for studying collision induced products resulting from the interaction of anionic beams with a neutral gas-phase molecular target. The precursor projectile was admitted into vacuum through a commercial pulsed valve, with the anionic beam produced in a hollow cathode discharge-induced plasma, and guided to the interaction region by a set of deflecting plates where it was made to interact with the target beam. Depending on the collision energy regime, negative and positive species can be formed in the collision region and ions were time-of-flight (TOF) mass-analysed. Here, we present data on O2 precursor projectile, where we show clear evidence of O(-) and O2(-) formation from the hollow cathode source as well as preliminary results on the interaction of these anions with nitromethane, CH3NO2. The negative ions formed in such collisions were analysed using time-of-flight mass spectrometry. The five most dominant product anions were assigned to H(-), O(-), NO(-), CNO(-) and CH3NO2(-).

  8. Spectroscopy with trapped highly charged ions

    Energy Technology Data Exchange (ETDEWEB)

    Beiersdorfer, P

    2008-01-23

    We give an overview of atomic spectroscopy performed on electron beam ion traps at various locations throughout the world. Spectroscopy at these facilities contributes to various areas of science and engineering, including but not limited to basic atomic physics, astrophysics, extreme ultraviolet lithography, and the development of density and temperature diagnostics of fusion plasmas. These contributions are accomplished by generating, for example, spectral surveys, making precise radiative lifetime measurements, accounting for radiative power emitted in a given wavelength band, illucidating isotopic effects, and testing collisional-radiative models. While spectroscopy with electron beam ion traps had originally focused on the x-ray emission from highly charged ions interacting with the electron beam, the operating modes of such devices have expanded to study radiation in almost all wavelength bands from the visible to the hard x-ray region; and at several facilities the ions can be studied even in the absence of an electron beam. Photon emission after charge exchange or laser excitation has been observed, and the work is no longer restricted to highly charged ions. Much of the experimental capabilities are unique to electron beam ion traps, and the work performed with these devices cannot be undertaken elsewhere. However, in other areas the work on electron beam ion traps rivals the spectroscopy performed with conventional ion traps or heavy-ion storage rings. The examples we present highlight many of the capabilities of the existing electron beam ion traps and their contributions to physics.

  9. Homogeneous gas phase models of relaxation kinetics in neon afterglow

    Directory of Open Access Journals (Sweden)

    Marković Vidosav Lj.

    2007-01-01

    Full Text Available The homogeneous gas phase models of relaxation kinetics (application of the gas phase effective coefficients to represent surface losses are applied for the study of charged and neutral active particles decay in neon afterglow. The experimental data obtained by the breakdown time delay measurements as a function of the relaxation time td (τ (memory curve is modeled in early, as well as in late afterglow. The number density decay of metastable states can explain neither the early, nor the late afterglow kinetics (memory effect, because their effective lifetimes are of the order of milliseconds and are determined by numerous collision quenching processes. The afterglow kinetics up to hundreds of milliseconds is dominated by the decay of molecular neon Ne2 + and nitrogen ions N2 + (present as impurities and the approximate value of N2 + ambipolar diffusion coefficient is determined. After the charged particle decay, the secondary emitted electrons from the surface catalyzed excitation of nitrogen atoms on the cathode determine the breakdown time delay down to the cosmic rays and natural radioactivity level. Due to the neglecting of number density spatial profiles, the homogeneous gas phase models give only the approximate values of the corresponding coefficients, but reproduce correctly other characteristics of afterglow kinetics from simple fits to the experimental data.

  10. Gas-Phase Thermolyses

    DEFF Research Database (Denmark)

    Carlsen, Lars; Egsgaard, Helge

    1982-01-01

    The unimolecular gas-phase thermolyses of 1,2,3-oxadithiolan 2-oxide and thiiran 1-oxide have been studied by the flash vacuum thermolysis–field ionization mass spectrometry (f.v.t.–f.i.m.s.) technique in the temperature range from 1 043 to 1 404 K. The reactions are rationalized in terms...

  11. Gas-Phase Thermolyses

    DEFF Research Database (Denmark)

    Carlsen, Lars; Egsgaard, Helge

    1982-01-01

    The unimolecular gas-phase thermolyses of the four methyl and ethyl monothioacetates (5)–(8) have been studied by the flash vacuum thermolysis–field ionization mass spectrometry technique in the temperature range 883–1 404 K. The types of reactions verified were keten formation, thiono...

  12. Gas-Phase Thermolysis

    DEFF Research Database (Denmark)

    Carlsen, Lars; Egsgaard, Helge; Schaumann, Ernst

    1980-01-01

    The unimolecular gas-phase thermolytic decomposition of three silylated thionocarboxylic acid derivatives (2b), (3), and (8) have been studied by the flash vacuum thermolysis–field ionization mass spectrometry technique in the temperature range from 783 to 1 404 K in order to elucidate its possib...

  13. Peptide sequencing and characterization of post-translational modifications by enhanced ion-charging and liquid chromatography electron-transfer dissociation tandem mass spectrometry

    DEFF Research Database (Denmark)

    Kjeldsen, Frank; Giessing, Anders; Ingrell, Christian R

    2007-01-01

    We have tested the effect of m-nitrobenzyl alcohol (m-NBA) as a method to increase the average charge state of protonated gas-phase molecular ions generated by ESI from tryptic peptides and phosphopeptides. Various concentrations of m-NBA were added to the mobile phases of a liquid chromatography...

  14. Erratum to "The mechanism and thermodynamics of transesterification of acetate-ester enolates in the gas phase" : [Int. J. Mass Spectrom. Ion Process. 172 (1998) 25

    Science.gov (United States)

    Haas, George W.; Giblin, Daryl E.; Gross, Michael L.

    1998-02-01

    In solution, base-catalyzed hydrolysis and transesterification of esters are initiated by hydroxide- or alkoxide-ion attack at the carbonyl carbon. At low pressures in the gas phase, however, transesterification proceeds by an attack of the enolate anion of an acetate ester on an alcohol. Fourier transform mass spectrometry (FTMS) indicates that the reaction is the second-order process: -CH2-CO2-R+R'-OH-->-CH2-CO2-R'+R-OH and there is little to no detectable production of either alkoxide anion. Labeling studies show that the product and reactant enolate anion esters undergo exchange of hydrogens located [alpha] to the carbonyl carbon with the deuterium of R'--OD. The extent of the H/D exchange increases with reaction time, pointing to a short-lived intermediate. The alcoholysis reaction rate constants increase with increasing acidity of the primary, straight-chained alkyl alcohols, whereas steric effects associated with branched alcohols cause the rate constants to decrease. Equilibrium constants, which were determined directly from measurements at equilibrium and which were calculated from the forward and reverse rate constants, are near unity and show internal consistency. In the absence of steric effects, the larger enolate is always the favored product at equilibrium. The intermediate for the transesterification reaction, which can be generated at a few tenths of a torr in a tandem mass spectrometer, is tetrahedral, but other adducts that are collisionally stabilized under these conditions are principally loosely bound complexes.

  15. Experimental recombination rates for highly charged ions

    Energy Technology Data Exchange (ETDEWEB)

    Reinhold Schuch [Dept. of Atomic Physics, Stockholm Univ., Frescativ., Stockholm (Sweden)

    2000-01-01

    Recent studies of recombination between free electrons and highly charged ions using electron coolers of heavy-ion storage rings have produced accurate rate coefficients of interest for plasma modeling and diagnostics. Some surprises were discovered which can lead to revisions of recombination models. With bare ions one finds at low energy a strong and puzzling deviation from radiative recombination theory. Dielectronic recombination with C3+, N4+ show that jj coupling gives essential contributions to the cross section also for light ions. (author)

  16. Production and ion-ion cooling of highly charged ions in electron string ion source.

    Science.gov (United States)

    Donets, D E; Donets, E D; Donets, E E; Salnikov, V V; Shutov, V B; Syresin, E M

    2009-06-01

    The scheme of an internal injection of Au atoms into the working space of the "Krion-2" electron string ion source (ESIS) was applied and tested. In this scheme Au atoms are evaporated from the thin tungsten wire surface in vicinity of the source electron string. Ion beams with charge states up to Au51+ were produced. Ion-ion cooling with use of C and O coolant ions was studied. It allowed increasing of the Au51+ ion yield by a factor of 2. Ions of Kr up to charge state 28+ were also produced in the source. Electron strings were first formed with injection electron energy up to 6 keV. Methods to increase the ESIS ion output are discussed.

  17. Simple setup for gas-phase H/D exchange mass spectrometry coupled to electron transfer dissociation and ion mobility for analysis of polypeptide structure on a liquid chromatographic time scale.

    Science.gov (United States)

    Mistarz, Ulrik H; Brown, Jeffery M; Haselmann, Kim F; Rand, Kasper D

    2014-12-01

    Gas-phase hydrogen/deuterium exchange (HDX) is a fast and sensitive, yet unharnessed analytical approach for providing information on the structural properties of biomolecules, in a complementary manner to mass analysis. Here, we describe a simple setup for ND3-mediated millisecond gas-phase HDX inside a mass spectrometer immediately after ESI (gas-phase HDX-MS) and show utility for studying the primary and higher-order structure of peptides and proteins. HDX was achieved by passing N2-gas through a container filled with aqueous deuterated ammonia reagent (ND3/D2O) and admitting the saturated gas immediately upstream or downstream of the primary skimmer cone. The approach was implemented on three commercially available mass spectrometers and required no or minor fully reversible reconfiguration of gas-inlets of the ion source. Results from gas-phase HDX-MS of peptides using the aqueous ND3/D2O as HDX reagent indicate that labeling is facilitated exclusively through gaseous ND3, yielding similar results to the infusion of purified ND3-gas, while circumventing the complications associated with the use of hazardous purified gases. Comparison of the solution-phase- and gas-phase deuterium uptake of Leu-Enkephalin and Glu-Fibrinopeptide B, confirmed that this gas-phase HDX-MS approach allows for labeling of sites (heteroatom-bound non-amide hydrogens located on side-chains, N-terminus and C-terminus) not accessed by classical solution-phase HDX-MS. The simple setup is compatible with liquid chromatography and a chip-based automated nanoESI interface, allowing for online gas-phase HDX-MS analysis of peptides and proteins separated on a liquid chromatographic time scale at increased throughput. Furthermore, online gas-phase HDX-MS could be performed in tandem with ion mobility separation or electron transfer dissociation, thus enabling multiple orthogonal analyses of the structural properties of peptides and proteins in a single automated LC-MS workflow.

  18. Coulomb crystallization of highly charged ions.

    Science.gov (United States)

    Schmöger, L; Versolato, O O; Schwarz, M; Kohnen, M; Windberger, A; Piest, B; Feuchtenbeiner, S; Pedregosa-Gutierrez, J; Leopold, T; Micke, P; Hansen, A K; Baumann, T M; Drewsen, M; Ullrich, J; Schmidt, P O; López-Urrutia, J R Crespo

    2015-03-13

    Control over the motional degrees of freedom of atoms, ions, and molecules in a field-free environment enables unrivalled measurement accuracies but has yet to be applied to highly charged ions (HCIs), which are of particular interest to future atomic clock designs and searches for physics beyond the Standard Model. Here, we report on the Coulomb crystallization of HCIs (specifically (40)Ar(13+)) produced in an electron beam ion trap and retrapped in a cryogenic linear radiofrequency trap by means of sympathetic motional cooling through Coulomb interaction with a directly laser-cooled ensemble of Be(+) ions. We also demonstrate cooling of a single Ar(13+) ion by a single Be(+) ion-the prerequisite for quantum logic spectroscopy with a potential 10(-19) accuracy level. Achieving a seven-orders-of-magnitude decrease in HCI temperature starting at megakelvin down to the millikelvin range removes the major obstacle for HCI investigation with high-precision laser spectroscopy.

  19. Gas-phase infrared photodissociation spectroscopy of cationic polyaromatic hydrocarbons

    NARCIS (Netherlands)

    Oomens, J.; van Roij, A. J. A.; Meijer, G.; von Helden, G.

    2000-01-01

    Infrared spectra of gas-phase cationic naphthalene, phenanthrene, anthracene, and pyrene are recorded in the 500-1600 cm(-1) range using multiphoton dissociation in an ion trap. Gas-phase polyaromatic hydrocarbons are photoionized by an excimer laser and stored in a quadrupole ion trap. Subsequent i

  20. Ion specific effects on charged interfaces

    OpenAIRE

    Medda, Luca

    2013-01-01

    The physico-chemical phenomena occurring at charged interfaces are specifically affected by the type and the concentration of electrolytes. This has implications both in living and in inorganic systems. The discovery of the ‘ion specific effects’ dates back to Hofmeister (1888), who observed the specific effect of salts in promoting egg white proteins precipitation. Nowadays we are aware that ion specific effects are ubiquitous in all fields of science and technology where electrolytes play a...

  1. Charge Exchange Effect on Space-Charge-Limited Current Densities in Ion Diode

    Institute of Scientific and Technical Information of China (English)

    石磊

    2002-01-01

    The article theoretically studied the charge-exchange effects on space charge limited electron and ion current densities of non-relativistic one-dimensional slab ion diode, and compared with those of without charge exchange.

  2. Production of Charge in Heavy Ion Collisions

    CERN Document Server

    Pratt, Scott; Ratti, Claudia

    2015-01-01

    By analyzing preliminary experimental measurements of charge-balance functions from the STAR Collaboration at the Relativistic-Heavy-Ion Collider (RHIC), it is found that pictures where balancing charges are produced in a single surge, and therefore separated by a single length scale, are inconsistent with data. In contrast, a model that assumes two surges, one associated with the formation of a thermalized quark-gluon plasma and a second associated with hadronization, provides a far superior reproduction of the data. A statistical analysis of the model comparison finds that the two-surge model best reproduces the data if the charge production from the first surge is similar to expectations for equilibrated matter taken from lattice gauge theory. The charges created in the first surge appear to separate by approximately one unit of spatial rapidity before emission, while charges from the second wave appear to have separated by approximately a half unit or less.

  3. Ion mobility-mass spectrometry of phosphorylase B ions generated with supercharging reagents but in charge-reducing buffer.

    Science.gov (United States)

    Hogan, Christopher J; Ogorzalek Loo, Rachel R; Loo, Joseph A; de la Mora, Juan Fernandez

    2010-11-01

    We investigate whether "supercharging" reagents able to shift the charge state distributions (CSDs) of electrosprayed protein ions upward also influence gas-phase protein structure. A differential mobility analyzer and a mass spectrometer are combined in series (DMA-MS) to measure the mass and mobility of monomer and multimeric phosphorylase B ions (monomer molecular weight ∼97 kDa) in atmospheric pressure air. Proteins are electrosprayed from charge-reducing triethylammonium formate in water (pH = 6.8) with and without the addition of the supercharging reagent tetramethylene sulfone (sulfolane). Because the DMA measures ion mobility prior to collisional heating or declustering, it probes the structure of supercharged protein ions immediately following solvent (water) evaporation. As in prior studies, the addition of sulfolane is found to drastically increase both the mean and maximum charge state of phosphorylase B ions. Ions from all protein n-mers were found to yield mobilities that, for a given charge state, were ∼6-10% higher in the absence of sulfolane. We find that the mobility decrease which arises with sulfolane is substantially smaller than that typically observed for folded-to-unfolded transitions in protein ions (where a ∼60% decrease in mobility is typical), suggesting that supercharging reagents do not cause structural protein modifications in solution as large as noted recently by Williams and colleagues [E. R. Williams et al., J. Am. Soc. Mass Spectrom., 2010, 21, 1762-1774]. In fact, the measurements described here indicate that the modest mobility decrease observed can be partly attributed to sulfolane trapping within the protein ions during DMA measurements, and probably also in solution. As the most abundant peaks in measured mass-mobility spectra for ions produced with and without sulfolane correspond to non-covalently bound phosphorylase B dimers, we find that in spite of a change in mobility/cross section, sulfolane addition does not

  4. Gas-phase chemistry of diphosphate anions as a tool to investigate the intrinsic requirements of phosphate ester enzymatic reactions: the [M1M2HP2O7]- ions.

    Science.gov (United States)

    Pepi, Federico; Barone, Vincenzo; Cimino, Paola; Ricci, Andreina

    2007-01-01

    Experimental studies on gaseous inorganic phosphate ions are practically nonexistent, yet they can prove helpful for a better understanding of the mechanisms of phosphate ester enzymatic processes. The present contribution extends our previous investigations on the gas-phase ion chemistry of diphosphate species to the [M(1)M(2)HP(2)O(7)](-) ions where M(1) and M(2) are the same or different and correspond to the Li, Na, K, Cs, and Rb cations. The diphosphate ions are formed by electrospray ionization of 10(-4) M solutions of Na(5)P(3)O(10) in CH(3)CN/H(2)O (1/1) and MOH bases or M salts as a source of M(+) cations. The joint application of mass spectrometric techniques and quantum-mechanical calculations makes it possible to characterize the gaseous [M(1)M(2)HP(2)O(7)](-) ions as a mixed ionic population formed by two isomeric species: linear diphosphate anion coordinated to two M(+) cations (group I) and [PO(3)M(1)M(2)HPO(4)](-) clusters (group II). The relative gas-phase stabilities and activation barriers for the isomerization I-->II, which depend on the nature of the M(+) cations, highlight the electronic susceptibility of P-O-P bond breaking in the active site of enzymes. The previously unexplored gas-phase reactivity of [M(1)M(2)HP(2)O(7)](-) ions towards alcohols of different acidity was investigated by Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR/MS). The reaction proceeds by addition of the alcohol molecule followed by elimination of a water molecule.

  5. Commercial intermediate pressure MALDI ion mobility spectrometry mass spectrometer capable of producing highly charged laserspray ionization ions.

    Science.gov (United States)

    Inutan, Ellen D; Wang, Beixi; Trimpin, Sarah

    2011-02-01

    The first examples of highly charged ions observed under intermediate pressure (IP) vacuum conditions are reported using laser ablation of matrix/analyte mixtures. The method and results are similar to those obtained at atmospheric pressure (AP) using laserspray ionization (LSI) and/or matrix assisted inlet ionization (MAII). Electrospray ionization (ESI), LSI, and MAII are methods operating at AP and have been shown, with or without the use of a voltage or a laser, to produce highly charged ions with very similar ion abundance and charge states. A commercial matrix-assisted laser desorption/ionization ion mobility spectrometry (IMS) mass spectrometry (MS) instrument (SYNAPT G2) was used for the IP developments. The necessary conditions for producing highly charged ions of peptides and small proteins at IP appear to be a pressure drop region and the use of suitable matrixes and laser fluence. Ionization to produce these highly charged ions under the low pressure conditions of IP does not require specific heating or a special inlet ion transfer region. However, under the current setup, ubiquitin is the highest molecular weight protein observed. These findings are in accord with the need to provide thermal energy in the pressure drop region, similar to LSI and MAII, to improve sensitivity and extend the types of compounds that produce highly charged ions. The practical utility of IP-LSI in combination with IMS-MS is demonstrated for the analysis of model mixtures composed of a lipid, peptides, and a protein. Further, endogenous multiply charged peptides are observed directly from delipified mouse brain tissue with drift time distributions that are nearly identical in appearance to those obtained from a synthesized neuropeptide standard analyzed by either LSI- or ESI-IMS-MS at AP. Efficient solvent-free gas-phase separation enabled by the IMS dimension separates the multiply charged peptides from lipids that remained on the delipified tissue. Lipid and peptide

  6. Radioactive decays of highly-charged ions

    Directory of Open Access Journals (Sweden)

    Gao B. S.

    2015-01-01

    Full Text Available Access to stored and cooled highly-charged radionuclides offers unprecedented opportunities to perform high-precision investigations of their decays. Since the few-electron ions, e.g. hydrogen- or helium-like ions, are quantum mechanical systems with clear electronic ground state configurations, the decay studies of such ions are performed under well-defined conditions and allow for addressing fundamental aspects of the decay process. Presented here is a compact review of the relevant experiments conducted at the Experimental Storage Ring ESR of GSI. A particular emphasis is given to the investigations of the two-body beta decay, namely the bound-state β-decay and its time-mirrored counterpart, orbital electron-capture.

  7. Dielectronic recombination of multiply charged ions

    Energy Technology Data Exchange (ETDEWEB)

    Datz, S.; Dittner, P.F.; Fou, C.M.; Miller, P.D.; Pepmiller, P.L.

    1986-09-01

    Using a merged electron-ion merged beam apparatus in conjunction with the ORNL EN Tandem Van de Graaff, we have measured dielectronic recombination in ..delta..n = 0 transitions for a number of Li-liked (B/sup 2 +/, C/sup 3 +/, N/sup 4 +/, and O/sup 5 +/), Be-like (C/sup 2 +/, N/sup 3 +/, and O/sup 4 +/), B-like (N/sup 2 +/, O/sup 3 +/, and F/sup 4 +/), and Na-like (P/sup 4 +/, S/sup 5 +/, and Cl/sup 6 +/) ions. The results are compared with theory which includes field enhancement and extension of the more highly charged ions is discussed. 11 refs., 11 figs.

  8. Size-to-charge dispersion of collision-induced dissociation product ions for enhancement of structural information and product ion identification.

    Science.gov (United States)

    Zinnel, Nathanael F; Russell, David H

    2014-05-20

    Ion mobility is used to disperse product ions formed by collision-induced dissociation (CID) on the basis of charge state and size-to-charge ratio. We previously described an approach for combining CID with ion mobility mass spectrometry (IM-MS) for dispersing fragment ions along charge state specific trend lines (Zinnel, N. F.; Pai, P. J.; Russell, D. H. Anal. Chem. 2012, 84, 3390; Sowell, R. A.; Koeniger, S. L.; Valentine, S. J.; Moon, M. H.; Clemmer, D. E. J. Am. Soc. Mass Spectrom. 2004, 15, 1341; McLean, J. A.; Ruotolo, B. T.; Gillig, K. J.; Russell, D. H. Int. J. Mass Spectrom. 2005, 240, 301), and this approach was used to assign metal ion binding sites for human metallothionein protein MT-2a (Chen, S. H.; Russell, W. K.; Russell, D. H. Anal. Chem. 2013, 85, 3229). Here, we use this approach to distinguish b-type N-terminal fragment ions from both internal fragment ions and y-type C-terminal fragment ions. We also show that in some cases specific secondary structural elements, viz., extended coils or helices, can be obtained for the y-type fragment ions series. The advantage of this approach is that product ion identity can be correlated to gas-phase ion structure, which provides rapid identification of the onset and termination of extended coil structure in peptides.

  9. Precision mass measurements of highly charged ions

    Science.gov (United States)

    Kwiatkowski, A. A.; Bale, J. C.; Brunner, T.; Chaudhuri, A.; Chowdhury, U.; Ettenauer, S.; Frekers, D.; Gallant, A. T.; Grossheim, A.; Lennarz, A.; Mane, E.; MacDonald, T. D.; Schultz, B. E.; Simon, M. C.; Simon, V. V.; Dilling, J.

    2012-10-01

    The reputation of Penning trap mass spectrometry for accuracy and precision was established with singly charged ions (SCI); however, the achievable precision and resolving power can be extended by using highly charged ions (HCI). The TITAN facility has demonstrated these enhancements for long-lived (T1/2>=50 ms) isobars and low-lying isomers, including ^71Ge^21+, ^74Rb^8+, ^78Rb^8+, and ^98Rb^15+. The Q-value of ^71Ge enters into the neutrino cross section, and the use of HCI reduced the resolving power required to distinguish the isobars from 3 x 10^5 to 20. The precision achieved in the measurement of ^74Rb^8+, a superallowed β-emitter and candidate to test the CVC hypothesis, rivaled earlier measurements with SCI in a fraction of the time. The 111.19(22) keV isomeric state in ^78Rb was resolved from the ground state. Mass measurements of neutron-rich Rb and Sr isotopes near A = 100 aid in determining the r-process pathway. Advanced ion manipulation techniques and recent results will be presented.

  10. Infrared Multiple-Photon Dissociation Spectroscopy of Tripositive Ions: Lanthanum-Tryptophan Complexes

    NARCIS (Netherlands)

    Verkerk, U. H.; Zhao, J. F.; Saminathan, I. S.; Lau, J. K. C.; Oomens, J.; Hopkinson, A. C.; Siu, K. W. M.

    2012-01-01

    Collision-induced charge disproportionation limits the stability of triply charged metal ion complexes and has thus far prevented successful acquisition of their gas-phase IR spectra. This has curtailed our understanding of the structures of triply charged metal complexes in the gas phase and in bio

  11. Humidity independent mass spectrometry for gas phase chemical analysis via ambient proton transfer reaction

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Hongying; Huang, Guangming, E-mail: gmhuang@ustc.edu.cn

    2015-03-31

    Graphical abstract: Direct and humidity independent mass spectrometry analysis of gas phase chemicals could be achieved via ambient proton transfer ionization, ion intensity was found to be stable with humidity ranged from ∼10% to ∼100%. - Highlights: • A humidity independent mass spectrometric method for gas phase samples analysis. • A universal and good sensitivity method. • The method can real time identify plant released raw chemicals. - Abstract: In this work, a humidity independent mass spectrometric method was developed for rapid analysis of gas phase chemicals. This method is based upon ambient proton transfer reaction between gas phase chemicals and charged water droplets, in a reaction chamber with nearly saturate humidity under atmospheric pressure. The humidity independent nature enables direct and rapid analysis of raw gas phase samples, avoiding time- and sample-consuming sample pretreatments in conventional mass spectrometry methods to control sample humidity. Acetone, benzene, toluene, ethylbenzene and meta-xylene were used to evaluate the analytical performance of present method. The limits of detection for benzene, toluene, ethylbenzene and meta-xylene are in the range of ∼0.1 to ∼0.3 ppbV; that of benzene is well below the present European Union permissible exposure limit for benzene vapor (5 μg m{sup −3}, ∼1.44 ppbV), with linear ranges of approximately two orders of magnitude. The majority of the homemade device contains a stainless steel tube as reaction chamber and an ultrasonic humidifier as the source of charged water droplets, which makes this cheap device easy to assemble and facile to operate. In addition, potential application of this method was illustrated by the real time identification of raw gas phase chemicals released from plants at different physiological stages.

  12. (The physics of highly charged ions)

    Energy Technology Data Exchange (ETDEWEB)

    Phaneuf, R.A.

    1990-10-12

    The Fifth International Conference on the Physics of Highly Charged Ions drew more than 200 participants, providing an excellent overview of this growing field. Important technical developments and experimental results in electron-ion collisions were reported. The merging of fast ion beams from accelerators or storage rings with advanced high-intensity electron-beam targets has yielded data of unprecedented quality on radiative and dielectronic recombination, providing stringent tests of theory. Long-awaited technical innovations in electron-impact excitation measurements were also reported. The level of activity in multicharged ion-surface interactions has increased. More sophisticated experimental studies of the neutralization process have shown the inadequacy of previously accepted mechanisms, and theoretical activity in this area is just being initiated. The IAEA meetings addressed atomic and molecular data needs for fusion research, with ITER providing a key focus. Such data are especially critical to modeling and diagnostics of the edge plasma. The ALADDIN data base system has been universally accepted and has streamlined the exchange of numerical data among data centers and the fusion community. The IAEA continues to play a pivotal role in the identification of data needs, and in the coordination of data compilation and research activities for fusion applications.

  13. Bond-specific dissociation following excitation energy transfer for distance constraint determination in the gas phase.

    Science.gov (United States)

    Hendricks, Nathan G; Lareau, Nichole M; Stow, Sarah M; McLean, John A; Julian, Ryan R

    2014-09-24

    Herein, we report chemistry that enables excitation energy transfer (EET) to be accurately measured via action spectroscopy on gaseous ions in an ion trap. It is demonstrated that EET between tryptophan or tyrosine and a disulfide bond leads to excited state, homolytic fragmentation of the disulfide bond. This phenomenon exhibits a tight distance dependence, which is consistent with Dexter exchange transfer. The extent of fragmentation of the disulfide bond can be used to determine the distance between the chromophore and disulfide bond. The chemistry is well suited for the examination of protein structure in the gas phase because native amino acids can serve as the donor/acceptor moieties. Furthermore, both tyrosine and tryptophan exhibit unique action spectra, meaning that the identity of the donating chromophore can be easily determined in addition to the distance between donor/acceptor. Application of the method to the Trpcage miniprotein reveals distance constraints that are consistent with a native-like fold for the +2 charge state in the gas phase. This structure is stabilized by several salt bridges, which have also been observed to be important previously in proteins that retain native-like structures in the gas phase. The ability of this method to measure specific distance constraints, potentially at numerous positions if combined with site-directed mutagenesis, significantly enhances our ability to examine protein structure in the gas phase.

  14. Study on charge equilibration time of highly charged ions in carbon foils

    Institute of Scientific and Technical Information of China (English)

    Fang Yan; Xiao Guo-Qing; Xu Hu-Shan; Sun Zhi-Yu; Zhao Yong-Wao; Hu Zheng-Guo; Xu Hua-Gen; Huang Wian-Heng; Wang Yu-Yu

    2008-01-01

    Charge state distribution of 0.8MeV/u uranium ions after transmission through a thin carbon foil has been studied.It is observed that the charge state distribution is equilibrated after the uranium ions have passed through a 15 μg/cm2 carbon foil.The equilibrated average charge state is 33.72 and the charge equilibration time of uranium ions in carbon foil is less than 5.4fs.

  15. Liquid gas phase transition in hypernuclei

    CERN Document Server

    Mallik, S

    2016-01-01

    The fragmentation of excited hypernuclear system formed in heavy ion collisions has been described by the canonical thermodynamical model extended to three component systems. The multiplicity distribution of the fragments has been analyzed in detail and it has been observed that the hyperons have the tendency to get attached to the heavier fragments. Another important observation is the phase coexistence of the hyperons, a phenomenon which is linked to liquid gas phase transition in strange matter.

  16. Laboratory and Ambient Studies of the Products of Gas-Phase Hydroxyl and Nitrate Ion Radical-Initiated Reactions with Selected PAHs

    Science.gov (United States)

    Zimmermann, Kathryn Jean

    Nitrated polycyclic aromatic hydrocarbon (nitro-PAH) product distributions from the gas-phase hydroxyl (OH) and nitrate (NO3) radical-initiated reactions with selected PAHs, as well as the heterogeneous reactions of surface-bound PAHs with N2O5 and HNO3, were investigated. Chapter 2 presents formation yields of nitro-PAHs from the gas-phase OH radical-initiated reactions of 1,7- and 2,7-dimethylnaphthalene (DMN) as a function of NO 2 concentration over the range 0.04-0.14 ppmv. The measured formation yields of dimethylnitronaphthalenes (DMNNs) under conditions that the OH-DMN adducts reacted solely with NO2 were 0.252 ± 0.094% for Σ1,7-DMNNs and 0.010 ± 0.005% for Σ2,7-DMNNs. 1,7-dimethyl-5-nitronaphthalene (1,7DM5NN) was the major nitro-isomer formed, with a limiting high-NO 2 concentration yield of 0.212 ± 0.080% and with equal reactions of the 1,7-DMN-OH adduct with NO2 and O2 occurring in air at 60 ± 39 ppbv of NO2, indicating that the OH-DMN adduct reaction with NO2 can be important at NO2 concentrations commonly found in urban atmospheres. Although the yields of the DMNNs are low, ≤0.3%, the DMNN (and ethylnitronaphthalene) profiles from chamber experiments match well with those observed in polluted urban areas under conditions where OH radical-initiated chemistry is dominant, such as Mexico City, Mexico. Chapter 3 examines the nitro-PAH products of gas-phase OH and NO 3 radicals and heterogeneous N2O5 reactions with fluoranthene, pyrene, benz[a]anthracene, chrysene, and triphenylene. Analysis of nitro-PAHs in the NIST diesel particulate SRM (1975) and selected ambient samples are also presented. 2-Nitrofluoranthene (2-NFL) was the most abundant nitro-PAH in Riverside, CA and Mexico City, and the mw 273 nitro-PAHs were observed in lower concentrations. However, in Tokyo, Japan, concentrations of 1- + 2-nitrotriphenylene (NTP) were more similar to those of 2-NFL. Comparing specific nitro-PAH ratios in ambient particulate samples from Tokyo, Mexico City

  17. Unusual hydroxyl migration in the fragmentation of β-alanine dication in the gas phase.

    Science.gov (United States)

    Piekarski, Dariusz Grzegorz; Delaunay, Rudy; Maclot, Sylvain; Adoui, Lamri; Martín, Fernando; Alcamí, Manuel; Huber, Bernd A; Rousseau, Patrick; Domaracka, Alicja; Díaz-Tendero, Sergio

    2015-07-14

    We present a combined experimental and theoretical study of the fragmentation of doubly positively charged β-alanine molecules in the gas phase. The dissociation of the produced dicationic molecules, induced by low-energy ion collisions, is analysed by coincidence mass spectrometric techniques; the coupling with ab initio molecular dynamics simulations allows rationalisation of the experimental observations. The present strategy gives deeper insights into the chemical mechanisms of multiply charged amino acids in the gas phase. In the case of the β-alanine dication, in addition to the expected Coulomb explosion and hydrogen migration processes, we have found evidence of hydroxyl-group migration, which leads to unusual fragmentation products, such as hydroxymethyl cation, and is necessary to explain some of the observed dominant channels.

  18. Interstellar molecule CCCN may be formed by charge-stripping of [CCCN]- in the gas phase, and when energized, undergoes loss of C with partial carbon scrambling.

    Science.gov (United States)

    Maclean, Micheal J; Fitzgerald, Mark; Bowie, John H

    2007-12-20

    Deprotonation of CH2=CHCN with HO- in the chemical ionization source of a VG ZAB 2HF mass spectrometer gives CH2=-CCN which fragments through [H- (HCCCN)] to give [CCCN]-. Similar reactions with 13CH2CHCN and CH2CH13CN give [13CCCN]- and [CC13CN]-. Collision induced dissociations of these anions, together with calculations at the CCSD(T)/aug-cc-pVDZ//B3LYP/6-31+G(d) level of theory indicate that the anions do not rearrange under conditions used to charge strip them to their neutrals. A comparison of the charge reversal (-CR+) and neutralization/reionization (-NR+) mass spectra of [CCCN]- indicate that neutral C3N species (formed by charge stripping of the anion) decompose by loss of C. Experimental studies with the 13C labeled analogues indicate that the loss of C occurs subsequent to or accompanying partial carbon scrambling of the CCCN backbone. Theoretical studies suggest that this scrambling may occur during equilibration of CCCN and CCNC via a decomposing "rhombic" C3N intermediate.

  19. Solution Versus Gas-Phase Modification of Peptide Cations with NHS-Ester Reagents

    Science.gov (United States)

    Mentinova, Marija; Barefoot, Nathan Z.; McLuckey, Scott A.

    2012-02-01

    A comparison between solution and gas phase modification of primary amine sites in model peptide cations with N-hydroxysuccinimide (NHS) ester reagents is presented. In all peptides, the site of modification in solution was directed to the N-terminus by conducting reactions at pH = 5, whereas for the same peptides, a lysine residue was preferentially modified in the gas phase. The difference in pKa values of the N-terminus and ɛ-amino group of the lysine allows for a degree of control over sites of protonation of the peptides in aqueous solution. With removal of the dielectric and multiple charging of the peptide ions in the gas phase, the accommodation of excess charge can affect the preferred sites of reaction. Interaction of the lone pair of the primary nitrogen with a proton reduces its nucleophilicity and, as a result, its reactivity towards NHS-esters. While no evidence for reaction of the N-terminus with sulfo-NHS-acetate was noted in the model peptide cations, a charge inversion experiment using bis[sulfosuccinimidyl] suberate, a cross-linking reagent with two sulfo-NHS-ester functionalities, showed modification of the N-terminus. Hence, an unprotonated N-terminus can serve as a nucleophile to displace NHS, which suggests that its lack of reactivity with the peptide cations is likely due to the participation of the N-terminus in solvating excess charge.

  20. Miniature free-piston homogeneous charge compression ignition engine-compressor concept - Part II: modeling HCCI combustion in small scales with detailed homogeneous gas phase chemical kinetics

    Energy Technology Data Exchange (ETDEWEB)

    Aichlmayr, H.T.; Kittelson, D.B.; Zachariah, M.R. [The University of Minnesota, Minneapolis (United States). Departments of Mechanical Engineering and Chemistry

    2002-10-01

    Operational maps for crankshaft-equipped miniature homogeneous charge compression ignition engines are established using performance estimation, detailed chemical kinetics, and diffusion models for heat transfer and radical loss. In this study, radical loss was found to be insignificant. In contrast, heat transfer was found to be increasingly significant for 10, 1, and 0.1 W engines, respectively. Also, temperature-pressure trajectories and ignition delay time maps are used to explore relationships between engine operational parameters and HCCI. Lastly, effects of engine operating conditions and design on the indicated fuel conversion efficiency are investigated. (author)

  1. Laboratory Studies of Stabilities of Heterocyclic Aromatic Molecules: Suggested Gas Phase Ion-Molecule Routes to Production in Interstellar Gas Clouds

    Science.gov (United States)

    Adams, Nigel G.; Fondren, L. Dalila; McLain, Jason L.; Jackson, Doug M.

    2006-01-01

    Several ring compounds have been detected in interstellar gas clouds, ISC, including the aromatic, benzene. Polycyclic aromatic hydrocarbons, PAHs, have been implicated as carriers of diffuse interstellar bands (DIBs) and unidentified infrared (UIR) bands. Heterocyclic aromatic rings of intermediate size containing nitrogen, possibly PreLife molecules, were included in early searches but were not detected and a recent search for Pyrimidine was unsuccessful. Our laboratory investigations of routes to such molecules could establish their existence in ISC and suggest conditions under which their concentrations would be maximized thus aiding the searches. The stability of such ring compounds (C5H5N, C4H4N2, C5H11N and C4H8O2) has been tested in the laboratory using charge transfer excitation in ion-molecule reactions. The fragmentation paths, including production of C4H4(+), C3H3N(+) and HCN, suggest reverse routes to the parent molecules, which are presently under laboratory investigation as production sources.

  2. Lithium-Ion Cell Charge-Control Unit Developed

    Science.gov (United States)

    Reid, Concha M.; Manzo, Michelle A.; Buton, Robert M.; Gemeiner, Russel

    2005-01-01

    A lithium-ion (Li-ion) cell charge-control unit was developed as part of a Li-ion cell verification program. This unit manages the complex charging scheme that is required when Li-ion cells are charged in series. It enables researchers to test cells together as a pack, while allowing each cell to charge individually. This allows the inherent cell-to-cell variations to be addressed on a series string of cells and reduces test costs substantially in comparison to individual cell testing.

  3. Water and Ion Permeation through Electrically Charged Nanopore

    Institute of Scientific and Technical Information of China (English)

    ZENG Li; ZUO Guang-Hong; GONG Xiao-Jing; LU Hang-Jun; WANG Chun-Lei; WU Ke-Fei; WAN Rong-Zheng

    2008-01-01

    @@ The behaviour of water and small solutes in confined geometries is important to a variety of chemical and nanofluidic applications. Here we investigate the permeation and distribution of water and ions in electrically charged carbon cylindrical nanopore during the osmotic process using molecular dynamics simulations. In the simulations, charges are distributed uniformly on the pores with diameter of 0.9 nm. For nanopores with no charge or a low charge, ions are difficult to enter. With the increasing of charge densities on the pores, ions will appear inside the nanopores because of the large electronic forces between the ions and the charged pores. Different ion entries induce varying effects on osmotic water flow. Our simulations reveal that the osmotic water can flow through the negatively charged pore occupied by K+ ions, while water flux through the positively charged pores will be disrupted by Cl- ions inside the pores. This may be explained by the different radial distributions of K+ions and Cl- ions inside the charged nanopores.

  4. Gas-phase chemical dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Weston, R.E. Jr.; Sears, T.J.; Preses, J.M. [Brookhaven National Laboratory, Upton, NY (United States)

    1993-12-01

    Research in this program is directed towards the spectroscopy of small free radicals and reactive molecules and the state-to-state dynamics of gas phase collision, energy transfer, and photodissociation phenomena. Work on several systems is summarized here.

  5. 原子核液-气相变的实验观察%Experimental Observables on Nuclear Liquid Gas Phase Transition

    Institute of Scientific and Technical Information of China (English)

    马余刚

    2007-01-01

    Progress on nuclear liquid gas phase transition (LGPT) or critical behavior has been simply reviewed and some signals of LGPT in heavy ion collisions, especially in NIMROD data, are focused. These signals include the power-law charge distribution, the largest fluctuation of the fragment observables, the nuclear Zipf law, caloric curve and critical exponent analysis etc.

  6. Frequency metrology using highly charged ions

    Science.gov (United States)

    Crespo López-Urrutia, J. R.

    2016-06-01

    Due to the scaling laws of relativistic fine structure splitting, many forbidden optical transitions appear within the ground state configurations of highly charged ions (HCI). In some hydrogen-like ions, even the hyperfine splitting of the 1s ground state gives rise to optical transitions. Given the very low polarizability of HCI, such laser-accessible transitions are extremely impervious to external perturbations and systematics that limit optical clock performance and arise from AC and DC Stark effects, such as black-body radiation and light shifts. Moreover, AC and DC Zeeman splitting are symmetric due to the much larger relativistic spin-orbit coupling and corresponding fine-structure splitting. Appropriate choice of states or magnetic sub-states with suitable total angular momentum and magnetic quantum numbers can lead to a cancellation of residual quadrupolar shifts. All these properties are very advantageous for the proposed use of HCI forbidden lines as optical frequency standards. Extremely magnified relativistic, quantum electrodynamic, and nuclear size contributions to the binding energies of the optically active electrons make HCI ideal tools for fundamental research, as in proposed studies of a possible time variation of the fine structure constant. Beyond this, HCI that cannot be photoionized by vacuum-ultraviolet photons could also provide frequency standards for future lasers operating in that range.

  7. Gas-phase peptide structures unraveled by far-IR spectroscopy: combining IR-UV ion-dip experiments with Born-Oppenheimer molecular dynamics simulations.

    Science.gov (United States)

    Jaeqx, Sander; Oomens, Jos; Cimas, Alvaro; Gaigeot, Marie-Pierre; Rijs, Anouk M

    2014-04-01

    Vibrational spectroscopy provides an important probe of the three-dimensional structures of peptides. With increasing size, these IR spectra become very complex and to extract structural information, comparison with theoretical spectra is essential. Harmonic DFT calculations have become a common workhorse for predicting vibrational frequencies of small neutral and ionized gaseous peptides. Although the far-IR region (IR spectra of peptides. Here, Born-Oppenheimer molecular dynamics (BOMD) is applied to predict the far-IR signatures of two γ-turn peptides. Combining experiments and simulations, far-IR spectra can provide structural information on gas-phase peptides superior to that extracted from mid-IR and amide A features.

  8. Producing highly charged ions without solvent using laserspray ionization: a total solvent-free analysis approach at atmospheric pressure.

    Science.gov (United States)

    Wang, Beixi; Lietz, Christopher B; Inutan, Ellen D; Leach, Samantha M; Trimpin, Sarah

    2011-06-01

    First examples of highly charged ions in mass spectrometry (MS) produced from the solid state without using solvent during either sample preparation or mass measurement are reported. Matrix material, matrix/analyte homogenization time and frequency, atmospheric pressure (AP) to vacuum inlet temperature, and mass analyzer ion trap conditions are factors that influence the abundance of the highly charged ions created by laserspray ionization (LSI). LSI, like matrix-assisted laser desorption/ionization (MALDI), uses laser ablation of a matrix/analyte mixture from a surface to produce ions. Preparing the matrix/analyte sample without the use of solvent provides the ability to perform total solvent-free analysis (TSA) consisting of solvent-free ionization and solvent-free gas-phase separation using ion mobility spectrometry (IMS) MS. Peptides and small proteins such as non-β-amyloid components of Alzheimer's disease and bovine insulin are examples in which LSI and TSA were combined to produce multiply charged ions, similar to electrospray ionization, but without the use of solvent. Advantages using solvent-free LSI and IMS-MS include simplicity, rapid data acquisition, reduction of sample complexity, and the potential for an enhanced effective dynamic range. This is achieved by more inclusive ionization and improved separation of mixture components as a result of multiple charging.

  9. Cooling of highly charged ions in a Penning trap

    Energy Technology Data Exchange (ETDEWEB)

    Gruber, L

    2000-03-31

    Highly charged ions are extracted from an electron beam ion trap and guided to Retrap, a cryogenic Penning trap, where they are merged with laser cooled Be{sup +} ions. The Be{sup +} ions act as a coolant for the hot highly charged ions and their temperature is dropped by about 8 orders of magnitude in a few seconds. Such cold highly charged ions form a strongly coupled nonneutral plasma exhibiting, under such conditions, the aggregation of clusters and crystals. Given the right mixture, these plasmas can be studied as analogues of high density plasmas like white dwarf interiors, and potentially can lead to the development of cold highly charged ion beams for applications in nanotechnology. Due to the virtually non existent Doppler broadening, spectroscopy on highly charged ions can be performed to an unprecedented precision. The density and the temperature of the Be{sup +} plasma were measured and highly charged ions were sympathetically cooled to similar temperatures. Molecular dynamics simulations confirmed the shape, temperature and density of the highly charged ions. Ordered structures were observed in the simulations.

  10. Unconventional hydrogen bonding to organic ions in the gas phase: stepwise association of hydrogen cyanide with the pyridine and pyrimidine radical cations and protonated pyridine.

    Science.gov (United States)

    Hamid, Ahmed M; El-Shall, M Samy; Hilal, Rifaat; Elroby, Shaaban; Aziz, Saadullah G

    2014-08-07

    Equilibrium thermochemical measurements using the ion mobility drift cell technique have been utilized to investigate the binding energies and entropy changes for the stepwise association of HCN molecules with the pyridine and pyrimidine radical cations forming the C5H5N(+·)(HCN)n and C4H4N2 (+·)(HCN)n clusters, respectively, with n = 1-4. For comparison, the binding of 1-4 HCN molecules to the protonated pyridine C5H5NH(+)(HCN)n has also been investigated. The binding energies of HCN to the pyridine and pyrimidine radical cations are nearly equal (11.4 and 12.0 kcal/mol, respectively) but weaker than the HCN binding to the protonated pyridine (14.0 kcal/mol). The pyridine and pyrimidine radical cations form unconventional carbon-based ionic hydrogen bonds with HCN (CH(δ+)⋯NCH). Protonated pyridine forms a stronger ionic hydrogen bond with HCN (NH(+)⋯NCH) which can be extended to a linear chain with the clustering of additional HCN molecules (NH(+)⋯NCH··NCH⋯NCH) leading to a rapid decrease in the bond strength as the length of the chain increases. The lowest energy structures of the pyridine and pyrimidine radical cation clusters containing 3-4 HCN molecules show a strong tendency for the internal solvation of the radical cation by the HCN molecules where bifurcated structures involving multiple hydrogen bonding sites with the ring hydrogen atoms are formed. The unconventional H-bonds (CH(δ+)⋯NCH) formed between the pyridine or the pyrimidine radical cations and HCN molecules (11-12 kcal/mol) are stronger than the similar (CH(δ+)⋯NCH) bonds formed between the benzene radical cation and HCN molecules (9 kcal/mol) indicating that the CH(δ+) centers in the pyridine and pyrimidine radical cations have more effective charges than in the benzene radical cation.

  11. Transfer ionization in collisions with a fast highly charged ion.

    Science.gov (United States)

    Voitkiv, A B

    2013-07-26

    Transfer ionization in fast collisions between a bare ion and an atom, in which one of the atomic electrons is captured by the ion whereas another one is emitted, crucially depends on dynamic electron-electron correlations. We show that in collisions with a highly charged ion a strong field of the ion has a very profound effect on the correlated channels of transfer ionization. In particular, this field weakens (strongly suppresses) electron emission into the direction opposite (perpendicular) to the motion of the ion. Instead, electron emission is redirected into those parts of the momentum space which are very weakly populated in fast collisions with low charged ions.

  12. Evaluation of ion mobility spectroscopy for determining charge-solvated versus salt-bridge structures of protonated trimers.

    Science.gov (United States)

    Wong, Richard L; Williams, Evan R; Counterman, Anne E; Clemmer, David E

    2005-07-01

    The cross sections of five different protonated trimers consisting of two base molecules and trifluoroacetic acid were measured by using ion mobility spectrometry. The gas-phase basicities of these five base molecules span an 8-kcal/mol range. These cross sections are compared with those determined from candidate low-energy salt-bridge and charge-solvated structures identified by using molecular mechanics calculations using three different force fields: AMBER*, MMFF, and CHARMm. With AMBER*, the charge-solvated structures are all globular and the salt-bridge structures are all linear, whereas with CHARMm, these two forms of the protonated trimers can adopt either shape. Globular structures have smaller cross sections than linear structures. Conclusions about the structure of these protonated trimers are highly dependent on the force field used to generate low-energy candidate structures. With AMBER*, all of the trimers are consistent with salt-bridge structures, whereas with MMFF the measured cross sections are more consistent with charge-solvated structures, although the assignments are ambiguous for two of the protonated trimers. Conclusions based on structures generated by using CHARMm suggest a change in structure from charge-solvated to salt-bridge structures with increasing gas-phase basicity of the constituent bases, a result that is most consistent with structural conclusions based on blackbody infrared radiative dissociation experiments for these protonated trimers and theoretical calculations on the uncharged base-acid pairs.

  13. Photons shedding light on electron capture by highly charged ions

    NARCIS (Netherlands)

    Hoekstra, Romke Anne

    1990-01-01

    In this thesis charge transfer is studied in collisions of highly charged ions (Aq+) with neutral particles (B). Because the electron is captured resonantly (i.e. without its binding energy) by the ion, a limited number of highly excited states (characterized by the quantum numbers nlm) is preferent

  14. Problems with Accurate Atomic Lfetime Measurements of Multiply Charged Ions

    Energy Technology Data Exchange (ETDEWEB)

    Trabert, E

    2009-02-19

    A number of recent atomic lifetime measurements on multiply charged ions have reported uncertainties lower than 1%. Such a level of accuracy challenges theory, which is a good thing. However, a few lessons learned from earlier precision lifetime measurements on atoms and singly charged ions suggest to remain cautious about the systematic errors of experimental techniques.

  15. Ion and water transport in charge-modified graphene nanopores

    CERN Document Server

    Qiu, Yinghua; Chen, Weiyu; Si, Wei; Tan, Qiyan; Chen, Yunfei

    2016-01-01

    Porous graphene has high mechanical strength and atomic layer thickness, which make it a promising material for material separation and biomolecule sensing. Electrostatic interactions between charges in aqueous solution are a kind of strong long-range interaction which may have great influence on the fluid transport through nanopores. Here, molecular dynamics simulations were conducted to investigate ion and water transport through a 1.05-nm-in-diameter monolayer graphene nanopore with its edge charge-modified. From the results, it is found that the nanopores are selective to counterions when they are charged. As the charge amount increases, the total ionic currents show an increase-decrease profile while the co-ion currents monotonously decrease. The co-ions rejection can reach 75% and 90% when the nanopores are negatively and positively charged, respectively. Cl ions current increases and reaches a plateau, and Na+ current decreases with the charge amount in the systems where they act as counterions. Beside...

  16. Ion mobility-mass spectrometry of charge-reduced protein complexes reveals general trends in the collisional ejection of compact subunits.

    Science.gov (United States)

    Bornschein, Russell E; Ruotolo, Brandon T

    2015-10-21

    Multiprotein complexes have been shown to play critical roles across a wide range of cellular functions, but most probes of protein quaternary structure are limited in their ability to analyze complex mixtures and polydisperse structures using small amounts of total protein. Ion mobility-mass spectrometry offers a solution to many of these challenges, but relies upon gas-phase measurements of intact multiprotein complexes, subcomplexes, and subunits that correlate well with solution structures. The greatest bottleneck in such workflows is the generation of representative subcomplexes and subunits. Collisional activation of complexes can act to produce product ions reflective of protein complex composition, but such product ions are typically challenging to interpret in terms of their relationship to solution structure due to their typically string-like conformations following activation and subsequent dissociation. Here, we used ion-ion chemistry to perform a broad survey of the gas-phase dissociation of charge-reduced protein complex ions, revealing general trends associated with the collisional ejection of compact, rather than unfolded, protein subunits. Furthermore, we also discover peptide and co-factor dissociation channels that dominate the product ion populations generated for such charge reduced complexes. We assess both sets of observations and discuss general principles that can be extended to the analysis of protein complex ions having unknown structures.

  17. Experimental results on charge fluctuations in heavy-ion collisions

    CERN Document Server

    Mishra, D K; Netrakanti, P K; Pant, L M; Mohanty, A K

    2016-01-01

    We present a subset of experimental results on charge fluctuation from the heavy-ion collisions to search for phase transition and location of critical point in the QCD phase diagram. Measurements from the heavy-ion experiments at the SPS and RHIC energies observe that total charge fluctuations increase from central to peripheral collisions. The net-charge fluctuations in terms of dynamical fluctuation measure $\

  18. Ion and water transport in charge-modified graphene nanopores

    Institute of Scientific and Technical Information of China (English)

    裘英华; 李堃; 陈伟宇; 司伟; 谭启檐; 陈云飞

    2015-01-01

    Porous graphene has a high mechanical strength and an atomic-layer thickness that makes it a promising material for material separation and biomolecule sensing. Electrostatic interactions between charges in aqueous solutions are a type of strong long-range interaction that may greatly infl uence fl uid transport through nanopores. In this study, molecular dynamic simulations were conducted to investigate ion and water transport through 1.05-nm diameter monolayer graphene nanopores, with their edges charge-modified. Our results indicated that these nanopores are selective to counterions when they are charged. As the charge amount increases, the total ionic currents show an increase–decrease profile while the co-ion currents monotonically decrease. The co-ion rejection can reach 76.5%and 90.2%when the nanopores are negatively and positively charged, respectively. The Cl−ion current increases and reaches a plateau, and the Na+current decreases as the charge amount increases in systems in which Na+ions act as counterions. In addition, charge modification can enhance water transport through nanopores. This is mainly due to the ion selectivity of the nanopores. Notably, positive charges on the pore edges facilitate water transport much more strongly than negative charges.

  19. Evaporative cooling of highly charged ions in EBIT (Electron Beam Ion Trap): An experimental realization

    Energy Technology Data Exchange (ETDEWEB)

    Schneider, M.B.; Levine, M.A.; Bennett, C.L.; Henderson, J.R.; Knapp, D.A.; Marrs, R.E.

    1988-12-01

    Both the total number and trapping lifetime of near-neon-like gold ions held in an electron beam ion trap have been greatly increased by a process of 'evaporative cooling'. A continuous flow of low-charge-state ions into the trap cools the high-charge-state ions in the trap. Preliminary experimental results using titanium ions as a coolant are presented. 8 refs., 6 figs., 2 tabs.

  20. Correlation of the structural information obtained for europium-chelate ensembles from gas-phase photoluminescence and ion-mobility spectroscopy with density-functional computations and ligand-field theory.

    Science.gov (United States)

    Greisch, Jean-François; Chmela, Jiří; Harding, Michael E; Wunderlich, Dirk; Schäfer, Bernhard; Ruben, Mario; Klopper, Wim; Schooss, Detlef; Kappes, Manfred M

    2017-02-22

    We report a combined investigation of europium(iii)9-oxo-phenalen-1-one (PLN) coordination complexes, [Eu(PLN)4AE](+) with AE = Mg, Ca, and Sr, using gas-phase photoluminescence, trapped ion-mobility spectrometry and density-functional computations. In order to sort out the structural impact of the alkali earth dications on the photoluminescence spectra, the experimental data are compared to the predicted ligand-field splittings as well as to the collision cross-sections for different isomers of [Eu(PLN)4AE](+). The best fitting interpretation is that one isomer family predominantly contributes to the recorded luminescence. The present work demonstrates the complexity of the coordination patterns of multicenter lanthanoid chelates involved in dynamical equilibria and the pertinence of using isolation techniques to elucidate their photophysical properties.

  1. The charge spectrum of positive ions in a hydrogen aurora

    Science.gov (United States)

    Lynch, J.; Pulliam, D.; Leach, R.; Scherb, F.

    1976-01-01

    An auroral ion charge spectrometer was flown into a hydrogen aurora on a Javelin sounding rocket launched from Churchill, Manitoba. The instrument contained an electrostatic analyzer which selected particles with incident energy per unit charge up to 20 keV/charge and an 80-kV power supply which accelerated these ions onto an array of solid state detectors. Ions tentatively identified as H(+), He(+2), and O(+) were detected from 225 to 820 km in altitude. The experiment did not discriminate between H(+) and He(+), or between O(+), N(+), and C(+). Upper limits of highly charged heavy ion abundances have been set at 20% of the He(+2) and 0.15% of the H(+). It is concluded that both terrestrial and solar wind sources play significant roles in auroral ion precipitation.

  2. Extremely supercharged proteins in mass spectrometry: profiling the pH of electrospray generated droplets, narrowing charge state distributions, and increasing ion fragmentation.

    Science.gov (United States)

    Zenaidee, Muhammad A; Donald, William A

    2015-03-21

    The effects of 12 acids, 4 solvents, and 8 low-volatility additives that increase analyte charging (i.e., superchargers) on the charge state distributions (CSDs) of protein ions in ESI-MS were investigated. We discovered that (i) relatively low concentrations [5% (v/v)] of 1,2-butylene carbonate (and 4-vinyl-1,3-dioxolan-2-one) can be added to ESI solutions to form higher charge states of cytochrome c and myoglobin ions than by using more traditional additives (e.g., propylene carbonate, sulfolane, or m-nitrobenzyl alcohol) under these conditions and (ii) the width of CSDs narrow as the effectiveness of superchargers increase, which concentrates protein ions into fewer detection channels. The use of strong acids (pKa values 0) results in significantly higher protein ion charging, less acid adduction, and narrower CSDs, indicating that protein ion supercharging in ESI can be significantly limited by the binding of conjugate base anions of acids that neutralize charge sites and broaden CSDs. The extent of protein charging as a function of acid identity (HA) does not strongly correlate with gas-phase proton transfer data (i.e., gas-phase basicity and proton affinity values for HA and A(-)), solution-phase protein secondary structures (as determined by circular dichroism spectroscopy), and/or acid molecule volatility data. For protein-denaturing solutions, these data were used to infer that the "effective" pH of ESI generated droplets near the moment of ion formation can be ∼0, which is ca. 1 to 3 pH units lower than the pH of the solutions prior to ESI. Electron capture dissociation (ECD) of [ubiquitin, 17H](17+) resulted in the identification of 223 cleavages, 74 of 75 inter-residue sites, and 92% ECD fragmentation efficiency, which correspond to highest of these values that have been obtained by ECD of a single isolated charge state of ubiquitin.

  3. A singly charged ion source for radioactive 11C ion acceleration

    Science.gov (United States)

    Katagiri, K.; Noda, A.; Nagatsu, K.; Nakao, M.; Hojo, S.; Muramatsu, M.; Suzuki, K.; Wakui, T.; Noda, K.

    2016-02-01

    A new singly charged ion source using electron impact ionization has been developed to realize an isotope separation on-line system for simultaneous positron emission tomography imaging and heavy-ion cancer therapy using radioactive 11C ion beams. Low-energy electron beams are used in the electron impact ion source to produce singly charged ions. Ionization efficiency was calculated in order to decide the geometric parameters of the ion source and to determine the required electron emission current for obtaining high ionization efficiency. Based on these considerations, the singly charged ion source was designed and fabricated. In testing, the fabricated ion source was found to have favorable performance as a singly charged ion source.

  4. A singly charged ion source for radioactive {sup 11}C ion acceleration

    Energy Technology Data Exchange (ETDEWEB)

    Katagiri, K.; Noda, A.; Nagatsu, K.; Nakao, M.; Hojo, S.; Muramatsu, M.; Suzuki, K.; Wakui, T.; Noda, K. [National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba-shi, Chiba 263-8555 (Japan)

    2016-02-15

    A new singly charged ion source using electron impact ionization has been developed to realize an isotope separation on-line system for simultaneous positron emission tomography imaging and heavy-ion cancer therapy using radioactive {sup 11}C ion beams. Low-energy electron beams are used in the electron impact ion source to produce singly charged ions. Ionization efficiency was calculated in order to decide the geometric parameters of the ion source and to determine the required electron emission current for obtaining high ionization efficiency. Based on these considerations, the singly charged ion source was designed and fabricated. In testing, the fabricated ion source was found to have favorable performance as a singly charged ion source.

  5. The role of space charge compensation for ion beam extraction and ion beam transport (invited)

    Energy Technology Data Exchange (ETDEWEB)

    Spädtke, Peter, E-mail: p.spaedtke@gsi.de [GSI Helmholtzzentrum für Schwerionenforschung GmbH (Germany)

    2014-02-15

    Depending on the specific type of ion source, the ion beam is extracted either from an electrode surface or from a plasma. There is always an interface between the (almost) space charge compensated ion source plasma, and the extraction region in which the full space charge is influencing the ion beam itself. After extraction, the ion beam is to be transported towards an accelerating structure in most cases. For lower intensities, this transport can be done without space charge compensation. However, if space charge is not negligible, the positive charge of the ion beam will attract electrons, which will compensate the space charge, at least partially. The final degree of Space Charge Compensation (SCC) will depend on different properties, like the ratio of generation rate of secondary particles and their loss rate, or the fact whether the ion beam is pulsed or continuous. In sections of the beam line, where the ion beam is drifting, a pure electrostatic plasma will develop, whereas in magnetic elements, these space charge compensating electrons become magnetized. The transport section will provide a series of different plasma conditions with different properties. Different measurement tools to investigate the degree of space charge compensation will be described, as well as computational methods for the simulation of ion beams with partial space charge compensation.

  6. In-Trap Spectroscopy of Charge-Bred Radioactive Ions

    Science.gov (United States)

    Lennarz, A.; Grossheim, A.; Leach, K. G.; Alanssari, M.; Brunner, T.; Chaudhuri, A.; Chowdhury, U.; Crespo López-Urrutia, J. R.; Gallant, A. T.; Holl, M.; Kwiatkowski, A. A.; Lassen, J.; Macdonald, T. D.; Schultz, B. E.; Seeraji, S.; Simon, M. C.; Andreoiu, C.; Dilling, J.; Frekers, D.

    2014-08-01

    In this Letter, we introduce the concept of in-trap nuclear decay spectroscopy of highly charged radioactive ions and describe its successful application as a novel spectroscopic tool. This is demonstrated by a measurement of the decay properties of radioactive mass A=124 ions (here, In124 and Cs124) in the electron-beam ion trap of the TITAN facility at TRIUMF. By subjecting the trapped ions to an intense electron beam, the ions are charge bred to high charge states (i.e., equivalent to the removal of N-shell electrons), and an increase of storage times to the level of minutes without significant ion losses is achieved. The present technique opens the venue for precision spectroscopy of low branching ratios and is being developed in the context of measuring electron-capture branching ratios needed for determining the nuclear ground-state properties of the intermediate odd-odd nuclei in double-beta (ββ) decay.

  7. Electron capture by highly charged ions from surfaces and gases

    Energy Technology Data Exchange (ETDEWEB)

    Allen, F.

    2008-01-11

    In this study highly charged ions produced in Electron Beam Ion Traps are used to investigate electron capture from surfaces and gases. The experiments with gas targets focus on spectroscopic measurements of the K-shell x-rays emitted at the end of radiative cascades following electron capture into Rydberg states of Ar{sup 17+} and Ar{sup 18+} ions as a function of collision energy. The ions are extracted from an Electron Beam Ion Trap at an energy of 2 keVu{sup -1}, charge-selected and then decelerated down to 5 eVu{sup -1} for interaction with an argon gas target. For decreasing collision energies a shift to electron capture into low orbital angular momentum capture states is observed. Comparative measurements of the K-shell x-ray emission following electron capture by Ar{sup 17+} and Ar{sup 18+} ions from background gas in the trap are made and a discrepancy in the results compared with those from the extraction experiments is found. Possible explanations are discussed. For the investigation of electron capture from surfaces, highly charged ions are extracted from an Electron Beam Ion Trap at energies of 2 to 3 keVu{sup -1}, charge-selected and directed onto targets comprising arrays of nanoscale apertures in silicon nitride membranes. The highly charged ions implemented are Ar{sup 16+} and Xe{sup 44+} and the aperture targets are formed by focused ion beam drilling in combination with ion beam assisted thin film deposition, achieving hole diameters of 50 to 300 nm and aspect ratios of 1:5 to 3:2. After transport through the nanoscale apertures the ions pass through an electrostatic charge state analyzer and are detected. The percentage of electron capture from the aperture walls is found to be much lower than model predictions and the results are discussed in terms of a capillary guiding mechanism. (orig.)

  8. Charge breeding of radioactive ions with EBIS and EBIT

    CERN Document Server

    Wenander, Fredrik

    2010-01-01

    A charge state breeder, which transforms externally injected singly charged ions to a higher charge state q+, is an important tool which has applications within atomic, nuclear and even particle physics. The charge breeding concept of radioactive ions has already been demonstrated at REX-ISOLDE/CERN with the use of an Electron beam Ion Source (EBIS) and at several facilities employing Electron Resonance Cyclotron Ion Sources (ECRIS). As will be demonstrated in this paper, EBIS and Electron Beam Ion Traps (EBIT), are well suited for the task as they are capable of delivering clean, highly charged beams within a short transformation time. The increasing demand for highly charged ions of all kind of elements and isotopes, stable and radioactive, to be used for low-energy experiments such as TITAN at TRIUMF and MATS at FAIR, but also for post-acceleration to higher energies, is now pushing the development of the breeders. The next challenge will be to satisfy the needs, for example space-charge capacity, of the s...

  9. Auger neutralization rates of multiply charged ions near metal surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Nedeljkovic, N.N.; Janev, R.K.; Lazur, V.Y.

    1988-08-15

    Transition rates for the Auger neutralization processes of multiply charged ions on metal surfaces are calculated in closed analytical form. The core potential of a multiply charged ion is represented by a pseudopotential, which accounts for the electron screening effects and allows transition to the pure Coulomb case (fully stripped ions). The relative importance of various neutralization channels in slow-ion--surface collisions is discussed for the examples of He/sup 2+/+Mo(100) and C/sup 3+/+Mo(100) collisional systems.

  10. Application of gas phase cryogenic vibrational spectroscopy to characterize the CO2, CO, N2 and N2O interactions with the open coordination site on a Ni(I) macrocycle using dual cryogenic ion traps

    Science.gov (United States)

    Craig, Stephanie M.; Menges, Fabian S.; Johnson, Mark A.

    2017-02-01

    Recent advances in gas phase ion chemistry, coupled with cryogenic ion vibrational predissociation spectroscopy, provide a powerful way to characterize the structures of small molecules bound to open coordination sites of organometallic compounds. Here we extend our previous measurements on the relatively weakly interacting CO2 molecule with a Ni(I) tetraaza-macrocyclic compound to enable the characterization of more strongly interacting substrates. We first confirm the calculated η2-C,O binding motif of CO2 using isotopic labeling by direct, one photon vibrational predissociation of the Ni(I)-CO2 complex. We then apply this approach to study complexation of N2 at the active site. The generality of the method is then expanded to include application to more strongly bound systems that cannot be photodissociated with one IR photon. This involves implementation of a recently developed scheme (Marsh et al., 2015) involving two temperature-controlled ion traps. The first is optimized to complex the substrate molecule to the active site and the second is cooled to around 10 K to enable condensation of weakly bound "tag" molecules onto the target complex so as to enable its characterization by linear vibrational predissociation spectroscopy. We demonstrate this capability by applying it to the coordination of CO to the active Ni(I) site, as well as to elucidate the nature of the products that are formed upon reaction with N2O.

  11. Charge reversal Fourier transform ion cyclotron resonance mass spectrometry.

    Science.gov (United States)

    Lobodin, Vladislav V; Savory, Joshua J; Kaiser, Nathan K; Dunk, Paul W; Marshall, Alan G

    2013-02-01

    We report the first charge reversal experiments performed by tandem-in-time rather than tandem-in-space MS/MS. Precursor odd-electron anions from fullerene C(60), and even-electron ions from 2,7-di-tert-butylfluorene-9-carboxylic acid and 3,3'-bicarbazole were converted into positive product ions ((-)CR(+)) inside the magnet of a Fourier transform ion cyclotron resonance mass spectrometer. Charge reversal was activated by irradiating precursor ions with high energy electrons or UV photons: the first reported use of those activation methods for charge reversal. We suggest that high energy electrons achieve charge reversal in one step as double electron transfer, whereas UV-activated (-)CR(+) takes place stepwise through two single electron transfers and formally corresponds to a neutralization-reionization ((-)NR(+)) experiment.

  12. Production of High-Intensity, Highly Charged Ions

    CERN Document Server

    Gammino, S

    2013-01-01

    In the past three decades, the development of nuclear physics facilities for fundamental and applied science purposes has required an increasing current of multicharged ion beams. Multiple ionization implies the formation of dense and energetic plasmas, which, in turn, requires specific plasma trapping configurations. Two types of ion source have been able to produce very high charge states in a reliable and reproducible way: electron beam ion sources (EBIS) and electron cyclotron resonance ion sources (ECRIS). Multiple ionization is also obtained in laser-generated plasmas (laser ion sources (LIS)), where the high-energy electrons and the extremely high electron density allow step-by-step ionization, but the reproducibility is poor. This chapter discusses the atomic physics background at the basis of the production of highly charged ions and describes the scientific and technological features of the most advanced ion sources. Particular attention is paid to ECRIS and the latest developments, since they now r...

  13. Production of highly charged argon ions from a room temperature electron beam ion trap

    Institute of Scientific and Technical Information of China (English)

    WANG Tie-Shan; PENG Hai-Bo; Ovsyannikov V P; Kentsch U; Ullmann F; CHENG Rui; Zschornack G

    2008-01-01

    In this work.highly charged ions have been extracted from the advanced Electron Beam Ion Source (EBIS-A) developed in a scientific cooperation between the Dresden University of Technology and the DREEBIT GmbH Dresden.The charge state distributions of ions extracted from the EBIS-A are measured in and extracted in the leaky mode.3×105 Ar18+ ions per pulse are extracted in the pulse mode.The ion charge state distribution is a function of the ionization time.

  14. Structure and Reactivity of Homocysteine Radical Cation in the Gas Phase Studied by Ion-Molecule Reactions and Infrared Multiple Photon Dissociation

    NARCIS (Netherlands)

    Osburn, S.; Burgie, T.; G. Berden,; Oomens, J.; O' Hair, R. A. J.; Ryzhov, V.

    2013-01-01

    The reactivity of the cysteine (Cys) and homocysteine (Hcy) radical cation was studied using ion molecule reactions. The radical cations were generated via collision-induced dissociation (CID) of their S-nitrosylated precursors. Cleavage of the S-NO bond led to the formation of the radical initially

  15. Charge Transfer and Ionization by Intermediate-Energy Heavy Ions

    Energy Technology Data Exchange (ETDEWEB)

    Toburen, L. H. [East Carolina University; McLawhorn, S. L. [East Carolina University; McLawhorn, R. A. [East Carolina University; Evans, N. L. [East Carolina University; Justiniano, E. L. B. [East Carolina University; Shinpaugh, J. L. [East Carolina University; Schultz, David Robert [ORNL; Reinhold, Carlos O [ORNL

    2006-11-01

    The use of heavy ion beams for microbeam studies of mammalian cell response leads to a need to better understand interaction cross sections for collisions of heavy ions with tissue constituents. For ion energies of a few MeV u-1 or less, ions capture electrons from the media in which they travel and undergo subsequent interactions as partially 'dressed' ions. For example, 16 MeV fluorine ions have an equilibrium charge of 7+, 32 MeV sulphur ions have an equilibrium charge of approx. 11+, and as the ion energies decrease the equilibrium charge decreases dramatically. Data for interactions of partially dressed ions are extremely rare, making it difficult to estimate microscopic patterns of energy deposition leading to damage to cellular components. Such estimates, normally obtained by Monte Carlo track structure simulations, require a comprehensive database of differential and total ionisation cross sections as well as charge transfer cross sections. To provide information for track simulation, measurement of total ionisation cross sections have been initiated at East Carolina University using the recoil ion time-of-flight method that also yields cross sections for multiple ionisation processes and charge transfer cross sections; multiple ionisation is prevalent for heavy ion interactions. In addition, measurements of differential ionisation cross sections needed for Monte Carlo simulation of detailed event-by-event particle tracks are under way. Differential, total and multiple ionisation cross sections and electron capture and loss cross sections measured for C+ ions with energies of 100 and 200 keV u-1 are described.

  16. Charge transfer and ionisation by intermediate-energy heavy ions.

    Science.gov (United States)

    Toburen, L H; McLawhorn, S L; McLawhorn, R A; Evans, N L; Justiniano, E L B; Shinpaugh, J L; Schultz, D R; Reinhold, C O

    2006-01-01

    The use of heavy ion beams for microbeam studies of mammalian cell response leads to a need to better understand interaction cross sections for collisions of heavy ions with tissue constituents. For ion energies of a few MeV u(-1) or less, ions capture electrons from the media in which they travel and undergo subsequent interactions as partially 'dressed' ions. For example, 16 MeV fluorine ions have an equilibrium charge of 7(+), 32 MeV sulphur ions have an equilibrium charge of approximately 11(+), and as the ion energies decrease the equilibrium charge decreases dramatically. Data for interactions of partially dressed ions are extremely rare, making it difficult to estimate microscopic patterns of energy deposition leading to damage to cellular components. Such estimates, normally obtained by Monte Carlo track structure simulations, require a comprehensive database of differential and total ionisation cross sections as well as charge transfer cross sections. To provide information for track simulation, measurement of total ionisation cross sections have been initiated at East Carolina University using the recoil ion time-of-flight method that also yields cross sections for multiple ionisation processes and charge transfer cross sections; multiple ionisation is prevalent for heavy ion interactions. In addition, measurements of differential ionisation cross sections needed for Monte Carlo simulation of detailed event-by-event particle tracks are under way. Differential, total and multiple ionisation cross sections and electron capture and loss cross sections measured for C(+) ions with energies of 100 and 200 keV u(-1) are described.

  17. Charge-transfer spectra of tetravalent lanthanide ions in oxides

    NARCIS (Netherlands)

    Hoefdraad, H.E.

    1975-01-01

    The charge-transfer spectra of Ce4+, Pr4+ and Tb4+ in a number of oxides are reported. It is noted that the position of the first charge-transfer band is fixed for the metal ion in an oxygen coordination of VI, but varies in VIII coordination as a function of the host lattice. It is argued that this

  18. Collision phenomena involving highly-charged ions in astronomical objects

    Science.gov (United States)

    Chutjian, A.

    2001-01-01

    A description of the role of highly charged ions in various astronomical objects; includes the use of critical quantities such as cross sections for excitation, charge-exchange, X-ray emission, radiative recombination (RR) and dielectronic recombination (DR); and lifetimes, branching ratios, and A-values.

  19. A vacuum spark ion source: High charge state metal ion beams

    Science.gov (United States)

    Yushkov, G. Yu.; Nikolaev, A. G.; Oks, E. M.; Frolova, V. P.

    2016-02-01

    High ion charge state is often important in ion beam physics, among other reasons for the very practical purpose that it leads to proportionately higher ion beam energy for fixed accelerating voltage. The ion charge state of metal ion beams can be increased by replacing a vacuum arc ion source by a vacuum spark ion source. Since the voltage between anode and cathode remains high in a spark discharge compared to the vacuum arc, higher metal ion charge states are generated which can then be extracted as an ion beam. The use of a spark of pulse duration less than 10 μs and with current up to 10 kA allows the production of ion beams with current of several amperes at a pulse repetition rate of up to 5 pps. We have demonstrated the formation of high charge state heavy ions (bismuth) of up to 15 + and a mean ion charge state of more than 10 +. The physics and techniques of our vacuum spark ion source are described.

  20. A vacuum spark ion source: High charge state metal ion beams

    Energy Technology Data Exchange (ETDEWEB)

    Yushkov, G. Yu., E-mail: gyushkov@mail.ru; Nikolaev, A. G.; Frolova, V. P. [High Current Electronics Institute, Siberian Branch of the Russian Academy of Science, Tomsk 634055 (Russian Federation); Oks, E. M. [High Current Electronics Institute, Siberian Branch of the Russian Academy of Science, Tomsk 634055 (Russian Federation); Tomsk State University of Control System and Radioelectronics, Tomsk 634050 (Russian Federation)

    2016-02-15

    High ion charge state is often important in ion beam physics, among other reasons for the very practical purpose that it leads to proportionately higher ion beam energy for fixed accelerating voltage. The ion charge state of metal ion beams can be increased by replacing a vacuum arc ion source by a vacuum spark ion source. Since the voltage between anode and cathode remains high in a spark discharge compared to the vacuum arc, higher metal ion charge states are generated which can then be extracted as an ion beam. The use of a spark of pulse duration less than 10 μs and with current up to 10 kA allows the production of ion beams with current of several amperes at a pulse repetition rate of up to 5 pps. We have demonstrated the formation of high charge state heavy ions (bismuth) of up to 15 + and a mean ion charge state of more than 10 +. The physics and techniques of our vacuum spark ion source are described.

  1. A compact source for bunches of singly charged atomic ions

    Science.gov (United States)

    Murböck, T.; Schmidt, S.; Andelkovic, Z.; Birkl, G.; Nörtershäuser, W.; Vogel, M.

    2016-04-01

    We have built, operated, and characterized a compact ion source for low-energy bunches of singly charged atomic ions in a vacuum beam line. It is based on atomic evaporation from an electrically heated oven and ionization by electron impact from a heated filament inside a grid-based ionization volume. An adjacent electrode arrangement is used for ion extraction and focusing by applying positive high-voltage pulses to the grid. The method is particularly suited for experimental environments which require low electromagnetic noise. It has proven simple yet reliable and has been used to produce μs-bunches of up to 106 Mg+ ions at a repetition rate of 1 Hz. We present the concept, setup and characterizing measurements. The instrument has been operated in the framework of the SpecTrap experiment at the HITRAP facility at GSI/FAIR to provide Mg+ ions for sympathetic cooling of highly charged ions by laser-cooled 24Mg+.

  2. Cryogenic linear Paul trap for cold highly charged ion experiments.

    Science.gov (United States)

    Schwarz, M; Versolato, O O; Windberger, A; Brunner, F R; Ballance, T; Eberle, S N; Ullrich, J; Schmidt, P O; Hansen, A K; Gingell, A D; Drewsen, M; López-Urrutia, J R Crespo

    2012-08-01

    Storage and cooling of highly charged ions require ultra-high vacuum levels obtainable by means of cryogenic methods. We have developed a linear Paul trap operating at 4 K capable of very long ion storage times of about 30 h. A conservative upper bound of the H(2) partial pressure of about 10(-15) mbar (at 4 K) is obtained from this. External ion injection is possible and optimized optical access for lasers is provided, while exposure to black body radiation is minimized. First results of its operation with atomic and molecular ions are presented. An all-solid state laser system at 313 nm has been set up to provide cold Be(+) ions for sympathetic cooling of highly charged ions.

  3. Charge-state-dependent energy loss of slow ions. I. Experimental results on the transmission of highly charged ions

    Science.gov (United States)

    Wilhelm, Richard A.; Gruber, Elisabeth; Smejkal, Valerie; Facsko, Stefan; Aumayr, Friedrich

    2016-05-01

    We report on energy loss measurements of slow (v ≪v0 ), highly charged (Q >10 ) ions upon transmission through a 1-nm-thick carbon nanomembrane. We emphasize here the scaling of the energy loss with the velocity and charge exchange or loss. We show that a weak linear velocity dependence exists, whereas charge exchange dominates the kinetic energy loss, especially in the case of a large charge capture. A universal scaling of the energy loss with the charge exchange and velocity is found and discussed in this paper. A model for charge-state-dependent energy loss for slow ions is presented in paper II in this series [R. A. Wilhelm and W. Möller, Phys. Rev. A 93, 052709 (2016), 10.1103/PhysRevA.93.052709].

  4. Stopping power of charged particles due to ion wave excitations

    Science.gov (United States)

    Nitta, H.; Muroki, C.; Nambu, M.

    2002-08-01

    Stopping power due to ion wave excitations is derived for a charged particle moving in a two-component plasma. Unlike previous theories based on ion-acoustic-wave approximation (IAWA), the excitation of short-wavelength ion waves is taken into account. The obtained stopping power has a magnitude larger than that of IAWA. Stopping power at subsonic velocities, where stopping power in IAWA disappears, is even larger than that of supersonic velocities.

  5. Stopping power of charged particles due to ion wave excitations.

    Science.gov (United States)

    Nitta, H; Muroki, C; Nambu, M

    2002-08-01

    Stopping power due to ion wave excitations is derived for a charged particle moving in a two-component plasma. Unlike previous theories based on ion-acoustic-wave approximation (IAWA), the excitation of short-wavelength ion waves is taken into account. The obtained stopping power has a magnitude larger than that of IAWA. Stopping power at subsonic velocities, where stopping power in IAWA disappears, is even larger than that of supersonic velocities.

  6. Production of High-Intensity, Highly Charged Ions

    OpenAIRE

    S. GamminoINFN, LNS, Catania

    2014-01-01

    In the past three decades, the development of nuclear physics facilities for fundamental and applied science purposes has required an increasing current of multicharged ion beams. Multiple ionization implies the formation of dense and energetic plasmas, which, in turn, requires specific plasma trapping configurations. Two types of ion source have been able to produce very high charge states in a reliable and reproducible way: electron beam ion sources (EBIS) and electron cyc...

  7. Reducing Space Charge Effects in a Linear Ion Trap by Rhombic Ion Excitation and Ejection

    Science.gov (United States)

    Zhang, Xiaohua; Wang, Yuzhuo; Hu, Lili; Guo, Dan; Fang, Xiang; Zhou, Mingfei; Xu, Wei

    2016-07-01

    Space charge effects play important roles in ion trap operations, which typically limit the ion trapping capacity, dynamic range, mass accuracy, and resolving power of a quadrupole ion trap. In this study, a rhombic ion excitation and ejection method was proposed to minimize space charge effects in a linear ion trap. Instead of applying a single dipolar AC excitation signal, two dipolar AC excitation signals with the same frequency and amplitude but 90° phase difference were applied in the x- and y-directions of the linear ion trap, respectively. As a result, mass selective excited ions would circle around the ion cloud located at the center of the ion trap, rather than go through the ion cloud. In this work, excited ions were then axially ejected and detected, but this rhombic ion excitation method could also be applied to linear ion traps with ion radial ejection capabilities. Experiments show that space charge induced mass resolution degradation and mass shift could be alleviated with this method. For the experimental conditions in this work, space charge induced mass shift could be decreased by ~50%, and the mass resolving power could be improved by ~2 times at the same time.

  8. Characterization of the internal ion environment of biofilms based on charge density and shape of ion.

    Science.gov (United States)

    Kurniawan, Andi; Tsuchiya, Yuki; Eda, Shima; Morisaki, Hisao

    2015-12-01

    Biofilm polymers contain both electrically positively and negatively charged sites. These charged sites enable the biofilm to trap and retain ions leading to an important role of biofilm such as nutrient recycling and pollutant purification. Much work has focused on the ion-exchange capacity of biofilms, and they are known to adsorb ions through an exchange mechanism between the ions in solution and the ions adsorbed to the charged sites on the biofilm polymer. However, recent studies suggest that the adsorption/desorption behavior of ions in a biofilm cannot be explained solely by this ion exchange mechanism. To examine the possibility that a substantial amount of ions are held in the interstitial region of the biofilm polymer by an electrostatic interaction, intact biofilms formed in a natural environment were immersed in distilled water and ion desorption was investigated. All of the detected ion species were released from the biofilms over a short period of time, and very few ions were subsequently released over more time, indicating that the interstitial region of biofilm polymers is another ion reserve. The extent of ion retention in the interstitial region of biofilms for each ion can be determined largely by charge density, |Z|/r, where |Z| is the ion valence as absolute value and r is the ion radius. The higher |Z|/r value an ion has, the stronger it is retained in the interstitial region of biofilms. Ion shape is also a key determinant of ion retention. Spherical and non-spherical ions have different correlations between the condensation ratio and |Z|/r. The generality of these findings were assured by various biofilm samples. Thus, the internal regions of biofilms exchange ions dynamically with the outside environment.

  9. Measurement of Metastable Lifetimes of Highly-Charged Ions

    Science.gov (United States)

    Smith, Steven J.; Chutjian, A.; Lozano, J.

    2002-01-01

    The present work is part of a series of measurements of metastable lifetimes of highly-charged ions (HCIs) which contribute to optical absorption, emission and energy balance in the Interstellar Medium (ISM), stellar atmospheres, etc. Measurements were carried out using the 14-GHz electron cyclotron resonance ion source (ECRIS) at the JPL HCI facility. The ECR provides useful currents of charge states such as C(sup(1-6)+), Mg(sup(1-6)+) and Fe(sup(1-17)+). In this work the HCI beam is focused into a Kingdon electrostatic ion trap for measuring lifetimes via optical decays.

  10. Solar photovoltaic charging of lithium-ion batteries

    Science.gov (United States)

    Gibson, Thomas L.; Kelly, Nelson A.

    Solar photovoltaic (PV) charging of batteries was tested by using high efficiency crystalline and amorphous silicon PV modules to recharge lithium-ion battery modules. This testing was performed as a proof of concept for solar PV charging of batteries for electrically powered vehicles. The iron phosphate type lithium-ion batteries were safely charged to their maximum capacity and the thermal hazards associated with overcharging were avoided by the self-regulating design of the solar charging system. The solar energy to battery charge conversion efficiency reached 14.5%, including a PV system efficiency of nearly 15%, and a battery charging efficiency of approximately 100%. This high system efficiency was achieved by directly charging the battery from the PV system with no intervening electronics, and matching the PV maximum power point voltage to the battery charging voltage at the desired maximum state of charge for the battery. It is envisioned that individual homeowners could charge electric and extended-range electric vehicles from residential, roof-mounted solar arrays, and thus power their daily commuting with clean, renewable solar energy.

  11. Charge exchange and energy loss of slow highly charged ions in 1 nm thick carbon nanomembranes.

    Science.gov (United States)

    Wilhelm, Richard A; Gruber, Elisabeth; Ritter, Robert; Heller, René; Facsko, Stefan; Aumayr, Friedrich

    2014-04-18

    Experimental charge exchange and energy loss data for the transmission of slow highly charged Xe ions through ultrathin polymeric carbon membranes are presented. Surprisingly, two distinct exit charge state distributions accompanied by charge exchange dependent energy losses are observed. The energy loss for ions exhibiting large charge loss shows a quadratic dependency on the incident charge state indicating that equilibrium stopping force values do not apply in this case. Additional angle resolved transmission measurements point on a significant contribution of elastic energy loss. The observations show that regimes of different impact parameters can be separated and thus a particle's energy deposition in an ultrathin solid target may not be described in terms of an averaged energy loss per unit length.

  12. Guided-Ion-Beam and ab Initio Study of the Li+, K+, and Rb+ Association Reactions with Gas-Phase Butanone and Cyclohexanone in Their Ground Electronic States

    Science.gov (United States)

    Lucas, J. M.; de Andrés, J.; López, E.; Albertí, M.; Bofill, J. M.; Bassi, D.; Ascenzi, D.; Tosi, P.; Aguilar, A.

    2009-08-01

    The association reactions between Li+, K+, and Rb+ (M) and butanone and cyclohexanone molecules under single collision conditions have been studied using a radiofrequency-guided ion-beam apparatus, characterizing the adducts by mass spectrometry. The excitation function for the [M-(molecule)]+ adducts (in arbitrary units) has been obtained at low collision energies in the 0.10 eV up to a few eV range in the center of mass frame. The measured relative cross sections decrease when collision energy increases, showing the expected energy dependence for adduct formation. The energetics and structure of the different adducts have been calculated ab initio at the MP2(full) level, showing that the M+-molecule interaction takes place through the carbonyl oxygen atom, as an example of a nontypical covalent chemical bond. The cross-section energy dependence and the role of radiative cooling rates allowing the stabilization of the collision complexes are also discussed.

  13. Absolute cross sections for charge capture from Rydberg targets by slow highly charged ions

    Energy Technology Data Exchange (ETDEWEB)

    DePaola, B.D.; Huang, M.; Winecki, S.; Stoeckli, M.P.; Kanai, Y. [J. R. Macdonald Laboratory, Kansas State University, Manhattan, Kansas 66506 (United States); Lundeen, S.R.; Fehrenbach, C.W.; Arko, S.A. [Department of Physics, Colorado State University, Fort Collins, Colorado 80523 (United States)

    1995-09-01

    A crossed beam experiment has been used to measure absolute charge capture cross sections in collisions of slow highly charged xenon ions with laser excited Rydberg atoms. The cross sections were measured for scaled projectile velocities {ital nv}{sub {ital p}} from 1.0 to 6.0, for projectile charges of 8, 16, 32, and 40, where {ital n} is the principal quantum number of the target electron. Experimental cross sections are compared with predictions of classical models.

  14. Gas-Phase Analysis of the Complex of Fibroblast GrowthFactor 1 with Heparan Sulfate: A Traveling Wave Ion Mobility Spectrometry (TWIMS) and Molecular Modeling Study

    Science.gov (United States)

    Zhao, Yuejie; Singh, Arunima; Xu, Yongmei; Zong, Chengli; Zhang, Fuming; Boons, Geert-Jan; Liu, Jian; Linhardt, Robert J.; Woods, Robert J.; Amster, I. Jonathan

    2016-09-01

    Fibroblast growth factors (FGFs) regulate several cellular developmental processes by interacting with cell surface heparan proteoglycans and transmembrane cell surface receptors (FGFR). The interaction of FGF with heparan sulfate (HS) is known to induce protein oligomerization, increase the affinity of FGF towards its receptor FGFR, promoting the formation of the HS-FGF-FGFR signaling complex. Although the role of HS in the signaling pathways is well recognized, the details of FGF oligomerization and formation of the ternary signaling complex are still not clear, with several conflicting models proposed in literature. Here, we examine the effect of size and sulfation pattern of HS upon FGF1 oligomerization, binding stoichiometry and conformational stability, through a combination of ion mobility (IM) and theoretical modeling approaches. Ion mobility-mass spectrometry (IMMS) of FGF1 in the presence of several HS fragments ranging from tetrasaccharide (dp4) to dodecasaccharide (dp12) in length was performed. A comparison of the binding stoichiometry of variably sulfated dp4 HS to FGF1 confirmed the significance of the previously known high-affinity binding motif in FGF1 dimerization, and demonstrated that certain tetrasaccharide-length fragments are also capable of inducing dimerization of FGF1. The degree of oligomerization was found to increase in the presence of dp12 HS, and a general lack of specificity for longer HS was observed. Additionally, collision cross-sections (CCSs) of several FGF1-HS complexes were calculated, and were found to be in close agreement with experimental results. Based on the (CCSs) a number of plausible binding modes of 2:1 and 3:1 FGF1-HS are proposed.

  15. Gas-Phase Analysis of the Complex of Fibroblast GrowthFactor 1 with Heparan Sulfate: A Traveling Wave Ion Mobility Spectrometry (TWIMS) and Molecular Modeling Study

    Science.gov (United States)

    Zhao, Yuejie; Singh, Arunima; Xu, Yongmei; Zong, Chengli; Zhang, Fuming; Boons, Geert-Jan; Liu, Jian; Linhardt, Robert J.; Woods, Robert J.; Amster, I. Jonathan

    2017-01-01

    Fibroblast growth factors (FGFs) regulate several cellular developmental processes by interacting with cell surface heparan proteoglycans and transmembrane cell surface receptors (FGFR). The interaction of FGF with heparan sulfate (HS) is known to induce protein oligomerization, increase the affinity of FGF towards its receptor FGFR, promoting the formation of the HS-FGF-FGFR signaling complex. Although the role of HS in the signaling pathways is well recognized, the details of FGF oligomerization and formation of the ternary signaling complex are still not clear, with several conflicting models proposed in literature. Here, we examine the effect of size and sulfation pattern of HS upon FGF1 oligomerization, binding stoichiometry and conformational stability, through a combination of ion mobility (IM) and theoretical modeling approaches. Ion mobility-mass spectrometry (IMMS) of FGF1 in the presence of several HS fragments ranging from tetrasaccharide (dp4) to dodecasaccharide (dp12) in length was performed. A comparison of the binding stoichiometry of variably sulfated dp4 HS to FGF1 confirmed the significance of the previously known high-affinity binding motif in FGF1 dimerization, and demonstrated that certain tetrasaccharide-length fragments are also capable of inducing dimerization of FGF1. The degree of oligomerization was found to increase in the presence of dp12 HS, and a general lack of specificity for longer HS was observed. Additionally, collision cross-sections (CCSs) of several FGF1-HS complexes were calculated, and were found to be in close agreement with experimental results. Based on the (CCSs) a number of plausible binding modes of 2:1 and 3:1 FGF1-HS are proposed.

  16. Adsorption of Potassium and Calcium Ions by Variable Charge Soils

    Institute of Scientific and Technical Information of China (English)

    LIHONG-YAN; JIGUO-LIANG

    1992-01-01

    Interactions of potassium and calcium ions with four typical variable charge soils in South China were examined by measuring pK-0.5pCa value with a potassium ion-selective electrode and a calcium ion-selective electrode,and pK value with a potassium ion-selective electrode.The results showed that adsorption of potassium and calcium ions increased with soil suspension pH,and the tendency of the pK-0.5pCa value changing with pH differed with respect to pH range and potassium to calcium ratio.Adsorption of equal amount of calcium and potassium ions led to release of an identical number of protons,suggesting similar adsorption characteristics of these two ions when adsorbed by variable charge soils.Compared with red soil,latosol and lateritic red soil had higher adsorption selectivities for calcium ion.The red soil had a greater affinity for potassium ion than that for calcium ion at low concentration,which seems to result from its possession of 2:1 type minerals,such as vermiculite and mica with a high affinity for potassium ion.The results indicated that adsorption of potassium and calcium ions by the variable charge soils was chiefly caused by the electrostatic attraction between the cations and the soil surfaces.Moreover,it was found that sulfate could affect the adsorption by changing soil surface properties and by forming ion-pair.

  17. A New Technique for Diagnosing Multi-charged Ion Beams Produced by ECR Ion Source

    Institute of Scientific and Technical Information of China (English)

    ZhangZimin; ZhaoHongwei; CaoYun; MaLei; MaBaohua; LiJinyu; WangHui; FengYucheng; DuJunfeng

    2003-01-01

    In order to study the transmission properties of multi-charged ion beams between the ECR ion source and the analyzing magnet, a new diagnostic system composed of three Wien-filters with three single-wires has been built and installed on the IMP ECR source test bcnch. The single-wire is used to measure the beam profile and the beam density distribution, and the Wien-filter is used to measure the charge state distribution of ion beam.

  18. Low-energy state-selective charge transfer by multiply charged ions

    NARCIS (Netherlands)

    Lubinski, G; Juhasz, Z; Morgenstern, R; Hoekstra, R

    2001-01-01

    We present a combined rf-guided ion beam and photon emission spectroscopy method, which facilitates state-selective charge-transfer measurements at energies of direct relevance for astrophysics and fusion-plasma diagnostics and modeling. Ion energies have been varied from 1000 eV/amu down to energie

  19. Adsorption of Potassium and Sodium Ions by Variable Charge Soils

    Institute of Scientific and Technical Information of China (English)

    LIHONG-YAN; JIGUO-LIANG

    1992-01-01

    Adsorption of potassium and sodium ions by four typical variable charge soils of South China was studied.The results indicated that the variable charge soils saturated with H and Al showed a much higher preference for potassium ions relative to sodium ions,and this tendence could not be changed by such factors as the pH,the concentration of the cations,the dielectric constant of solvent,the accompanying anions and the iron oxide content etc.,suggesting that this difference in affinity is caused by the difference in the nature of the two cations.It was observed that a negative adsorption of sodium ions by latosol and lateritic red soil in a mixed system containing equal amount of potassium and sodium ions at low pH,which is caused by a competitive adsorption of potassium and sodium ions and repulsion of positive charge on the surfaces of soil particles for cations.The adsorption of potassium and sodium ions increased with the decreases in the dielectric constant of solvent and the iron oxide content.Sulfate affected the adsorption of potassium and sodium ions through changing the surface properties of the soils.

  20. Study on space charge compensation in negative hydrogen ion beam.

    Science.gov (United States)

    Zhang, A L; Peng, S X; Ren, H T; Zhang, T; Zhang, J F; Xu, Y; Guo, Z Y; Chen, J E

    2016-02-01

    Negative hydrogen ion beam can be compensated by the trapping of ions into the beam potential. When the beam propagates through a neutral gas, these ions arise due to gas ionization by the beam ions. However, the high neutral gas pressure may cause serious negative hydrogen ion beam loss, while low neutral gas pressure may lead to ion-ion instability and decompensation. To better understand the space charge compensation processes within a negative hydrogen beam, experimental study and numerical simulation were carried out at Peking University (PKU). The simulation code for negative hydrogen ion beam is improved from a 2D particle-in-cell-Monte Carlo collision code which has been successfully applied to H(+) beam compensated with Ar gas. Impacts among ions, electrons, and neutral gases in negative hydrogen beam compensation processes are carefully treated. The results of the beam simulations were compared with current and emittance measurements of an H(-) beam from a 2.45 GHz microwave driven H(-) ion source in PKU. Compensation gas was injected directly into the beam transport region to modify the space charge compensation degree. The experimental results were in good agreement with the simulation results.

  1. Study on space charge compensation in negative hydrogen ion beam

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, A. L.; Chen, J. E. [University of Chinese Academy of Sciences, Beijing 100049 (China); State Key Laboratory of Nuclear Physics and Technology, Institute of Heavy Ion Physics, School of Physics, Peking University, Beijing 100871 (China); Peng, S. X., E-mail: sxpeng@pku.edu.cn; Ren, H. T.; Zhang, T.; Zhang, J. F.; Xu, Y.; Guo, Z. Y. [State Key Laboratory of Nuclear Physics and Technology, Institute of Heavy Ion Physics, School of Physics, Peking University, Beijing 100871 (China)

    2016-02-15

    Negative hydrogen ion beam can be compensated by the trapping of ions into the beam potential. When the beam propagates through a neutral gas, these ions arise due to gas ionization by the beam ions. However, the high neutral gas pressure may cause serious negative hydrogen ion beam loss, while low neutral gas pressure may lead to ion-ion instability and decompensation. To better understand the space charge compensation processes within a negative hydrogen beam, experimental study and numerical simulation were carried out at Peking University (PKU). The simulation code for negative hydrogen ion beam is improved from a 2D particle-in-cell-Monte Carlo collision code which has been successfully applied to H{sup +} beam compensated with Ar gas. Impacts among ions, electrons, and neutral gases in negative hydrogen beam compensation processes are carefully treated. The results of the beam simulations were compared with current and emittance measurements of an H{sup −} beam from a 2.45 GHz microwave driven H{sup −} ion source in PKU. Compensation gas was injected directly into the beam transport region to modify the space charge compensation degree. The experimental results were in good agreement with the simulation results.

  2. Charge state distribution analysis of Al and Pb ions from the laser ion source at IMP

    CERN Document Server

    Shan, Sha; Zhang-Min, Li; Xiao-Hong, Guo; Lun-Cai, Zhou; Guo-Zhu, Cai; Liang-ting, Sun; Xue-Zhen, Zhang; Huan-Yu, Zhao; Xi-Meng, Chen; Hong-Wei, Zhao

    2013-01-01

    A prototype laser ion source that could demonstrate the possibility of producing intense pulsed high charge state ion beams has been established with a commercial Nd:YAG laser (E max = 3 J, 1064 nm, 8-10 ns) to produce laser plasma for the research of Laser Ion Source (LIS). At the laser ion source test bench, high purity (99.998 %) aluminum and lead targets have been tested for laser plasma experiment. An Electrostatic Ion Analyzer (EIA) and Electron Multiply Tube (EMT) detector were used to analyze the charge state and energy distribution of the ions produced by the laser ion source. The maximum charge states of Al12+ and Pb7+ were achieved. The results will be presented and discussed in this paper.

  3. Synthesis of carbon nanotubes by plasma-enhanced CVD process: gas phase study of synthesis conditions

    OpenAIRE

    Guláš, Michal; Cojocaru, Costel Sorin; Fleaca, Claudiu; Farhat, Samir; Veis, Pavel; Le Normand, Francois

    2008-01-01

    International audience; To support experimental investigations, a model based on ChemkinTM software was used to simulate gas phase and surface chemistry during plasma-enhanced catalytic CVD of carbon nanotubes. According to these calculations, gas phase composition, etching process and growth rates are calculated. The role of several carbon species, hydrocarbon molecules and ions in the growth mechanism of carbon nanotubes is presented in this study. Study of different conditions of gas phase ...

  4. Synthesis of carbon nanbotubes by plasma-enhanced CVD process: gas phase study of synthesis conditions

    Science.gov (United States)

    Guláš, M.; Cojocaru, C. S.; Fleaca, C. T.; Farhat, S.; Veis, P.; Le Normand, F.

    2008-09-01

    To support experimental investigations, a model based on Chemkin^TM software was used to simulate gas phase and surface chemistry during plasma-enhanced catalytic CVD of carbon nanotubes. According to these calculations, gas phase composition, etching process and growth rates are calculated. The role of several carbon species, hydrocarbon molecules and ions in the growth mechanism of carbon nanotubes is presented in this study. Study of different conditions of gas phase activation sources and pressure is performed.

  5. Atomic physics with highly charged ions

    Energy Technology Data Exchange (ETDEWEB)

    Richard, P.

    1991-08-01

    This report discusses: One electron outer shell processes in fast ion-atom collisions; role of electron-electron interaction in two-electron processes; multi-electron processes at low energy; multi-electron processes at high energy; inner shell processes; molecular fragmentation studies; theory; and, JRM laboratory operations.

  6. High Intensity High Charge State ECR Ion Sources

    CERN Document Server

    Leitner, Daniela

    2005-01-01

    The next-generation heavy ion beam accelerators such as the proposed Rare Isotope Accelerator (RIA), the Radioactive Ion Beam Factory at RIKEN, the GSI upgrade project, the LHC-upgrade, and IMP in Lanzhou require a great variety of high charge state ion beams with a magnitude higher beam intensity than currently achievable. High performance Electron Cyclotron Resonance (ECR) ion sources can provide the flexibility since they can routinely produce beams from hydrogen to uranium. Over the last three decades, ECR ion sources have continued improving the available ion beam intensities by increasing the magnetic fields and ECR heating frequencies to enhance the confinement and the plasma density. With advances in superconducting magnet technology, a new generation of high field superconducting sources is now emerging, designed to meet the requirements of these next generation accelerator projects. The talk will briefly review the field of high performance ECR ion sources and the latest developments for high intens...

  7. Gas-phase spectroscopy of ferric heme-NO complexes

    DEFF Research Database (Denmark)

    Wyer, J.A.; Jørgensen, Anders; Pedersen, Bjarke;

    2013-01-01

    Weakly bound complexes between ferric heme cations and NO were synthesised in the gas phase from ion-molecule reactions, and their absorption measured based on photodissociation yields. The Soret band, which serves as an important marker band for heme-protein spectroscopy, is maximal at 357±5 nm...

  8. Parity nonconservation in dielectronic recombination of multiply charged ions

    CERN Document Server

    Kozlov, M G; Currell, F J

    2007-01-01

    We discuss a parity nonconserving (PNC) asymmetry in the cross section of dielectronic recombination of polarized electrons on multiply charged ions with Z>40. This effect is strongly enhanced for close doubly-excited states of opposite parity in the intermediate compound ion. Such states are known for He-like ions. However, these levels have large energy and large radiative widths which hampers observation of the PNC asymmetry. We argue that accidentally degenerate states of the more complex ions may be more suitable for the corresponding experiment.

  9. Are ionic liquids pairwise in gas phase? A cluster approach and in situ IR study.

    Science.gov (United States)

    Dong, Kun; Zhao, Lidong; Wang, Qian; Song, Yuting; Zhang, Suojiang

    2013-04-28

    In this work, we discussed the vaporization and gas species of ionic liquids (ILs) by a cluster approach of quantum statistical thermodynamics proposed by R. Luwig (Phys. Chem. Chem. Phys., 10, 4333), which is a controversial issue up to date. Based on the different sized clusters (2-12 ion-pairs) of the condensed phase, the molar enthalpies of vaporization (ΔvapH, 298.15 K, 1bar) of four representative ILs, 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([Emim][NTf2]) 1-ethyl-2,3-dimethylimidazolium bis(trifluoromethylsulfonyl)imide ([Emmim][NTf2]) 1-ethyl-3-methylimidazolium chloride ([Emim]Cl) and ethylammonium nitrate ([EtAm][NO3]), were calculated. The predicted ΔvapH were increased remarkably; even the values of [EtAm][NO3] were larger than 700 kJ mol(-1) when the charged isolated ions were assumed to be gas species. However, the ΔvapH were close to experimental measurements when the gas species assumed to be anion-cation pairwise, indicating that the different conformational ion-pairs can coexist in the gas phase when the IL is evaporated. Particularly for the protic IL, [EtAm][NO3], even the neutral precursor molecules by proton transfer can occur in gas phase. In addition, it's found that the effect of hydrogen bonds on the vaporization cannot be negligible by comparing the ΔvapH of [Emim][NTf2] with [Emmim][NTf2]. The in situ and calculated IR spectra provided the further proof that the ions are pairwise in gas phase.

  10. Emission of ions and charged soot particles by aircraft engines

    Directory of Open Access Journals (Sweden)

    A. Sorokin

    2003-01-01

    Full Text Available In this article, a model which examines the formation and evolution of chemiions in an aircraft engine is proposed. This model which includes chemiionisation, electron thermo-emission, electron attachment to soot particles and to neutral molecules, electron-ion and ion-ion recombination, ion-soot interaction, allows the determination of the ion concentration at the exit of the combustor and at the nozzle exit of the engine. It also allows the determination of the charge of the soot particles. For the engine considered, the upper limit for the ion emission index EIi is of the order of (2-5 x1016 ions/kg-fuel if ion-soot interactions are ignored and the introduction of ion-soot interactions lead about to a 50% reduction. The results also show that most of the soot particles are either positively or negatively charged, the remaining neutral particles representing approximately 20% of the total particles. A comparison of the model results with the available ground-based experimental data obtained on the ATTAS research aircraft engines during the SULFUR experiments (Schumann, 2002 shows an excellent agreement.

  11. Electrochemical model based charge optimization for lithium-ion batteries

    Science.gov (United States)

    Pramanik, Sourav; Anwar, Sohel

    2016-05-01

    In this paper, we propose the design of a novel optimal strategy for charging the lithium-ion battery based on electrochemical battery model that is aimed at improved performance. A performance index that aims at minimizing the charging effort along with a minimum deviation from the rated maximum thresholds for cell temperature and charging current has been defined. The method proposed in this paper aims at achieving a faster charging rate while maintaining safe limits for various battery parameters. Safe operation of the battery is achieved by including the battery bulk temperature as a control component in the performance index which is of critical importance for electric vehicles. Another important aspect of the performance objective proposed here is the efficiency of the algorithm that would allow higher charging rates without compromising the internal electrochemical kinetics of the battery which would prevent abusive conditions, thereby improving the long term durability. A more realistic model, based on battery electro-chemistry has been used for the design of the optimal algorithm as opposed to the conventional equivalent circuit models. To solve the optimization problem, Pontryagins principle has been used which is very effective for constrained optimization problems with both state and input constraints. Simulation results show that the proposed optimal charging algorithm is capable of shortening the charging time of a lithium ion cell while maintaining the temperature constraint when compared with the standard constant current charging. The designed method also maintains the internal states within limits that can avoid abusive operating conditions.

  12. Reactive intermediates in the gas phase generation and monitoring

    CERN Document Server

    Setser, D W

    2013-01-01

    Reactive Intermediates in the Gas Phase: Generation and Monitoring covers methods for reactive intermediates in the gas phase. The book discusses the generation and measurement of atom and radical concentrations in flow systems; the high temperature flow tubes, generation and measurement of refractory species; and the electronically excited long-lived states of atoms and diatomic molecules in flow systems. The text also describes the production and detection of reactive species with lasers in static systems; the production of small positive ions in a mass spectrometer; and the discharge-excite

  13. Electrokinetic inversion of ion screening charges in nano-channels

    CERN Document Server

    Zhu, Xin; Ni, Sheng; Zhang, Xingye; Liu, Yang

    2016-01-01

    This work studies a counter-intuitive but basic process of ionic screening in nano-fluidic channels. Numerical simulations and perturbation analysis reveal that, under significant electrokinetic transport, the ion screening charges can be locally inverted in the channels: their charge sign becomes the same as that of the channel surface charges. The process is identified to originate from the coupling of longitudinal transport and junction electrostatics. This finding may revise the common understanding of ionic screening in nano-channels and indicates that their ion selectivity can be locally changed by transport. Furthermore, the charge inversion process results in a body force torque on channel fluids, which is a possible mechanism for vortex generation in the channels.

  14. Controlled charge exchange between alkaline earth metals and their ions

    Science.gov (United States)

    Gacesa, Marko; Côté, Robin

    2015-05-01

    We theoretically investigate the prospects of realizing controlled charge exchange via magnetic Feshbach resonances in cold and ultracold collisions of atoms and ions. In particular, we focus on near-resonant charge exchange in heteroisotopic combinations of alkaline earth metals, such as 9Be++10 Be9 Be+10Be+ , which exhibit favorable electronic and hyperfine structure. The quantum scattering calculations are performed for a range of initial states and experimentally attainable magnetic fields in standard coupled-channel Feshbach projection formalism, where higher-order corrections such as the mass-polarization term are explicitely included. In addition, we predict a number of magnetic Feshbach resonances for different heteronuclear isotopic combinations of the listed and related alkaline earth elements. Our results imply that near-resonant charge-exchange could be used to realize atom-ion quantum gates, as well as controlled charge transfer in optically trapped cold quantum gases. This work is partially supported by ARO.

  15. Gas-Phase Reactivity of Microsolvated Anions

    DEFF Research Database (Denmark)

    Thomsen, Ditte Linde

    intrinsic factors and solvent effects is the enhanced reactivity of α-nucleophiles – nucleophiles with a lone-pair adjacent to the attacking site – referred to as the α-effect. This thesis concerns the reactivity of microsolvated anions and in particular how the presence of a single solvent molecule affects...... the gas-phase α-effect. The experimental studies are performed by means of the flowing after glow selected ion flow tube technique, and these are supplemented by electronic structure calculations. The α-nucleophile employed is the microsolvated hydrogen peroxide anion whose reactivity is compared...... to that of a series of microsolvated oxygen centered anions. The association of the nucleophiles with a single water or methanol molecule allows the α-effect to be observed in the SN2 reaction with methyl chloride; this effect was not apparent in the reactions of the unsolvated anions. The results suggest...

  16. Charge Breeding and Production of Multiply Charged Ions in EBIS and ECRIS

    CERN Document Server

    Wenander, Frederik J C

    2001-01-01

    The REXEBIS is an Electron Beam Ion Source (EBIS) developed for charge breeding of the exotic and sometimes short-lived isotopes that are produced at ISOLDE for the REX-ISOLDE post accelerator. Bunches of singly charged radioactive ions are injected into the EBIS and charge bred to a charge-to-mass ratio of approximately ¼, and thereafter extracted and injected into a short 3-stage LINAC for acceleration to a few MeV/u. This novel concept, employing a Penning trap to bunch and cool the ions from an on-line mass separator in combination with a charge breeding EBIS, should result in an efficient and compact system. The REXEBIS is based on a 0.5 A electron beam produced in the fringe field of a magnetic solenoid, and compressed to a current density of >200 A/cm2. The 2 T magnetic field is provided by a warm-bore superconducting solenoid, thus giving easy accessibility but no cryogenic pumping. The EBIS is switched between 60 kV (ion injection) and ~20 kV (ion extraction). This thesis presents the design and con...

  17. Atomic physics with highly charged ions. Progress report

    Energy Technology Data Exchange (ETDEWEB)

    Richard, P.

    1994-08-01

    The study of inelastic collision phenomena with highly charged projectile ions and the interpretation of spectral features resulting from these collisions remain as the major focal points in the atomic physics research at the J.R. Macdonald Laboratory, Kansas State University, Manhattan, Kansas. The title of the research project, ``Atomic Physics with Highly Charged Ions,`` speaks to these points. The experimental work in the past few years has divided into collisions at high velocity using the primary beams from the tandem and LINAC accelerators and collisions at low velocity using the CRYEBIS facility. Theoretical calculations have been performed to accurately describe inelastic scattering processes of the one-electron and many-electron type, and to accurately predict atomic transition energies and intensities for x rays and Auger electrons. Brief research summaries are given for the following: (1) electron production in ion-atom collisions; (2) role of electron-electron interactions in two-electron processes; (3) multi-electron processes; (4) collisions with excited, aligned, Rydberg targets; (5) ion-ion collisions; (6) ion-molecule collisions; (7) ion-atom collision theory; and (8) ion-surface interactions.

  18. Atomic and molecular physics in the gas phase

    Energy Technology Data Exchange (ETDEWEB)

    Toburen, L.H.

    1990-09-01

    The spatial and temporal distributions of energy deposition by high-linear-energy-transfer radiation play an important role in the subsequent chemical and biological processes leading to radiation damage. Because the spatial structures of energy deposition events are of the same dimensions as molecular structures in the mammalian cell, direct measurements of energy deposition distributions appropriate to radiation biology are infeasible. This has led to the development of models of energy transport based on a knowledge of atomic and molecular interactions process that enable one to simulate energy transfer on an atomic scale. Such models require a detailed understanding of the interactions of ions and electrons with biologically relevant material. During the past 20 years there has been a great deal of progress in our understanding of these interactions; much of it coming from studies in the gas phase. These studies provide information on the systematics of interaction cross sections leading to a knowledge of the regions of energy deposition where molecular and phase effects are important and that guide developments in appropriate theory. In this report studies of the doubly differential cross sections, crucial to the development of stochastic energy deposition calculations and track structure simulation, will be reviewed. Areas of understanding are discussed and directions for future work addressed. Particular attention is given to experimental and theoretical findings that have changed the traditional view of secondary electron production for charged particle interactions with atomic and molecular targets.

  19. High-Intensity, High Charge-State Heavy Ion Sources

    CERN Document Server

    Alessi, J

    2004-01-01

    There are many accelerator applications for high intensity heavy ion sources, with recent needs including dc beams for RIA, and pulsed beams for injection into synchrotrons such as RHIC and LHC. The present status of sources producing high currents of high charge state heavy ions will be reviewed. These sources include ECR, EBIS, and Laser ion sources. The benefits and limitations for these type sources will be described, for both dc and pulsed applications. Possible future improvements in these type sources will also be discussed.

  20. Chemical ionization mass spectrometry (CIMS may not measure all gas-phase sulfuric acid if base molecules are present

    Directory of Open Access Journals (Sweden)

    T. Kurtén

    2010-12-01

    Full Text Available The state-of-the art method for measuring atmospheric gas-phase sulfuric acid is chemical ionization mass spectrometry (CIMS based on nitrate reagent ions. Using computed proton affinities and reaction thermodynamics for the relevant charging reactions, we show that in the presence of strong bases such as amines, which tend to cluster with the sulfuric acid molecules, a significant fraction of the total gas-phase sulfuric acid may not be measured by a CIMS instrument. If this is the case, this effect has to be taken into account in the interpretation of atmospheric sulfuric acid measurement data, as well as in intercomparison of different CIMS instruments, which likely have different susceptibilities to amine-sulfuric acid clustering.

  1. Electron impact ionization of highly charged lithiumlike ions

    Energy Technology Data Exchange (ETDEWEB)

    Wong, K L

    1992-10-01

    Electron impact ionization cross sections can provide valuable information about the charge-state and power balance of highly charged ions in laboratory and astrophysical plasmas. In the present work, a novel technique based on x-ray measurements has been used to infer the ionization cross section of highly charged lithiumlike ions on the Livermore electron beam ion trap. In particular, a correspondence is established between an observed x ray and an ionization event. The measurements are made at one energy corresponding to approximately 2.3 times the threshold energy for ionization of lithiumlike ions. The technique is applied to the transition metals between Z=22 (titanium, Ti[sup 19+]) and Z=26 (iron, Fe[sup 23+]) and to Z=56 (barium, Ba[sup 53+]). The results for the transition metals, which have an estimated 17-33% uncertainty, are in good overall agreement with a relativistic distorted-wave calculation. However, less good agreement is found for barium, which has a larger uncertainty. Methods for properly accounting for the polarization in the x-ray intensities and for inferring the charge-state abundances from x-ray observations, which were developed for the ionization measurements, as well as an x-ray model that assists in the proper interpretation of the data are also presented.

  2. Electron dynamics at surfaces induced by highly charged ions

    NARCIS (Netherlands)

    Morgenstern, R

    1998-01-01

    Energy spectra of electrons resulting from hydrogen-like multiply charged N6+ and Q(7+) ions on various surfaces are presented and discussed. Por metal target surfaces thr formation and decay of hollow atoms during the approach towards the surface is rather well understood in terms of the classical

  3. Review of highly charged heavy ion production with electron cyclotron resonance ion source (invited)

    Science.gov (United States)

    Nakagawa, T.

    2014-02-01

    The electron cyclotron resonance ion source (ECRIS) plays an important role in the advancement of heavy ion accelerators and other ion beam applications worldwide, thanks to its remarkable ability to produce a great variety of intense highly charged heavy ion beams. Great efforts over the past decade have led to significant ECRIS performance improvements in both the beam intensity and quality. A number of high-performance ECRISs have been built and are in daily operation or are under construction to meet the continuously increasing demand. In addition, comprehension of the detailed and complex physical processes in high-charge-state ECR plasmas has been enhanced experimentally and theoretically. This review covers and discusses the key components, leading-edge developments, and enhanced ECRIS performance in the production of highly charged heavy ion beams.

  4. Emission of ions and charged soot particles by aircraft engines

    Directory of Open Access Journals (Sweden)

    A. Sorokin

    2002-11-01

    Full Text Available In this article, a model which examines the formation and evolution of chemiions in an aircraft engine is proposed. This model which includes chemiionisation, electron thermo-emission, electron attachment to soot particles and to neutral molecules, electron-ion and ion-ion recombination, ion-soot interaction, allows the determination of the ion concentration at the exit of the combustor and at the nozzle exit of the engine. It also allows the determination of the charge of the soot particles. A comparison of the model results with the available ground-based experimental data obtained on the ATTAS research aircraft engines during the SULFUR experiments (Schumann, 2002 shows an excellent agreement.

  5. [Probabilistic calculations of biomolecule charge states that generate mass spectra of multiply charged ions].

    Science.gov (United States)

    Raznikova, M O; Raznikov, V V

    2015-01-01

    In this work, information relating to charge states of biomolecule ions in solution obtained using the electrospray ionization mass spectrometry of different biopolymers is analyzed. The data analyses have mainly been carried out by solving an inverse problem of calculating the probabilities of retention of protons and other charge carriers by ionogenic groups of biomolecules with known primary structures. The approach is a new one and has no known to us analogues. A program titled "Decomposition" was developed and used to analyze the charge distribution of ions of native and denatured cytochrome c mass spectra. The possibility of splitting of the charge-state distribution of albumin into normal components, which likely corresponds to various conformational states of the biomolecule, has been demonstrated. The applicability criterion for using previously described method of decomposition of multidimensional charge-state distributions with two charge carriers, e.g., a proton and a sodium ion, to characterize the spatial structure of biopolymers in solution has been formulated. In contrast to known mass-spectrometric approaches, this method does not require the use of enzymatic hydrolysis or collision-induced dissociation of the biopolymers.

  6. Charged Hadron Multiplicity Distribution at Relativistic Heavy-Ion Colliders

    Directory of Open Access Journals (Sweden)

    Ashwini Kumar

    2013-01-01

    Full Text Available The present paper reviews facts and problems concerning charge hadron production in high energy collisions. Main emphasis is laid on the qualitative and quantitative description of general characteristics and properties observed for charged hadrons produced in such high energy collisions. Various features of available experimental data, for example, the variations of charged hadron multiplicity and pseudorapidity density with the mass number of colliding nuclei, center-of-mass energies, and the collision centrality obtained from heavy-ion collider experiments, are interpreted in the context of various theoretical concepts and their implications. Finally, several important scaling features observed in the measurements mainly at RHIC and LHC experiments are highlighted in the view of these models to draw some insight regarding the particle production mechanism in heavy-ion collisions.

  7. Comparing the gas-phase fragmentation reactions of protonated and radical cations of the tripeptides GXR

    Science.gov (United States)

    Wee, Sheena; O'Hair, Richard A. J.; McFadyen, W. David

    2004-05-01

    Electrospray ionization (ESI) mass spectrometry of methanolic solutions of mixtures of the copper salt (2,2':6',2''-terpyridine)copper(II) nitrate monohydrate ([Cu(II)(tpy)(NO3)2].H2O) and a tripeptide GXR (where X = 1 of the 20 naturally occurring amino acids) yielded [Cu(II)(tpy)(GXR)][radical sign]2+ ions, which were then subjected to collision induced dissociation (CID). In all but one case (GRR), these [Cu(II)(tpy)(GXR)][radical sign]2+ ions fragment to form odd electron GXR[radical sign]+ radical cations with sufficient abundance to examine their gas-phase fragmentation reactions. The GXR[radical sign]+ radical cations undergo a diverse range of fragmentation reactions which depend on the nature of the side chain of X. Many of these reactions can be rationalized as arising from the intermediacy of isomeric distonic ions in which the charge (i.e. proton) is sequestered by the highly basic arginine side chain and the radical site is located at various positions on the tripeptide including the peptide back bone and side chains. The radical sites in these distonic ions often direct the fragmentation reactions via the expulsion of small radicals (to yield even electron ions) or small neutrals (to form radical cations). Both classes of reaction can yield useful structural information, allowing for example, distinction between leucine and isoleucine residues. The gas-phase fragmentation reactions of the GXR[radical sign]+ radical cations are also compared to their even electron [GXR+H]+ and [GXR+2H]2+ counterparts. The [GXR+H]+ ions give fewer sequence ions and more small molecule losses while the [GXR+2H]2+ ions yield more sequence information, consistent with the [`]mobile proton model' described in previous studies. In general, all three classes of ions give complementary structural information, but the GXR[radical sign]+ radical cations exhibit a more diverse loss of small species (radicals and neutrals). Finally, links between these gas-phase results and key

  8. Systematics of heavy-ion charge-exchange straggling

    Science.gov (United States)

    Sigmund, P.; Schinner, A.

    2016-10-01

    The dependence of heavy-ion charge-exchange straggling on the beam energy has been studied theoretically for several ion-target combinations. Our previous work addressed ions up to krypton, while the present study focuses on heavier ions, especially uranium. Particular attention has been paid to a multiple-peak structure which has been predicted theoretically in our previous work. For high-Z1 and high-Z2 systems, exemplified by U in Au, we identify three maxima in the energy dependence of charge-exchange straggling, while the overall magnitude is comparable with that of collisional straggling. Conversely, for U in C, charge-exchange straggling dominates, but only two peaks lie in the energy range where we presently are able to produce credible predictions. For U-Al we find good agreement with experiment in the energy range around the high-energy maximum. The position of the high-energy peak - which is related to processes in the projectile K shell - is found to scale as Z12 , in contrast to the semi-empirical Z13/2 dependence proposed by Yang et al. Measurements for heavy ions in heavy targets are suggested in order to reconcile a major discrepancy between the present calculations and the frequently-used formula by Yang et al.

  9. MULTIPLY CHARGED IONS COLLISIONS WITH ATOMS INTO EXCITED STATES

    Institute of Scientific and Technical Information of China (English)

    PanGuangyan

    1990-01-01

    The emission spectra in collisions between Ions and Atoms have been measured by an Optical Multichannel Analysis System (OMA).The experimental results demonstrate that there are two channels of excitation in collision between single charged ions and atoms and three channels of excitation in collision between double charged ions and atoms.Emission cross cestions and excitation cross sections have been obtained.K.Kadota et al and R.Shingal et al suggested that,under the appropriate conditions,the H42+-Li and He2++Na collision systems can be used efficiently to produce a laser of Lyman-α(30,4nm) and Lyman-β(25.6nm)lines via cascade to He+(2P)state.

  10. Laserspray ionization on a commercial atmospheric pressure-MALDI mass spectrometer ion source: selecting singly or multiply charged ions.

    Science.gov (United States)

    McEwen, Charles N; Larsen, Barbara S; Trimpin, Sarah

    2010-06-15

    Multiply charged ions, similar to those obtained with electrospray ionization, are produced at atmospheric pressure (AP) using standard MALDI conditions of laser fluence and reflective geometry. Further, the charge state can be switched to singly charged ions nearly instantaneously by changing the voltage applied to the MALDI target plate. Under normal AP-MALDI operating conditions in which a voltage is applied to the target plate, primarily singly charged ions are observed, but at or near zero volts, highly charged ions are observed for peptides and proteins. Thus, switching between singly and multiply charged ions requires only manipulation of a single voltage. As in ESI, multiple charging, produced using the AP-MALDI source, allows compounds with molecular weights beyond the mass-to-charge limit of the mass spectrometer to be observed and improves the fragmentation relative to singly charged ions.

  11. High resolution charge spectroscopy of heavy ions with FNTD technology

    Science.gov (United States)

    Bartz, J. A.; Kodaira, S.; Kurano, M.; Yasuda, N.; Akselrod, M. S.

    2014-09-01

    This paper is focused on the improvement of the heavy charge particle charge resolution of Fluorescent Nuclear Track Detector (FNTD) technology. Fluorescent intensity of individual heavy charge particle tracks is used to construct the spectrum. Sources of spectroscopic line broadening were investigated and several fluorescent intensity correction procedures were introduced to improve the charge resolution down to δZ = 0.25 c.u. and enable FNTD technology to distinguish between all projectile fragments of 290 MeV carbon ions. The benefits of using FNTD technology for fragmentation study include large dynamic range and wide angular acceptance. While we describe these developments in the context of fragmentation studies, the same techniques are readily extended to FNTD LET spectroscopy in general.

  12. Strong-field relativistic processes in highly charged ions

    Energy Technology Data Exchange (ETDEWEB)

    Postavaru, Octavian

    2010-12-08

    In this thesis we investigate strong-field relativistic processes in highly charged ions. In the first part, we study resonance fluorescence of laser-driven highly charged ions in the relativistic regime by solving the time-dependent master equation in a multi-level model. Our ab initio approach based on the Dirac equation allows for investigating highly relativistic ions, and, consequently, provides a sensitive means to test correlated relativistic dynamics, bound-state quantum electrodynamic phenomena and nuclear effects by applying coherent light with x-ray frequencies. Atomic dipole or multipole moments may be determined to unprecedented accuracy by measuring the interference-narrowed fluorescence spectrum. Furthermore, we investigate the level structure of heavy hydrogenlike ions in laser beams. Interaction with the light field leads to dynamic shifts of the electronic energy levels, which is relevant for spectroscopic experiments. We apply a fully relativistic description of the electronic states by means of the Dirac equation. Our formalism goes beyond the dipole approximation and takes into account non-dipole effects of retardation and interaction with the magnetic field components of the laser beam. We predicted cross sections for the inter-shell trielectronic recombination (TR) and quadruelectronic recombination processes which have been experimentally confirmed in electron beam ion trap measurements, mainly for C-like ions, of Ar, Fe and Kr. For Kr{sup 30}+, inter-shell TR contributions of nearly 6% to the total resonant photorecombination rate were found. (orig.)

  13. A compact source for bunches of singly charged atomic ions.

    Science.gov (United States)

    Murböck, T; Schmidt, S; Andelkovic, Z; Birkl, G; Nörtershäuser, W; Vogel, M

    2016-04-01

    We have built, operated, and characterized a compact ion source for low-energy bunches of singly charged atomic ions in a vacuum beam line. It is based on atomic evaporation from an electrically heated oven and ionization by electron impact from a heated filament inside a grid-based ionization volume. An adjacent electrode arrangement is used for ion extraction and focusing by applying positive high-voltage pulses to the grid. The method is particularly suited for experimental environments which require low electromagnetic noise. It has proven simple yet reliable and has been used to produce μs-bunches of up to 10(6) Mg(+) ions at a repetition rate of 1 Hz. We present the concept, setup and characterizing measurements. The instrument has been operated in the framework of the SpecTrap experiment at the HITRAP facility at GSI/FAIR to provide Mg(+) ions for sympathetic cooling of highly charged ions by laser-cooled (24)Mg(+).

  14. High ion charge states in a high-current, short-pulse, vacuum ARC ion sources

    Energy Technology Data Exchange (ETDEWEB)

    Anders, A.; Brown, I.; MacGill, R.; Dickinson, M. [Lawrence Berkeley National Lab., CA (United States)

    1996-08-01

    Ions of the cathode material are formed at vacuum arc cathode spots and extracted by a grid system. The ion charge states (typically 1-4) depend on the cathode material and only little on the discharge current as long as the current is low. Here the authors report on experiments with short pulses (several {mu}s) and high currents (several kA); this regime of operation is thus approaching a more vacuum spark-like regime. Mean ion charge states of up to 6.2 for tungsten and 3.7 for titanium have been measured, with the corresponding maximum charge states of up to 8+ and 6+, respectively. The results are discussed in terms of Saha calculations and freezing of the charge state distribution.

  15. Charge-dependent dissociation of insulin cations via ion/ion electron transfer

    Science.gov (United States)

    Liu, Jian; Gunawardena, Harsha P.; Huang, Teng-Yi; McLuckey, Scott A.

    2008-10-01

    The dissociation reactions of various charge states of insulin cations obtained directly from nano-electrospray were investigated as a result of ion/ion electron transfer from azobenzene anions. Data were collected with and without simultaneous ion trap collisional excitation of the first generation charge-reduced product during the ion/ion reaction period. Neither separation of the two constituent chains nor cleavages within the loop defined by the disulfide bridges were observed under normal electron transfer dissociation (ETD) conditions for any of the charge states studied. However, substantial sequence coverage (exocyclic region: 82.6%; entire protein: 38.8%) outside the ring structure was obtained for insulin +6, while only limited coverage (exocyclic: 43.5%; entire protein: 20.4%) was observed for insulin +5 and no dissociation, aside from low abundance side-chain losses, was noted for insulin +4 and +3 in the normal ETD spectra. When the first generation charge-reduced precursor ions were subjected to collisional activation during the ion/ion reaction period, higher sequence coverages were obtained for both insulin +5 (entire protein: 34.7%) and +4 (entire protein: 20.4%) with backbone cleavages occurring within the loop defined by the disulfide bonds. Dissociation of insulin +3 was not significantly improved by the additional activation. Separation of the two constituent chains resulting from cleavages of both of the two disulfide bridges that link the chains was observed for insulin +6, +5, and +4 when the charge-reduced species were activated. The dissociation of disulfide linkages in this study suggests that as the charge state decreases, disulfide bond cleavages dominate over N-C[alpha] bond cleavages in the electron transfer dissociation process.

  16. Irradiation of graphene field effect transistors with highly charged ions

    Science.gov (United States)

    Ernst, P.; Kozubek, R.; Madauß, L.; Sonntag, J.; Lorke, A.; Schleberger, M.

    2016-09-01

    In this work, graphene field-effect transistors are used to detect defects due to irradiation with slow, highly charged ions. In order to avoid contamination effects, a dedicated ultra-high vacuum set up has been designed and installed for the in situ cleaning and electrical characterization of graphene field-effect transistors during irradiation. To investigate the electrical and structural modifications of irradiated graphene field-effect transistors, their transfer characteristics as well as the corresponding Raman spectra are analyzed as a function of ion fluence for two different charge states. The irradiation experiments show a decreasing mobility with increasing fluences. The mobility reduction scales with the potential energy of the ions. In comparison to Raman spectroscopy, the transport properties of graphene show an extremely high sensitivity with respect to ion irradiation: a significant drop of the mobility is observed already at fluences below 15 ions/μm2, which is more than one order of magnitude lower than what is required for Raman spectroscopy.

  17. Influence of solar wind ions on photoemission charging of dust

    Science.gov (United States)

    Nouzak, Libor; Richterova, Ivana; Pavlu, Jiri; Safrankova, Jana; Nemecek, Zdenek

    2016-04-01

    The lunar surface covered by a layer of dust grains is exposed to solar wind particles and photons coming from the Sun on the sunlit side. Solar wind ions cause sputtering of dust grains or can be implanted into grains. We suppose that as a consequence of ion implantation, an additional energy is transferred to grains, more valence band electrons are excited, and the photoelectron yield is increased. An increase of the photoelectron current causes the enhanced density of electrons that form a sheet above the illuminated lunar surface. Thus, an influence of solar wind ions on the Debye length and photoelectron sheet formation is expected. We present laboratory estimations of work functions and photoelectron yields of a single micron-sized silica grain before and after ion implantation. The silica grain used as a lunar simulant is caught in the electrodynamic trap. Grain's specific charge is evaluated by an analysis of the grain motion within the trap, while its work function is determined from observations of a time evolution of the charge-to-mass ratio when the grain is irradiated by photons of different emission lines. By comparison of the photoelectron current (from grain) with photon flux (from UV source), we establish the photoelectron yield of the trapped object. The influence of ion implantation is thoroughly analyzed and discussed.

  18. Peripheral collisions of highly charged ions with metal clusters

    Institute of Scientific and Technical Information of China (English)

    Zhang Cheng-Jun; Hu Bi-Tao; Luo Xian-Wen

    2012-01-01

    Within the framework of the dynamical classical over-barrier model,the soft collisions between slow highly charged ions(SHCIs)Ar17+ and the large copper clusters under large impact parameters have been studied in this paper.We present the dominant mechanism of the electron transfer between SHCls and a large metal cluster by computational simulation.The evolution of the occupation of projectile ions,KLχ satellite lines,X-ray yields,Auger electron spectrum and scattering angles are provided.

  19. Single ion induced surface nanostructures: a comparison between slow highly charged and swift heavy ions.

    Science.gov (United States)

    Aumayr, Friedrich; Facsko, Stefan; El-Said, Ayman S; Trautmann, Christina; Schleberger, Marika

    2011-10-05

    This topical review focuses on recent advances in the understanding of the formation of surface nanostructures, an intriguing phenomenon in ion-surface interaction due to the impact of individual ions. In many solid targets, swift heavy ions produce narrow cylindrical tracks accompanied by the formation of a surface nanostructure. More recently, a similar nanometric surface effect has been revealed for the impact of individual, very slow but highly charged ions. While swift ions transfer their large kinetic energy to the target via ionization and electronic excitation processes (electronic stopping), slow highly charged ions produce surface structures due to potential energy deposited at the top surface layers. Despite the differences in primary excitation, the similarity between the nanostructures is striking and strongly points to a common mechanism related to the energy transfer from the electronic to the lattice system of the target. A comparison of surface structures induced by swift heavy ions and slow highly charged ions provides a valuable insight to better understand the formation mechanisms.

  20. Semiconductor characterization by scanning ion beam induced charge (IBIC) microscopy

    CERN Document Server

    Vittone, E; Olivero, P; Manfredotti, C; Jaksic, M; Giudice, A Lo; Fizzotti, F; Colombo, E

    2016-01-01

    The acronym IBIC (Ion Beam Induced Charge) was coined in early 1990's to indicate a scanning microscopy technique which uses MeV ion beams as probes to image the basic electronic properties of semiconductor materials and devices. Since then, IBIC has become a widespread analytical technique to characterize materials for electronics or for radiation detection, as testified by more than 200 papers published so far in peer-reviewed journals. Its success stems from the valuable information IBIC can provide on charge transport phenomena occurring in finished devices, not easily obtainable by other analytical techniques. However, IBIC analysis requires a robust theoretical background to correctly interpret experimental data. In order to illustrate the importance of using a rigorous mathematical formalism, we present in this paper a benchmark IBIC experiment aimed to test the validity of the interpretative model based on the Gunn's theorem and to provide an example of the analytical capability of IBIC to characteriz...

  1. An electrostatic deceleration lens for highly charged ions.

    Science.gov (United States)

    Rajput, J; Roy, A; Kanjilal, D; Ahuja, R; Safvan, C P

    2010-04-01

    The design and implementation of a purely electrostatic deceleration lens used to obtain beams of highly charged ions at very low energies is presented. The design of the lens is such that it can be used with parallel as well as diverging incoming beams and delivers a well focused low energy beam at the target. In addition, tuning of the final energy of the beam over a wide range (1 eV/q to several hundred eV/q, where q is the beam charge state) is possible without any change in hardware configuration. The deceleration lens was tested with Ar(8+), extracted from an electron cyclotron resonance ion source, having an initial energy of 30 keV/q and final energies as low as 70 eV/q have been achieved.

  2. Low charge state heavy ion production with sub-nanosecond laser

    Energy Technology Data Exchange (ETDEWEB)

    Kanesue, T., E-mail: tkanesue@bnl.gov; Okamura, M. [Collider-Accelerator Department, Brookhaven National Laboratory, Upton, New York 11973 (United States); Kumaki, M. [Research Institute for Science and Engineering, Waseda University, Tokyo 169-8555 (Japan); Nishina Center for Accelerator-Based Science, RIKEN, Saitama 351-0198 (Japan); Ikeda, S. [Nishina Center for Accelerator-Based Science, RIKEN, Saitama 351-0198 (Japan); Interdisciplinary Graduate School of Science and Engineering, Tokyo Institute of Technology, Kanagawa 226-8503 (Japan)

    2016-02-15

    We have investigated laser ablation plasma of various species using nanosecond and sub-nanosecond lasers for both high and low charge state ion productions. We found that with sub-nanosecond laser, the generated plasma has a long tail which has low charge state ions determined by an electrostatic ion analyzer even under the laser irradiation condition for highly charged ion production. This can be caused by insufficient laser absorption in plasma plume. This property might be suitable for low charge state ion production. We used a nanosecond laser and a sub-nanosecond laser for low charge state ion production to investigate the difference of generated plasma using the Zirconium target.

  3. Low charge state heavy ion production with sub-nanosecond laser.

    Science.gov (United States)

    Kanesue, T; Kumaki, M; Ikeda, S; Okamura, M

    2016-02-01

    We have investigated laser ablation plasma of various species using nanosecond and sub-nanosecond lasers for both high and low charge state ion productions. We found that with sub-nanosecond laser, the generated plasma has a long tail which has low charge state ions determined by an electrostatic ion analyzer even under the laser irradiation condition for highly charged ion production. This can be caused by insufficient laser absorption in plasma plume. This property might be suitable for low charge state ion production. We used a nanosecond laser and a sub-nanosecond laser for low charge state ion production to investigate the difference of generated plasma using the Zirconium target.

  4. Progress in quantum electrodynamics theory of highly charged ions

    OpenAIRE

    Volotka, A. V.; Glazov, D. A.; Plunien, G.; Shabaev, V. M.

    2013-01-01

    Recent progress in quantum electrodynamics (QED) calculations of highly charged ions is reviewed. The theoretical predictions for the binding energies, the hyperfine splittings, and the g factors are presented and compared with available experimental data. Special attention is paid to tests of bound-state QED at strong field regime. Future prospects for tests of QED at the strongest electric and magnetic fields as well as for determination of the fine structure constant and the nuclear magnet...

  5. A perspective on MALDI alternatives-total solvent-free analysis and electron transfer dissociation of highly charged ions by laserspray ionization.

    Science.gov (United States)

    Trimpin, Sarah

    2010-05-01

    Progress in research is hindered by analytical limitations, especially in biological areas in which sensitivity and dynamic range are critical to success. Inherent difficulties of characterization associated with complexity arising from heterogeneity of various materials including topologies (isomeric composition) and insolubility also limit progress. For this reason, we are developing methods for total solvent-free analysis by mass spectrometry consisting of solvent-free ionization followed by solvent-free gas-phase separation. We also recently constructed a novel matrix-assisted laser desorption ionization (MALDI) source that provides a simple, practical and sensitive way of producing highly charged ions by laserspray ionization (LSI) or singly charged ions commonly observed with MALDI by choice of matrix or matrix preparation. This is the first ionization source with such freedom-an extremely powerful analytical 'switch'. Multiply charged LSI ions allow molecules exceeding the mass-to-charge range of the instrument to be observed and permit for the first time electron transfer dissociation fragment ion analysis.

  6. Laboratory Studies of Thermal Energy Charge Transfer of Multiply Charged Ions in Astrophysical Plasmas

    Science.gov (United States)

    Kwong, Victor H. S.

    2003-01-01

    The laser ablation/ion storage facility at the UNLV Physics Department has been dedicated to the study of atomic and molecular processes in low temperature plasmas. Our program focuses on the charge transfer (electron capture) of multiply charged ions and neutrals important in astrophysics. The electron transfer reactions with atoms and molecules is crucial to the ionization condition of neutral rich photoionized plasmas. With the successful deployment of the Far Ultraviolet Spectroscopic Explorer (FUSE) and the Chandra X-ray Observatory by NASA high resolution VUV and X-ray emission spectra fiom various astrophysical objects have been collected. These spectra will be analyzed to determine the source of the emission and the chemical and physical environment of the source. The proper interpretation of these spectra will require complete knowledge of all the atomic processes in these plasmas. In a neutral rich environment, charge transfer can be the dominant process. The rate coefficients need to be known accurately. We have also extended our charge transfer measurements to KeV region with a pulsed ion beam. The inclusion of this facility into our current program provides flexibility in extending the measurement to higher energies (KeV) if needed. This flexibility enables us to address issues of immediate interest to the astrophysical community as new observations are made by high resolution space based observatories.

  7. Effects of Ions Charge-Mass Ratio on Energy and Energy Spread of Accelerated Ions in Laser Driven Plasma

    Institute of Scientific and Technical Information of China (English)

    SANG Hai-Bo; DENG Shi-Qiang; XIE Bai-Song

    2013-01-01

    Effects of ions charge-mass ratio on energy and energy spread of accelerated ions in laser driven plasma are investigated in detail by proposing a simple double-layer model for a foil target driven by an ultrastrong laser.The radiation pressure acceleration mechanism plays an important role on the studied problem.For the ions near the plasma mirror,i.e.electrons layer,the dependence of ions energy on their charge-mass ratio is derived theoretically.It is found that the larger the charge-mass ratio is,the higher the accelerated ions energy gets.For those ions far away from the layer,the dependence of energy and energy spread on ions charge-mass ratio are also obtained by numerical performance.It exhibits that,as ions charge-mass ratio increases,not only the accelerated ions energy but also the energy spread will become large.

  8. Highly charged ion X-rays from Electron-Cyclotron Resonance Ion Sources

    OpenAIRE

    Indelicato, Paul; Boucard, S.; Covita, D. S.; Gotta, D.; Gruber, A; Hirtl, A.; Fuhrmann, H.; Le Bigot, E.-O.; Schlesser, S.; dos Santos, J. M. F.; Simons, L.M.; Stingelin, L.; Trassinelli, Martino; Veloso, J.; Wasser, A.

    2006-01-01

    Radiation from the highly-charged ions contained in the plasma of Electron-Cyclotron Resonance Ion Sources constitutes a very bright source of X-rays. Because the ions have a relatively low kinetic energy ($\\approx 1$~eV) transitions can be very narrow, containing only small Doppler broadening. We describe preliminary accurate measurements of two and three-electron ions with $Z=16$--18. We show how these measurement can test sensitively many-body relativistic calculations or can be used as X-...

  9. Production of a highly charged uranium ion beam with RIKEN superconducting electron cyclotron resonance ion source

    Energy Technology Data Exchange (ETDEWEB)

    Higurashi, Y.; Ohnishi, J.; Nakagawa, T.; Haba, H.; Fujimaki, M.; Komiyama, M.; Kamigaito, O. [RIKEN Nishina Center, 2-1 Hirosawa, Wako-shi, Saitama 351-0198 (Japan); Tamura, M.; Aihara, T.; Uchiyama, A. [SHI Accelerator Service Ltd., 1-17-6 Osaki, Shinagawa, Tokyo 141-0032 (Japan)

    2012-02-15

    A highly charged uranium (U) ion beam is produced from the RIKEN superconducting electron cyclotron resonance ion source using 18 and 28 GHz microwaves. The sputtering method is used to produce this U ion beam. The beam intensity is strongly dependent on the rod position and sputtering voltage. We observe that the emittance of U{sup 35+} for 28 GHz microwaves is almost the same as that for 18 GHz microwaves. It seems that the beam intensity of U ions produced using 28 GHz microwaves is higher than that produced using 18 GHz microwaves at the same Radio Frequency (RF) power.

  10. Charge density asymmetry of heavy-ion fusion reactions

    Energy Technology Data Exchange (ETDEWEB)

    Poenaru, N.D.; Ivascu, M.; Mazilu, D.; Sandulescu, A. (Institutul de Fizica si Inginerie Nucleara, Bucharest (Romania))

    1980-01-01

    The generalized liquid-drop model replacing surface energy by double folded Yukawa-plus-exponential function is extended for fusion of heavy ions with different charge densities. Calculated interaction barriers for some 58 pairs of nuclei are in good agreement with experimental ones, within -10% and +7%. For even-even beta-stable nuclei with Z =4-104 the general trend of variation of interaction barriers and fusion Q-values show the regions where the charge density asymmetry cannot be neglected. PES for the entrance channel of the reactions /sup 109/Ag + /sup 40/Ar, /sup 138/Ce + /sup 57/Fe, /sup 144/Nd + /sup 84/Kr and the corresponding charge-equilibrated system have been computed.

  11. The effect of H2SO4 - amine clustering on chemical ionization mass spectrometry (CIMS) measurements of gas-phase sulfuric acid

    DEFF Research Database (Denmark)

    Kurten, T.; Petaja, T.; Smith, J.;

    2011-01-01

    by the CIMS instrument, though the most reliable computational methods employed predict this fraction to be small; on the order of ten percent or less. Third, the amine molecules will evaporate practically immediately after charging, thus evading detection. These effects may need to be taken into account......The state-of-the art method for measuring atmospheric gas-phase sulfuric acid is chemical ionization mass spectrometry (CIMS) based on nitrate reagent ions. We have assessed the possible effect of the sulfuric acid molecules clustering with base molecules on CIMS measurements using computational...... chemistry. From the computational data, three conclusions can be drawn. First, a significant fraction of the gas-phase sulfuric acid molecules are very likely clustered with amines if the amine concentration is around or above a few ppt. Second, some fraction of these acid-amine clusters may not be charged...

  12. Experimental Results on Charge Fluctuations in Heavy-Ion Collisions

    Directory of Open Access Journals (Sweden)

    D. K. Mishra

    2017-01-01

    Full Text Available We present a subset of experimental results on charge fluctuation from the heavy-ion collisions to search for phase transition and location of critical point in the QCD phase diagram. Measurements from the heavy-ion experiments at the SPS and RHIC energies observe that total charge fluctuations increase from central to peripheral collisions. The net-charge fluctuations in terms of dynamical fluctuation measure ν(+-,dyn are studied as a function of collision energy (sNN and centrality of the collisions. The product of ν(+-,dyn and 〈Nch〉 shows a monotonic decrease with collision energies, which indicates that at LHC energy the fluctuations have their origin in the QGP phase. The fluctuations in terms of higher moments of net-proton, net-electric charge, and net-kaon have been measured for various sNN. Deviations are observed in both Sσ and κσ2 for net-proton multiplicity distributions from the Skellam and hadron resonance gas model for sNN<39 GeV. Higher moment results of the net-electric charge and net-kaon do not observe any significant nonmonotonic behavior as a function of collision energy. We also discuss the extraction of the freeze-out parameters using particle ratios and experimentally measured higher moments of net-charge fluctuations. The extracted freeze-out parameters from experimentally measured moments and lattice calculations are found to be in agreement with the results obtained from the fit of particle ratios to the thermal model calculations.

  13. Dynamics of Ion Beam Charge Neutralization by Ferroelectric Plasma Sources

    Science.gov (United States)

    Stepanov, Anton D.; Gilson, Erik P.; Grisham, Larry R.; Kaganovich, Igor D.; Davidson, Ronald C.; Ji, Qing; Persaud, Arun; Seidl, Peter A.; Schenkel, Thomas

    2016-10-01

    Ferroelectric Plasma Sources (FEPSs) can generate plasma that provides effective space-charge neutralization of intense high-perveance ion beams. Here we present experimental results on charge neutralization of a high-perveance 38 keV Ar+ beam by a FEPS plasma. By comparing the measured beam radius with the envelope model for space-charge expansion, it is shown that a charge neutralization fraction of 98% is attainable. The transverse electrostatic potential of the ion beam is reduced from 15 V before neutralization to 0.3 V, implying that the energy of the neutralizing electrons is below 0.3 eV. Near-complete charge neutralization is established 5 μs after the driving pulse is applied to the FEPS, and can last for 35 μs. It is argued that the duration of neutralization is much longer than a reasonable lifetime of the plasma produced in the sub- μs surface discharge. Measurements of current flow in the driving circuit of the FEPS suggest that plasma can be generated for tens of μs after the high voltage pulse is applied. This is confirmed by fast photography of the plasma in the 1-meter long FEPS on NDCX-II, where effective charge neutralization of the beam was achieved with the optimized FEPS timing. This work was supported by the Office of Science of the US Department of Energy under contracts DE-AC0209CH11466 (PPPL) and DE-AC0205CH11231 (LBNL).

  14. The uses of electron beam ion traps in the study of highly charged ions

    Energy Technology Data Exchange (ETDEWEB)

    Knapp, D.

    1994-11-02

    The Electron Beam Ion Trap (EBIT) is a relatively new tool for the study of highly charged ions. Its development has led to a variety of new experimental opportunities; measurements have been performed with EBITs using techniques impossible with conventional ion sources or storage rings. In this paper, I will highlight the various experimental techniques we have developed and the results we have obtained using the EBIT and higher-energy Super-EBIT built at the Lawrence Livermore National Laboratory. The EBIT employs a high-current-density electron beam to trap, ionize, and excite a population of ions. The ions can be studied in situ or extracted from the trap for external experiments. The trapped ions form an ionization-state equilibrium determined by the relative ionization and recombination rates. Ions of several different elements may simultaneously be present in the trap. The ions are nearly at rest, and, for most systems, all in their ground-state configurations. The electron-ion interaction energy has a narrow distribution and can be varied over a wide range. We have used the EBIT devices for the measurement of electron-ion interactions, ion structure, ion-surface interactions, and the behavior of low-density plasmas.

  15. Physical mechanisms leading to high currents of highly charged ions in laser-driven ion sources

    Energy Technology Data Exchange (ETDEWEB)

    Haseroth, Helmut [European Organization for Nuclear Research, Geneva (Switzerland); Hora, Heinrich [New South Wales Univ., Kensington, NSW (Australia)]|[Regensburg Inst. of Tech. (Germany). Anwenderzentrum

    1996-12-31

    Heavy ion sources for the big accelerators, for example, the LHC, require considerably more ions per pulse during a short time than the best developed classical ion source, the electron cyclotron resonance (ECR) provides; thus an alternative ion source is needed. This can be expected from laser-produced plasmas, where dramatically new types of ion generation have been observed. Experiments with rather modest lasers have confirmed operation with one million pulses of 1 Hz, and 10{sup 11} C{sup 4+} ions per pulse reached 2 GeV/u in the Dubna synchrotron. We review here the complexities of laser-plasma interactions to underline the unique and extraordinary possibilities that the laser ion source offers. The complexities are elaborated with respect to keV and MeV ion generation, nonlinear (ponderomotive) forces, self-focusing, resonances and ``hot`` electrons, parametric instabilities, double-layer effects, and the few ps stochastic pulsation (stuttering). Recent experiments with the laser ion source have been analyzed to distinguish between the ps and ns interaction, and it was discovered that one mechanism of highly charged ion generation is the electron impact ionization (EII) mechanism, similar to the ECR, but with so much higher plasma densities that the required very large number of ions per pulse are produced. (author).

  16. Ion beam induced charge characterisation of a silicon microdosimeter using a heavy ion microprobe

    Science.gov (United States)

    Cornelius, Iwan; Siegele, Rainer; Rosenfeld, Anatoly B.; Cohen, David D.

    2002-05-01

    An ion beam induced charge (IBIC) facility has been added to the existing capabilities of the ANSTO heavy ion microprobe and the results of the first measurements are presented. Silicon on insulator (SOI) diode arrays with microscopic junction sizes have recently been proposed as microdosimeters for hadron therapy. A 20 MeV carbon beam was used to perform IBIC imaging of a 10 μm thick SOI device.

  17. The covalently bound HC tbnd N dimer ions HC dbnd N-N dbnd CH rad + and HC dbnd N-C( dbnd N)H rad + are stable species in the gas-phase, but the neutral counterparts are not

    Science.gov (United States)

    Jobst, Karl J.; Hanifa, M. Ruzni; Ruttink, Paul J. A.; Terlouw, Johan K.

    2009-05-01

    Tandem mass spectrometry based experiments and computational chemistry (CBS-QB3/APNO methods) indicate that ionized s-tetrazine eliminates N 2 to yield the elusive linear HC tbnd N dimer ion HC dbnd N-N dbnd CH rad + ( 1). The ion is stable in the rarefied gas-phase but, as it is generated with considerable internal energy, it readily interconverts with HC dbnd N-C( dbnd N)H rad + ( 2), via a 1,2-HCN shift. This more stable HCN dimer ion was generated independently by loss of HCN from ionized s-triazine. Whereas the HN tbnd C dimer ion HN dbnd C dbnd C dbnd NH rad + has a (kinetically) stable neutral counterpart, theory and experiment (neutralization-reionization mass spectrometry) agree that the HC tbnd N dimer ions 1 and 2 do not.

  18. Electronic transitions in highly charged ion-atom collisions

    Science.gov (United States)

    Schmidt-Böcking, H.; Ullrich, J.; Schuch, R.; Olson, R. E.; Dörner, R.

    1989-09-01

    Three different aspects of electronic transitions in fast, highly charged ion-atom collisions are discussed. First, experimental data and n-CTMC calculations for differential multiple ionization cross sections of 1.4 {MeV}/{u} U 32+on rare gas atoms are presented. It is shown that the electronic motion has a dramatic influence on the kinematics of the emitted particles (in particular the nuclei). The possibility is discussed to measure in fast ionizing processes by a recoil ion-projectile coincidence technique the internal sum momentum of "electron clusters" in atoms. This new "technique" opens a new field of atomic structure research at high-energy heavy-ion accelerators. Second, the use of the H-like heavy ions as projectiles is discussed to measure, through observable interference structures, static and dynamic properties of transiently formed superheavy quasimolecular systems. Third, the "ancient" gas target-solid target difference in the impact-parameter dependence of K-shell ionization in nearly symmetric ion-atom collisions is presented. This severe discrepancy between gas and solid still remains an unsolved fundamental problem in the field of inner-shell ionization in the MO regime.

  19. Charge exchange spectroscopy as a fast ion diagnostic on TEXTORa)

    Science.gov (United States)

    Delabie, E.; Jaspers, R. J. E.; von Hellermann, M. G.; Nielsen, S. K.; Marchuk, O.

    2008-10-01

    An upgraded charge exchange spectroscopy diagnostic has been taken into operation at the TEXTOR tokamak. The angles of the viewing lines with the toroidal magnetic field are close to the pitch angles at birth of fast ions injected by one of the neutral beam injectors. Using another neutral beam for active spectroscopy, injected counter the direction in which fast ions injected by the first beam are circulating, we can simultaneously measure a fast ion tail on the blue wing of the Dα spectrum while the beam emission spectrum is Doppler shifted to the red wing. An analysis combining the two parts of the spectrum offers possibilities to improve the accuracy of the absolute (fast) ion density profiles. Fast beam modulation or passive viewing lines cannot be used for background subtraction on this diagnostic setup and therefore the background has to be modeled and fitted to the data together with a spectral model for the slowing down feature. The analysis of the fast ion Dα spectrum obtained with the new diagnostic is discussed.

  20. Two-photon processes in highly charged ions

    Energy Technology Data Exchange (ETDEWEB)

    Jahrsetz, Thorsten

    2015-03-05

    Two-photon processes are atomic processes in which an atom interacts simultaneously with two photons. Such processes describe a wide range of phenomena, such as two-photon decay and elastic or inelastic scattering of photons. In recent years two-photon processes involving highly charged heavy ions have become an active area of research. Such studies do not only consider the total transition or scattering rates but also their angular and polarization dependence. To support such examinations in this thesis I present a theoretical framework to describe these properties in all two-photon processes with bound initial and final states and involving heavy H-like or He-like ions. I demonstrate how this framework can be used in some detailed studies of different two-photon processes. Specifically a detailed analysis of two-photon decay of H-like and He-like ions in strong external electromagnetic fields shows the importance of considering the effect of such fields for the physics of such systems. Furthermore I studied the elastic Rayleigh as well as inelastic Raman scattering by heavy H-like ions. I found a number of previously unobserved phenomena in the angular and polarization dependence of the scattering cross-sections that do not only allow to study interesting details of the electronic structure of the ion but might also be useful for the measurement of weak physical effects in such systems.

  1. Electron Flood Charge Compensation Device for Ion Trap Secondary Ion Mass Spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Appelhans, Anthony David; Ward, Michael Blair; Olson, John Eric

    2002-11-01

    During secondary ion mass spectrometry (SIMS) analyses of organophosphorous compounds adsorbed onto soils, the measured anion signals were lower than expected and it was hypothesized that the low signals could be due to sample charging. An electron flood gun was designed, constructed and used to investigate sample charging of these and other sample types. The flood gun was integrated into one end cap of an ion trap secondary ion mass spectrometer and the design maintained the geometry of the self-stabilizing extraction optics used in this instrument. The SIMION ion optics program was used to design the flood gun, and experimental results agreed with the predicted performance. Results showed the low anion signals from the soils were not due to sample charging. Other insulating and conducting samples were tested using both a ReO4- and a Cs+ primary ion beam. The proximity of the sample and electron source to the ion trap aperture resulted in generation of background ions in the ion trap via electron impact (EI) ionization during the period the electron gun was flooding the sample region. When using the electron gun with the ReO4- primary beam, the required electron current was low enough that the EI background was negligible; however, the high electron flood current required with the Cs+ beam produced background EI ions that degraded the quality of the mass spectra. The consequences of the EI produced cations will have to be evaluated on a sample-by-sample basis when using electron flood. It was shown that the electron flood gun could be intentionally operated to produce EI spectra in this instrument. This offers the opportunity to measure, nearly simultaneously, species evaporating from a sample, via EI, and species bound to the surface, via SIMS.

  2. An Ion Switch Regulates Fusion of Charged Membranes

    Science.gov (United States)

    Siepi, Evgenios; Lutz, Silke; Meyer, Sylke; Panzner, Steffen

    2011-01-01

    Here we identify the recruitment of solvent ions to lipid membranes as the dominant regulator of lipid phase behavior. Our data demonstrate that binding of counterions to charged lipids promotes the formation of lamellar membranes, whereas their absence can induce fusion. The mechanism applies to anionic and cationic liposomes, as well as the recently introduced amphoteric liposomes. In the latter, an additional pH-dependent lipid salt formation between anionic and cationic lipids must occur, as indicated by the depletion of membrane-bound ions in a zone around pH 5. Amphoteric liposomes fuse under these conditions but form lamellar structures at both lower and higher pH values. The integration of these observations into the classic lipid shape theory yielded a quantitative link between lipid and solvent composition and the physical state of the lipid assembly. The key parameter of the new model, κ(pH), describes the membrane phase behavior of charged membranes in response to their ion loading in a quantitative way. PMID:21575575

  3. Ferroelectric Plasma Source for Heavy Ion Beam Charge Neutralization

    CERN Document Server

    Efthimion, Philip; Gilson, Erik P; Grisham, Larry; Logan, B G; Waldron, William; Yu, Simon

    2005-01-01

    Plasmas are employed as a medium for charge neutralizing heavy ion beams to allow them to focus to a small spot size. Calculations suggest that plasma at a density of 1-100 times the ion beam density and at a length ~ 0.1-1 m would be suitable. To produce 1 meter plasma, large-volume plasma sources based upon ferroelectric ceramics are being considered. These sources have the advantage of being able to increase the length of the plasma and operate at low neutral pressures. The source will utilize the ferroelectric ceramic BaTiO3 to form metal plasma. The drift tube inner surface of the Neutralized Drift Compression Experiment (NDCX) will be covered with ceramic. High voltage (~ 1-5 kV) is applied between the drift tube and the front surface of the ceramic by placing a wire grid on the front surface. A prototype ferroelectric source 20 cm long produced plasma densities ~ 5x1011 cm-3. The source was integrated into the experiment and successfully charge neutralized the K ion beam. Presently, the 1 meter source ...

  4. The α-Effect and Competing Mechanisms: The Gas-Phase Reactions of Microsolvated Anions with Methyl Formate

    Science.gov (United States)

    Thomsen, Ditte L.; Nichols, Charles M.; Reece, Jennifer N.; Hammerum, Steen; Bierbaum, Veronica M.

    2013-12-01

    The enhanced reactivity of α-nucleophiles, which contain an electron lone pair adjacent to the reactive site, has been demonstrated in solution and in the gas phase and, recently, for the gas-phase SN2 reactions of the microsolvated HOO-(H2O) ion with methyl chloride. In the present work, we continue to explore the significance of microsolvation on the α-effect as we compare the gas-phase reactivity of the microsolvated α-nucleophile HOO-(H2O) with that of microsolvated normal alkoxy nucleophiles, RO-(H2O), in reactions with methyl formate, where three competing reactions are possible. The results reveal enhanced reactivity of HOO-(H2O) towards methyl formate, and clearly demonstrate the presence of an overall α-effect for the reactions of the microsolvated α-nucleophile. The association of the nucleophiles with a single water molecule significantly lowers the degree of proton abstraction and increases the SN2 and BAC2 reactivity compared with the unsolvated analogs. HOO-(H2O) reacts with methyl formate exclusively via the BAC2 channel. While microsolvation lowers the overall reaction efficiency, it enhances the BAC2 reaction efficiency for all anions compared with the unsolvated analogs. This may be explained by participation of the solvent water molecule in the BAC2 reaction in a way that continuously stabilizes the negative charge throughout the reaction.

  5. Advancement of highly charged ion beam production by superconducting ECR ion source SECRAL (invited)

    Science.gov (United States)

    Sun, L.; Guo, J. W.; Lu, W.; Zhang, W. H.; Feng, Y. C.; Yang, Y.; Qian, C.; Fang, X.; Ma, H. Y.; Zhang, X. Z.; Zhao, H. W.

    2016-02-01

    At Institute of Modern Physics (IMP), Chinese Academy of Sciences (CAS), the superconducting Electron Cyclotron Resonance (ECR) ion source SECRAL (Superconducting ECR ion source with Advanced design in Lanzhou) has been put into operation for about 10 years now. It has been the main working horse to deliver intense highly charged heavy ion beams for the accelerators. Since its first plasma at 18 GHz, R&D work towards more intense highly charged ion beam production as well as the beam quality investigation has never been stopped. When SECRAL was upgraded to its typical operation frequency 24 GHz, it had already showed its promising capacity of very intense highly charged ion beam production. And it has also provided the strong experimental support for the so called scaling laws of microwave frequency effect. However, compared to the microwave power heating efficiency at 18 GHz, 24 GHz microwave heating does not show the ω2 scale at the same power level, which indicates that microwave power coupling at gyrotron frequency needs better understanding. In this paper, after a review of the operation status of SECRAL with regard to the beam availability and stability, the recent study of the extracted ion beam transverse coupling issues will be discussed, and the test results of the both TE01 and HE11 modes will be presented. A general comparison of the performance working with the two injection modes will be given, and a preliminary analysis will be introduced. The latest results of the production of very intense highly charged ion beams, such as 1.42 emA Ar12+, 0.92 emA Xe27+, and so on, will be presented.

  6. Advancement of highly charged ion beam production by superconducting ECR ion source SECRAL (invited)

    Energy Technology Data Exchange (ETDEWEB)

    Sun, L., E-mail: sunlt@impcas.ac.cn; Lu, W.; Zhang, W. H.; Feng, Y. C.; Qian, C.; Ma, H. Y.; Zhang, X. Z.; Zhao, H. W. [Institute of Modern Physics, CAS, Lanzhou 730000 (China); Guo, J. W.; Yang, Y.; Fang, X. [Institute of Modern Physics, CAS, Lanzhou 730000 (China); University of Chinese Academy of Sciences, Beijing 100049 (China)

    2016-02-15

    At Institute of Modern Physics (IMP), Chinese Academy of Sciences (CAS), the superconducting Electron Cyclotron Resonance (ECR) ion source SECRAL (Superconducting ECR ion source with Advanced design in Lanzhou) has been put into operation for about 10 years now. It has been the main working horse to deliver intense highly charged heavy ion beams for the accelerators. Since its first plasma at 18 GHz, R&D work towards more intense highly charged ion beam production as well as the beam quality investigation has never been stopped. When SECRAL was upgraded to its typical operation frequency 24 GHz, it had already showed its promising capacity of very intense highly charged ion beam production. And it has also provided the strong experimental support for the so called scaling laws of microwave frequency effect. However, compared to the microwave power heating efficiency at 18 GHz, 24 GHz microwave heating does not show the ω{sup 2} scale at the same power level, which indicates that microwave power coupling at gyrotron frequency needs better understanding. In this paper, after a review of the operation status of SECRAL with regard to the beam availability and stability, the recent study of the extracted ion beam transverse coupling issues will be discussed, and the test results of the both TE{sub 01} and HE{sub 11} modes will be presented. A general comparison of the performance working with the two injection modes will be given, and a preliminary analysis will be introduced. The latest results of the production of very intense highly charged ion beams, such as 1.42 emA Ar{sup 12+}, 0.92 emA Xe{sup 27+}, and so on, will be presented.

  7. Simple setup for gas-phase h/d exchange mass spectrometry coupled to electron transfer dissociation and ion mobility for analysis of polypeptide structure on a liquid chromatographic time scale

    DEFF Research Database (Denmark)

    Mistarz, Ulrik Hvid; Brown, Jeffery M; Haselmann, Kim F

    2014-01-01

    inside a mass spectrometer immediately after ESI (gas-phase HDX-MS) and show utility for studying the primary and higher-order structure of peptides and proteins. HDX was achieved by passing N2-gas through a container filled with aqueous deuterated ammonia reagent (ND3/D2O) and admitting the saturated....../D2O as HDX reagent indicate that labeling is facilitated exclusively through gaseous ND3, yielding similar results to the infusion of purified ND3-gas, while circumventing the complications associated with the use of hazardous purified gases. Comparison of the solution-phase- and gas-phase deuterium...... separation or electron transfer dissociation, thus enabling multiple orthogonal analyses of the structural properties of peptides and proteins in a single automated LC-MS workflow....

  8. Ion Transport through Diffusion Layer Controlled by Charge Mosaic Membrane

    Directory of Open Access Journals (Sweden)

    Akira Yamauchi

    2012-01-01

    Full Text Available The kinetic transport behaviors in near interface of the membranes were studied using commercial anion and cation exchange membrane and charge mosaic membrane. Current-voltage curve gave the limiting current density that indicates the ceiling of conventional flux. From chronopotentiometry above the limiting current density, the transition time was estimated. The thickness of boundary layer was derived with conjunction with the conventional limiting current density and the transition time from steady state flux. On the other hand, the charge mosaic membrane was introduced in order to examine the ion transport on the membrane surface in detail. The concentration profile was discussed by the kinetic transport number with regard to the water dissociation (splitting on the membrane surface.

  9. Modelling surface restructuring by slow highly charged ions

    Science.gov (United States)

    Wachter, G.; Tőkési, K.; Betz, G.; Lemell, C.; Burgdörfer, J.

    2013-12-01

    We theoretically investigate surface modifications on alkaline earth halides due to highly charged ion impact, focusing on recent experimental evidence for both etch pit and nano-hillock formation on CaF2 (A.S. El-Said et al., Phys. Rev. Lett. 109, (2012) 117602 [1]). We discuss mechanisms for converting the projectile potential and kinetic energies into thermal energy capable of changing the surface structure. A proof-of-principle classical molecular dynamics simulation suggests the existence of two thresholds which we associate with etch pit and nano-hillock formation in qualitative agreement with experiment.

  10. Modelling surface restructuring by slow highly charged ions

    Energy Technology Data Exchange (ETDEWEB)

    Wachter, G., E-mail: georg.wachter@tuwien.ac.at [Institute for Theoretical Physics, Vienna University of Technology, Wiedner Hauptstraße 8-10, A-1040 Vienna (Austria); Tőkési, K. [Institute of Nuclear Research of the Hungarian Academy of Science (ATOMKI), H-4001 Debrecen, P.O. Box 51 (Hungary); Betz, G. [Institute for Applied Physics, Vienna University of Technology, Wiedner Hauptstraße 8-10, A-1040 Vienna (Austria); Lemell, C.; Burgdörfer, J. [Institute for Theoretical Physics, Vienna University of Technology, Wiedner Hauptstraße 8-10, A-1040 Vienna (Austria)

    2013-12-15

    We theoretically investigate surface modifications on alkaline earth halides due to highly charged ion impact, focusing on recent experimental evidence for both etch pit and nano-hillock formation on CaF{sub 2} (A.S. El-Said et al., Phys. Rev. Lett. 109, (2012) 117602 [1]). We discuss mechanisms for converting the projectile potential and kinetic energies into thermal energy capable of changing the surface structure. A proof-of-principle classical molecular dynamics simulation suggests the existence of two thresholds which we associate with etch pit and nano-hillock formation in qualitative agreement with experiment.

  11. Analysis of Ion Charge States in Solar Wind and CMEs

    Indian Academy of Sciences (India)

    Arati Dasgupta; J. M. Laming

    2008-03-01

    We discuss needs in dielectronic recombination data motivated by recent work directed at a quantitative understanding of ion charge states of various elements observed in situ in the solar wind and CMEs. The competing processes of ionization and recombination lead to departures from collision ionization equilibrium. The use of this as a diagnostic of acceleration and heating processes of the solar wind and CMEs is sensitive to the accuracy of the atomic rates in a way that steady state ionization equilibrium plasmas are not. The most pressing need is dielectronic recombination rates for ions Fe8+-12+. These are among the dominant species observed in various regions of the solar wind and CMEs, and in remotely sensed EUV spectra.

  12. Highly confined ions store charge more efficiently in supercapacitors.

    Science.gov (United States)

    Merlet, C; Péan, C; Rotenberg, B; Madden, P A; Daffos, B; Taberna, P-L; Simon, P; Salanne, M

    2013-01-01

    Liquids exhibit specific properties when they are adsorbed in nanoporous structures. This is particularly true in the context of supercapacitors, for which an anomalous increase in performance has been observed for nanoporous electrodes. This enhancement has been traditionally attributed in experimental studies to the effect of confinement of the ions from the electrolyte inside sub-nanometre pores, which is accompanied by their partial desolvation. Here we perform molecular dynamics simulations of realistic supercapacitors and show that this picture is correct at the microscopic scale. We provide a detailed analysis of the various environments experienced by the ions. We pick out four different adsorption types, and we, respectively, label them as edge, planar, hollow and pocket sites upon increase of the coordination of the molecular species by carbon atoms from the electrode. We show that both the desolvation and the local charge stored on the electrode increase with the degree of confinement.

  13. Influence of ion size and charge on osmosis.

    Science.gov (United States)

    Cannon, James; Kim, Daejoong; Maruyama, Shigeo; Shiomi, Junichiro

    2012-04-12

    Osmosis is fundamental to many processes, such as in the function of biological cells and in industrial desalination to obtain clean drinking water. The choice of solute in industrial applications of osmosis is highly important in maximizing efficiency and minimizing costs. The macroscale process of osmosis originates from the nanoscale properties of the solvent, and therefore an understanding of the mechanisms of how these properties determine osmotic strength can be highly useful. For this reason, we have undertaken molecular dynamics simulations to systematically study the influence of ion size and charge on the strength of osmosis of water through carbon nanotube membranes. Our results show that strong osmosis occurs under optimum conditions of ion placement near the region of high water density near the membrane wall and of maintenance of a strong water hydration shell around the ions. The results in turn allow greater insight into the origin of the strong osmotic strength of real ions such as NaCl. Finally, in terms of practical simulation, we highlight the importance of avoiding size effects that can occur if the simulation cell is too small.

  14. Energy dissipation of highly charged ions on Al oxide films.

    Science.gov (United States)

    Lake, R E; Pomeroy, J M; Sosolik, C E

    2010-03-03

    Slow highly charged ions (HCIs) carry a large amount of potential energy that can be dissipated within femtoseconds upon interaction with a surface. HCI-insulator collisions result in high sputter yields and surface nanofeature creation due to strong coupling between the solid's electronic system and lattice. For HCIs interacting with Al oxide, combined experiments and theory indicate that defect mediated desorption can explain reasonably well preferential O atom removal and an observed threshold for sputtering due to potential energy. These studies have relied on measuring mass loss on the target substrate or probing craters left after desorption. Our approach is to extract highly charged ions onto the Al oxide barriers of metal-insulator-metal tunnel junctions and measure the increased conductance in a finished device after the irradiated interface is buried under the top metal layer. Such transport measurements constrain dynamic surface processes and provide large sets of statistics concerning the way individual HCI projectiles dissipate their potential energy. Results for Xe(q +) for q = 32, 40, 44 extracted onto Al oxide films are discussed in terms of postirradiation electrical device characteristics. Future work will elucidate the relationship between potential energy dissipation and tunneling phenomena through HCI modified oxides.

  15. Negative Ion MALDI Mass Spectrometry of Polyoxometalates (POMs): Mechanism of Singly Charged Anion Formation and Chemical Properties Evaluation

    Science.gov (United States)

    Boulicault, Jean E.; Alves, Sandra; Cole, Richard B.

    2016-08-01

    MALDI-MS has been developed for the negative ion mode analysis of polyoxometalates (POMs). Matrix optimization was performed using a variety of matrix compounds. A first group of matrixes offers MALDI mass spectra containing abundant intact singly charged anionic adduct ions, as well as abundant in-source fragmentations at elevated laser powers. A relative ranking of the ability to induce POM fragmentation is found to be: DAN > CHCA > CNA > DIT> HABA > DCTB > IAA. Matrixes of a second group provide poorer quality MALDI mass spectra without observable fragments. Sample preparation, including the testing of salt additives, was performed to optimize signals for a model POM, POMc12, the core structure of which bears four negative charges. The matrix 9-cyanoanthracene (CNA) provided the best signals corresponding to singly charged intact POMc12 anions. Decompositions of these intact anionic species were examined in detail, and it was concluded that hydrogen radical-induced mechanisms were not prevalent, but rather that the observed prompt fragments originate from transferred energy derived from initial electronic excitation of the CNA matrix. Moreover, in obtained MALDI mass spectra, clear evidence of electron transfer to analyte POM species was found: a manifestation of the POMs ability to readily capture electrons. The affinity of polyanionic POMc12 toward a variety of cations was evaluated and the following affinity ranking was established: Fe3+ > Al3+ > Li+ > Ga3+ > Co2+ > Cr3+ > Cu2+ > [Mn2+, Mg2+] > [Na+, K+]. Thus, from the available cationic species, specific adducts are preferentially formed, and evidence is given that these higher affinity POM complexes are formed in the gas phase during the early stages of plume expansion.

  16. Charge Breeding of Radioactive Ions in an Electron Cyclotron Resonance Ion Source(ECRIS) at ISOLDE

    CERN Multimedia

    Lindroos, M

    2002-01-01

    The development of an efficient charge breeding scheme for the next generation of RIB facilities will have a strong impact on the post-accelerator for several Radioactive Ion Beam (RIB) projects at European large scale facilities. At ISOLDE/CERN there will be the unique possibility to carry out experiments with the two possible charge breeding set-ups with a large variety of radioactive isotopes using identical injection conditions. One charge breeding set-up is the Penning trap/EBIS combination which feeds the REX-ISOLDE linear accelerator and which is in commissioning now. The second charge breeder is a new ECRIS PHOENIX developed at the ISN ion source laboratory at Grenoble. This ECRIS is now under investigation with a 14 GHz amplifier to characterize its performance. The experiments are accompanied by theoretical studies in computer simulations in order to optimize the capture of the ions in the ECRIS plasma. A second identical PHOENIX ECRIS which is under investigation at the Daresbury Laboratory is avai...

  17. Theoretical Studies of Gas Phase Elementary and Carbon Nanostructure Growth Reactions

    Science.gov (United States)

    2013-09-19

    DOI: 10.1021/ct1000268. 26. A. J. Midey, T. M. Miller, A. A. Viggiano, N. C. Bera, S. Maeda, and K. Morokuma, Chemistry of VX Surrogates and Ion...THEORETICAL STUDIES OF GAS PHASE ELEMENTARY AND CARBON NANOSTRUCTURE GROWTH REACTIONS KEIJI MOROKUMA EMORY UNIVERSITY 09/19/2013 Final Report...Z39.18 30-09-2013 Final Performance Report 1 July 2010 - 30 June 2013 Theoretical Studies of Gas Phase Elementary and Carbon Nanostructure Growth

  18. Highly-charged-ion-induced electron emission from C-60 thin films

    NARCIS (Netherlands)

    Bodewits, E.; Hoekstra, R.; Kowarik, G.; Dobes, K.; Aumayr, F.

    2011-01-01

    The secondary electron yields as a result of highly charged ions impinging on clean Au(111) and thin films of C-60 on Au have been measured. This has been done for film thicknesses of one to five monolayers and several charge states of Ar and Xe ions. For all ions an increase of 35% in the secondary

  19. Additional considerations about the role of ion size in charge reversal

    Energy Technology Data Exchange (ETDEWEB)

    Martin-Molina, A; Hidalgo-Alvarez, R [Grupo de Fisica de Fluidos y Biocoloides, Departamento de Fisica Aplicada, Facultad de Ciencias, Universidad de Granada, Granada 18071 (Spain); Quesada-Perez, M, E-mail: almartin@ugr.e [Departamento de Fisica, Universidad de Jaen, Escuela Politecnica Superior de Linares, 23700 Linares, Jaen (Spain)

    2009-10-21

    The effect of the ion size on the charge reversal process is studied via canonical Monte Carlo simulation. To this end, a primitive model of electrolyte is used to analyze the electric double layer formed by an asymmetric electrolyte in the presence of a charged planar wall. Different values of ion diameters and surface charge densities are used so as to determine the conditions at which the charge reversal first occurs. For each case, the apparent surface charge density is calculated as a function of the distance from the charged wall for the different electrolyte concentrations in order to establish the minimal salt concentration required for the charge reversal. We will refer to this electrolyte concentration as the reversal concentration and will show how it depends on the surface charge density and on the ion size. From the apparent surface charge density profiles, the distance from the wall at which the charge reversal arises as well as its intensity can be also inferred.

  20. Theory for charge states of energetic oxygen ions in the earth's radiation belts

    Science.gov (United States)

    Spjeldvik, W. N.; Fritz, T. A.

    1978-01-01

    Fluxes of geomagnetically trapped energetic oxygen ions have been studied in detail. Ion distributions in radial locations below the geostationary orbit, energy spectra between 1 keV and 100 MeV, and the distribution over charge states have been computed for equatorially mirroring ions. Both ionospheric and solar wind oxygen ion sources have been considered, and it is found that the charge state distributions in the interior of the radiation belts are largely independent of the charge state characteristics of the sources. In the MeV range, oxygen ions prove to be a more sensitive probe for radiation belt dynamics than helium ions and protons.

  1. Development of a Kingdon ion trap system for trapping externally injected highly charged ions.

    Science.gov (United States)

    Numadate, Naoki; Okada, Kunihiro; Nakamura, Nobuyuki; Tanuma, Hajime

    2014-10-01

    We have developed a Kingdon ion trap system for the purpose of the laboratory observation of the x-ray forbidden transitions of highly charged ions (HCIs). Externally injected Ar(q+) (q = 5-7) with kinetic energies of 6q keV were successfully trapped in the ion trap. The energy distribution of trapped ions is discussed in detail on the basis of numerical simulations. The combination of the Kingdon ion trap and the time-of-flight mass spectrometer enabled us to measure precise trapping lifetimes of HCIs. As a performance test of the instrument, we measured trapping lifetimes of Ar(q+) (q = 5-7) under a constant number density of H2 and determined the charge-transfer cross sections of Ar(q+)(q = 5, 6)-H2 collision systems at binary collision energies of a few eV. It was confirmed that the present cross section data are consistent with previous data and the values estimated by some scaling formula.

  2. Observation of an unusually facile fragmentation pathway of gas-phase peptide ions: a study on the gas-phase fragmentation mechanism and energetics of tryptic peptides modified with 4-sulfophenyl isothiocyanate (SPITC) and 4-chlorosulfophenyl isocyanate (SPC) and their 18-crown-6 complexes.

    Science.gov (United States)

    Shin, Joong-Won; Lee, Yong Ho; Hwang, Sungu; Lee, Sang-Won

    2007-03-01

    Various peptide modifications have been explored recently to facilitate the acquisition of sequence information. N-terminal sulfonation is an interesting modification because it allows unambiguous de novo sequencing of peptides, especially in conjunction with MALDI-PSD-TOF analysis; such modified peptide ions undergo fragmentation at energies lower than those required conventionally for unmodified peptide ions. In this study, we systematically investigated the fragmentation mechanisms of N-terminal sulfonated peptide ions prepared using two different N-terminal sulfonation reagents: 4-sulfophenyl isothiocyanate (SPITC) and 4-chlorosulfophenyl isocyanate (SPC). Collision-induced dissociation (CID) of the SPC-modified peptide ions produced a set of y-series ions that were more evenly distributed relative to those observed for the SPITC-modified peptides; y(n-1) ion peaks were consistently and significantly larger than the signals of the other y-ions. We experimentally investigated the differences between the dissociation energies of the SPITC- and SPC-modified peptide ions by comparing the MS/MS spectra of the complexes formed between the crown ether 18-crown-6 (CE) and the modified peptides. Upon CID, the complexes formed between 18-crown-6 ether and the protonated amino groups of C-terminal lysine residues underwent either peptide backbone fragmentation or complex dissociation. Although the crown ether complexes of the unmodified ([M + CE + 2H]2+) and SPC-modified ([M* + CE + 2H]2+) peptides underwent predominantly noncovalent complex dissociation upon CID, the low-energy dissociations of the crown ether complexes of the SPITC-modified peptides ([M' + CE + 2H]2+) unexpectedly resulted in peptide backbone fragmentations, along with a degree of complex dissociation. We performed quantum mechanical calculations to address the energetics of fragmentations observed for the modified peptides.

  3. Effects of Charge in Heavy Ions on Solitary Kinetic Alfvén Waves in Double-Ion Plasmas

    Institute of Scientific and Technical Information of China (English)

    YANG Lei; WU De-Jin

    2006-01-01

    @@ After the charge of heavy ions is considered, a Sagdeev equation is obtained for the solitary kinetic Alfvén waves (SKAWs) in a low-β(me/mp<<β<<1 or mp/me>>α>>1), three-component (electrons, protons, and highly charged heavy ions) plasma. Numerical results show that the charge number q of heavy ions can cause the width of the solitary structure to decrease, but increase for the maximum of electron density nem≤1.2 and the initial abundance of heavy ions Cb0 ≤ 0.1. The parallel phase speed of the waves increases with larger q.

  4. Ion-induced nucleation of dibutyl phthalate vapors on spherical and nonspherical singly and multiply charged polyethylene glycol ions.

    Science.gov (United States)

    Nasibulin, Albert G; de la Mora, Juan Fernandez; Kauppinen, Esko I

    2008-02-14

    Dibutyl phthalate vapor nucleation induced by positive polyethylene glycol (PEG) ions with controlled sizes and charges was experimentally studied. The ions were produced by electrospray ionization, classified in a high-resolution differential mobility analyzer, and studied in a nano condensation nucleus counter of the mixing type. Ionic radii of PEG varied from 0.52 to 1.56 nm, including from singly to quadruply charged ions. Some of these ions are fully stretched chains, other are spherical, and others have intermediate forms, all of them having been previously characterized by mobility and mass spectrometry studies. Activation of PEG1080(+2) requires a supersaturation almost as high as that required for small singly charged ions and higher than for PEG1080(+). This anomaly is explained by the Coulombic stretching of the ion into a long chain, where the two charged centers appear to be relatively decoupled from each other. The critical supersaturation for singly charged spherical ions falls below Thomson's (capillary) theory and even below the already low values seen previously for tetraheptyl ammonium bromide clusters. Spherical PEG4120(+2) falls close to the Thomson curve. The trends observed for slightly nonspherical PEG4120(+3) and highly nonspherical (but not quite linear) PEG4120(+4) are intermediate between those of multiply charged spheres and small singly charged ions.

  5. New development of laser ion source for highly charged ion beam production at Institute of Modern Physics (invited)

    Science.gov (United States)

    Zhao, H. Y.; Zhang, J. J.; Jin, Q. Y.; Liu, W.; Wang, G. C.; Sun, L. T.; Zhang, X. Z.; Zhao, H. W.

    2016-02-01

    A laser ion source based on Nd:YAG laser has been being studied at the Institute of Modern Physics for the production of high intensity high charge state heavy ion beams in the past ten years, for possible applications both in a future accelerator complex and in heavy ion cancer therapy facilities. Based on the previous results for the production of multiple-charged ions from a wide range of heavy elements with a 3 J/8 ns Nd:YAG laser [Zhao et al., Rev. Sci. Instrum. 85, 02B910 (2014)], higher laser energy and intensity in the focal spot are necessary for the production of highly charged ions from the elements heavier than aluminum. Therefore, the laser ion source was upgraded with a new Nd:YAG laser, the maximum energy of which is 8 J and the pulse duration can be adjusted from 8 to 18 ns. Since then, the charge state distributions of ions from various elements generated by the 8 J Nd:YAG laser were investigated for different experimental conditions, such as laser energy, pulse duration, power density in the focal spot, and incidence angle. It was shown that the incidence angle is one of the most important parameters for the production of highly charged ions. The capability of producing highly charged ions from the elements lighter than silver was demonstrated with the incidence angle of 10° and laser power density of 8 × 1013 W cm-2 in the focal spot, which makes a laser ion source complementary to the superconducting electron cyclotron resonance ion source for the future accelerator complex especially in terms of the ion beam production from some refractory elements. Nevertheless, great efforts with regard to the extraction of intense ion beams, modification of the ion beam pulse duration, and reliability of the ion source still need to be made for practical applications.

  6. New development of laser ion source for highly charged ion beam production at Institute of Modern Physics (invited)

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, H. Y., E-mail: zhaohy@impcas.ac.cn; Zhang, J. J.; Jin, Q. Y.; Sun, L. T.; Zhang, X. Z.; Zhao, H. W. [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Liu, W.; Wang, G. C. [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); University of Chinese Academy of Sciences, Beijing 100049 (China)

    2016-02-15

    A laser ion source based on Nd:YAG laser has been being studied at the Institute of Modern Physics for the production of high intensity high charge state heavy ion beams in the past ten years, for possible applications both in a future accelerator complex and in heavy ion cancer therapy facilities. Based on the previous results for the production of multiple-charged ions from a wide range of heavy elements with a 3 J/8 ns Nd:YAG laser [Zhao et al., Rev. Sci. Instrum. 85, 02B910 (2014)], higher laser energy and intensity in the focal spot are necessary for the production of highly charged ions from the elements heavier than aluminum. Therefore, the laser ion source was upgraded with a new Nd:YAG laser, the maximum energy of which is 8 J and the pulse duration can be adjusted from 8 to 18 ns. Since then, the charge state distributions of ions from various elements generated by the 8 J Nd:YAG laser were investigated for different experimental conditions, such as laser energy, pulse duration, power density in the focal spot, and incidence angle. It was shown that the incidence angle is one of the most important parameters for the production of highly charged ions. The capability of producing highly charged ions from the elements lighter than silver was demonstrated with the incidence angle of 10° and laser power density of 8 × 10{sup 13} W cm{sup −2} in the focal spot, which makes a laser ion source complementary to the superconducting electron cyclotron resonance ion source for the future accelerator complex especially in terms of the ion beam production from some refractory elements. Nevertheless, great efforts with regard to the extraction of intense ion beams, modification of the ion beam pulse duration, and reliability of the ion source still need to be made for practical applications.

  7. New development of laser ion source for highly charged ion beam production at Institute of Modern Physics (invited).

    Science.gov (United States)

    Zhao, H Y; Zhang, J J; Jin, Q Y; Liu, W; Wang, G C; Sun, L T; Zhang, X Z; Zhao, H W

    2016-02-01

    A laser ion source based on Nd:YAG laser has been being studied at the Institute of Modern Physics for the production of high intensity high charge state heavy ion beams in the past ten years, for possible applications both in a future accelerator complex and in heavy ion cancer therapy facilities. Based on the previous results for the production of multiple-charged ions from a wide range of heavy elements with a 3 J/8 ns Nd:YAG laser [Zhao et al., Rev. Sci. Instrum. 85, 02B910 (2014)], higher laser energy and intensity in the focal spot are necessary for the production of highly charged ions from the elements heavier than aluminum. Therefore, the laser ion source was upgraded with a new Nd:YAG laser, the maximum energy of which is 8 J and the pulse duration can be adjusted from 8 to 18 ns. Since then, the charge state distributions of ions from various elements generated by the 8 J Nd:YAG laser were investigated for different experimental conditions, such as laser energy, pulse duration, power density in the focal spot, and incidence angle. It was shown that the incidence angle is one of the most important parameters for the production of highly charged ions. The capability of producing highly charged ions from the elements lighter than silver was demonstrated with the incidence angle of 10° and laser power density of 8 × 10(13) W cm(-2) in the focal spot, which makes a laser ion source complementary to the superconducting electron cyclotron resonance ion source for the future accelerator complex especially in terms of the ion beam production from some refractory elements. Nevertheless, great efforts with regard to the extraction of intense ion beams, modification of the ion beam pulse duration, and reliability of the ion source still need to be made for practical applications.

  8. Charge Exchange Collisions between Ultracold Fermionic Lithium Atoms and Calcium Ions

    CERN Document Server

    Haze, Shinsuke; Saito, Ryoichi; Mukaiyama, Takashi

    2014-01-01

    An observation of charge exchange collisions between ultracold fermionic 6Li atoms and 40Ca+ ions is reported. The reaction product of the charge exchange collision is dentified via mass spectrometry where the motion of the ions is excited parametrically. We measure the cross section of the charge exchange collisions between the 6Li atoms in the ground state and the 40Ca+ ions in the ground and metastable excited states. Investigation of the inelastic collision characteristics in the atom-ion mixture is an important step toward ultracold chemistry based on ultracold atoms and ions.

  9. Intrinsic slow charge response in the perovskite solar cells: Electron and ion transport

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Jiangjian; Xu, Xin; Zhang, Huiyin; Luo, Yanhong; Li, Dongmei; Meng, Qingbo, E-mail: qbmeng@iphy.ac.cn [Key Laboratory for Renewable Energy, Chinese Academy of Sciences, Beijing 100190 (China); Beijing Key Laboratory for New Energy Materials and Devices, Beijing 100190 (China); Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China)

    2015-10-19

    The intrinsic charge response and hysteresis characteristic in the perovskite solar cell has been investigated by an electrically modulated transient photocurrent technology. An ultraslow charge response process in the timescale of seconds is observed, which can be well explained by the ion migration in the perovskite CH{sub 3}NH{sub 3}PbI{sub 3} film driven by multiple electric fields derived from the heterojunction depletion charge, the external modulation, and the accumulated ion charge. Furthermore, theoretical calculation of charge transport reveals that the hysteresis behavior is also significantly influenced by the interfacial charge extraction velocity and the carrier transport properties inside the cell.

  10. Beamline for low-energy transport of highly charged ions at HITRAP

    Energy Technology Data Exchange (ETDEWEB)

    Andelkovic, Z., E-mail: z.andelkovic@gsi.de [GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt (Germany); Herfurth, F.; Kotovskiy, N. [GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt (Germany); König, K.; Maaß, B.; Murböck, T. [Technische Universität Darmstadt (Germany); Neidherr, D. [GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt (Germany); Schmidt, S. [Technische Universität Darmstadt (Germany); Johannes Gutenberg-Universität Mainz (Germany); Steinmann, J. [GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt (Germany); Hochschule Darmstadt (Germany); Vogel, M.; Vorobjev, G. [GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt (Germany)

    2015-09-21

    A beamline for transport of highly charged ions with energies as low as a few keV/charge has been constructed and commissioned at GSI. Complementary to the existing infrastructure of the HITRAP facility for deceleration of highly charged ions from the GSI accelerator, the new beamline connects the HITRAP ion decelerator and an EBIT with the associated experimental setups. Therefore, the facility can now transport the decelerated heavy highly charged ions to the experiments or supply them offline with medium-heavy highly charged ions from the EBIT, both at energies as low as a few keV/charge. Here we present the design of the 20 m long beamline with the corresponding beam instrumentation, as well as its performance in terms of energy and transport efficiency.

  11. Improved charge breeding efficiency of light ions with an electron cyclotron resonance ion source

    Energy Technology Data Exchange (ETDEWEB)

    Vondrasek, R.; Kutsaev, Sergey [Argonne National Laboratory, Argonne, Illinois 60439 (United States); Delahaye, P.; Maunoury, L. [Grand Accelerateur National d' Ions Lourds (GANIL), CEA/DSM-CNRS/IN2P3, Blvd Henri Becquerel, 14076 Caen (France)

    2012-11-15

    The Californium Rare Isotope Breeder Upgrade is a new radioactive beam facility for the Argonne Tandem Linac Accelerator System (ATLAS). The facility utilizes a {sup 252}Cf fission source coupled with an electron cyclotron resonance ion source to provide radioactive beam species for the ATLAS experimental program. The californium fission fragment distribution provides nuclei in the mid-mass range which are difficult to extract from production targets using the isotope separation on line technique and are not well populated by low-energy fission of uranium. To date the charge breeding program has focused on optimizing these mid-mass beams, achieving high charge breeding efficiencies of both gaseous and solid species including 14.7% for the radioactive species {sup 143}Ba{sup 27+}. In an effort to better understand the charge breeding mechanism, we have recently focused on the low-mass species sodium and potassium which up to present have been difficult to charge breed efficiently. Unprecedented charge breeding efficiencies of 10.1% for {sup 23}Na{sup 7+} and 17.9% for {sup 39}K{sup 10+} were obtained injecting stable Na{sup +} and K{sup +} beams from a surface ionization source.

  12. Continuous-Flow Gas-Phase Bioreactors

    Science.gov (United States)

    Wise, Donald L.; Trantolo, Debra J.

    1994-01-01

    Continuous-flow gas-phase bioreactors proposed for biochemical, food-processing, and related industries. Reactor contains one or more selected enzymes dehydrated or otherwise immobilized on solid carrier. Selected reactant gases fed into reactor, wherein chemical reactions catalyzed by enzyme(s) yield product biochemicals. Concept based on discovery that enzymes not necessarily placed in traditional aqueous environments to function as biocatalysts.

  13. Gas-Phase Infrared; JCAMP Format

    Science.gov (United States)

    SRD 35 NIST/EPA Gas-Phase Infrared; JCAMP Format (PC database for purchase)   This data collection contains 5,228 infrared spectra in the JCAMP-DX (Joint Committee for Atomic and Molecular Physical Data "Data Exchange") format.

  14. Formation and fragmentation of quadruply charged molecular ions by intense femtosecond laser pulses.

    Science.gov (United States)

    Yatsuhashi, Tomoyuki; Nakashima, Nobuaki

    2010-07-22

    We investigated the formation and fragmentation of multiply charged molecular ions of several aromatic molecules by intense nonresonant femtosecond laser pulses of 1.4 mum with a 130 fs pulse duration (up to 2 x 10(14) W cm(-2)). Quadruply charged states were produced for 2,3-benzofluorene and triphenylene molecular ion in large abundance, whereas naphthalene and 1,1'-binaphthyl resulted only in up to triply charged molecular ions. The laser wavelength was nonresonant with regard to the electronic transitions of the neutral molecules, and the degree of fragmentation was strongly correlated with the absorption of the singly charged cation radical. Little fragmentation was observed for naphthalene (off-resonant with cation), whereas heavy fragmentation was observed in the case of 1,1'-binaphthyl (resonant with cation). The degree of H(2) (2H) and 2H(2) (4H) elimination from molecular ions increased as the charge states increased in all the molecules examined. A striking difference was found between triply and quadruply charged 2,3-benzofluorene: significant suppression of molecular ions with loss of odd number of hydrogen was observed in the quadruply charged ions. The Coulomb explosion of protons in the quadruply charged state and succeeding fragmentation resulted in the formation of triply charged molecular ions with an odd number of hydrogens. The hydrogen elimination mechanism in the highly charged state is discussed.

  15. Charging of Proteins in Native Mass Spectrometry

    Science.gov (United States)

    Susa, Anna C.; Xia, Zijie; Tang, Henry Y. H.; Tainer, John A.; Williams, Evan R.

    2017-02-01

    Factors that influence the charging of protein ions formed by electrospray ionization from aqueous solutions in which proteins have native structures and function were investigated. Protein ions ranging in molecular weight from 12.3 to 79.7 kDa and pI values from 5.4 to 9.6 were formed from different solutions and reacted with volatile bases of gas-phase basicities higher than that of ammonia in the cell of a Fourier-transform ion cyclotron resonance mass spectrometer. The charge-state distribution of cytochrome c ions formed from aqueous ammonium or potassium acetate is the same. Moreover, ions formed from these two solutions do not undergo proton transfer to 2-fluoropyridine, which is 8 kcal/mol more basic than ammonia. These results provide compelling evidence that proton transfer between ammonia and protein ions does not limit protein ion charge in native electrospray ionization. Both circular dichroism and ion mobility measurements indicate that there are differences in conformations of proteins in pure water and aqueous ammonium acetate, and these differences can account for the difference in the extent of charging and proton-transfer reactivities of protein ions formed from these solutions. The extent of proton transfer of the protein ions with higher gas-phase basicity bases trends with how closely the protein ions are charged to the value predicted by the Rayleigh limit for spherical water droplets approximately the same size as the proteins. These results indicate that droplet charge limits protein ion charge in native mass spectrometry and are consistent with these ions being formed by the charged residue mechanism.

  16. Spontaneous Mass and Charge Losses from Single Multi-Megadalton Ions Studied by Charge Detection Mass Spectrometry

    Science.gov (United States)

    Keifer, David Z.; Alexander, Andrew W.; Jarrold, Martin F.

    2017-01-01

    Spontaneous mass and charge losses from individual multi-megadalton ions have been observed with charge detection mass spectrometry (CDMS) by trapping single hepatitis B virus (HBV) capsids for 3 s. Gradual increases in the oscillation frequency of single ions in the ion trap are attributed mainly to mass loss (probably solvent, water, and/or salt). The total mass lost during the 3 s trapping period peaks at around 20 kDa for 4 MDa HBV T = 4 capsids. Discrete frequency drops punctuate the gradual increases in the oscillation frequencies. The drops are attributed to a sudden loss of charge. In most cases a single positive charge is lost along with some mass (on average around 1000 Da). Charge loss occurs for over 40% of the trapped ions. It usually occurs near the beginning of the trapping event, and it occurs preferentially in regions of the trap with strong electric fields, indicating that external electric fields promote charge loss. This process may contribute to the decrease in m/z resolution that often occurs with megadalton ions.

  17. Charge-transfer energy in closed-shell ion-atom interactions. [for H and Li ions in He

    Science.gov (United States)

    Alvarez-Rizzatti, M.; Mason, E. A.

    1975-01-01

    The importance of charge-transfer energy in the interactions between closed-shell ions and atoms is investigated. Ab initio calculations on H(plus)-He and Li(plus)-He are used as a guide for the construction of approximate methods for the estimation of the charge-transfer energy for more complicated systems. For many alkali ion-rate gas systems the charge-transfer energy is comparable to the induction energy in the region of the potential minimum, although for doubly charged alkaline-earth ions in rare gases the induction energy always dominates. Surprisingly, an empirical combination of repulsion energy plus asymptotic induction energy plus asymptotic dispersion energy seems to give a fair representation of the total interaction, especially if the repulsion energy is parameterized, despite the omission of any explicit charge-transfer contribution. More refined interaction models should consider the charge-transfer energy contribution.

  18. Radical Reactions in the Gas Phase: Recent Development and Application in Biomolecules

    Directory of Open Access Journals (Sweden)

    Yang Gao

    2014-01-01

    Full Text Available This review summarizes recent literature describing the use of gas phase radical reactions for structural characterization of complex biomolecules other than peptides. Specifically, chemical derivatization, in-source chemical reaction, and gas phase ion/ion reactions have been demonstrated as effective ways to generate radical precursor ions that yield structural informative fragments complementary to those from conventional collision-induced dissociation (CID. Radical driven dissociation has been applied to a variety of biomolecules including peptides, nucleic acids, carbohydrates, and phospholipids. The majority of the molecules discussed in this review see limited fragmentation from conventional CID, and the gas phase radical reactions open up completely new dissociation channels for these molecules and therefore yield high fidelity confirmation of the structures of the target molecules. Due to the extensively studied peptide fragmentation, this review focuses only on nonpeptide biomolecules such as nucleic acids, carbohydrates, and phospholipids.

  19. Quantitative evaluation of charge-reduction effect in cluster constituent ions passing through a foil

    Energy Technology Data Exchange (ETDEWEB)

    Chiba, A., E-mail: chiba.atsuya@jaea.go.jp [Takasaki Advanced Radiation Research Institute, Japan Atomic Energy Agency (JAEA), 1233 Watanuki-machi, Takasaki-shi, Gunma 370-1292 (Japan); Saitoh, Y.; Narumi, K.; Yamada, K. [Takasaki Advanced Radiation Research Institute, Japan Atomic Energy Agency (JAEA), 1233 Watanuki-machi, Takasaki-shi, Gunma 370-1292 (Japan); Kaneko, T. [Department of Applied Physics, Okayama University of Science, 1-1 Ridai-cho, kita-ku, Okayama-shi, Okayama 700-0005 (Japan)

    2013-11-15

    Swift cluster ions, which cause characteristic irradiation effects on a solid surface, have a possibility of establishing a new ion irradiation technique for high-sensitivity surface analysis and innovative surface modification. However, the mechanism of cluster irradiation effects has not been understood completely. We have focused on the charge reduction effect in some physical phenomena and performed a quantitative evaluation of the relationship between the charge state and the interatomic distance of the constituent ions moving in the solid. This technique is based on the refined analysis of the divergence angle of the constituent ions resulting from the foil-induced dissociation of the two-atomic molecular ion. The results derived from this analytical approach clearly showed the correlation between the average charge and the interatomic distance of the constituent ions and implied that the average charge of the constituent ions emerging from the foil varies according to the interatomic distance at the instant of cluster dissociation.

  20. Theoretical investigations of the IO,{sup q+} (q = 2, 3, 4) multi-charged ions: Metastability, characterization and spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Hammami, H. [Université Paris-Est, Laboratoire Modélisation et Simulation Multi Echelle, MSME UMR 8208 CNRS, 5 bd Descartes, 77454 Marne-la-Vallée (France); EMIR, Institut Préparatoire aux Etudes d’Ingénieurs, Monastir (Tunisia); Yazidi, O. [Laboratoire de Spectroscopie Atomique Moléculaire et Applications, Département de Physique, Faculté des Sciences de Tunis, Université de Tunis-El Manar, Le Belvédère, 1060 Tunis (Tunisia); Ben El Hadj Rhouma, M. [EMIR, Institut Préparatoire aux Etudes d’Ingénieurs, Monastir (Tunisia); Al Mogren, M. M. [Chemistry Department, Faculty of Science, King Saud University, PO Box 2455, Riyadh 11451 (Saudi Arabia); Hochlaf, M., E-mail: hochlaf@univ-mlv.fr [Université Paris-Est, Laboratoire Modélisation et Simulation Multi Echelle, MSME UMR 8208 CNRS, 5 bd Descartes, 77454 Marne-la-Vallée (France)

    2014-07-07

    Using ab initio methodology, we studied the IO{sup q+} (q = 2, 3, 4) multi-charged ions. Benchmark computations on the IO(X{sup 2}Π) neutral species allow validate the current procedure. For IO{sup 2+}, several potential wells were found on the ground and the electronic excited states potentials with potential barriers with respect to dissociation, where this dication can exist in the gas phase as long-lived metastable molecules. We confirm hence the recent observation of the dication by mass spectrometry. Moreover, we predict the existence of the metastable IO{sup 3+} trication, where a shallow potential well along the IO internuclear distance is computed. This potential well supports more than 10 vibrational levels. The IO{sup 3+} excited states are repulsive in nature, as well as the computed potentials for the IO{sup 4+} tetracation. For the bound states, we give a set of spectroscopic parameters including excitation transition energies, equilibrium distances, harmonic and anharmonic vibrational terms, and rotational constants. At the MRCI + Q/aug-cc-pV5Z(-PP) level, the adiabatic double and triple ionization energies of IO are computed to be ∼28.1 eV and ∼55.0 eV, respectively.

  1. Highly charged ions as a basis of optical atomic clockwork of exceptional accuracy.

    Science.gov (United States)

    Derevianko, Andrei; Dzuba, V A; Flambaum, V V

    2012-11-02

    We propose a novel class of atomic clocks based on highly charged ions. We consider highly forbidden laser-accessible transitions within the 4f(12) ground-state configurations of highly charged ions. Our evaluation of systematic effects demonstrates that these transitions may be used for building exceptionally accurate atomic clocks which may compete in accuracy with recently proposed nuclear clocks.

  2. Relativistic, QED and nuclear effects in highly charged ions revealed by resonant electron-ion recombination in storage rings

    OpenAIRE

    Schippers, Stefan

    2008-01-01

    Dielectronic recombination (DR) of few-electron ions has evolved into a sensitive spectroscopic tool for highly charged ions. This is due to technological advances in electron-beam preparation and ion-beam cooling techniques at heavy-ion storage rings. Recent experiments prove unambiguously that DR collision spectroscopy has become sensitive to 2nd order QED and to nuclear effects. This review discusses the most recent developments in high-resolution spectroscopy of low-energy DR resonances, ...

  3. Study on the Optimal Charging Strategy for Lithium-Ion Batteries Used in Electric Vehicles

    Directory of Open Access Journals (Sweden)

    Shuo Zhang

    2014-10-01

    Full Text Available The charging method of lithium-ion batteries used in electric vehicles (EVs significantly affects its commercial application. This paper aims to make three contributions to the existing literature. (1 In order to achieve an efficient charging strategy for lithium-ion batteries with shorter charging time and lower charring loss, the trade-off problem between charging loss and charging time has been analyzed in details through the dynamic programing (DP optimization algorithm; (2 To reduce the computation time consumed during the optimization process, we have proposed a database based optimization approach. After off-line calculation, the simulation results can be applied to on-line charge; (3 The novel database-based DP method is proposed and the simulation results illustrate that this method can effectively find the suboptimal charging strategies under a certain balance between the charging loss and charging time.

  4. Tuning Charge Transfer in Ion-Surface Collisions at Hyperthermal Energies.

    Science.gov (United States)

    Yao, Yunxi; Giapis, Konstantinos P

    2016-05-18

    Charge exchange in ion-surface collisions may be influenced by surface adsorbates to alter the charge state of the scattered projectiles. We show here that the positive-ion yield, observed during ion scattering on metal surfaces at low incident energies, is greatly enhanced by adsorbing electronegative species onto the surface. Specifically, when beams of N(+) and O(+) ions are scattered off of clean Au surfaces at hyperthermal energies, no positive ions are observed exiting. Partial adsorption of F atoms on the Au surface, however, leads to the appearance of positively charged primary ions scattering off of Au, a direct result of the increase in the Au work function. The inelastic energy losses for positive-ion exits are slightly larger than the corresponding ionization energies of the respective N and O atoms, which suggest that the detected positive ions are formed by surface reionization during the hard collision event.

  5. QED corrections to atomic wavefunctions in highly charged ions

    Energy Technology Data Exchange (ETDEWEB)

    Holmberg, Johan

    2015-11-18

    Bound electron states in highly charged ions are strongly influenced by the effects of relativity and quantum electrodynamics (QED). These effects induce shifts of the binding energies as well as corrections to observables related to atomic processes. In this work a numerical procedure is described and implemented in which the QED effects are treated as corrections to relativistic bound-state wavefunctions. This approach, which is based on the recently developed covariant evolution-operator formalism, allows for a merging of QED with the standard methods of many-body perturbation theory. In particular, it enables an evaluation of the combined effect of QED and electron correlation in few-electron systems. Numerical results for this effect are presented for the ground state energy of helium-like ions. A detailed analysis of the contribution from the electron self-energy is carried out in both the Feynman and Coulomb gauge. It is found that the Feynman gauge suffers from large numerical cancellations and acquires significant contributions from terms involving multiple interactions with the nuclear potential (the so-called many-potential terms), while the Coulomb gauge is well suited for an approximate treatment based on terms involving only freely propagating electrons (the zero-potential terms). With the help of QED-corrected wavefunctions it is also possible to compute corrections to observables in basic atomic processes. In this work some of the one-loop QED corrections (those derivable from perturbed wavefunctions and energies) to the differential cross section and distribution of polarization in radiative recombination of initially bare uranium nuclei are evaluated, as well as the corresponding corrections to the ratio τ{sub E1}/τ{sub M2} of the electric dipole and magnetic quadrupole transition amplitudes in the 2p{sub 3/2}→1s radiative decay of hydrogenlike uranium. The results from these calculations are all of the expected magnitude, namely on the order

  6. Modifications of gallium phosphide single crystals using slow highly charged ions and swift heavy ions

    Science.gov (United States)

    El-Said, A. S.; Wilhelm, R. A.; Heller, R.; Akhmadaliev, Sh.; Schumann, E.; Sorokin, M.; Facsko, S.; Trautmann, C.

    2016-09-01

    GaP single crystals were irradiated with slow highly charged ions (HCI) using 114 keV 129Xe(33-40)+ and with various swift heavy ions (SHI) of 30 MeV I9+ and 374 MeV-2.2 GeV 197Au25+. The irradiated surfaces were investigated by scanning force microscopy (SFM). The irradiations with SHI lead to nanohillocks protruding from the GaP surfaces, whereas no changes of the surface topography were observed after the irradiation with HCI. This result indicates that a potential energy above 38.5 keV is required for surface nanostructuring of GaP. In addition, strong coloration of the GaP crystals was observed after irradiation with SHI. The effect was stronger for higher energies. This was confirmed by measuring an increased extinction coefficient in the visible light region.

  7. Lithium-Ion Battery Failure: Effects of State of Charge and Packing Configuration

    Science.gov (United States)

    2016-08-22

    Naval Research Laboratory Washington, DC 20375-5320 NRL/MR/6180--16-9689 Lithium-Ion Battery Failure: Effects of State of Charge and Packing ...PAGES 17. LIMITATION OF ABSTRACT Lithium-Ion Battery Failure: Effects of State of Charge and Packing Configuration Neil S. Spinner,* Katherine M. Hinnant...geometries, abuse scenarios, and analysis techniques. In this report, different states of charge and packing configurations of a commercially available

  8. Charge Breeding Techniques in an Electron Beam Ion Trap for High Precision Mass Spectrometry at TITAN

    Science.gov (United States)

    MacDonald, T. D.; Simon, M. C.; Bale, J. C.; Chowdhury, U.; Eibach, M.; Gallant, A. T.; Lennarz, A.; Simon, V. V.; Chaudhuri, A.; Grossheim, A.; Kwiatkowski, A. A.; Schultz, B. E.; Dilling, J.

    2012-10-01

    Penning trap mass spectrometry is the most accurate and precise method available for performing atomic mass measurements. TRIUMF's Ion Trap for Atomic and Nuclear science is currently the only facility to couple its Penning trap to a rare isotope facility and an electron beam ion trap (EBIT). The EBIT is a valuable tool for beam preparation: since the precision scales linearly with the charge state, it takes advantage of the precision gained by using highly charged ions. However, this precision gain is contingent on fast and efficient charge breeding. An optimization algorithm has been developed to identify the optimal conditions for running the EBIT. Taking only the mass number and half-life of the isotope of interest as inputs, the electron beam current density, charge breeding time, charge state, and electron beam energy are all specified to maximize this precision. An overview of the TITAN charge breeding program, and the results of charge breeding simulations will be presented.

  9. Experimental characterization of the Hitrap Cooler trap with highly charged ions.

    OpenAIRE

    Fedotova, Svetlana

    2013-01-01

    The HITRAP (Highly charged Ions TRAP)facility is being set up and commissioned at GSI, Darmstadt. It will provide heavy, highly charged ions at low velocities to high-precision atomic physics experiments. Within this work the Cooler trap- the key element of the HITRAP facility was tested. The Cooler trap was assembled, aligned, and commissioned in trapping experiments with ions from off-line sources.The work performed within the scope of this thesis provided the baseline for further operation...

  10. Space-charge-dominated mass spectrometry ion sources: Modeling and sensitivity.

    Science.gov (United States)

    Busman, M; Sunner, J; Vogel, C R

    1991-01-01

    The factors determining the sensitivity of space-charge-dominated (SCD) unipolar ion sources, such as electrospray (ESP) and corona atmospheric pressure ionization (API) have been studied theoretically. The most important parameters are the ion density and ion drift time in the vicinity of the sampling orifice. These are obtained by solving a system of differential equations, "the space-charge problem." For some simple geometries, analytical solutions are known. For a more realistic "needle-in-can" geometry, a solution to the space-charge problem was obtained using a finite-element method. The results illustrate some general characteristics of SCD ion sources. It is shown that for typical operating conditions the minimum voltage required to overcome the space-charge effect in corona API or ESP ion sources constitutes a dominant or significant fraction of total applied voltage. Further, the electric field and the ion density in the region of the ion-sampling orifice as well as the ion residence time in the source are determined mainly by the space charge. Finally, absolute sensitivities of corona API ion sources were calculated by using a geometry-independent treatment of space charge.

  11. Ionic Charge State Distribution of Au Plasma for 7-Ion System

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The present work extends the previous work[2] on 5-ion system to consider 7-ion system (i.e., Au47+ ~ Au53+). It is found that more highly charged ions, e.g., Au53+, Au54+ etc., could be able to be neglected, however, less highly charged ions, e.g., Au47+, Au46+ etc., are rather important. Therefore, a new idea to consider 8-ion system, i.e., Au46+ ~ Au53+, is under way. As a supplement, we discuss the simultaneous reaction, which would be important in this sort of works.

  12. Techniques and mechanisms applied in electron cyclotron resonance sources for highly charged ions

    NARCIS (Netherlands)

    Drentje, AG

    2003-01-01

    Electron cyclotron resonance ion sources are delivering beams of highly charged ions for a wide range of applications in many laboratories. For more than two decades, the development of these ion sources has been to a large extent an intuitive and experimental enterprise. Much effort has been spent

  13. Recent Excitation, Charge Exchange, and Lifetime Results in Highly Charged Ions Relevant to Stellar, Interstellar, Solar and Comet Phenomena

    Science.gov (United States)

    Chutjian, A.; Hossain, S.; Mawhorter, R. J.; Smith, S. J.

    2006-01-01

    Recent JPL absolute excitation and charge exchange cross sections, and measurements of lifetimes of metastable levels in highly-charged ions (HCIs) are reported. These data provide benchmark comparisons to results of theoretical calculations. Theoretical approaches can then be used to calculate the vast array of data which cannot be measured due to experimental constraints. Applications to the X-ray emission from comets are given.

  14. Nahoon: Time-dependent gas-phase chemical model

    Science.gov (United States)

    Wakelam, V.

    2014-09-01

    Nahoon is a gas-phase chemical model that computes the chemical evolution in a 1D temperature and density structure. It uses chemical networks downloaded from the KInetic Database for Astrochemistry (KIDA) but the model can be adapted to any network. The program is written in Fortran 90 and uses the DLSODES (double precision) solver from the ODEPACK package to solve the coupled stiff differential equations. The solver computes the chemical evolution of gas-phase species at a fixed temperature and density and can be used in one dimension (1D) if a grid of temperature, density, and visual extinction is provided. Grains, both neutral and negatively charged, and electrons are considered as chemical species and their concentrations are computed at the same time as those of the other species. Nahoon contains a test to check the temperature range of the validity of the rate coefficients and avoid extrapolations outside this range. A test is also included to check for duplication of chemical reactions, defined over complementary ranges of temperature.

  15. Modulation and interactions of charged biomimetic membranes with bivalent ions

    Science.gov (United States)

    Kazadi Badiambile, Adolphe

    biomolecules in a dynamic environment and the lack of appropriate physical and biochemical tools. In contrast, biomimetic membrane models that rely on the amphiphilic properties of phospholipids are powerful tools that enable the study of these molecules in vitro. By having control over the different experimental parameters such as temperature and pH, reliable and repeatable experimental conditions can be created. One of the key questions I investigated in this thesis is related to the clustering mechanism of PtdIns(4, 5)P2 into pools or aggregates that enable independent cellular control of this species by geometric separation. The lateral aggregation of PtdIns(4, 5)P2 and its underlying physical causes is still a matter of debate. In the first part of this thesis I introduce the general information on lipid membranes with a special focus on the PtdIns family and their associated signaling events. In addition, I explain the Langmuir-Blodgett film balance (LB) system as tool to study lipid membranes and lipid interactions. In the second chapter, I describe my work on the lateral compressibility of PtdIns(4, 5)P2, PtdIns and DOPG monolayers and its modulation by bivalent ions using Langmuir monolayers. In addition, a theoretical framework of compressibility that depends on a surface potential induced by a planar layer of charged molecules and ions in the bulk was provided. In the third part, I present my work on the excess Gibbs free energy of the lipid systems PtdIns(4, 5)P2 --POPC, PtdIns(4, 5)P2, and POPC as they are modulated by bivalent ions. In the fourth part, I report on my foray in engineering a light-based system that relies on different dye properties to simulate calcium induced calcium release (CICR) that occurs in many cell types. In the final chapter, I provide a general conclusion and present directions for future research that would build on my findings.

  16. Transport, charge exchange and loss of energetic heavy ions in the earth's radiation belts - Applicability and limitations of theory

    Science.gov (United States)

    Spjeldvik, W. N.

    1981-01-01

    Computer simulations of processes which control the relative abundances of ions in the trapping regions of geospace are compared with observations from discriminating ion detectors. Energy losses due to Coulomb collisions between ions and exospheric neutrals are considered, along with charge exchange losses and internal charge exchanges. The time evolution of energetic ion fluxes of equatorially mirroring ions under radial diffusion is modelled to include geomagnetic and geoelectric fluctutations. Limits to the validity of diffusion transport theory are discussed, and the simulation is noted to contain provisions for six ionic charge states and the source effect on the radiation belt oxygen ion distributions. Comparisons are made with ion flux data gathered on Explorer 45 and ISEE-1 spacecraft and results indicate that internal charge exchanges cause the radiation belt ion charge state to be independent of source charge rate characteristics, and relative charge state distribution is independent of the radially diffusive transport rate below the charge state redistribution zone.

  17. Optimization of electron-cyclotron-resonance charge-breeder ions : Final CRADA Report.

    Energy Technology Data Exchange (ETDEWEB)

    Pardo, R.; Physics; Far-Tech, Inc.

    2009-10-09

    Measurements of 1+ beam properties and associated performance of ECR Charge Breeder source determined by total efficiency measurement and charge state distributions from the ECR Charge Breeder. These results were communicated to Far-Tech personnel who used them to benchmark the newly developed programs that model ion capture and charge breeding in the ECR Charge Breeder Source. Providing the basic data described above and in the discussion below to Far-Tech allowed them to improve and refine their calculational tools for ECR ion sources. These new tools will be offered for sale to industry and will also provide important guidance to other research labs developing Charge Breeding ion sources for radioactive beam physics research.

  18. Highly charged ions trapping for lifetime measurements; Piegeage d'ions tres charges pour la mesure de duree de vie d'etats metastables

    Energy Technology Data Exchange (ETDEWEB)

    Attia, D

    2007-10-15

    A new experimental setup dedicated to highly charged ion trapping is presented in this work. The final goal is to perform lifetime measurement of metastable states produced by our ECR (Electron Cyclotron Resonance) ion source. Lifetimes to be measured are in the range of a few ms and more. We have measured the lifetimes of the M1 transitions of the metastable states of Ar{sup 9+}, Ar{sup 13+} and Ar{sup 14+}. These measurements are useful to test the N-body problem in the relativistic range. The trap we have built, was designed a few years ago at the Weizman Institute in Israel, it allows ions with an energy of several keV to be trapped for lifetimes of about 1 second. This trap was originally designed to study the dynamics of excited molecules. We have shown for the first time how the trap operates and that it can operate with highly charged ions. We have studied the beam dynamics of highly charged ions and the trap has been tested with various species of ions and different charge states: from O{sup +} to O{sup 6+}, from Ar{sup 8+} to Ar{sup 13+}, and from Kr{sup 13+} to Kr{sup 20+}.

  19. CHEMKIN-III: A FORTRAN chemical kinetics package for the analysis of gas-phase chemical and plasma kinetics

    Energy Technology Data Exchange (ETDEWEB)

    Kee, R.J.; Rupley, F.M.; Meeks, E.; Miller, J.A.

    1996-05-01

    This document is the user`s manual for the third-generation CHEMKIN package. CHEMKIN is a software package whose purpose is to facilitate the formation, solution, and interpretation of problems involving elementary gas-phase chemical kinetics. It provides a flexible and powerful tool for incorporating complex chemical kinetics into simulations of fluid dynamics. The package consists of two major software components: an Interpreter and a Gas-Phase Subroutine Library. The Interpreter is a program that reads a symbolic description of an elementary, user-specified chemical reaction mechanism. One output from the Interpreter is a data file that forms a link to the Gas-Phase Subroutine Library. This library is a collection of about 100 highly modular FORTRAN subroutines that may be called to return information on equations of state, thermodynamic properties, and chemical production rates. CHEMKIN-III includes capabilities for treating multi-fluid plasma systems, that are not in thermal equilibrium. These new capabilities allow researchers to describe chemistry systems that are characterized by more than one temperature, in which reactions may depend on temperatures associated with different species; i.e. reactions may be driven by collisions with electrons, ions, or charge-neutral species. These new features have been implemented in such a way as to require little or no changes to CHEMKIN implementation for systems in thermal equilibrium, where all species share the same gas temperature. CHEMKIN-III now has the capability to handle weakly ionized plasma chemistry, especially for application related to advanced semiconductor processing.

  20. Measurements of Ion Selective Containment on the RF Charge Breeder Device BRIC

    CERN Document Server

    Variale, Vincenzo; Batazova, Marina; Boggia, Antonio; Clauser, Tarcisio; Kuznetsov, Gennady I; Rainò, Antonio; Shiyankov, Sergey; Skarbo, Boris A; Valentino, Vincenzo; Verrone, Grazia

    2005-01-01

    The "charge state breeder" BRIC (BReeding Ion Charge) is based on an EBIS source and it is designed to accept Radioactive Ion Beam (RIB) with charge +1, in a slow injection mode, to increase their charge state up to +n. BRIC has been developed at the INFN section of Bari (Italy) during these last 3 years with very limited funds. Now, it has been assembled at the LNL (Italy) where are in progress the first tests as stand alone source. The new feature of BRIC, with respect to the classical EBIS, is given by the insertion, in the ion drift chamber, of a Radio Frequency (RF) Quadrupole aiming to filtering the unwanted elements and then making a more efficient containment of the wanted ions. In this contribution, the measurements of the selective effect on the ion charge state containement of the RF quadrupole field, applied on the ion chamber, will be reported and discussed. The ion charge state analisys of the ions trapped in BRIC seem confirm, as foreseen by simulation results carried out previously, that the s...

  1. Highly charged ion research at the Livermore electron beam ion traps

    Energy Technology Data Exchange (ETDEWEB)

    Beiersdorfer, P

    2004-01-04

    Spectroscopy performed with the three Livermore electron beam ion traps is reviewed, which is continuing and complementing the innumerable contributions to atomic physics provided over the years by heavy-ion accelerators. Numerous spectrometers were developed that cover the spectral bands from the visible to the hard x ray region. These enabled exhaustive line surveys useful for x-ray astrophysics and for systematic studies along iso-electronic sequences, such as the 4s-4p, 3s-3p, and 2s-2p transitions in ions of the Cu-I, Na-I, and Li-I sequences useful for studying QED and correlation effects as well as for precise determinations of atomic-nuclear interactions. They also enabled measurements of radiative transition probabilities of very long-lived (milli- and microseconds) and very short-live (femtosecond) levels. Because line excitation processes can be controlled by choice of the electron beam energy, the observed line intensities are used to infer cross sections for electron-impact excitation, dielectronic recombination, resonance excitation, and innershell ionization. These capabilities have recently been expanded to simulate x-ray emission from comets by charge exchange. Specific contributions to basic atomic physics, nuclear physics, and high-temperature diagnostics are illustrated.

  2. Development of Monopole Interaction Models for Ionic Compounds. Part I: Estimation of Aqueous Henry’s Law Constants for Ions and Gas Phase pKa Values for Acidic Compounds

    Science.gov (United States)

    The SPARC (SPARC Performs Automated Reasoning in Chemistry) physicochemical mechanistic models for neutral compounds have been extended to estimate Henry’s Law Constant (HLC) for charged species by incorporating ionic electrostatic interaction models. Combinations of absolute aq...

  3. Ion-ion reactions for charge reduction of biopolymer at atmospheric pressure ambient

    Institute of Scientific and Technical Information of China (English)

    Yue Ming Zhou; Jian Hua Ding; Xie Zhang; Huan Wen Chen

    2007-01-01

    Extractive electrospray ionization source (EESI) was adapted for ion-ion reaction, which was demonstrated by using a linear quadrupole ion trap mass spectrometer for the first ion-ion reaction of biopolymers in the atmospheric pressure ambient.

  4. Intense beam production of highly charged heavy ions by the superconducting electron cyclotron resonance ion source SECRAL.

    Science.gov (United States)

    Zhao, H W; Sun, L T; Zhang, X Z; Guo, X H; Cao, Y; Lu, W; Zhang, Z M; Yuan, P; Song, M T; Zhao, H Y; Jin, T; Shang, Y; Zhan, W L; Wei, B W; Xie, D Z

    2008-02-01

    There has been increasing demand to provide higher beam intensity and high enough beam energy for heavy ion accelerator and some other applications, which has driven electron cyclotron resonance (ECR) ion source to produce higher charge state ions with higher beam intensity. One of development trends for highly charged ECR ion source is to build new generation ECR sources by utilization of superconducting magnet technology. SECRAL (superconducting ECR ion source with advanced design in Lanzhou) was successfully built to produce intense beams of highly charged ion for Heavy Ion Research Facility in Lanzhou (HIRFL). The ion source has been optimized to be operated at 28 GHz for its maximum performance. The superconducting magnet confinement configuration of the ion source consists of three axial solenoid coils and six sextupole coils with a cold iron structure as field booster and clamping. An innovative design of SECRAL is that the three axial solenoid coils are located inside of the sextupole bore in order to reduce the interaction forces between the sextupole coils and the solenoid coils. For 28 GHz operation, the magnet assembly can produce peak mirror fields on axis of 3.6 T at injection, 2.2 T at extraction, and a radial sextupole field of 2.0 T at plasma chamber wall. During the commissioning phase at 18 GHz with a stainless steel chamber, tests with various gases and some metals have been conducted with microwave power less than 3.5 kW by two 18 GHz rf generators. It demonstrates the performance is very promising. Some record ion beam intensities have been produced, for instance, 810 e microA of O(7+), 505 e microA of Xe(20+), 306 e microA of Xe(27+), and so on. The effect of the magnetic field configuration on the ion source performance has been studied experimentally. SECRAL has been put into operation to provide highly charged ion beams for HIRFL facility since May 2007.

  5. Space Charge Compensation in the Linac4 Low Energy Beam Transport Line with Negative Hydrogen Ions

    CERN Document Server

    Valerio-Lizarraga, C; Leon-Monzon, I; Lettry, J; Midttun, O; Scrivens, R

    2014-01-01

    The space charge effect of low energy, unbunched ion beams can be compensated by the trapping of ions or electrons into the beam potential. This has been studied for the 45 keV negative hydrogen ion beam in the CERN Linac4 Low Energy Beam Tranport (LEBT) using the package IBSimu1, which allows the space charge calculation of the particle trajectories. The results of the beam simulations will be compared to emittance measurements of an H- beam at the CERN Linac4 3 MeV test stand, where the injection of hydrogen gas directly into the beam transport region has been used to modify the space charge compensation degree.

  6. Testing spatial α-variation with optical atomic clocks based on highly charged ions

    Directory of Open Access Journals (Sweden)

    Berengut J. C.

    2013-08-01

    Full Text Available We review recent works illustrating the potential use of highly charged ions as the basis of optical atomic clocks of exceptional accuracy and very high sensitivity to variation of the fine structure constant, α. The tendency towards large transition energies in highly charged ions can be overcome using level crossings, which allow transitions between different orbitals to be within the range of usual lasers. We present simple scaling laws that demonstrate reduced systematics that could be realised in highly charged ion clocks. Such clocks could allow us to corroborate astronomical studies that suggest a spatial gradient in values of α across the Universe.

  7. Performance on the low charge state laser ion source in BNL

    Energy Technology Data Exchange (ETDEWEB)

    Okamura, M.; Alessi, J.; Beebe, E.; Costanzo, M.; DeSanto, L.; Jamilkowski, J.; Kanesue, T.; Lambiase, R.; Lehn, D.; Liaw, C. J.; McCafferty, D.; Morris, J.; Olsen, R.; Pikin, A.; Raparia, D.; Steszyn, A.; Ikeda, S.

    2015-09-07

    On March 2014, a Laser Ion Source (LIS) was commissioned which delivers high-brightness, low-charge-state heavy ions for the hadron accelerator complex in Brookhaven National Laboratory (BNL). Since then, the LIS has provided many heavy ion species successfully. The low-charge-state (mostly singly charged) beams are injected to the Electron Beam Ion Source (EBIS), where ions are then highly ionized to fit to the following accelerator’s Q/M acceptance, like Au32+. Recently we upgraded the LIS to be able to provide two different beams into EBIS on a pulse-to-pulse basis. Now the LIS is simultaneously providing beams for both the Relativistic Heavy Ion Collider (RHIC) and NASA Space Radiation Laboratory (NSRL).

  8. Highly charged ions from laser-cluster interactions: local-field-enhanced impact ionization and frustrated electron-ion recombination.

    Science.gov (United States)

    Fennel, Thomas; Ramunno, Lora; Brabec, Thomas

    2007-12-07

    Our molecular dynamics analysis of Xe_{147-5083} clusters identifies two mechanisms that contribute to the yet unexplained observation of extremely highly charged ions in intense laser cluster experiments. First, electron impact ionization is enhanced by the local cluster electric field, increasing the highest charge states by up to 40%; a corresponding theoretical method is developed. Second, electron-ion recombination after the laser pulse is frustrated by acceleration electric fields typically used in ion detectors. This increases the highest charge states by up to 90%, as compared to the usual assumption of total recombination of all cluster-bound electrons. Both effects together augment the highest charge states by up to 120%, in reasonable agreement with experiments.

  9. Probing lithium-ion batteries' state-of-charge using ultrasonic transmission - Concept and laboratory testing

    Science.gov (United States)

    Gold, Lukas; Bach, Tobias; Virsik, Wolfgang; Schmitt, Angelika; Müller, Jana; Staab, Torsten E. M.; Sextl, Gerhard

    2017-03-01

    For electrically powered applications such as consumer electronics and especially for electric vehicles a precise state-of-charge estimation for their lithium-ion batteries is desired to reduce aging, e.g. avoiding detrimental states-of-charge. Today, this estimation is performed by battery management systems that solely rely on charge bookkeeping and cell voltage measurements. In the present work we introduce a new, physical probe for the state-of-charge based on ultrasonic transmission. Within the simple experimental setup raised cosine pulses are applied to lithium-ion battery pouch cells, whose signals are sensitive to changes in porosity of the graphite anode during charging/dis-charging and, therefore, to the state-of-charge. The underlying physical principle can be related to Biot's theory about propagation of waves in fluid saturated porous media and by including scattering by boundary layers inside the cell.

  10. Molecular effect on equilibrium charge-state distributions. [of nitrogen ions injected through carbon foil

    Science.gov (United States)

    Wickholm, D.; Bickel, W. S.

    1976-01-01

    The paper describes an experiment consisting of the acceleration of N(+) and N2(+) ions to energies between 0.25 and 1.75 MeV and their injection through a thin carbon foil, whereupon they were charge-state analyzed with an electrostatic analyzer. A foil-covered electrically suppressed Faraday cup, connected to a stepping motor, moved in the plane of the dispersed beams. The Faraday cup current, which was proportional to the number of incident ions, was sent to a current digitizer and computer programmed as a multiscaler. The energy-dependent charge-state fractions, the mean charge and the distribution width were calculated. It was shown that for incident atoms, the charge state distribution appeared to be spread over more charge states, while for the incident molecules, there was a greater fraction of charge states near the mean charge.

  11. Experiments and Researches on Production of Highly Charged Metallic Ions

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    To satisfy the requirements of HIRFL (Heavy Ion Research Facility in Lanzhou), series of experiments have been done to produce metallic ion beams on the 14.5 GHz ECR ion source. By now, numerous methods have been tested, in which oven heating and MIVOC (Metallic Ion from Volatile Compounds) are both included.According to the experiments, the results show that oven heating is much better than MIVOC. In most of our

  12. Receptors useful for gas phase chemical sensing

    Energy Technology Data Exchange (ETDEWEB)

    Jaworski, Justyn W; Lee, Seung-Wuk; Majumdar, Arunava; Raorane, Digvijay A

    2015-02-17

    The invention provides for a receptor, capable of binding to a target molecule, linked to a hygroscopic polymer or hydrogel; and the use of this receptor in a device for detecting the target molecule in a gaseous and/or liquid phase. The invention also provides for a method for detecting the presence of a target molecule in the gas phase using the device. In particular, the receptor can be a peptide capable of binding a 2,4,6-trinitrotoluene (TNT) or 2,4,-dinitrotoluene (DNT).

  13. Gas phase thermochemistry of organogermanium compounds

    Energy Technology Data Exchange (ETDEWEB)

    Engel, J.P.

    1993-12-07

    A variety of silyl- and alkyl-germylene precursors have been synthesized and subsequently pyrolyzed in the gas phase. Arrhenius parameters were obtained employing a pulsed-stirred flow reactor for these unimolecular decompositions. These precursors are divided into two major categories by mechanism of germylene extrusion: {alpha}-elimination precursors and germylacetylenes. The extrusion of germylenes from germylacetylene precursors is of primary interest. A mechanism is proposed employing a germacyclopropene intermediate. Evidence supporting this mechanism is presented. In the process of exploring germylacetylenes as germylene precursors, an apparent dyatropic rearrangement between germanium and silicon was observed. This rearrangement was subsequently explored.

  14. Role of Nearby Charges on the Electronic Structure of π-Conjugated Molecules: Symmetric versus Asymmetric Charge Distributions in Oligo(p-phenyleneethynylene)

    DEFF Research Database (Denmark)

    Kirketerp, Maj-Britt Suhr; Ryhding, Torben; Støchkel, Kristian;

    2011-01-01

    of these chromophores are affected by nearby charges. An OPE3 chromophore with two nearby ammonium groups was synthesized. This molecule and a related OPE3 with only one amine protonation site were transferred to the gas phase by electrospray ionization and subjected to action spectroscopy. Ions were bunched in a 14......Oligo(p-phenyleneethynylene)s (OPEs) are conjugated oligomers of great interest within materials science and molecular electronics on account of their highly applicable electronic and optical properties. Here we use gas-phase action spectroscopy to elucidate how the intrinsic electronic properties...... on the microsecond time scale. The gas-phase absorption of the mono- and dication was measured and compared to that of neutral chromophores in solution. Similar absorption was found for neutral chromophores (in solution) and the dication (in gas phase or solution), whereas the monocation absorbs at lower energies...

  15. Aberration of a negative ion beam caused by space charge effect

    Energy Technology Data Exchange (ETDEWEB)

    Miyamoto, K. [Naruto University of Education, 748 Nakashima, Takashima, Naruto-cho, Naruto-shi, Tokushima 772-8502 (Japan); Wada, S.; Hatayama, A. [Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522 (Japan)

    2010-02-15

    Aberrations are inevitable when the charged particle beams are extracted, accelerated, transmitted, and focused with electrostatic and magnetic fields. In this study, we investigate the aberration of a negative ion accelerator for a neutral beam injector theoretically, especially the spherical aberration caused by the negative ion beam expansion due to the space charge effect. The negative ion current density profiles with the spherical aberration are compared with those without the spherical aberration. It is found that the negative ion current density profiles in a log scale are tailed due to the spherical aberration.

  16. The description of charge transfer in fast negative ions scattering on water covered Si(100) surfaces

    Science.gov (United States)

    Chen, Lin; Qiu, Shunli; Liu, Pinyang; Xiong, Feifei; Lu, Jianjie; Liu, Yuefeng; Li, Guopeng; Liu, Yiran; Ren, Fei; Xiao, Yunqing; Gao, Lei; Zhao, Qiushuang; Ding, Bin; Li, Yuan; Guo, Yanling; Chen, Ximeng

    2016-11-01

    Doping has significantly affected the characteristics and performance of semiconductor electronic devices. In this work, we study the charge transfer processes for 8.5-22.5 keV C- and F- ions scattering on H2O-terminated p-type Si(100) surfaces with two different doping concentrations. We find that doping has no influence on negative-ion formation for fast collisions in this relatively high energy range. Moreover, we build a model to calculate negative ion fractions including the contribution from positive ions. The calculations support the nonadiabatic feature of charge transfer.

  17. CrossRef Space-charge effects in Penning ion traps

    CERN Document Server

    Porobić, T; Breitenfeldt, M; Couratin, C; Finlay, P; Knecht, A; Fabian, X; Friedag, P; Fléchard, X; Liénard, E; Ban, G; Zákoucký, D; Soti, G; Van Gorp, S; Weinheimer, Ch; Wursten, E; Severijns, N

    2015-01-01

    The influence of space-charge on ion cyclotron resonances and magnetron eigenfrequency in a gas-filled Penning ion trap has been investigated. Off-line measurements with View the MathML source using the cooling trap of the WITCH retardation spectrometer-based setup at ISOLDE/CERN were performed. Experimental ion cyclotron resonances were compared with ab initio Coulomb simulations and found to be in agreement. As an important systematic effect of the WITCH experiment, the magnetron eigenfrequency of the ion cloud was studied under increasing space-charge conditions. Finally, the helium buffer gas pressure in the Penning trap was determined by comparing experimental cooling rates with simulations.

  18. Time-dependent cylindrical and spherical ion-acoustic solitary structures in relativistic degenerate multi-ion plasmas with positively-charged heavy ions

    Energy Technology Data Exchange (ETDEWEB)

    Hossen, M. R.; Nahar, L.; Mamun, A. A. [Jahangirnagar University,Savar, Dhaka (Bangladesh)

    2014-12-15

    The properties of time-dependent cylindrical and spherical, modified ion-acoustic (mIA) solitary structures in relativistic degenerate multi-ion plasmas (containing degenerate electron fluids, inertial positively-, as well as negatively-, charged light ions, and positively-charged static heavy ions) have been investigated theoretically. This investigation is valid for both non-relativistic and ultrarelativistic limits. The well-known reductive perturbation method has been used to derive the Korteweg-de Vries (K-dV) and the mK-dV equations for studying the basic features of solitary waves. The fundamental characteristics of mIA solitary waves are found to be significantly modified by the effects of the degenerate pressures of the electron and the ion fluids, their number densities, and the various charge states of heavy ions. The relevance of our results in astrophysical compact objects like white dwarfs and neutron stars, which are of scientific interest, is briefly discussed.

  19. Influence of argon and oxygen on charge-state-resolved ion energydistributions of filtered aluminum arcs

    Energy Technology Data Exchange (ETDEWEB)

    Rosen, Johanna; Anders, Andre; Mraz, Stanislav; Atiser, Adil; Schneider, Jochen M.

    2006-03-23

    The charge-state-resolved ion energy distributions (IEDs) in filtered aluminum vacuum arc plasmas were measured and analyzed at different oxygen and argon pressures in the range 0.5 8.0 mTorr. A significant reduction of the ion energy was detected as the pressure was increased, most pronounced in an argon environment and for the higher charge states. The corresponding average charge state decreased from 1.87 to 1.0 with increasing pressure. The IEDs of all metal ions in oxygen were fitted with shifted Maxwellian distributions. The results show that it is possible to obtain a plasma composition with a narrow charge-state distribution as well as a narrow IED. These data may enable tailoring thin-film properties through selecting growth conditions that are characterized by predefined charge state and energy distributions.

  20. Recoil ion charge state distributions in low energy Ar{sup q+} {minus} Ar collisions

    Energy Technology Data Exchange (ETDEWEB)

    Vancura, J.; Marchetti, V.; Kostroun, V.O.

    1992-12-31

    We have measured the recoil ion charge state distributions in Ar{sup q+} -- Ar (8{le}q{le}16) collisions at 2.3 qkeV and 0.18qkeV by time of flight (TOF) spectroscopy. For Ar{sup 8-16+}, recoil ion charge states up to 6+ are clearly present, indicating that the 3p subshell in the target atom is being depleted, while for Ar{sup 10-16+}, there is evidence that target 3s electrons are also being removed. Comparison of the recoil ion charge state spectra at 2.3 and 0.18 qkeV shows that for a given projectile charge, there is very little dependence of the observed recoil target charge state distribution on projectile energy.

  1. The structure of C5H 5RFe (+) (R = F, Cl, Br, I, O, OH, OCH3, C 6H 5, H) ions in the gas phase and the generation of their neutral counterparts by neutralization-reionization mass spectrometry.

    Science.gov (United States)

    Zagorevskii, D V; Holmes, J L; Zverev, D V; Orlova, T Y; Nekrasov, Y S

    1995-12-01

    The structure of C5H5FeR(+·) ions was studied by tandem mass spectromerry that included the neutralization-reionization (NR) method. Halogen-containing species (R = F, Cl, Br, I) showed fragmentation that was consistent with a structure that has the cyclopentadienyl ring and R as separate ligands at the metal atom (structure A). This structure also was identified for C5H5FeO(+) and CpFeOH(+·) ions, but these species also easily isomerized to metal-cyclopentadiene structure, RC5H5Fe(+·) (B), followed by hydrogen rearrangement(s) and CO loss. B was the dominant structure of C5H5FeH(+·) and C5H5FeC6H 5 (+·) ions. All ions that have structure A showed recovery signals in their NR mass spectra that indicated that their stable neutral counterparts were generated. The NR mass spectra also provided complementary information about the structure of ions before neutralization and after reionization.

  2. The effect of the charging protocol on the cycle life of a Li-ion battery

    Science.gov (United States)

    Zhang, Sheng Shui

    The effect of the charging protocol on the cycle life of a commercial 18650 Li-ion cell was studied using three methods: (1) constant current (CC) charging, (2) constant power (CP) charging, and (3) multistage constant current (MCC) charging. The MCC-charging consists of two CC steps, which starts with a low current to charge the initial 10% capacity followed by a high current charging until the cell voltage reaches 4.2 V. Using these methods, respectively, the cell was charged to 4.2 V followed by a constant voltage (CV) charging until the current declined to 0.05 C. Results showed that the cycle life of the cell strongly depended on the charging protocol even if the same charging rate was used. Among these three methods, the CC-method was found to be more suitable for slow charging (0.5 C) while the CP-method was better for fast charging (1 C). Impedance analyses indicated that the capacity loss during cycling was mainly attributed to the increase of charge-transfer resistance as a result of the progressive growth of surface layers on the surface of two electrodes. Fast charging resulted in an accelerated capacity fading due to the loss of Li + ions and the related growth of a surface layer, which was associated with metallic lithium plating onto the anode and a high polarization at the electrolyte-electrode interface. Analyses of the cell electrochemistry showed that use of a reduced current to charge the initial 10% capacity and near the end of charge, respectively, was favorable for long cycle life.

  3. Bound state properties and photodetachment of the negatively charged hydrogen ions

    Science.gov (United States)

    Frolov, Alexei M.

    2015-05-01

    Absorption of infrared and visible radiation from stellar emission spectra by the negatively charged hydrogen ions H- is considered. The explicit formula for the photodetachment cross-section of the negatively charged hydrogen ion(s) is derived. Photodetachemnt cross-sections of the {∞}H-, {3}H- (or T-), {2}H- (or D-) and {1}H- ions are determined to high accuracy and for a large number of photo-electron momenta/energies. We introduce criteria which can be used to evaluate the overall quality of highly accurate wave functions of the hydrogen ion(s). One of these criteria is based on highly accurate calculations of the lowest order QED corrections in the negatively charged hydrogen ions, including {1}H- (protium), {2}H- (deuterium), {3}H- (tritium) and model ion with the infinitely heavy nucleus {∞}H-. An effective approach has been developed to calculate three-body integrals with the Bessel functions of different orders. Some preliminary evaluations of the phototdetachment cross-sections of the negatively charged hydrogen ions are performed. Inverse bremsstrahlung in the field of the neutral hydrogen atom is briefly discussed.

  4. Reactions of molecular dications in the gas phase

    CERN Document Server

    Tafadar, N N

    2001-01-01

    This thesis presents the results from a series of experiments investigating the reactivity of gas phase molecular dications with neutral collision partners, at collision energies between 3 and 13 eV in the laboratory frame using a crossed-beam apparatus. The experiments involve measurement of product ion intensities, which are determined by means of time of flight mass spectrometry. The experimental methodology, together with relevant theory is described in the thesis. The relative intensities of product ions formed are a powerful probe of the reaction mechanism. Where appropriate, the reactions are examined for isotope effects by using the isotopic analogue of the neutral collision partner. Our investigation of the CF sub 3 sup 2 sup + /Ar collision system shows neutral loss and electron transfer dominating the product ion yield. The variation of the neutral loss ion yield with collision energy provides a first estimate of the bond energy of the weak CF sub 2 sup 2 sup + -F bond. Ab initio calculations indic...

  5. A New Poisson-Nernst-Planck Model with Ion-Water Interactions for Charge Transport in Ion Channels.

    Science.gov (United States)

    Chen, Duan

    2016-08-01

    In this work, we propose a new Poisson-Nernst-Planck (PNP) model with ion-water interactions for biological charge transport in ion channels. Due to narrow geometries of these membrane proteins, ion-water interaction is critical for both dielectric property of water molecules in channel pore and transport dynamics of mobile ions. We model the ion-water interaction energy based on realistic experimental observations in an efficient mean-field approach. Variation of a total energy functional of the biological system yields a new PNP-type continuum model. Numerical simulations show that the proposed model with ion-water interaction energy has the new features that quantitatively describe dielectric properties of water molecules in narrow pores and are possible to model the selectivity of some ion channels.

  6. Microbeam Studies of Diffusion Time Resolved Ion Beam Induced Charge Collection from Stripe-Like Junctions

    Energy Technology Data Exchange (ETDEWEB)

    GUO,B.N.; BOUANANI,M.E.; RENFROW,S.N.; WALSH,DAVID S.; DOYLE,BARNEY L.; ATON,T.J.; SMITH,E.B.; BAUMANN,R.C.; DUGGAN,J.L.; MCDANIEL,F.D.

    2000-06-14

    To design more radiation tolerant Integrated Circuits (ICs), it is essential to create and test accurate models of ionizing radiation induced charge collection dynamics within microcircuits. A new technique, Diffusion Time Resolved Ion Beam Induced Charge Collection (DTRIBICC), is proposed to measure the average arrival time of the diffused charge at the junction. Specially designed stripe-like junctions were experimentally studied using a 12 MeV carbon microbeam with a spot size of 1 {micro}m. The relative arrival time of ion-generated charge is measured along with the charge collection using a multiple parameter data acquisition system. The results show the importance of the diffused charge collection by junctions, which is especially significant in accounting for Multiple Bit Upset (MBUs) in digital devices.

  7. Net-charge probability distributions in heavy ion collisions at chemical freeze-out

    CERN Document Server

    Braun-Munzinger, P; Karsch, F; Redlich, K; Skokov, V

    2011-01-01

    We explore net charge probability distributions in heavy ion collisions within the hadron resonance gas model. The distributions for strangeness, electric charge and baryon number are derived. We show that, within this model, net charge probability distributions and the resulting fluctuations can be computed directly from the measured yields of charged and multi-charged hadrons. The influence of multi-charged particles and quantum statistics on the shape of the distribution is examined. We discuss the properties of the net proton distribution along the chemical freeze-out line. The model results presented here can be compared with data at RHIC energies and at the LHC to possibly search for the relation between chemical freeze-out and QCD cross-over lines in heavy ion collisions.

  8. Do all the protic ionic liquids exist as molecular aggregates in the gas phase?

    Science.gov (United States)

    Zhu, Xiao; Wang, Yong; Li, Haoran

    2011-10-21

    According to an EI-MS study of 1,1,3,3-tetramethylguanidium-based protic ionic liquids (PILs), it has been concluded that not all PILs exist as molecular aggregates in the gas phase. The detection of both ions of m/z 115.0 and m/z 116.0 for the 1,1,3,3-tetramethylguanidinium trifluoromethylsulfonate (TMGS) protic ionic liquid indicates that both the molecular and ionic aggregates co-exist in the gas phase, which is to say that the TMGS may also evaporate via the ionic aggregates just like aprotic ionic liquids. Furthermore, investigation on triethylamine-based and 1-methylimidazole-based PILs confirmed that the gas phase structure of PILs depends on both the acidity and basicity of the corresponding acid and base.

  9. Highly charged ions impinging on a stepped metal surface under grazing incidence

    NARCIS (Netherlands)

    Robin, A; Niemann, D; Stolterfoht, N; Heiland, W

    2003-01-01

    We report on energy loss measurements and charge state distributions for 60 keV N6+ and 75 keV N5+ ions scattered off a Pt(110)(1x2) single crystal surface. In particular, the influence of surface steps on the energy loss and the outgoing charge states is discussed. The scattering angle and the angl

  10. Charge state studies of low energy heavy ions passing through hydrogen and helium gas

    CERN Document Server

    Liu, W; Buchmann, L; Chen, A A; D'Auria, J M; D'Onofrio, A; Engel, S; Gialanella, L; Greife, U; Hunter, D; Hussein, A; Hutcheon, D A; Olin, A; Ottewell, D; Rogalla, D; Rogers, J; Romano, M; Roy, G; Terrasi, F

    2003-01-01

    Studies of the charge state distribution of low energy (<1.5 MeV/u), low Z (<13) heavy ions passing through hydrogen and helium gas of varying target pressure have been performed using separate windowless gas target systems at TRIUMF and the University of Naples. Semi-empirical relationships have been deduced to estimate the equilibrium charge state distributions as a function of beam energy. From these distributions, cross-sections for the relevant charge changing reactions have been deduced.

  11. Removal of charged micropollutants from water by ion-exchange polymers -- effects of competing electrolytes.

    Science.gov (United States)

    Bäuerlein, Patrick S; Ter Laak, Thomas L; Hofman-Caris, Roberta C H M; de Voogt, Pim; Droge, Steven T J

    2012-10-15

    A wide variety of environmental compounds of concern, e.g. pharmaceuticals or illicit drugs, are acids or bases that may predominantly be present as charged species in drinking water sources. These charged micropollutants may prove difficult to remove by currently used water treatment steps (e.g. UV/H(2)O(2), activated carbon (AC) or membranes). We studied the sorption affinity of some ionic organic compounds to both AC and different charged polymeric materials. Ion-exchange polymers may be effective as additional extraction phases in water treatment, because sorption of all charged compounds to oppositely charged polymers was stronger than to AC, especially for the double-charged cation metformin. Tested below 1% of the polymer ion-exchange capacity, the sorption affinity of charged micropollutants is nonlinear and depends on the composition of the aqueous medium. Whereas oppositely charged electrolytes do not impact sorption of organic ions, equally charged electrolytes do influence sorption indicating ion-exchange (IE) to be the main sorption mechanism. For the tested polymers, a tenfold increased salt concentration lowered the IE-sorption affinity by a factor two. Different electrolytes affect IE with organic ions in a similar way as inorganic ions on IE-resins, and no clear differences in this trend were observed between the sulphonated and the carboxylated cation-exchanger. Sorption of organic cations is five fold less in Ca(2+) solutions compared to similar concentrations of Na(+), while that of anionic compounds is three fold weaker in SO(4)(2-) solutions compared to equal concentrations of Cl(-).

  12. Prospects for Parity Non-conservation Experiments with Highly Charged Heavy Ions

    OpenAIRE

    Maul, M.; A. Schäfer; Greiner, W.; Indelicato, P.

    1996-01-01

    We discuss the prospects for parity non-conservation experiments with highly charged heavy ions. Energy levels and parity mixing for heavy ions with two to five electrons are calculated. We investigate two-photon-transitions and the possibility to observe interference effects between weak-matrix elements and Stark matrix elements for periodic electric field configurations.

  13. Prospects for parity-nonconservation experiments with highly charged heavy ions

    OpenAIRE

    Maul, Martin; Schäfer, Andreas; Greiner, Walter; Indelicato, Paul

    2006-01-01

    We discuss the prospects for parity-nonconservation experiments with highly charged heavy ions. Energy levels and parity mixing for heavy ions with 2–5 electrons are calculated. We investigate two-photon transitions and the possibility of observing interference effects between weak-matrix elements and Stark matrix elements for periodic electric field configurations.

  14. The study towards high intensity high charge state laser ion sources

    Science.gov (United States)

    Zhao, H. Y.; Jin, Q. Y.; Sha, S.; Zhang, J. J.; Li, Z. M.; Liu, W.; Sun, L. T.; Zhang, X. Z.; Zhao, H. W.

    2014-02-01

    As one of the candidate ion sources for a planned project, the High Intensity heavy-ion Accelerator Facility, a laser ion source has been being intensively studied at the Institute of Modern Physics in the past two years. The charge state distributions of ions produced by irradiating a pulsed 3 J/8 ns Nd:YAG laser on solid targets of a wide range of elements (C, Al, Ti, Ni, Ag, Ta, and Pb) were measured with an electrostatic ion analyzer spectrometer, which indicates that highly charged ions could be generated from low-to-medium mass elements with the present laser system, while the charge state distributions for high mass elements were relatively low. The shot-to-shot stability of ion pulses was monitored with a Faraday cup for carbon target. The fluctuations within ±2.5% for the peak current and total charge and ±6% for pulse duration were demonstrated with the present setup of the laser ion source, the suppression of which is still possible.

  15. SMILETRAP - A Penning trap facility for precision mass measurements using highly charged ions

    CERN Document Server

    Bergström, I; Fritioff, T; Douysset, G; Schoenfelder, J; Schuch, R

    2002-01-01

    The precision of mass measurements in a Penning trap increases linearly with the charge of the ion. Therefore we have attached a Penning trap, named SMILETRAP, to the electron beam ion source CRYSIS at MSL. CRYSIS is via an isotope separator connected to an ion source that can deliver singly charged ions of practically any element. In CRYSIS charge state breeding occurs by intense electron bombardment. We have shown that it is possible to produce, catch and measure the cyclotron frequencies of ions in the charge region 1+ to 52+. The relevant observable in mass measurements using a Penning trap is the ratio of the cyclotron frequencies of the ion of interest and ion used as a mass reference. High precision requires that the two frequencies are measured after one another in the shortest possible time. For reasons of convenience the precision trap operates at room temperature. So far it has been believed that warm traps working at 4 K are required for high mass precision with exactly one ion in the trap at a ti...

  16. Optimization of a charge-state analyzer for electron cyclotron resonance ion source beams

    NARCIS (Netherlands)

    Saminathan, S.; Beijers, J. P. M.; Kremers, H. R.; Mironov, V.; Mulder, J.; Brandenburg, S.

    2012-01-01

    A detailed experimental and simulation study of the extraction of a 24 keV He+ beam from an ECR ion source and the subsequent beam transport through an analyzing magnet is presented. We find that such a slow ion beam is very sensitive to space-charge forces, but also that the neutralization of the b

  17. Ion pair formation and primary charging behavior of titanium oxide (anastase and rutile)

    NARCIS (Netherlands)

    Bourikas, K.; Hiemstra, T.; Riemsdijk, van W.H.

    2001-01-01

    The primary charging behavior of titanium oxide (anatase, rutile, and P25) and the ion pair formation of the electrolyte ions with the surface groups have been extensively studied. A large number of titration and electrokinetic data sets available in the literature have been successfully described,

  18. The study towards high intensity high charge state laser ion sources.

    Science.gov (United States)

    Zhao, H Y; Jin, Q Y; Sha, S; Zhang, J J; Li, Z M; Liu, W; Sun, L T; Zhang, X Z; Zhao, H W

    2014-02-01

    As one of the candidate ion sources for a planned project, the High Intensity heavy-ion Accelerator Facility, a laser ion source has been being intensively studied at the Institute of Modern Physics in the past two years. The charge state distributions of ions produced by irradiating a pulsed 3 J/8 ns Nd:YAG laser on solid targets of a wide range of elements (C, Al, Ti, Ni, Ag, Ta, and Pb) were measured with an electrostatic ion analyzer spectrometer, which indicates that highly charged ions could be generated from low-to-medium mass elements with the present laser system, while the charge state distributions for high mass elements were relatively low. The shot-to-shot stability of ion pulses was monitored with a Faraday cup for carbon target. The fluctuations within ±2.5% for the peak current and total charge and ±6% for pulse duration were demonstrated with the present setup of the laser ion source, the suppression of which is still possible.

  19. Negative Ion CID Fragmentation of O-linked Oligosaccharide Aldoses—Charge Induced and Charge Remote Fragmentation

    Science.gov (United States)

    Doohan, Roisin A.; Hayes, Catherine A.; Harhen, Brendan; Karlsson, Niclas Göran

    2011-06-01

    Collision induced dissociation (CID) fragmentation was compared between reducing and reduced sulfated, sialylated, and neutral O-linked oligosaccharides. It was found that fragmentation of the [M - H]- ions of aldoses with acidic residues gave unique Z-fragmentation of the reducing end GalNAc containing the acidic C-6 branch, where the entire C-3 branch was lost. This fragmentation pathway, which is not seen in the alditols, showed that the process involved charge remote fragmentation catalyzed by a reducing end acidic anomeric proton. With structures containing sialic acid on both the C-3 and C-6 branch, the [M - H]- ions were dominated by the loss of sialic acid. This fragmentation pathway was also pronounced in the [M - 2H]2- ions revealing both the C-6 Z-fragment plus its complementary C-3 C-fragment in addition to glycosidic and cross ring fragmentation. This generation of the Z/C-fragment pairs from GalNAc showed that the charges were not participating in their generation. Fragmentation of neutral aldoses showed pronounced Z-fragmentation believed to be generated by proton migration from the C-6 branch to the negatively charged GalNAc residue followed by charge remote fragmentation similar to the acidic oligosaccharides. In addition, A-type fragments generated by charge induced fragmentation of neutral oligosaccharides were observed when the charge migrated from C-1 of the GalNAc to the GlcNAc residue followed by rearrangement to accommodate the 0,2A-fragmentation. LC-MS also showed that O-linked aldoses existed as interchangeable α/β pyranose anomers, in addition to a third isomer (25% of the total free aldose) believed to be the furanose form.

  20. Laser Plasmas : Multiple charge states of titanium ions in laser produced plasma

    Indian Academy of Sciences (India)

    M Shukla; S Bandhyopadhyay; V N Rai; A V Kilpio; H C Pant

    2000-11-01

    An intense laser radiation (1012 to 1014 W/cm-2) focused on the solid target creates a hot (≥ 1 keV) and dense plasma having high ionization state. The multiple charged ions with high current densities produced during laser matter interaction have potential application in accelerators as an ion source. This paper presents generation and detection of highly stripped titanium ions (Ti) in laser produced plasma. An Nd:glass laser (KAMETRON) delivering 50 J energy ( = 0.53 m) in 2.5 ns was focused onto a titanium target to produce plasma. This plasma was allowed to drift across a space of ∼ 3 m through a diagnostic hole in the focusing mirror before ions are finally detected with the help of electrostatic ion analyzer. Maximum current density was detected for the charge states of +16 and +17 of Ti ions for laser intensity of ∼ 1014 W/cm-2.

  1. ECR Ion Source of High Charge States%高电荷态ECR离子源

    Institute of Scientific and Technical Information of China (English)

    张子民; 刘占稳; 赵红卫

    2000-01-01

    介绍了目前ECR离子源的发展状况和国际上几台典型的ECR离子源.%Electron cyclotron resonance (ECR) ion source is the most efficient facility for producing highly charged ions.So far more than 1 emA of O6+ and 0.02eμA of U55+ have been delivered by ECR ion source. In this paper the latest develop-ment of ECR ion source is presented and several typical ECR ion sources in the world is introduced.

  2. Charge distribution of Kr ions produced upon photoionization around the 2s edge

    Energy Technology Data Exchange (ETDEWEB)

    Santos, A.C.F., E-mail: toni@if.ufrj.br [Instituto de Física, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21991-972 (Brazil); Pilling, S. [Laboratório Nacional de Luz Síncroton, Campinas 13084-971 (Brazil); Almeida, D.P. [Departamento de Física, Universidade Federal de Santa Catarina, Florianópolis 88040-979 (Brazil)

    2015-08-15

    Highlights: • Charge spectra of Kr after photoionization of the L shell have been measured. • Multiple photoionization of krypton around the 2s edge is a collective process. • Electron correlation plays an important role in multiple ionization of heavy atoms. - Abstract: Charge state spectra of krypton ions generated after ionization (by a single photon) of the L shell have been measured by using the PEPICO technique. Relative abundances of Kr{sup q+} ions in charge state up to 8+ were obtained using monochromatized synchrotron radiation. A comparison with other experimental and theoretical data is presented.

  3. Stabilized enzymes in continuous gas phase reactions

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Fangxiao; LeJeune, K.; Yang, Zhen [Univ. of Pittsburgh, PA (United States)] [and others

    1995-12-01

    We are assessing the utility of enzymes to catalyze reactions in a continuous gas phase reactor. First, alcohol dehydrogenase has been used to oxidize an unsaturated alcohol, 3-methyl-2-buten-1-ol (UOL), to the corresponding unsaturated aldehyde, 3-methyl-2-butenal (UAL). Cofactor NAD{sup +} was regenerated by concomitant acetone reduction to isopropyl alcohol. Second, organophosphorus hydrolase (OPH) has been used to hydrolyze pesticide vapors. In order to control enzyme hydration level, enzyme water adsorption isotherms at different temperature have been studied. Huttig`s isotherm model has been found suitable to describe adsorption behavior. The influence of enzyme hydration level, enzyme loading on glass beads, reaction temperature and flow rate on enzymatic reaction rate and biocatalyst stability were investigated. Reaction kinetics were studied and a kinetic model was proposed. We will also report our attempts to further stabilize enzymes for use in gas reactions by incorporating them into polymer matrices.

  4. Gas phase grown silicon germanium nanocrystals

    Science.gov (United States)

    Mohan, A.; Tichelaar, F. D.; Kaiser, M.; Verheijen, M. A.; Schropp, R. E. I.; Rath, J. K.

    2016-09-01

    We report on the gas phase synthesis of highly crystalline and homogeneously alloyed Si1-xGex nanocrystals in continuous and pulsed plasmas. Agglomerated nanocrystals have been produced with remarkable control over their composition by altering the precursor GeH4 gas flow in a continuous plasma. We specially highlight that in the pulsed plasma mode, we obtain quantum-sized free standing alloy nanocrystals with a mean size of 7.3 nm. The presence of Si1-xGex alloy particles is confirmed with multiple techniques, i.e. Raman spectroscopy, XRD (Xray diffraction) and HRTEM (high resolution transmission electron microscopy) studies, with each of these methods consistently yielding the same composition. The nanocrystals synthesized here have potential applications in band-gap engineering for multijunction solar cells.

  5. X-ray emission from charge exchange of highly-charged ions in atoms and molecules

    Science.gov (United States)

    Greenwood, J. B.; Williams, I. D.; Smith, S. J.; Chutjian, A.

    2000-01-01

    Charge exchange followed by radiative stabilization are the main processes responsible for the recent observations of X-ray emission from comets in their approach to the Sun. A new apparatus was constructed to measure, in collisions of HCIs with atoms and molecules, (a) absolute cross sections for single and multiple charge exchange, and (b) normalized X-ray emission cross sections.

  6. Humidity independent mass spectrometry for gas phase chemical analysis via ambient proton transfer reaction.

    Science.gov (United States)

    Zhu, Hongying; Huang, Guangming

    2015-03-31

    In this work, a humidity independent mass spectrometric method was developed for rapid analysis of gas phase chemicals. This method is based upon ambient proton transfer reaction between gas phase chemicals and charged water droplets, in a reaction chamber with nearly saturate humidity under atmospheric pressure. The humidity independent nature enables direct and rapid analysis of raw gas phase samples, avoiding time- and sample-consuming sample pretreatments in conventional mass spectrometry methods to control sample humidity. Acetone, benzene, toluene, ethylbenzene and meta-xylene were used to evaluate the analytical performance of present method. The limits of detection for benzene, toluene, ethylbenzene and meta-xylene are in the range of ∼0.1 to ∼0.3 ppbV; that of benzene is well below the present European Union permissible exposure limit for benzene vapor (5 μg m(-3), ∼1.44 ppbV), with linear ranges of approximately two orders of magnitude. The majority of the homemade device contains a stainless steel tube as reaction chamber and an ultrasonic humidifier as the source of charged water droplets, which makes this cheap device easy to assemble and facile to operate. In addition, potential application of this method was illustrated by the real time identification of raw gas phase chemicals released from plants at different physiological stages.

  7. Spatial distribution of charged particles along the ion-optical axis in electron cyclotron resonance ion sources. Experimental results

    Energy Technology Data Exchange (ETDEWEB)

    Panitzsch, Lauri

    2013-02-08

    The experimental determination of the spatial distribution of charged particles along the ion-optical axis in electron cyclotron resonance ion sources (ECRIS) defines the focus of this thesis. The spatial distributions of different ion species were obtained in the object plane of the bending magnet ({approx}45 cm downstream from the plasma electrode) and in the plane of the plasma electrode itself, both in high spatial resolution. The results show that each of the different ion species forms a bloated, triangular structure in the aperture of the plasma electrode. The geometry and the orientation of these structures are defined by the superposition of the radial and axial magnetic fields. The radial extent of each structure is defined by the charge of the ion. Higher charge states occupy smaller, more concentrated structures. The total current density increases towards the center of the plasma electrode. The circular and star-like structures that can be observed in the beam profiles of strongly focused, extracted ion beams are each dominated by ions of a single charge state. In addition, the spatially resolved current density distribution of charged particles in the plasma chamber that impinge on the plasma electrode was determined, differentiating between ions and electrons. The experimental results of this work show that the electrons of the plasma are strongly connected to the magnetic field lines in the source and thus spatially well confined in a triangular-like structure. The intensity of the electrons increases towards the center of the plasma electrode and the plasma chamber, as well. These electrons are surrounded by a spatially far less confined and less intense ion population. All the findings mentioned above were already predicted in parts by simulations of different groups. However, the results presented within this thesis represent the first (and by now only) direct experimental verification of those predictions and are qualitatively transferable to

  8. Measurements of excitation spectra and level lifetimes for highly charged neon ions

    Institute of Scientific and Technical Information of China (English)

    王友德; 马新文; 杨治虎; 杜一飞; 刘惠萍; 赵孟春; 郭天瑞; 王春芳

    1997-01-01

    Beam foil experiments were carried out for 47 MeV Ne ions passing through C (39 μg/cm2) and Al (3 4mg/cm2) foils. Highly charged H-, He-, Li-, and Be-like ions were obtained after the foils. The excitation spectra and level lifetimes for these ions were measured, and transition configurations for most measured lines were identified

  9. Discrimination of Isomeric Carbohydrates as the Electron Transfer Products of Group II Cation Adducts by Ion Mobility Spectrometry and Tandem Mass Spectrometry.

    Science.gov (United States)

    Huang, Yuting; Dodds, Eric D

    2015-06-01

    The rapid and unambiguous distinction of isomeric carbohydrate structures persists as a tremendous analytical challenge. This paper reports the first exploitation of carbohydrate/metal ion interactions in concert with gas-phase ion chemistry to improve discrimination of oligosaccharide isomers by both ion mobility spectrometry and tandem mass spectrometry. This is demonstrated for two isomeric pentasaccharides and two isomeric hexasaccharides, each studied in an underivatized form as their calcium ion adducts, barium ion adducts, and gas-phase electron transfer products thereof. With appropriate selection of the charge carrier, transfer of a single electron to the carbohydrate metal ion adducts resulted in isomer-distinguishing shifts in their ion/neutral collision cross sections and the appearance of unique features in their vibrational activation/dissociation spectra. These findings suggest novel and elegant gas-phase strategies for rapid differentiation of isomeric oligosaccharides.

  10. Single and double charge transfer of He(2+) ions with molecules at near-thermal energies

    Science.gov (United States)

    Tosh, R. E.; Johnsen, R.

    1993-01-01

    Rate coefficients were measured for charge-transfer reactions of He(2+) ions with H2, N2, O2, CO, CO2, and H2O. The experiments were carried out using a selected-ion drift-tube mass spectrometer. Total rate coefficients are found to be very large and are generally close to the limiting Langevin capture rate coefficients or the corresponding ADO-model (Su and Bowers, 1973) coefficients. The product-ion spectra indicate that both single and double charge transfer and possibly transfer ionization occur in these reactions.

  11. High precision wavelength measurements of QED-sensitive forbidden transitions in highly charged argon ions.

    Science.gov (United States)

    Draganić, I; Crespo López-Urrutia, J R; DuBois, R; Fritzsche, S; Shabaev, V M; Orts, R Soria; Tupitsyn, I I; Zou, Y; Ullrich, J

    2003-10-31

    We present the results of an experimental study of magnetic dipole (M1) transitions in highly charged argon ions (Ar X, Ar XI, Ar XIV, Ar XV) in the visible spectral range using an electron beam ion trap. Their wavelengths were determined with, for highly charged ions, unprecedented accuracy up to the sub-ppm level and compared with theoretical calculations. The QED contributions, calculated in this Letter, are found to be 4 orders of magnitude larger than the experimental error and are absolutely indispensable to bring theory and experiment to a good agreement. This method shows great potential for the study of QED effects in relativistic few-electron systems.

  12. Possible Diamond-Like Nanoscale Structures Induced by Slow Highly-Charged Ions on Graphite (HOPG)

    Energy Technology Data Exchange (ETDEWEB)

    Sideras-Haddad, E.; Schenkel, T.; Shrivastava, S.; Makgato, T.; Batra, A.; Weis, C. D.; Persaud, A.; Erasmus, R.; Mwakikunga, B.

    2009-01-06

    The interaction between slow highly-charged ions (SHCI) of different charge states from an electron-beam ion trap and highly oriented pyrolytic graphite (HOPG) surfaces is studied in terms of modification of electronic states at single-ion impact nanosizeareas. Results are presented from AFM/STM analysis of the induced-surface topological features combined with Raman spectroscopy. I-V characteristics for a number of different impact regions were measured with STM and the results argue for possible formation of diamond-like nanoscale structures at the impact sites.

  13. Novel aspects on the irradiation of HOPG surfaces with slow highly charged ions

    Energy Technology Data Exchange (ETDEWEB)

    Ritter, R. [Institute of Applied Physics, TU Wien, 1040 Vienna (Austria); Shen, Q. [Institute of Physics, Montanuniversität Leoben, 8700 Leoben (Austria); Wilhelm, R.A. [Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden-Rossendorf, 01328 Dresden (Germany); Technische Universität Dresden, 01062 Dresden (Germany); Heller, R. [Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden-Rossendorf, 01328 Dresden (Germany); Ginzel, R.; Crespo López-Urrutia, J.R. [Max Planck Institute for Nuclear Physics, 69117 Heidelberg (Germany); Facsko, S. [Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden-Rossendorf, 01328 Dresden (Germany); Teichert, C. [Institute of Physics, Montanuniversität Leoben, 8700 Leoben (Austria); Aumayr, F., E-mail: aumayr@iap.tuwien.ac.at [Institute of Applied Physics, TU Wien, 1040 Vienna (Austria)

    2013-11-15

    As a continuation of our previous work, we present new results regarding the interaction of slow highly charged ions with HOPG. Lateral atomic force microscopy measurements with calibrated cantilevers were performed to investigate in more detail the locally enhanced friction at ion impact sites, which has been reported earlier. For very high charge states, apart from ever-present changes in frictional and electronic properties, we find evidence for true topographic surface modifications (hillocks). In complementary studies, we have investigated these structures regarding their conductivity by employing high-resolution conductive atomic force microscopy. In addition, we demonstrate the possibility to etch ion-induced surface structures by thermal annealing.

  14. Neutralization Of Multiply Charged Rydberg Ions Interacting With Solid Surfaces Under The Grazing Incidence Geometry

    Science.gov (United States)

    Majkic, M. D.; Nedeljkovic, N. N.; Galijas, S. M. D.

    2010-07-01

    We elaborated the time-symmetric, two-state vector model to investigate the intermediate stages of the electron capture into the Rydberg states of multiply charged ions interacting with solid surface under the grazing incidence geometry. The neutralization distances for the ions XeZ+ interacting with Al-surface are calculated, for core charges Z ?[5,30]. The corresponding mean neutralization distances are in agreement with the data deduced from the measured kinetic energy gain due to the image acceleration of the ions.

  15. Efficiently photo-charging lithium-ion battery by perovskite solar cell

    OpenAIRE

    Xu, Jiantie; Chen, Yonghua; Dai, Liming

    2015-01-01

    Electric vehicles using lithium-ion battery pack(s) for propulsion have recently attracted a great deal of interest. The large-scale practical application of battery electric vehicles may not be realized unless lithium-ion batteries with self-charging suppliers will be developed. Solar cells offer an attractive option for directly photo-charging lithium-ion batteries. Here we demonstrate the use of perovskite solar cell packs with four single CH3NH3PbI3 based solar cells connected in series f...

  16. Charge breeding results and future prospects with electron cyclotron resonance ion source and electron beam ion source (invited).

    Science.gov (United States)

    Vondrasek, R; Levand, A; Pardo, R; Savard, G; Scott, R

    2012-02-01

    The Californium Rare Ion Breeder Upgrade (CARIBU) of the Argonne National Laboratory ATLAS facility will provide low-energy and reaccelerated neutron-rich radioactive beams for the nuclear physics program. A 70 mCi (252)Cf source produces fission fragments which are thermalized and collected by a helium gas catcher into a low-energy particle beam with a charge of 1+ or 2+. An electron cyclotron resonance (ECR) ion source functions as a charge breeder in order to raise the ion charge sufficiently for acceleration in the ATLAS linac. The final CARIBU configuration will utilize a 1 Ci (252)Cf source to produce radioactive beams with intensities up to 10(6) ions∕s for use in the ATLAS facility. The ECR charge breeder has been tested with stable beam injection and has achieved charge breeding efficiencies of 3.6% for (23)Na(8+), 15.6% for (84)Kr(17+), and 13.7% for (85)Rb(19+) with typical breeding times of 10 ms∕charge state. For the first radioactive beams, a charge breeding efficiency of 11.7% has been achieved for (143)Cs(27+) and 14.7% for (143)Ba(27+). The project has been commissioned with a radioactive beam of (143)Ba(27+) accelerated to 6.1 MeV∕u. In order to take advantage of its lower residual contamination, an EBIS charge breeder will replace the ECR charge breeder in the next two years. The advantages and disadvantages of the two techniques are compared taking into account the requirements of the next generation radioactive beam facilities.

  17. Langevin Poisson-Boltzmann equation: point-like ions and water dipoles near a charged surface.

    Science.gov (United States)

    Gongadze, Ekaterina; van Rienen, Ursula; Kralj-Iglič, Veronika; Iglič, Aleš

    2011-06-01

    Water ordering near a charged membrane surface is important for many biological processes such as binding of ligands to a membrane or transport of ions across it. In this work, the mean-field Poisson-Boltzmann theory for point-like ions, describing an electrolyte solution in contact with a planar charged surface, is modified by including the orientational ordering of water. Water molecules are considered as Langevin dipoles, while the number density of water is assumed to be constant everywhere in the electrolyte solution. It is shown that the dielectric permittivity of an electrolyte close to a charged surface is decreased due to the increased orientational ordering of water dipoles. The dielectric permittivity close to the charged surface is additionally decreased due to the finite size of ions and dipoles.

  18. Tuning the Fabrication of Nanostructures by Low-Energy Highly Charged Ions

    Science.gov (United States)

    El-Said, Ayman S.; Wilhelm, Richard A.; Heller, Rene; Sorokin, Michael; Facsko, Stefan; Aumayr, Friedrich

    2016-09-01

    Slow highly charged ions have been utilized recently for the creation of monotype surface nanostructures (craters, calderas, or hillocks) in different materials. In the present study, we report on the ability of slow highly charged xenon ions (129Xe Q+ ) to form three different types of nanostructures on the LiF(100) surface. By increasing the charge state from Q =15 to Q =36 , the shape of the impact induced nanostructures changes from craters to hillocks crossing an intermediate stage of caldera structures. A dimensional analysis of the nanostructures reveals an increase of the height up to 1.5 nm as a function of the potential energy of the incident ions. Based on the evolution of both the geometry and size of the created nanostructures, defect-mediated desorption and the development of a thermal spike are utilized as creation mechanisms of the nanostructures at low and high charge states, respectively.

  19. Tuning the Fabrication of Nanostructures by Low-Energy Highly Charged Ions.

    Science.gov (United States)

    El-Said, Ayman S; Wilhelm, Richard A; Heller, Rene; Sorokin, Michael; Facsko, Stefan; Aumayr, Friedrich

    2016-09-16

    Slow highly charged ions have been utilized recently for the creation of monotype surface nanostructures (craters, calderas, or hillocks) in different materials. In the present study, we report on the ability of slow highly charged xenon ions (^{129}Xe^{Q+}) to form three different types of nanostructures on the LiF(100) surface. By increasing the charge state from Q=15 to Q=36, the shape of the impact induced nanostructures changes from craters to hillocks crossing an intermediate stage of caldera structures. A dimensional analysis of the nanostructures reveals an increase of the height up to 1.5 nm as a function of the potential energy of the incident ions. Based on the evolution of both the geometry and size of the created nanostructures, defect-mediated desorption and the development of a thermal spike are utilized as creation mechanisms of the nanostructures at low and high charge states, respectively.

  20. Aberrations due to solenoid focusing of a multiply charged high-current ion beam

    CERN Document Server

    Grégoire, G; Lisi, N; Schnuriger, J C; Scrivens, R; Tambini, J

    2000-01-01

    At the output of a laser ion source, a high current of highly charged ions with a large range of charge states is available. The focusing of such a beam by magnetic elements causes a nonlinear space-charge field to develop which can induce large aberrations and emittance growth in the beam. Simulation of the beam from the CERN laser ion source will be presented for an ideal magnetic and electrostatic system using a radially symmetric model. In addition, the three dimensional software KOBRA3 is used for the simulation of the solenoid line. The results of these simulations will be compared with experiments performed on the CERN laser ion source with solenoids (resulting in a hollow beam) and a series of gridded electrostatic lenses. (5 refs).

  1. Laboratory Studies of Thermal Energy Charge Transfer of Silicon and Iron Ions in Astrophysical Plasmas

    Science.gov (United States)

    Kwong, Victor H. S.

    1997-01-01

    The laser ablation/ion storage facility at the UNLV Physics Department is dedicated to the study of atomic processes in low temperature plasmas. Our current program is directed to the study of charge transfer of multiply charged ions and neutrals that are of importance to astrophysics at energies less than 1 eV (about 10(exp 4) K). Specifically, we measure the charge transfer rate coefficient of ions such as N(2+), Si(3+), Si(3+), with helium and Fe(2+) with molecular and atomic hydrogen. All these ions are found in a variety of astrophysical plasmas. Their electron transfer reactions with neutral atoms can affect the ionization equilibrium of the plasma.

  2. Penning traps with unitary architecture for storage of highly charged ions

    CERN Document Server

    Tan, Joseph N; Guise, Nicholas D; 10.1063/1.3685246

    2012-01-01

    Penning traps are made extremely compact by embedding rare-earth permanent magnets in the electrode structure. Axially-oriented NdFeB magnets are used in unitary architectures that couple the electric and magnetic components into an integrated structure. We have constructed a two- magnet Penning trap with radial access to enable the use of laser or atomic beams, as well as the collection of light. An experimental apparatus equipped with ion optics is installed at the NIST electron beam ion trap (EBIT) facility, constrained to fit within 1 meter at the end of a horizontal beamline for transporting highly charged ions. Highly charged ions of neon and argon, extracted with initial energies up to 4000 eV per unit charge, are captured and stored to study the confinement properties of a one-magnet trap and a two-magnet trap. Design considerations and some test results are discussed.

  3. Penning traps with unitary architecture for storage of highly charged ions.

    Science.gov (United States)

    Tan, Joseph N; Brewer, Samuel M; Guise, Nicholas D

    2012-02-01

    Penning traps are made extremely compact by embedding rare-earth permanent magnets in the electrode structure. Axially-oriented NdFeB magnets are used in unitary architectures that couple the electric and magnetic components into an integrated structure. We have constructed a two-magnet Penning trap with radial access to enable the use of laser or atomic beams, as well as the collection of light. An experimental apparatus equipped with ion optics is installed at the NIST electron beam ion trap (EBIT) facility, constrained to fit within 1 meter at the end of a horizontal beamline for transporting highly charged ions. Highly charged ions of neon and argon, extracted with initial energies up to 4000 eV per unit charge, are captured and stored to study the confinement properties of a one-magnet trap and a two-magnet trap. Design considerations and some test results are discussed.

  4. Fragmentation of phosphorylated and singly charged peptide ions via interaction with metastable atoms.

    Science.gov (United States)

    Berkout, Vadym D; Doroshenko, Vladimir M

    2008-12-01

    Fragmentation of phosphorylated peptide ions via interaction with electronically excited metastable argon atoms was studied in a linear trap - time-of-flight mass spectrometer. Doubly charged ions of phosphorylated peptides from an Enolase digest were produced by electrospray ionization and subjected to a metastable atom beam in the linear trap. The metastable argon atoms were generated using a glow-discharge source. An intensive series of c- and z- ions were observed in all cases, with the phosphorylation group intact. The formation of molecular radical cations with reduced charge indicated that an electron transfer from a highly excited metastable state of argon to the peptide cation occurred. Additionally, singly charged Bradykinin, Substance P and Fibrinopeptide A molecular ions were fragmented via interaction with electronically excited metastable helium atoms. The fragmentation mechanism was different in this case and involved Penning ionization.

  5. Charge states distribution of 3350 keV He ions channeled in silicon

    CERN Document Server

    Bentini, G G; Bianconi, M; Lotti, R; Lulli, G

    2002-01-01

    When an ion beam is aligned along a major crystalline axis the dominant interaction is with valence electrons. In this condition the charge exchange processes mostly concern the interaction between the incident ion and a quasi-free electron gas and a strong reduction of the charge-changing probabilities is expected. In this work, 3350 keV He sup + and He sup 2 sup + ions were aligned at small tilt angles about the axis of a 4650 A silicon crystalline membrane. The charge state distribution (CSD) of the transmitted ions was detected by an electro-magnetic analyzer having a very small acceptance angle. In these conditions the equilibration of the CSD was not yet reached and this allowed, making use of simple approximations, for the measurement of the valence electron loss cross-section.

  6. Gas-phase intramolecular elimination reaction studies of steviol glycosides in positive electrospray and tandem mass spectrometry.

    Science.gov (United States)

    Upreti, Mani; Clos, John F; Somayajula, Kasi V; Milanowski, Dennis J; Mocek, Ulla; Dubois, Grant E; Prakash, Indra

    2009-01-01

    This paper reports the first study of the gas-phase intramolecular elimination reaction of steviol glycosides in positive electrospray mass spectrometry. The observed glycosylated product ions are proposed to be formed via an intramolecular elimination of sugar units from the parent molecule ion. It was further proven by MS/MS studies and deuterium labeling experiments with one of the steviol glycosides, rebaudioside A. These mass spectrometric results confirmed that the new glycosylated product ions observed are most likely formed by the combination of glucose moieties (Glu) II-IV and Glu I via a gas-phase intramolecular elimination reaction.

  7. Fundamentals of gas phase plasmas for treatment of human tissue.

    Science.gov (United States)

    Kushner, Mark J; Babaeva, Natalia Yu

    2011-01-01

    The use of gas phase plasmas for treating human tissue is at the intersection of two disciplines - plasma physics and engineering, and medicine. In this paper, a primer will be provided for the medical practitioner on the fundamentals of generating gas phase plasmas at atmospheric pressure in air for the treatment of human tissue. The mechanisms for gas phase plasmas interacting with tissue and biological fluids will also be discussed using results from computer modeling.

  8. Elusive Sulfurous Acid: Gas-Phase Basicity and IR Signature of the Protonated Species.

    Science.gov (United States)

    Sinha, Rajeev K; Scuderi, Debora; Maitre, Philippe; Chiavarino, Barbara; Crestoni, Maria Elisa; Fornarini, Simonetta

    2015-05-01

    The ion corresponding to protonated sulfurous acid, H3SO3(+), has been successfully delivered into the gas phase by electrospray ionization of the solution of a suitable precursor and an in-source fragmentation process. The neutral acid is a highly elusive molecule. However, its gas-phase basicity has been ascertained by means of a kinetic study of proton-transfer reactivity. The structure of the H3SO3(+) sampled ion has been probed by IRMPD spectroscopy in two complementary IR frequency ranges in conjunction with density functional theory calculations and found to conform to a trihydroxosulfonium ion. The characteristic IR signatures may aid in deciphering the presence of this species in extraterrestrial atmospheres.

  9. Generation of naphthoquinone radical anions by electrospray ionization: solution, gas-phase, and computational chemistry studies.

    Science.gov (United States)

    Vessecchi, Ricardo; Naal, Zeki; Lopes, José N C; Galembeck, Sérgio E; Lopes, Norberto P

    2011-06-02

    Radical anions are present in several chemical processes, and understanding the reactivity of these species may be described by their thermodynamic properties. Over the last years, the formation of radical ions in the gas phase has been an important issue concerning electrospray ionization mass spectrometry studies. In this work, we report on the generation of radical anions of quinonoid compounds (Q) by electrospray ionization mass spectrometry. The balance between radical anion formation and the deprotonated molecule is also analyzed by influence of the experimental parameters (gas-phase acidity, electron affinity, and reduction potential) and solvent system employed. The gas-phase parameters for formation of radical species and deprotonated species were achieved on the basis of computational thermochemistry. The solution effects on the formation of radical anion (Q(•-)) and dianion (Q(2-)) were evaluated on the basis of cyclic voltammetry analysis and the reduction potentials compared with calculated electron affinities. The occurrence of unexpected ions [Q+15](-) was described as being a reaction between the solvent system and the radical anion, Q(•-). The gas-phase chemistry of the electrosprayed radical anions was obtained by collisional-induced dissociation and compared to the relative energy calculations. These results are important for understanding the formation and reactivity of radical anions and to establish their correlation with the reducing properties by electrospray ionization analyses.

  10. PREFACE: 8th International Conference on the Physics of Highly Charged Ions (HCI-96)

    Science.gov (United States)

    Awaya, Yohko; Kambara, Tadashi

    1997-01-01

    These proceedings contain the papers presented at the Eighth International Conference on the Physics of Highly Charged Ions (HCI-96) which was held on September 23-26, 1996 in Omiya, Saitama, Japan, hosted by the Institute of Physical and Chemical Research (RIKEN). The first conference of this series was held in Stockholm, Sweden in 1982. The subject was the "Production and Physics of Highly Charged Ions". The conference has since been held every other year; in Oxford, UK (1984), Groningen, the Netherlands (1986), Grenoble, France (1988), Giessen, Germany (1990), Manhattan, Kansas, USA (1992) and Vienna, Austria (1994). When the first conference of this series was held, various highly charged ions were available from many heavy ion accelerators, which had been constructed since the 1960's, and ion sources such as EBIS and ECRIS, which were then new facilities. Subsequently, many other experimental techniques have been developed to study or to control highly charged ions, such as ion traps, EBIT's, storage rings, high-brilliance synchrotron radiation, and so forth. Now the properties of highly charged ions themselves and their interactions with various kinds of materials can be studied systematically using ions of any element at various collision energies. These studies will result in a deeper insight into their nature as well as giving us important basic data for use in the fields closely related to atomic physics. About 190 scientists from 18 countries registered at the HCI-96. The number of invited talks was 21 and that of contrib- uted papers 215. In these proceedings, 20 papers of invited talks and 116 papers on contributions are included. They are classified into categories of "Structure and Spectroscopy of Highly Charged Ions and Fundamental Aspects", "Highly Charged Ions in Plasmas and Strong Fields", "Interactions of Highly Charged Ions with Atoms and Ions", "Dynamic Processes Related to Molecules and Clusters", "Interactions of Highly Charged Ions with

  11. Properties of Laser-Produced Highly Charged Heavy Ions for Direct Injection Scheme

    CERN Document Server

    Sakakibara, Kazuhiko; Hayashizaki, Noriyosu; Ito, Taku; Kashiwagi, Hirotsugu; Okamura, Masahiro

    2005-01-01

    To accelerate highly charged intense ion beam, we have developed the Direct Plasma Injection Scheme (DPIS) with laser ion source. In this scheme an ion beam from a laser ion source is injected directly to a RFQ linac without a low energy beam transport (LEBT) and the beam loss in the LEBT can be avoided. We achieved high current acceleration of carbon ions (60mA) by DPIS with the high current optimized RFQ. As the next setp we will use heavier elements like Ag, Pb, Al and Cu as target in LIS (using CO2, Nd-YAG or other laser) for DPIS and will examine properties of laser-produced plasma (the relationship of between charge state and laser power density, the current dependence of the distance from the target, etc).

  12. Charge-to-mass-ratio-dependent ion heating during magnetic reconnection in the MST RFP

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, S. T. A.; Almagri, A. F.; Den Hartog, D. J.; Nornberg, M. D.; Sarff, J. S.; Terry, P. W. [Department of Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States); Center for Magnetic Self-Organization in Laboratory and Astrophysical Plasmas, University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States); Craig, D. [Wheaton College, Wheaton, Illinois 60187 (United States)

    2013-05-15

    Temperature evolution during magnetic reconnection has been spectroscopically measured for various ion species in a toroidal magnetized plasma. Measurements are made predominantly in the direction parallel to the equilibrium magnetic field. It is found that the increase in parallel ion temperature during magnetic reconnection events increases with the charge-to-mass ratio of the ion species. This trend can be understood if the heating mechanism is anisotropic, favoring heating in the perpendicular degree of freedom, with collisional relaxation of multiple ion species. The charge-to-mass ratio trend for the parallel temperature derives from collisional isotropization. This result emphasizes that collisional isotropization and energy transfer must be carefully modeled when analyzing ion heating measurements and comparing to theoretical predictions.

  13. Space charge effect on parametric resonances of ion cloud in a linear Paul trap

    CERN Document Server

    Mandal, P; De Munshi, D; Dutta, T; Mukherjee, M

    2013-01-01

    The effect of the presence of a finite number of ions on their parametric resonances inside a Paul trap has been investigated both experimentally and theoretically. The Coulomb coupling among the charged particles results in two distinct phenomena: one is the frequency shift of the trapped ion oscillators and second is the collective oscillation of the trapped ion cloud. We observe both in a linear trap configuration. It is found that the strength and the secular frequency of individual ion-oscillation decrease while the strength of the collective oscillation increases with increasing number of trapped ions. The observation has been modeled by considering the space charge potential as an effective dc potential inside the trap. It describes the observations well within the experimental uncertainties.

  14. Surface Erosion of GaN Bombarded by Highly Charged 208Pbq+-Ions

    Institute of Scientific and Technical Information of China (English)

    ZHANG Li-Qing; ZHANG Chong-Hong; YANG Yi-Tao; YAO Cun-Feng; LI Bing-Sheng; JIN Yun-Fan; SUN You-Mei; SONG Shu-Jian

    2008-01-01

    Surface change of gallium nitride specimens after bombardment by highly charged Pbq+-ions (q=25, 35) at room temperature is studied by means of atomic force microscopy. The experimental results reveal that the surface of GaN specimens is significantly etched and erased. An unambiguous step-up is observed. The erosion depth not only strongly depends on the charge state of ions, but also is related to the incident angle of Pbq+ -ions and the ion dose. The erosion depth of the specimens in 60°incidence (tilted incidence) is significantly deeper than that of the normal incidence. The erosion behaviour of specimens has little dependence on the kinetic energy of ion (E,k=360, 700keV). On the other hand, surface roughness of the irradiated area is obviously decreased due to erosion compared with the un-irradiated area. A flat terrace is formed.

  15. Transverse Schottky spectra and beam transfer functions of coasting ion beams with space charge

    Energy Technology Data Exchange (ETDEWEB)

    Paret, Stefan

    2010-02-22

    A study of the transverse dynamics of coasting ion beams with moderate space charge is presented in this work. From the dispersion relation with linear space charge, an analytic model describing the impact of space charge on transverse beam transfer functions (BTFs) and the stability limits of a beam is derived. The dielectric function obtained in this way is employed to describe the transverse Schottky spectra with linear space charge as well. The difference between the action of space charge and impedances is highlighted. The setup and the results of an experiment performed in the heavy ion synchrotron SIS-18 at GSI to detect space-charge effects at different beam intensities are explicated. The measured transverse Schottky spectra and BTFs are compared with the linear space-charge model. The stability diagrams constructed from the BTFs are presented. The space-charge parameters evaluated from the Schottky and BTF measurements are compared with estimations based on measured beam parameters. The impact of collective effects on the Schottky and BTF diagnostics is also investigated through numerical simulations. For this purpose the self-field of beams with linear and non-linear transverse density-distributions is computed on a twodimensional grid. The noise of the random particle distribution causes fluctuations of the dipole moment of the beam which produce the Schottky spectrum. BTFs are simulated by exciting the beam with transverse kicks. The simulation results are used to verify the space-charge model. (orig.)

  16. Effect of Negatively Charged Ions on the Formation of Microarc Oxidation Coating on 2024 Aluminium Alloy

    Institute of Scientific and Technical Information of China (English)

    Wei Yang; Bailing Jiang; Aiying Wang; Huiying Shi

    2012-01-01

    The present study deals with the effect of negatively charged ions on the ceramic coating formation on 2024 aluminium alloy during microarc oxidation (MAO) process. On the basis of the experimental results, two steps (the formation of an incipient film without arc presence and the growth of a ceramic coating with arc discharge) of MAO process have been observed. For comparison, four different negatively charged ions studied. It is proved that negatively charged ions strongly participated in the formation of an incipient film with high impedance value at the first step. The growth of ceramic coating depends on the combination between AI of the substrate and O from the electrolyte, and the negatively charged ions are little consumed. As an anodic oxide coating is prepared on the sample surface instead of the incipient film, the first step occurs easily and the growth of ceramic coating is accelerated. Furthermore, the mechanism of negatively charged ions in the formation of the MAO coating has been proposed.

  17. Interaction of singly and multiply charged ions with a lithium-fluoride surface

    CERN Document Server

    Wirtz, L

    2001-01-01

    Charge transfer between slow ions and an ionic crystal surface still poses a considerable challenge to theory due to the intrinsic many-body character of the system. For the neutralization of multiply charged ions in front of metal surfaces, the Classical Over the Barrier (COB) model is a widely used tool. We present an extension of this model to ionic crystal surfaces where the localization of valence electrons at the anion sites and the lack of cylindrical symmetry of the ion-surface system impede a simple analytical estimate of electron transfer rates. We use a classical trajectory Monte Carlo approach to calculate electron transfer rates for different charge states of the projectile ion. With these rates we perform a Monte Carlo simulation of the neutralization of slow Ne10+ ions in vertical incidence on an LiF surface. Capture of one or several electrons may lead to a local positive charge up of the surface. The projectile dynamics depends on the balance between the repulsion due to this charge and the a...

  18. Dielectronic recombination measurements of highly-charged heliumlike and neonlike ions using an electron beam ion trap

    Energy Technology Data Exchange (ETDEWEB)

    Schneider, M.B.; Knapp, D.A.; Beiersdorfer, P.; Chen, M.H.; Scofield, J.H.; Bennett, C.L.; DeWitt, D.R.; Henderson, J.R.; Lee, P.; Marrs, R.E.; Schneider, D. (Lawrence Livermore National Lab., CA (United States)); Levine, M.A. (Lawrence Berkeley Lab., CA (United States))

    1991-01-01

    The electron beam ion trap (EBIT) at LLNL is a unique device designed to measure the interactions of electrons with highly-charged ions. We describe three methods used at EBIT to directly measure the dielectronic recombination (DR) process: the intensity of the stabilizing x-rays is measured as a function of electron beam energy; the ions remaining in a particular ionization state are counted after the electron beam has been held at a fixed electron energy for a fixed time; and high-resolution spectroscopy is used to resolve individual DR satellite lines. In our discussions, we concentrate on the KLL resonances of the heliumlike target ions (V{sup 21+} to Ba{sup 54+}), and the LMM resonances of the neonlike target ions (Xe{sup 44+} to Th{sup 80+}). 12 refs., 8 figs.

  19. High temperature electron beam ion source for the production of single charge ions of most elements of the Periodic Table

    CERN Document Server

    Panteleev, V N; Barzakh, A E; Fedorov, D V; Ivanov, V S; Moroz, F V; Orlov, S Y; Seliverstov, D M; Stroe, L; Tecchio, L B; Volkov, Y M

    2003-01-01

    A new type of a high temperature electron beam ion source (HTEBIS) with a working temperature up to 2500 deg. C was developed for production of single charge ions of practically all elements. Off-line tests and on-line experiments making use of the developed ion source coupled with uranium carbide targets of different density, have been carried out. The ionization efficiency measured for stable atoms of many elements varied in the interval of 1-6%. Using the HTEBIS, the yields and on-line production efficiency of neutron rich isotopes of Mn, Fe, Co, Cu, Rh, Pd, Ag, Cd, In, Sn and isotopes of heavy elements Pb, Bi, Po and some others have been determined. The revealed confinement effect of the ions produced in the narrow electron beam inside a hot ion source cavity has been discussed.

  20. Ion distributions at charged aqueous surfaces: Synchrotron X-ray scattering studies

    Energy Technology Data Exchange (ETDEWEB)

    Bu, Wei [Iowa State Univ., Ames, IA (United States)

    2009-01-01

    Surface sensitive synchrotron X-ray scattering studies were performed to obtain the distribution of monovalent ions next to a highly charged interface at room temperature. To control surface charge density, lipids, dihexadecyl hydrogen-phosphate (DHDP) and dimysteroyl phosphatidic acid (DMPA), were spread as monolayer materials at the air/water interface, containing CsI at various concentrations. Five decades in bulk concentrations (CsI) are investigated, demonstrating that the interfacial distribution is strongly dependent on bulk concentration. We show that this is due to the strong binding constant of hydronium H3O+ to the phosphate group, leading to proton-transfer back to the phosphate group and to a reduced surface charge. Using anomalous reflectivity off and at the L3 Cs+ resonance, we provide spatial counterion (Cs+) distributions next to the negatively charged interfaces. The experimental ion distributions are in excellent agreement with a renormalized surface charge Poisson-Boltzmann theory for monovalent ions without fitting parameters or additional assumptions. Energy Scans at four fixed momentum transfers under specular reflectivity conditions near the Cs+ L3 resonance were conducted on 10-3 M CsI with DHDP monolayer materials on the surface. The energy scans exhibit a periodic dependence on photon momentum transfer. The ion distributions obtained from the analysis are in excellent agreement with those obtained from anomalous reflectivity measurements, providing further confirmation to the validity of the renormalized surface charge Poisson-Boltzmann theory for monovalent ions. Moreover, the dispersion corrections f0 and f00 for Cs+ around L3 resonance, revealing the local environment of a Cs+ ion in the solution at the interface, were extracted simultaneously with output of ion distributions.

  1. Study on the ECR Ion Source and Application Technology of the Charged Particle Beam

    Energy Technology Data Exchange (ETDEWEB)

    Oh, B. H.; Lee, K. W.; Jin, J. T.; and others

    2012-12-15

    Recently, Korea has launched the world's top class heavy ion accelerator project, and for the machine it is necessary to develop related physic and technology for the high charge state beam including a 28 GHz superconducting ECR ion source. This study is prepared to support this activity including transport of TRIAC(Tokai Radioactive Accelerator Complex) and development of ECR ion source technology. TRIAC, which was developed by KEK Japan, was a one of a heavy ion accelerator. This work is especially necessary to support the originality of the experiments with the heavy ion accelerator in the future in Korea. New accelerator DIAC will be used to support Korea Rare Isotope Accelerator project, and also will be applied to other heavy ion beam physics and engineering research. Based on the conceptual design results of the 28 GHz superconducting ECR ion source, an engineering design and construction will be started from next fiscal year.

  2. Charge transfer to ground-state ions produces free electrons

    Science.gov (United States)

    You, D.; Fukuzawa, H.; Sakakibara, Y.; Takanashi, T.; Ito, Y.; Maliyar, G. G.; Motomura, K.; Nagaya, K.; Nishiyama, T.; Asa, K.; Sato, Y.; Saito, N.; Oura, M.; Schöffler, M.; Kastirke, G.; Hergenhahn, U.; Stumpf, V.; Gokhberg, K.; Kuleff, A. I.; Cederbaum, L. S.; Ueda, K.

    2017-01-01

    Inner-shell ionization of an isolated atom typically leads to Auger decay. In an environment, for example, a liquid or a van der Waals bonded system, this process will be modified, and becomes part of a complex cascade of relaxation steps. Understanding these steps is important, as they determine the production of slow electrons and singly charged radicals, the most abundant products in radiation chemistry. In this communication, we present experimental evidence for a so-far unobserved, but potentially very important step in such relaxation cascades: Multiply charged ionic states after Auger decay may partially be neutralized by electron transfer, simultaneously evoking the creation of a low-energy free electron (electron transfer-mediated decay). This process is effective even after Auger decay into the dicationic ground state. In our experiment, we observe the decay of Ne2+ produced after Ne 1s photoionization in Ne-Kr mixed clusters.

  3. How accurate is Poisson-Boltzmann theory for monovalent ions near highly charged interfaces?

    Science.gov (United States)

    Bu, Wei; Vaknin, David; Travesset, Alex

    2006-06-20

    Surface sensitive synchrotron X-ray scattering studies were performed to obtain the distribution of monovalent ions next to a highly charged interface. A lipid phosphate (dihexadecyl hydrogen-phosphate) was spread as a monolayer at the air-water interface to control surface charge density. Using anomalous reflectivity off and at the L3 Cs+ resonance, we provide spatial counterion (Cs+) distributions next to the negatively charged interfaces. Five decades in bulk concentrations are investigated, demonstrating that the interfacial distribution is strongly dependent on bulk concentration. We show that this is due to the strong binding constant of hydronium H3O+ to the phosphate group, leading to proton-transfer back to the phosphate group and to a reduced surface charge. The increase of Cs+ concentration modifies the contact value potential, thereby causing proton release. This process effectively modifies surface charge density and enables exploration of ion distributions as a function of effective surface charge-density. The experimentally obtained ion distributions are compared to distributions calculated by Poisson-Boltzmann theory accounting for the variation of surface charge density due to proton release and binding. We also discuss the accuracy of our experimental results in discriminating possible deviations from Poisson-Boltzmann theory.

  4. Efficiently photo-charging lithium-ion battery by perovskite solar cell.

    Science.gov (United States)

    Xu, Jiantie; Chen, Yonghua; Dai, Liming

    2015-08-27

    Electric vehicles using lithium-ion battery pack(s) for propulsion have recently attracted a great deal of interest. The large-scale practical application of battery electric vehicles may not be realized unless lithium-ion batteries with self-charging suppliers will be developed. Solar cells offer an attractive option for directly photo-charging lithium-ion batteries. Here we demonstrate the use of perovskite solar cell packs with four single CH3NH3PbI3 based solar cells connected in series for directly photo-charging lithium-ion batteries assembled with a LiFePO4 cathode and a Li4Ti5O12 anode. Our device shows a high overall photo-electric conversion and storage efficiency of 7.80% and excellent cycling stability, which outperforms other reported lithium-ion batteries, lithium-air batteries, flow batteries and super-capacitors integrated with a photo-charging component. The newly developed self-chargeable units based on integrated perovskite solar cells and lithium-ion batteries hold promise for various potential applications.

  5. Efficiently photo-charging lithium-ion battery by perovskite solar cell

    Science.gov (United States)

    Xu, Jiantie; Chen, Yonghua; Dai, Liming

    2015-01-01

    Electric vehicles using lithium-ion battery pack(s) for propulsion have recently attracted a great deal of interest. The large-scale practical application of battery electric vehicles may not be realized unless lithium-ion batteries with self-charging suppliers will be developed. Solar cells offer an attractive option for directly photo-charging lithium-ion batteries. Here we demonstrate the use of perovskite solar cell packs with four single CH3NH3PbI3 based solar cells connected in series for directly photo-charging lithium-ion batteries assembled with a LiFePO4 cathode and a Li4Ti5O12 anode. Our device shows a high overall photo-electric conversion and storage efficiency of 7.80% and excellent cycling stability, which outperforms other reported lithium-ion batteries, lithium–air batteries, flow batteries and super-capacitors integrated with a photo-charging component. The newly developed self-chargeable units based on integrated perovskite solar cells and lithium-ion batteries hold promise for various potential applications. PMID:26311589

  6. The structure of geminal imidazolium bis(trifluoromethylsulfonyl)amide ionic liquids: a theoretical study of the gas phase ionic complexes.

    Science.gov (United States)

    Bodo, E; Caminiti, R

    2010-12-02

    In this work we report molecular mechanics and ab initio calculations on the geminal di-imidazolium bis(trifluoromethylsulfonyl)amide ionic liquid in the gas phase. We report the likely energetically preferred geometries of the ionic complex and its main features in terms of charge distribution, electronic density, structure, and energetics. We find that the gas phase structure of the ionic complex is quite compact and that the alkyl chain connecting the two imidazolium charged rings is strongly bent in order to maximize their electrostatic interactions with the two anions.

  7. Strongly Enhanced Effects of Lorentz-Symmetry Violation in Yb$^+$ and Highly Charged Ions

    CERN Document Server

    Safronova, M S

    2016-01-01

    A Lorentz-symmetry test with Ca$^+$ ions demonstrated the potential of using quantum information inspired technology for tests of fundamental physics. A systematic study of atomic-system sensitivities to Lorentz violation identified the ytterbium ion as an ideal system with high sensitivity as well as excellent experimental controllability. A test of Lorentz-violating physics in the electron-photon sector with Yb$^+$ ions has the potential to reach levels of 10$^{-23}$, five orders of magnitude more sensitive than the current best bounds. Similar sensitivities may be also reached with highly charged ions.

  8. Shot-to-shot reproducibility in the emission of fast highly charged metal ions from a laser ion source.

    Science.gov (United States)

    Krása, J; Velyhan, A; Margarone, D; Krouský, E; Krouský, L; Jungwirth, K; Rohlena, K; Ullschmied, J; Parys, P; Ryć, L; Wołowski, J

    2012-02-01

    The generation of fast highly charged metal ions with the use of the sub-nanosecond Prague Asterix Laser System, operated at a fundamental wavelength of 1315 nm, is reported. Particular attention is paid to shot-to-shot reproducibility in the ion emission. Au and Pd targets were exposed to intensities up to 5 × 10(16) W∕cm(2). Above the laser intensity threshold of ∼3 × 10(14) W∕cm(2) the plasma is generated in a form of irregular bursts. The maximum energy of protons constituting the leading edge of the fastest burst reaches a value up to 1 MeV. The fast ions in the following bursts have energy gradually decreasing with the increasing burst number, namely, from a value of about 0.5 MeV∕charge regardless of the atomic number and mass of the ionized species.

  9. A compact electron beam ion source with integrated Wien filter providing mass and charge state separated beams of highly charged ions.

    Science.gov (United States)

    Schmidt, M; Peng, H; Zschornack, G; Sykora, S

    2009-06-01

    A Wien filter was designed for and tested with a room temperature electron beam ion source (EBIS). Xenon charge state spectra up to the charge state Xe46+ were resolved as well as the isotopes of krypton using apertures of different sizes. The complete setup consisting of an EBIS and a Wien filter has a length of less than 1 m substituting a complete classical beamline setup. The Wien filter is equipped with removable permanent magnets. Hence total beam current measurements are possible via simple removal of the permanent magnets. In dependence on the needs of resolution a weak (0.2 T) or a strong (0.5 T) magnets setup can be used. In this paper the principle of operation and the design of the Wien filter meeting the requirements of an EBIS are briefly discussed. The first ion beam extraction and separation experiments with a Dresden EBIS are presented.

  10. Particles inside electrolytes with ion-specific interactions, their effective charge distributions, and effective interactions

    Science.gov (United States)

    Ding, Mingnan; Liang, Yihao; Xing, Xiangjun

    2016-10-01

    In this work, we explore the statistical physics of colloidal particles that interact with electrolytes via ion-specific interactions. Firstly we study particles interacting weakly with electrolyte using linear response theory. We find that the mean potential around a particle is linearly determined by the effective charge distribution of the particle, which depends both on the bare charge distribution and on ion-specific interactions. We also discuss the effective interaction between two such particles and show that, in the far field regime, it is bilinear in the effective charge distributions of two particles. We subsequently generalize the above results to the more complicated case where particles interact strongly with the electrolyte. Our results indicate that in order to understand the statistical physics of non-dilute electrolytes, both ion-specific interactions and ionic correlations have to be addressed in a single unified and consistent framework. Project supported by the National Natural Science Foundation of China (Grant Nos. 11174196 and 91130012).

  11. Electroweak Decay Studies of Highly Charged Radioactive Ions with TITAN at TRIUMF

    CERN Document Server

    Leach, K G; Klawitter, R; Leistenschneider, E; Lennarz, A; Brunner, T; Frekers, D; Andreiou, C; Kwiatkowski, A A; Dilling, J

    2016-01-01

    Several modes of electroweak radioactive decay require an interaction between the nucleus and bound electrons within the constituent atom. Thus, the probabilities of the respective decays are not only influenced by the structure of the initial and final states in the nucleus, but can also depend strongly on the atomic charge. Conditions suitable for the partial or complete ionization of these rare isotopes occur naturally in hot, dense astrophysical environments, but can also be artificially generated in the laboratory to selectively block certain radioactive decay modes. Direct experimental studies on such scenarios are extremely difficult due to the laboratory conditions required to generate and store radioactive ions at high charge states. A new electron-beam ion trap (EBIT) decay setup with the TITAN experiment at TRIUMF has successfully demonstrated such techniques for performing spectroscopy on the radioactive decay of highly charged ions.

  12. Space charge compensation in the Linac4 low energy beam transport line with negative hydrogen ions.

    Science.gov (United States)

    Valerio-Lizarraga, Cristhian A; Lallement, Jean-Baptiste; Leon-Monzon, Ildefonso; Lettry, Jacques; Midttun, Øystein; Scrivens, Richard

    2014-02-01

    The space charge effect of low energy, unbunched ion beams can be compensated by the trapping of ions or electrons into the beam potential. This has been studied for the 45 keV negative hydrogen ion beam in the CERN Linac4 Low Energy Beam Transport using the package IBSimu [T. Kalvas et al., Rev. Sci. Instrum. 81, 02B703 (2010)], which allows the space charge calculation of the particle trajectories. The results of the beam simulations will be compared to emittance measurements of an H(-) beam at the CERN Linac4 3 MeV test stand, where the injection of hydrogen gas directly into the beam transport region has been used to modify the space charge compensation degree.

  13. Space charge compensation in the Linac4 low energy beam transport line with negative hydrogen ions

    Energy Technology Data Exchange (ETDEWEB)

    Valerio-Lizarraga, Cristhian A., E-mail: cristhian.alfonso.valerio.lizarraga@cern.ch [CERN, Geneva (Switzerland); Departamento de Investigación en Física, Universidad de Sonora, Hermosillo (Mexico); Lallement, Jean-Baptiste; Lettry, Jacques; Scrivens, Richard [CERN, Geneva (Switzerland); Leon-Monzon, Ildefonso [Facultad de Ciencias Fisico-Matematicas, Universidad Autónoma de Sinaloa, Culiacan (Mexico); Midttun, Øystein [CERN, Geneva (Switzerland); University of Oslo, Oslo (Norway)

    2014-02-15

    The space charge effect of low energy, unbunched ion beams can be compensated by the trapping of ions or electrons into the beam potential. This has been studied for the 45 keV negative hydrogen ion beam in the CERN Linac4 Low Energy Beam Transport using the package IBSimu [T. Kalvas et al., Rev. Sci. Instrum. 81, 02B703 (2010)], which allows the space charge calculation of the particle trajectories. The results of the beam simulations will be compared to emittance measurements of an H{sup −} beam at the CERN Linac4 3 MeV test stand, where the injection of hydrogen gas directly into the beam transport region has been used to modify the space charge compensation degree.

  14. FY1995 development of a clean CVD process by evaluation and control of gas phase nucleation phenomena; 1995 nendo kisokaku seisei gensho no hyoka to seigyo ni yoru clean CVD process no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-03-01

    The purpose of this study is to develop a high-rate and clean chemical vapor deposition (CVD) process as a breakthrough technique to overcome the problems that particles generated in the gas phase during CVD process for preparation of functional thin films cause reduced product yield and deterioration of the films. In the CVD process proposed here, reactant gas and generated particles are electrically charged to control the motion of them with an electric field. In this study, gas-phase nucleation phenomena are evaluated both theoretically and experimentally. A high-rate, ionized CVD method is first developed, in which reactant gas and generated particles are charged with negative ions generated from a radioisotope source and the UV/photoelectron method, and the motion of the charged gas and particles is controlled with an electric field. Charging and transport processes of fine particles are then investigated experimentally and theoretically to develop a clean CVD method in which generated particles are removed with the electric forces. As a result, quantitative evaluation of the charging and transport process was made possible. We also developed devices for measuring the size distribution and concentration of fine particles in low pressure gas such as those found in plasma CVD processes. In addition, numerical simulation and experiments in this study for a TEOS/O{sub 3} CVD process to prepare thin films could determine reaction rates which have not been known so far and give information on selecting good operation conditions for the process. (NEDO)

  15. Proceedings of the workshop on opportunities for atomic physics using slow, highly-charged ions

    Energy Technology Data Exchange (ETDEWEB)

    1987-01-01

    The study of atomic physics with highly-charged ions is an area of intense activity at the present time because of a convergence of theoretical interest and advances in experimental techniques. The purpose of the Argonne ''Workshop on Opportunities for Atomic Physics Using Slow, Highly-Charged Ions'' was to bring together atomic, nuclear, and accelerator physicists in order to identify what new facilities would be most useful for the atomic physics community. The program included discussion of existing once-through machines, advanced ion sources, recoil ion techniques, ion traps, and cooler rings. One of the topics of the Workshop was to discuss possible improvement to the ANL Tandem-Linac facility (ATLAS) to enhance the capability for slowing down ions after they are stripped to a high-charge state (the Accel/Decel technique). Another topic was the opportunity for atomic physics provided by the ECR ion source which is being built for the Uranium Upgrade of ATLAS. 18 analytics were prepared for the individual papers in this volume.

  16. Trapped-ion probing of light-induced charging effects on dielectrics

    Energy Technology Data Exchange (ETDEWEB)

    Harlander, M; Brownnutt, M; Haensel, W; Blatt, R, E-mail: max.harlander@uibk.ac.a [Institut fuer Experimentalphysik, Universitaet Innsbruck, Technikerstrasse 25, A-6020 Innsbruck (Austria)

    2010-09-15

    We use a string of confined {sup 40}Ca{sup +} ions to measure perturbations to a trapping potential which are caused by the light-induced charging of an antireflection-coated window and of insulating patches on the ion-trap electrodes. The electric fields induced at the ions' position are characterized as a function of distance to the dielectric and as a function of the incident optical power and wavelength. The measurement of the ion-string position is sensitive to as few as 40 elementary charges per {radical}(Hz) on the dielectric at distances of the order of millimetres, and perturbations are observed for illuminations with light of wavelengths as large as 729 nm. This has important implications for the future of miniaturized ion-trap experiments, notably with regard to the choice of electrode material and the optics that must be integrated in the vicinity of the ion. The method presented here can be readily applied to the investigation of charging effects beyond the context of ion-trap experiments.

  17. Opposite counter-ion effects on condensed bundles of highly charged supramolecular nanotubes in water.

    Science.gov (United States)

    Wei, Shenghui; Chen, Mingming; Wei, Chengsha; Huang, Ningdong; Li, Liangbin

    2016-07-20

    Although ion specificity in aqueous solutions is well known, its manifestation in unconventional strong electrostatic interactions remains implicit. Herein, the ionic effects in dense packing of highly charged polyelectrolytes are investigated in supramolecular nanotube prototypes. Distinctive behaviors of the orthorhombic arrays composed of supramolecular nanotubes in various aqueous solutions were observed by Small Angle X-ray Scattering (SAXS), depending on the counter-ions' size and affiliation to the surface -COO(-) groups. Bigger tetra-alkyl ammonium (TAA(+)) cations weakly bonding to -COO(-) will compress the orthorhombic arrays, while expansion is induced by smaller alkaline metal (M(+)) ions with strong affiliation to -COO(-). Careful analysis of the changes in the SAXS peaks with different counter/co-ion combinations indicates dissimilar mechanisms underlying the two explicit types of ionic effects. The pH measurements are in line with the ion specificity by SAXS and reveal the strong electrostatic character of the system. It is proposed that the small distances between the charged surfaces, in addition to the selective adsorption of counter-ions by the surface charge, bring out the observed distinctive ionic effects. Our results manifest the diverse mechanisms and critical roles of counter-ion effects in strong electrostatic interactions.

  18. Histidine-containing radicals in the gas phase.

    Science.gov (United States)

    Turecek, Frantisek; Yao, Chunxiang; Fung, Y M Eva; Hayakawa, Shigeo; Hashimoto, Mami; Matsubara, Hiroshi

    2009-05-21

    Radicals containing the histidine residue have been generated in the gas phase by femtosecond electron transfer to protonated histidine-N-methylamide (1H+), Nalpha-acetylhistidine-N-methylamide (2H+), Nalpha-glycylhistidine (3H+), and Nalpha-histidylglycine (4H+). Radicals generated by collisional electron transfer from dimethyldisulfide to ions 1H+ and 2H+ at 7 keV collision energies were found to dissociate completely on the microsecond time scale, as probed by reionization to cations. The main dissociations produced fragments from the imidazole side chain and the cleavage of the C(alpha)CO bond, whereas products of NCalpha bond cleavage were not observed. Electron transfer from gaseous potassium atoms to ions 3H+ and 4H+ at 2.97 keV collision energies not only caused backbone NCalpha bond dissociations but also furnished fractions of stable radicals that were detected after conversion to anions. Ion structures, ion-electron recombination energies, radical structures, electron affinities, and dissociation and transition-state energies were obtained by combined density functional theory and Møller-Plesset perturbational calculations (B3-PMP2) and basis sets ranging from 6-311+G(2d,p) to aug-cc-pVTZ. The Rice-Ramsperger-Kassel-Marcus theory was used to calculate rate constants on the B3-PMP2 potential energy surfaces to aid interpretation of the mass spectrometric data. The stability of Nalpha-histidylglycine-derived radicals is attributed to an exothermic isomerization in the imidazole ring, which is internally catalyzed by reversible proton transfer from the carboxyl group. The isomerization depends on the steric accessibility of the histidine side chain and the carboxyl group and involves a novel cation radical-COO salt-bridge intermediate.

  19. Ionization efficiency studies with charge breeder and conventional electron cyclotron resonance ion source

    Energy Technology Data Exchange (ETDEWEB)

    Koivisto, H., E-mail: hannu.koivisto@phys.jyu.fi; Tarvainen, O.; Toivanen, V.; Komppula, J.; Kronholm, R. [Department of Physics, University of Jyväskylä (JYFL), Jyväskylä (Finland); Lamy, T.; Angot, J. [LPSC, Université Joseph Fourier Grenoble 1, Grenoble INP, 53 rue des martyrs, 38026 Grenoble Cedex (France); Delahaye, P.; Maunoury, L. [GANIL, CEA/DSM-CNRS/IN2P3, Caen Cedex 05 (France); Galata, A. [INFN-Laboratori Nazionali di Legnaro, Legnaro, Padova (Italy); Patti, G. [INFN-Laboratori Nazionali del Sud, Catania (Italy); Standylo, L.; Steczkiewicz, O.; Choinski, J. [Heavy Ion Laboratory, University of Warsaw, Warsaw (Poland)

    2014-02-15

    Radioactive Ion Beams play an increasingly important role in several European research facility programs such as SPES, SPIRAL1 Upgrade, and SPIRAL2, but even more for those such as EURISOL. Although remarkable advances of ECRIS charge breeders (CBs) have been achieved, further studies are needed to gain insight on the physics of the charge breeding process. The fundamental plasma processes of charge breeders are studied in the frame of the European collaboration project, EMILIE, for optimizing the charge breeding. Important information on the charge breeding can be obtained by conducting similar experiments using the gas mixing and 2-frequency heating techniques with a conventional JYFL 14 GHz ECRIS and the LPSC-PHOENIX charge breeder. The first experiments were carried out with noble gases and they revealed, for example, that the effects of the gas mixing and 2-frequency heating on the production of high charge states appear to be additive for the conventional ECRIS. The results also indicate that at least in the case of noble gases the differences between the conventional ECRIS and the charge breeder cause only minor impact on the production efficiency of ion beams.

  20. Homogenization of the Poisson-Nernst-Planck Equations for Ion Transport in Charged Porous Media

    CERN Document Server

    Schmuck, Markus

    2012-01-01

    Effective Poisson-Nernst-Planck (PNP) equations are derived for macroscopic ion transport in charged porous media. Homogenization analysis is performed for a two-component pe- riodic composite consisting of a dilute electrolyte continuum (described by standard PNP equations) and a continuous dielectric matrix, which is impermeable to the ions and carries a given surface charge. Three new features arise in the upscaled equations: (i) the effective ionic diffusivities and mobilities become tensors, related to the microstructure; (ii) the effective permittivity is also a tensor, depending on the electrolyte/matrix permittivity ratio and the ratio of the Debye screening length to mean pore size; and (iii) the surface charge per volume appears as a continuous "background charge density". The coeffcient tensors in the macroscopic PNP equations can be calculated from periodic reference cell problem, and several examples are considered. For an insulating solid matrix, all gradients are corrected by a single tortuosit...

  1. Collisionless damping of dust-acoustic waves in a charge varying dusty plasma with nonextensive ions

    Energy Technology Data Exchange (ETDEWEB)

    Amour, Rabia; Tribeche, Mouloud [Faculty of Physics, Theoretical Physics Laboratory (TPL), Plasma Physics Group (PPG), University of Bab-Ezzouar, USTHB, B.P. 32, El Alia, Algiers 16111 (Algeria)

    2014-12-15

    The charge variation induced nonlinear dust-acoustic wave damping in a charge varying dusty plasma with nonextensive ions is considered. It is shown that the collisionless damping due to dust charge fluctuation causes the nonlinear dust acoustic wave propagation to be described by a damped Korteweg-de Vries (dK-dV) equation the coefficients of which depend sensitively on the nonextensive parameter q. The damping term, solely due to the dust charge variation, is affected by the ion nonextensivity. For the sake of completeness, the possible effects of nonextensivity and collisionless damping on weakly nonlinear wave packets described by the dK-dV equation are succinctly outlined by deriving a nonlinear Schrödinger-like equation with a complex nonlinear coefficient.

  2. Spectroscopic investigation of the charge dynamics of heavy ions penetrating solid and gaseous targets

    Energy Technology Data Exchange (ETDEWEB)

    Korostiy, S.

    2007-01-15

    This thesis presents the study of the slowing down process of fast heavy ions inside matter. In the framework of this research, the influence of the target density on the stopping process is investigated. Experiments on the interaction of {sup 48}Ca{sup 6+}-{sup 48}Ca{sup 10+} and {sup 26}Mg{sup 5+} ion beams with initial energies of 11.4 MeV/u and 5.9 MeV/u with solid and gaseous targets have been carried out. A novel diagnostic method, X-ray spectroscopy of K-shell projectile radiation, is used to determine the ion charge state in relation to its velocity during the penetration of fast heavy ions inside the stopping material. A spatially resolved analysis of the projectile and target radiation in solids is achieved for the first time. The application of low-density silica aerogels as stopping media provided a stretching of the ion stopping length by 20 - 100 times in comparison with solid quartz. The Doppler Effect observed on the projectile K-shell spectra is used to calculate the ion velocity in dependence on the ion penetration depth in the target material. A comparative analysis of K{sub {alpha}} spectra of fast heavy ions is performed in solid (silica aerogels) and gaseous targets (Ar and Ne gases) at the same ion energy. It is shown that the dominant role of collisions in dense matter leads to an increase of the effective ionization cross section at high ion velocity and suppression of the electron capture to the projectile ion excited states at low ion velocity. As a result, an increase of the ion charge state in dense matter is observed. The experimentally detected effects are interpreted with numerical calculations of the projectile population kinetics, which are in good agreement with measurements. (orig.)

  3. Light charged particle emission in heavy-ion reactions – What have we learnt?

    Indian Academy of Sciences (India)

    S Kailas

    2001-07-01

    Light charged particles emitted in heavy-ion induced reactions, their spectra and angular distributions measured over a range of energies, carry the signature of the underlying reaction mechanisms. Analysis of data of light charged particles, both inclusive and exclusive measured in coincidence with gamma rays, fission products, evaporation residues have yielded interesting results which bring out the influence of nuclear structure, nuclear mean field and dynamics on the emission of these particles.

  4. Recoil ion charge state distribution following the beta(sup +) decay of {sup 21}Na

    Energy Technology Data Exchange (ETDEWEB)

    Scielzo, Nicholas D.; Freedman, Stuart J.; Fujikawa, Brian K.; Vetter, Paul A.

    2003-01-03

    The charge state distribution following the positron decay of 21Na has been measured, with a larger than expected fraction of the daughter 21Ne in positive charge states. No dependence on either the positron or recoil nucleus energy is observed. The data is compared to a simple model based on the sudden approximation. Calculations suggest a small but important contribution from recoil ionization has important consequences for precision beta decay correlation experiments detecting recoil ions.

  5. Ion selection of charge-modified large nanopores in a graphene sheet

    Science.gov (United States)

    Zhao, Shijun; Xue, Jianming; Kang, Wei

    2013-09-01

    Water desalination becomes an increasingly important approach for clean water supply to meet the rapidly growing demand of population boost, industrialization, and urbanization. The main challenge in current desalination technologies lies in the reduction of energy consumption and economic costs. Here, we propose to use charged nanopores drilled in a graphene sheet as ion exchange membranes to promote the efficiency and capacity of desalination systems. Using molecular dynamics simulations, we investigate the selective ion transport behavior of electric-field-driven KCl electrolyte solution through charge modified graphene nanopores. Our results reveal that the presence of negative charges at the edge of graphene nanopore can remarkably impede the passage of Cl- while enhance the transport of K+, which is an indication of ion selectivity for electrolytes. We further demonstrate that this selectivity is dependent on the pore size and total charge number assigned at the nanopore edge. By adjusting the nanopore diameter and electric charge on the graphene nanopore, a nearly complete rejection of Cl- can be realized. The electrical resistance of nanoporous graphene, which is a key parameter to evaluate the performance of ion exchange membranes, is found two orders of magnitude lower than commercially used membranes. Our results thus suggest that graphene nanopores are promising candidates to be used in electrodialysis technology for water desalinations with a high permselectivity.

  6. Charge Transfer Based Colorimetric Detection of Silver Ion

    Energy Technology Data Exchange (ETDEWEB)

    Han, Seung Choul; Kim, Kwang Seob; Choi, Soon Kyu; Oh, Jinho; Lee, Jae Wook [Dong-A Univ., Busan (Korea, Republic of)

    2014-05-15

    We have demonstrated the colorimetric chemosensor for detection of Ag{sup +} via formation of nanoparticles which is based on the intramolecular CT interaction between the electron-rich (2,6-dialkoxynaphthalene; Np) moiety and the electron-deficient (methyl viologen; MV{sup 2+}) moiety of a single sensor molecule. Under irradiation of light, Ag{sup +} was reduced to very small silver nanoparticle by CT interaction in the presence of OEGs as flexible recognition moiety of Ag{sup +} and stabilizer for Ag nanoparticles, thus Ag nanoparticles resulted to reddish brown in the color change of sensor solution, gradually. Therefore, the charge-transfer interaction between an electron-deficient and an electron-rich units existing at a sensor molecule can be regarded as a new and efficient method to construct various colorimetric chemosensors. Donor.acceptor interactions or charge transfer (CT) interactions are an important class of non-covalent interactions and have been widely exploited in self-assembling systems. Beyond molecular chemistry, supramolecular chemistry aims at constituting highly complex, functional chemical systems from components held together by intermolecular forces. Chemosensors are the molecules of abiotic origin that bind selectively and reversibly with the analyte with concomitant change in one or more properties of the system. The recognition and signaling of ionic and neutral species of varying complexity is one of the most intensively studied areas of contemporary supramolecular chemistry.

  7. Theory of a stationary microwave discharge with multiply charged ions in an expanding gas jet

    Science.gov (United States)

    Shalashov, A. G.; Abramov, I. S.; Golubev, S. V.; Gospodchikov, E. D.

    2016-08-01

    The formation of a jet of a nonequilibrium multiply charged ion plasma is studied in the inhomogeneous gas jet. It is shown that the geometrical divergence of the jet restricts the maximum ion charge state and results in the spatial localization of the discharge. Stationary solutions corresponding to such regimes are constructed. The model proposed can be used to optimize modern experiments on generation of hard UV radiation due to the line emission of multiply ionized atoms in a gas jet heated by high-power millimeter and submillimeter radiation.

  8. Highly charged ion impact on uracil: Cross sections measurements and scaling

    Science.gov (United States)

    Agnihotri, A. N.; Kasthurirangan, S.; Champion, C.; Rivarola, R. D.; Tribedi, L. C.

    2014-04-01

    Absolute total ionization cross sections (TCS) of uracil in collisions with highly charge C, O and F ions are measured. The scaling properties of cross sections are obtained as a function of projectile charge state and energy. The measurements are compared with the CDW-EIS, CB1 and CTMC calculations. The absolute double differential cross sections (DDCS) of secondary electron emission from uracil in collisions with bare MeV energy C and O ions are also measured. Large enhancement in forward emission is observed.

  9. X-ray resonant photoexcitation: linewidths and energies of Kα transitions in highly charged Fe ions.

    Science.gov (United States)

    Rudolph, J K; Bernitt, S; Epp, S W; Steinbrügge, R; Beilmann, C; Brown, G V; Eberle, S; Graf, A; Harman, Z; Hell, N; Leutenegger, M; Müller, A; Schlage, K; Wille, H-C; Yavaş, H; Ullrich, J; Crespo López-Urrutia, J R

    2013-09-06

    Photoabsorption by and fluorescence of the Kα transitions in highly charged iron ions are essential mechanisms for x-ray radiation transfer in astrophysical environments. We study photoabsorption due to the main Kα transitions in highly charged iron ions from heliumlike to fluorinelike (Fe24+ to Fe17+) using monochromatic x rays around 6.6 keV at the PETRA III synchrotron photon source. Natural linewidths were determined with hitherto unattained accuracy. The observed transitions are of particular interest for the understanding of photoexcited plasmas found in x-ray binary stars and active galactic nuclei.

  10. Properties of cold ions produced by synchrotron radiation and by charged particle impact

    Science.gov (United States)

    Levin, J. C.; Biedermann, C.; Cederquist, H.; O, C.-S.; Short, R. T.; Sellin, I. A.

    1989-04-01

    Argon recoil ions produced by beams of 0.8 MeV/u Cl 5+ have been detected by time-of-flight (TOF) techniques in coincidence with the loss of from one to five projectile electrons. Recoil-ion energies have been determined to be more than an order of magnitude higher than those of highly charged ions produced by unmonochromatized synchrotron radiation. Charge-state distributions, however, show similarities, suggesting that loss of projectile electrons corresponds, in some cases, to inner-shell target ionization producing vacancy cascades. In an essential improvement to the usual multinomial description of ionization in the independent-electron-ejection model, we find the inclusion of Auger vacancy cascades significantly alters the description of the recoil ion spectra corresponding to the projectile-electron loss. These conclusions are consistent with impact parameters inferred from determination of mean recoil energy.

  11. Theoretical study of charge transfer dynamics in collisions of C6+ carbon ions with pyrimidine nucleobases

    Science.gov (United States)

    Bacchus-Montabonel, M. C.

    2012-07-01

    A theoretical approach of the charge transfer dynamics induced by collision of C6+ ions with biological targets has been performed in a wide collision energy range by means of ab-initio quantum chemistry molecular methods. The process has been investigated for the target series thymine, uracil and 5-halouracil corresponding to similar molecules with different substituent on carbon C5. Such a study may be related to hadrontherapy treatments by C6+carbon ions and may provide, in particular, information on the radio-sensitivity of the different bases with regard to ion-induced radiation damage. The results have been compared to a previous analysis concerning the collision of C4+ carbon ions with the same biomolecular targets and significant charge effects have been pointed out.

  12. Surface charging of thick porous water ice layers relevant for ion sputtering experiments

    Science.gov (United States)

    Galli, A.; Vorburger, A.; Pommerol, A.; Wurz, P.; Jost, B.; Poch, O.; Brouet, Y.; Tulej, M.; Thomas, N.

    2016-07-01

    We use a laboratory facility to study the sputtering properties of centimeter-thick porous water ice subjected to the bombardment of ions and electrons to better understand the formation of exospheres of the icy moons of Jupiter. Our ice samples are as similar as possible to the expected moon surfaces but surface charging of the samples during ion irradiation may distort the experimental results. We therefore monitor the time scales for charging and discharging of the samples when subjected to a beam of ions. These experiments allow us to derive an electric conductivity of deep porous ice layers. The results imply that electron irradiation and sputtering play a non-negligible role for certain plasma conditions at the icy moons of Jupiter. The observed ion sputtering yields from our ice samples are similar to previous experiments where compact ice films were sputtered off a micro-balance.

  13. Interaction of low-energy highly charged ions with matter; Wechselwirkung niederenergetischer hochgeladener Ionen mit Materie

    Energy Technology Data Exchange (ETDEWEB)

    Ginzel, Rainer

    2010-06-09

    The thesis presented herein deals with experimental studies of the interaction between highly charged ions and neutral matter at low collision energies. The energy range investigated is of great interest for the understanding of both charge exchange reactions between ions comprising the solar wind and various astrophysical gases, as well as the creation of near-surface nanostructures. Over the course of this thesis an experimental setup was constructed, capable of reducing the kinetic energy of incoming ions by two orders of magnitude and finally focussing the decelerated ion beam onto a solid or gaseous target. A coincidence method was employed for the simultaneous detection of photons emitted during the charge exchange process together with the corresponding projectile ions. In this manner, it was possible to separate reaction channels, whose superposition presumably propagated large uncertainties and systematic errors in previous measurements. This work has unveiled unexpectedly strong contributions of slow radiative decay channels and clear evidence of previously only postulated decay processes in charge exchange-induced X-ray spectra. (orig.)

  14. Cathode material comparison of thermal runaway behavior of Li-ion cells at different state of charges including over charge

    Science.gov (United States)

    Mendoza-Hernandez, Omar Samuel; Ishikawa, Hiroaki; Nishikawa, Yuuki; Maruyama, Yuki; Umeda, Minoru

    2015-04-01

    The analysis of Li-ion secondary cells under outstanding conditions, as overcharge and high temperatures, is important to determine thermal abuse characteristics of electroactive materials and precise risk assessments on Li-ion cells. In this work, the thermal runaway behavior of LiCoO2 and LiMn2O4 cathode materials were compared at different state of charges (SOCs), including overcharge, by carrying out accelerating rate calorimetry (ARC) measurements using 18650 Li-ion cells. Onset temperatures of self-heating reactions and thermal runaway behavior were identified, and by using these onset points thermal mapping plots were made. We were able to identify non-self-heating, self-heating and thermal runaway regions as a function of state of charge and temperature. The cell using LiMn2O4 cathode material was found to be more thermally stable than the cell using LiCoO2. In parallel with the ARC measurements, the electrochemical behavior of the cells was monitored by measuring the OCV and internal resistance of the cells. The electrochemical behavior of the cells showed a slightly dependency on SOC.

  15. Ultracold, radiative charge transfer in hybrid Yb ion - Rb atom traps

    CERN Document Server

    McLaughlin, B M; Lane, I C; McCann, J F

    2014-01-01

    Ultracold hybrid ion-atom traps offer the possibility of microscopic manipulation of quantum coherences in the gas using the ion as a probe. However, inelastic processes, particularly charge transfer can be a significant process of ion loss and has been measured experimentally for the Yb$^{+}$ ion immersed in a Rb vapour. We use first-principles quantum chemistry codes to obtain the potential energy curves and dipole moments for the lowest-lying energy states of this complex. Calculations for the radiative decay processes cross sections and rate coefficients are presented for the total decay processes. Comparing the semi-classical Langevin approximation with the quantum approach, we find it provides a very good estimate of the background at higher energies. The results demonstrate that radiative decay mechanisms are important over the energy and temperature region considered. In fact, the Langevin process of ion-atom collisions dominates cold ion-atom collisions. For spin dependent processes \\cite{kohl13} the...

  16. Resonant charge transfer in low-energy ion scattering: Information depth in the reionization regime.

    Science.gov (United States)

    Primetzhofer, D; Spitz, M; Taglauer, E; Bauer, P

    2011-11-01

    Time-Of-Flight Low-energy ion scattering (TOF-LEIS) experiments were performed for He(+) ions scattered from Cu(100) and Cu(0.5)Au(0.5)(100). Probabilities for resonant neutralization and reionization in close collisions were deduced in a wide energy range. To learn about the information depth in LEIS, in a next step ion spectra were analyzed for polycrystalline Cu samples. The relative yield of backscattered projectiles, which have undergone distinct charge exchange processes, was calculated. Results indicate a strong contribution to the ion yield that origins from particles reionized in a close collision in deeper layers when experiments are performed at energies where reionization is prominent. The surface sensitivity of the ion signal at different energies is quantified. Based on these results, the total ion spectrum was quantitatively modelled by two consistent, but different approaches.

  17. Charge-exchange Induced Modulation of the Heliosheath Ion Distribution Downstream of the Termination Shock

    Science.gov (United States)

    Fahr, H. J.; Fichtner, H.; Scherer, K.

    2015-12-01

    We consider the evolution of the solar wind ion distribution function alongthe plasma flow downstream from the termination shock induced by chargeexchange processes with cold interstellar H-atoms. We start from a kineticphase space transport equation valid in the bulk frame of the plasma flowthat takes into account convective changes, cooling processes, energydiffusion and ion injection, and describes solar wind and pick-up ionsas a co-moving, isotropic, joint ion population. From this kinetic transportequation one can ascend to an equation for the pressure moment of the iondistribution function, a so-called pressure transport equation, describingthe evolution of the ion pressure in the comoving rest frame. Assuming thatthe local ion distribution can be represented by an adequate kappa functionwith a kappa parameter that varies with the streamline coordinate, weobtain an ordinary differential equation for kappa as function of thestreamline coordinate s. With this result then we gain the heliosheath iondistribution function downstream of the termination shock. The latter thencan be used to predict the Voyager-2 measured moments of the distributionfunction like ion density and ion temperature, and it can also be used topredict spectral fluxes of ENA`s originating from these ions and registeredby IBEX-Hi and IBEX-Lo.We especially analyse the solar wind ion temperature decreasemeasured by Voyager-2 between the years 2008 to 2011 and try to explain itas a charge-exchange induced cooling of the ion distribution function duringthe associated ion convection period.

  18. Production of intense highly charged ion beams by IMP 14.5 GHz electron cyclotron resonance ion source

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A new 14.5 GHz Electron Cyclotron Resonance (ECR) ion source has been constructed over the last two years. The source was designed and tested by making use of the latest results from ECR ion source development, such as high mirror magnetic field, large plasma volume, and biased probe. 140μA of O7+, 185μA of Ar11+ and 50 μA of Xe26+ could be produced with a RF power of 800 W. The intense beams of highly charged metallic ions are produced by means of the method of a metal evaporation oven and volatile compound through axial access. The test results are 130μA of Ca11+, 70μA of Ca12+ and 65μA of Fe10+. The ion source has been put into operation for the cyclotron at the Institute of Modern Physics (IMP).

  19. Spectroscopy of few-electron highly charged ions

    CERN Document Server

    Tarbutt, M R

    2000-01-01

    attainable precision is as high as 0.2%. New techniques for measuring QED effects in the ground states of the hydrogen-like ions are proposed, which avoid the need for absolute x-ray calibration. Using the fast-beam laser resonance technique the 1s2p sup 3 P sub 0 - sup 3 P sub 1 fine-structure interval in helium-like Mg sup 1 sup 0 sup + has been measured, with the result nu-tilde sub 0 sub 1 = 833.133 (14) cm sup - sup 1. This measurement is a very sensitive test of the higher-order relativistic and QED terms of the theory for the fine-structure in helium and the light helium-like ions. This theory will be used to obtain a new value for the fine structure constant by comparing its results with precision measurements of the n = 2 fine structure in helium. Although there is a large discrepancy between the present measurement and the current theoretical value for this interval, the discrepancy lies within the estimated size of the unevaluated terms in the theory. A preliminary measurement of the 2s Lamb shift ...

  20. Potential and Kinetic Electron Emissions from HOPG Surface Irradiated by Highly Charged Xenon and Neon Ions

    Institute of Scientific and Technical Information of China (English)

    WANG Yu-Yu; ZHAO Yong-Tao; SUN Jian-Rong; LI De-Hui; QAYYUM Abdul; LI Jin-Yu; WANG Ping-Zhi; XIAO Guo-Qing

    2011-01-01

    Highly charged 129 Xeq+ (q =10-30) and 40Neq+ (q =4-8) ion-induced secondary electron emissions on the surface of highly oriented pyrolytic graphite (HOPG) are reported. The total secondary electron yield is measured as a function of the potential energy of incident ions. The experimental data are used to separate contributions of kinetic and potential electron yields. Our results show that about 4.5% and 13.2% of ion's potential energies are consumed in potential electron emission due to different Xeq+-HOPG and Neq+-HOPG combinations. A simple formula is introduced to estimate the fraction of ion's potential energy for potential electron emission.%@@ Highly charged 129 Xeq+(q =10-30) and 40Neq+(q =4-8) ion-induced secondary electron emissions on the surface of highly oriented pyrolytic graphite(HOPG) are reported.The total secondary electron yield is measured as a function of the potential energy of incident ions.The experimental data are used to separate contributions of kinetic and potential electron yields.Our results show that about 4.5% and 13.2% of ion's potential energies are consumed in potential electron emission due to different Xeq+-HOPG and Neq+-HOPG combinations.A simple formula is introduced to estimate the fraction of ion's potential energy for potential electron emission.

  1. Contribution of charge-transfer processes to ion-induced electron emission

    Energy Technology Data Exchange (ETDEWEB)

    Roesler, M. [Departamento de Fisica de Materiales, Facultad de Quimica, UPV/EHU, Apartado 1072, 20080 San Sebastian (Spain); Garcia de Abajo, F.J. [Departamento de Ciencias de la Computacion e Inteligencia Artificial, Facultad de Informatica, UPV/EHU, Apartado 649, 20080 San Sebastian (Spain)

    1996-12-01

    Charge changing events of ions moving inside metals are shown to contribute significantly to electron emission in the intermediate velocity regime via electrons coming from projectile ionization. Inclusion of equilibrium charge state fractions, together with two-electron Auger processes and resonant-coherent electron loss from the projectile, results in reasonable agreement with previous calculations for frozen protons, though a significant part of the emission is now interpreted in terms of charge exchange. The quantal character of the surface barrier transmission is shown to play an important role. The theory compares well with experimental observations for {ital H} projectiles. {copyright} {ital 1996 The American Physical Society.}

  2. Charge-state-dependent energy loss of slow ions. II. Statistical atom model

    Science.gov (United States)

    Wilhelm, Richard A.; Möller, Wolfhard

    2016-05-01

    A model for charge-dependent energy loss of slow ions is developed based on the Thomas-Fermi statistical model of atoms. Using a modified electrostatic potential which takes the ionic charge into account, nuclear and electronic energy transfers are calculated, the latter by an extension of the Firsov model. To evaluate the importance of multiple collisions even in nanometer-thick target materials we use the charge-state-dependent potentials in a Monte Carlo simulation in the binary collision approximation and compare the results to experiment. The Monte Carlo results reproduce the incident charge-state dependence of measured data well [see R. A. Wilhelm et al., Phys. Rev. A 93, 052708 (2016), 10.1103/PhysRevA.93.052708], even though the experimentally observed charge exchange dependence is not included in the model.

  3. Ion optics and beam dynamics optimization at the HESR storage ring for the SPARC experiments with highly charged heavy ions

    Energy Technology Data Exchange (ETDEWEB)

    Kovalenko, Oleksandr

    2015-06-24

    The High-Energy Storage Ring (HESR) is a part of an upcoming International Facility for Antiproton and Ion Research (FAIR) at GSI in Darmstadt. A key part of a scientific program, along with antiproton physics, will be physics with highly-charged heavy ions. Phase-space cooled beams together with fixed internal target will provide an excellent environment for storage ring experiments at the HESR for the SPARC collaboration. Until recently, however, the existing ion optical lattice for the HESR was designed only for the experiments with antiproton beams. The thesis presents a new ion optical mode developed specifically for the operation of the HESR with highly charged heavy ions. The presence of the errors, such as beam momentum spread, magnetic field impurities or magnets misalignments, leads to disruption of beam dynamics: exciting of resonant motion and loss of beam stability. Within the paper, these effects are investigated with the help of numerical codes for particle accelerator design and simulation MAD-X and MIRKO. A number of correction techniques are applied to minimize the nonlinear impact on the beam dynamics and improve the experimental conditions. The application of the analytical and numerical tools is demonstrated in the experiment with uranium U{sup 90+} beam at the existing storage ring ESR, GSI.

  4. Potential energy, force distribution and oscillatory motion of chloride ion inside electrically charged carbon nanotubes

    Science.gov (United States)

    Sadeghi, F.; Ansari, R.; Darvizeh, M.

    2016-06-01

    In this research, a continuum-based model is presented to explore potential energy, force distribution and oscillatory motion of ions, and in particular chloride ion, inside carbon nanotubes (CNTs) decorated by functional groups at two ends. To perform this, van der Waals (vdW) interactions between ion and nanotube are modeled by the 6-12 Lennard-Jones (LJ) potential, whereas the electrostatic interactions between ion and functional groups are modeled by the Coulomb potential and the total interactions are analytically derived by summing the vdW and electrostatic interactions. Making the assumption that carbon atoms and charge of functional groups are all uniformly distributed over the nanotube surface and the two ends of nanotube, respectively, a continuum approach is utilized to evaluate the related interactions. Based on the actual force distribution, the equation of motion is also solved numerically to arrive at the time history of displacement and velocity of inner core. With respect to the proposed formulations, comprehensive studies on the variations of potential energy and force distribution are carried out by varying functional group charge and nanotube length. Moreover, the effects of these parameters together with initial conditions on the oscillatory behavior of system are studied and discussed in detail. It is found out that chloride ion escapes more easily from negatively charged CNTs which is followed by uncharged and positively charged ones. It is further shown that the presence of functional groups leads to enhancing the operating frequency of such oscillatory systems especially when the electric charges of ion and functional groups have different signs.

  5. Charge collection efficiency degradation induced by MeV ions in semiconductor devices: Model and experiment

    Energy Technology Data Exchange (ETDEWEB)

    Vittone, E., E-mail: ettore.vittone@unito.it [Department of Physics, NIS Research Centre and CNISM, University of Torino, via P. Giuria 1, 10125 Torino (Italy); Pastuovic, Z. [Centre for Accelerator Science (ANSTO), Locked bag 2001, Kirrawee DC, NSW 2234 (Australia); Breese, M.B.H. [Centre for Ion Beam Applications (CIBA), Department of Physics, National University of Singapore, Singapore 117542 (Singapore); Garcia Lopez, J. [Centro Nacional de Aceleradores (CNA), Sevilla University, J. Andalucia, CSIC, Av. Thomas A. Edison 7, 41092 Sevilla (Spain); Jaksic, M. [Department for Experimental Physics, Ruder Boškovic Institute (RBI), P.O. Box 180, 10002 Zagreb (Croatia); Raisanen, J. [Department of Physics, University of Helsinki, Helsinki 00014 (Finland); Siegele, R. [Centre for Accelerator Science (ANSTO), Locked bag 2001, Kirrawee DC, NSW 2234 (Australia); Simon, A. [International Atomic Energy Agency (IAEA), Vienna International Centre, P.O. Box 100, 1400 Vienna (Austria); Institute of Nuclear Research of the Hungarian Academy of Sciences (ATOMKI), Debrecen (Hungary); Vizkelethy, G. [Sandia National Laboratories (SNL), PO Box 5800, Albuquerque, NM (United States)

    2016-04-01

    Highlights: • We study the electronic degradation of semiconductors induced by ion irradiation. • The experimental protocol is based on MeV ion microbeam irradiation. • The radiation induced damage is measured by IBIC. • The general model fits the experimental data in the low level damage regime. • Key parameters relevant to the intrinsic radiation hardness are extracted. - Abstract: This paper investigates both theoretically and experimentally the charge collection efficiency (CCE) degradation in silicon diodes induced by energetic ions. Ion Beam Induced Charge (IBIC) measurements carried out on n- and p-type silicon diodes which were previously irradiated with MeV He ions show evidence that the CCE degradation does not only depend on the mass, energy and fluence of the damaging ion, but also depends on the ion probe species and on the polarization state of the device. A general one-dimensional model is derived, which accounts for the ion-induced defect distribution, the ionization profile of the probing ion and the charge induction mechanism. Using the ionizing and non-ionizing energy loss profiles resulting from simulations based on the binary collision approximation and on the electrostatic/transport parameters of the diode under study as input, the model is able to accurately reproduce the experimental CCE degradation curves without introducing any phenomenological additional term or formula. Although limited to low level of damage, the model is quite general, including the displacement damage approach as a special case and can be applied to any semiconductor device. It provides a method to measure the capture coefficients of the radiation induced recombination centres. They can be considered indexes, which can contribute to assessing the relative radiation hardness of semiconductor materials.

  6. Kinetic Modeling of the Neutral Gas, Ions, and Charged Dust in Europa's Exosphere

    Science.gov (United States)

    Tenishev, V.; Borovikov, D.; Rubin, M.; Jia, X.; Combi, M. R.

    2015-12-01

    The interaction of the Jovian magnetosphere with Europa has been a subject of active research during the last few decades both through in-situ and remote sensing observations as well as theoretical considerations. Linking the magnetosphere and the moon's surface and interior, Europa's exosphere has become one of the primary objects of study in the field. Understanding the physical processes occurring in the exosphere and its chemical composition is required for the understanding of the interaction between Europa and Jupiter. Europa's surface-bound exosphere originates mostly from ion sputtering of the water ice surface. Minor neutral species and ions of exospheric origin are produced via photolytic and electron impact reactions. The interaction of the Jovian magnetosphere and Europa affects the exospheric population of both neutrals and ions via source and loss processes. Moreover, the Lorentz force causes the newly created exospheric ions to move preferably aligned with the magnetic field lines. Contrary to the ions, heavier and slow-moving charged dust grains are mostly affected by gravity and the electric field component of the Lorentz force. As a result, escaping dust forms a narrow tail aligned in the direction of the convection electric field. Here we present results of a kinetic model of the neutral species (H2O, OH, O2, O, and H), ions (O+, O2+, H+, H2+, H2O+, and OH+), and neutral and charged dust in Europa's exosphere. In our model H2O and O2 are produced via sputtering and other exospheric neutral and ions species are produced via photolytic and electron impact reactions. For the charged dust we compute the equilibrium grain charge by balancing the electron and ion collecting currents according to the local plasma flow conditions at the grain's location. For the tracking of the ions, charged dust, and the calculation of the grains' charge we use plasma density and velocity, and the magnetic field derived from our multi-fluid MHD model of Europa

  7. Nuclear Liquid-Gas Phase Transition: Experimental Signals

    Science.gov (United States)

    D'Agostino, M.; Bruno, M.; Gulminelli, F.; Cannata, F.; Chomaz, Ph.; Casini, G.; Geraci, E.; Gramegna, F.; Moroni, A.; Vannini, G.

    2005-03-01

    The connection between the thermodynamics of charged finite nuclear systems and the asymptotically measured partitions in heavy ion collisions is discussed. Different independent signals compatible with a liquid-to-gas-like phase transition are reported. In particular abnormally large fluctuations in the measured observables are presented as a strong evidence of a first order phase transition with negative heat capacity.

  8. Nuclear liquid-gas phase transition: Experimental signals

    Energy Technology Data Exchange (ETDEWEB)

    D' Agostino, M. [Dipartimento di Fisica and INFN, Bologna (Italy); Bruno, M. [Dipartimento di Fisica and INFN, Bologna (Italy); Gulminelli, F. [LPC Caen (IN2P3-CNRS/ISMRA et Universite), F-14050 Caen Cedex (France); Cannata, F. [Dipartimento di Fisica and INFN, Bologna (Italy); Chomaz, Ph. [GANIL, DSM-CEA/IN2P3-CNRS (France); Casini, G. [INFN Sezione di Firenze (Italy); Geraci, E. [Dipartimento di Fisica and INFN, Bologna (Italy); Gramegna, F. [INFN Laboratorio Nazionale di Legnaro (Italy); Moroni, A. [Dipartimento di Fisica and INFN, Milano (Italy); Vannini, G. [Dipartimento di Fisica and INFN, Bologna (Italy)

    2005-03-07

    The connection between the thermodynamics of charged finite nuclear systems and the asymptotically measured partitions in heavy ion collisions is discussed. Different independent signals compatible with a liquid-to-gas-like phase transition are reported. In particular abnormally large fluctuations in the measured observables are presented as a strong evidence of a first order phase transition with negative heat capacity.

  9. Electron cooling of highly charged ions in penning traps; Elektronenkuehlung hochgeladener Ionen in Penningfallen

    Energy Technology Data Exchange (ETDEWEB)

    Moellers, B.

    2007-02-08

    For many high precision experiments with highly charged ions in ion traps it is necessary to work with low energy ions. One possibility to slow ions down to a very low energy in a trap is electron cooling, a method, which is already successfully used in storage rings to produce ion beams with high phase space density. Fast ions and a cold electron plasma are inserted into a Penning trap. The ions lose their energy due to Coulomb interaction with the electrons while they cross the plasma, the electrons are heated. The cooling time is the time, which is needed to cool an ion from a given initial energy to a low final energy. To calculate cooling times it is necessary to solve coupled differential equations for the ion energy and electron temperature. In a Penning trap the strong external magnetic field constitutes a theoretical challenge, as it influences the energy loss of the ions in an electron plasma, which can no longer be calculated analytically. In former estimates of cooling times this influence is neglected. But simulations show a dramatic decrease of the energy loss in the presence of a strong magnetic field, so it is necessary to investigate the effect of the magnetic field on the cooling times. This work presents a model to calculate cooling times, which includes both the magnetic field and the trap geometry. In a first step a simplified model without the external trap potential is developed. The energy loss of the ions in the magnetized electron plasma is calculated by an analytic approximation, which requires a numerical solution of integrals. With this model the dependence of the cooling time on different parameters like electron and ion density, magnetic field and the angle between ion velocity and magnetic field is studied for fully ionized uranium. In addition the influence of the electron heating is discussed. Another important topic in this context is the recombination between ions and electrons. The simplified model for cooling times allows to

  10. Stability of gas-phase tartaric acid anions investigated by quantum chemistry, mass spectrometry, and infrared spectroscopy.

    Science.gov (United States)

    Tonner, Ralf; Schwerdtfeger, Peter; May, Amanda L; Steill, Jeffrey D; Berden, Giel; Oomens, Jos; Campagna, Shawn R; Compton, Robert N

    2012-05-17

    In an effort to understand the chemical factors that stabilize dianions, experimental and theoretical studies on the stability of the tartrate dianion were performed. Quantum chemical calculations at the coupled cluster level reveal only a metastable state with a possible decomposition pathway (O(2)C-CH(OH)-CH(OH)-CO(2))(2-) → (O(2)C-CH(OH)-CH(OH))(•-) + CO(2) + e(-) explaining the observed gas-phase instability of this dianion. Further theoretical data were collected for the bare dianion, this molecule complexed to water, sodium, and a proton, in both the meso and l forms as well as for the uncomplexed radical anion and neutral diradical. The calculations suggest that the l-tartrate dianion is more thermodynamically stable than the dianion of the meso stereoisomer and that either dianion can be further stabilized by association with a separate species that can help to balance the charge of the molecular complex. Mass spectrometry was then used to measure the energy needed to initiate collisionally induced dissociation of the racemic tartrate dianion and for the proton and sodium adducts of both the racemic and meso form of this molecule. Infrared action spectra of the dianion stereoisomers complexed with sodium were also acquired to determine the influence of the metal ion on the vibrations of the dianions and validate the computationally predicted structures. These experimental data support the theoretical conclusions and highlight the instability of the bare tartrate dianion. From the experimental work, it could also be concluded that the pathway leading to dissociation is under kinetic control because the sodium adduct of the racemic stereoisomer dissociated at lower collisional energy, although it was calculated to be more stable, and that decomposition proceeded via C-C bond dissociation as computationally predicted. Taken together, these data provide insight into the gas-phase stability of the tartrate dianion and highlight the role of adducts in

  11. Database for inelastic collisions of lithium atoms with electrons, protons, and multiply charged ions

    NARCIS (Netherlands)

    Schweinzer, J; Brandenburg, R; Bray, [No Value; Hoekstra, R; Aumayr, F; Janev, RK; Winter, HP

    1999-01-01

    New experimental and theoretical cross-section data for inelastic collision processes of Li atoms in the ground state and excited states (up to n = 4) with electrons, protons, and multiply charged ions have been reported since the database assembled by Wutte et al. [ATOMIC DATA AND NUCLEAR DATA TABL

  12. Effect of ion compensation of the beam space charge on gyrotron operation

    Energy Technology Data Exchange (ETDEWEB)

    Fokin, A. P.; Glyavin, M. Yu. [Institute of Applied Physics, Russian Academy of Sciences, Nizhny Novgorod 603950 (Russian Federation); Nusinovich, G. S. [Institute for Research in Electronics and Applied Physics, University of Maryland, College Park, Maryland 20742-3511 (United States)

    2015-04-15

    In gyrotrons, the coherent radiation of electromagnetic waves takes place when the cyclotron resonance condition between the wave frequency and the electron cyclotron frequency or its harmonic holds. The voltage depression caused by the beam space charge field changes the relativistic cyclotron frequency and, hence, can play an important role in the beam-wave interaction process. In long pulse and continuous-wave regimes, the beam space charge field can be partially compensated by the ions, which appear due to the beam impact ionization of neutral molecules of residual gases in the interaction space. In the present paper, the role of this ion compensation of the beam space charge on the interaction efficiency is analyzed. We also analyze the effect of the electron velocity spread on the limiting currents and discuss some effects restricting the ion-to-beam electron density ratio in the saturation stage. It is shown that the effect of the ion compensation on the voltage depression caused by the beam space charge field can cause significant changes in the efficiency of gyrotron operation and, in some cases, even result in the break of oscillations.

  13. ELECTRON-CAPTURE IN HIGHLY-CHARGED ION-ATOM COLLISIONS

    NARCIS (Netherlands)

    MORGENSTERN, R

    1993-01-01

    An attempt is made to identify the most important mechanisms responsible for the rearrangement of electrons during collisions between multiply charged ions and atoms at keV energies. It is discussed to which extent the influence of binding energy, angular momentum of heavy particles and electrons, a

  14. A metal ion charged mixed matrix membrane for selective adsorption of hemoglobin

    NARCIS (Netherlands)

    Tetala, K.K.R.; Skrzypek, K.; Levisson, M.; Stamatialis, D.F.

    2013-01-01

    In this work, we developed a mixed matrix membrane by incorporating 20–40 µm size iminodiacetic acid modified immobeads within porous Ethylene vinyl alcohol (EVAL) polymer matrix. The MMM were charged with copper ions for selective adsorption of bovine hemoglobin in presence of bovine serum albumin.

  15. Solid-state NMR Study of Ion Adsorption and Charge Storage in Graphene Film Supercapacitor Electrodes

    Science.gov (United States)

    Li, Kecheng; Bo, Zheng; Yan, Jianhua; Cen, Kefa

    2016-12-01

    Graphene film has been demonstrated as promising active materials for electric double layer capacitors (EDLCs), mainly due to its excellent mechanical flexibility and freestanding morphology. In this work, the distribution and variation pattern of electrolyte ions in graphene-film based EDLC electrodes are investigated with a 11B magic-angle spinning nuclear magnetic resonance (MAS-NMR) spectroscopy. For neutral graphene films soaked with different amounts of electrolytes (1 M TEABF4/ACN), weakly and strongly adsorbed anions are identified based on the resonances at different 11B chemical shifts. Unlike other porous carbonaceous materials, the strongly adsorbed anions are found as the major electrolyte anions components in graphene films. Further measurements on the ion population upon charging are carried out with applying different charging voltages on the graphene films. Results indicate that the charging process of graphene-film based EDLCs can be divided into two distinct charge storage stages (i.e., ejection of co-ions and adsorption of counter-ions) for different voltages. The as-obtained results will be useful for the design and fabrication of high performance graphene-film based EDLCs.

  16. Charged patchy particle models in explicit salt: Ion distributions, electrostatic potentials, and effective interactions

    Energy Technology Data Exchange (ETDEWEB)

    Yigit, Cemil; Dzubiella, Joachim, E-mail: joachim.dzubiella@helmholtz-berlin.de [Soft Matter and Functional Materials, Helmholtz-Zentrum Berlin, 14109 Berlin (Germany); Helmholtz Virtual Institute “Multifunctional Biomaterials for Medicine,” 14513 Teltow (Germany); Institut für Physik, Humboldt-Universität zu Berlin, 12489 Berlin (Germany); Heyda, Jan [Department of Physical Chemistry, University of Chemistry and Technology, Prague, 166 28 Praha 6 (Czech Republic)

    2015-08-14

    We introduce a set of charged patchy particle models (CPPMs) in order to systematically study the influence of electrostatic charge patchiness and multipolarity on macromolecular interactions by means of implicit-solvent, explicit-ion Langevin dynamics simulations employing the Gromacs software. We consider well-defined zero-, one-, and two-patched spherical globules each of the same net charge and (nanometer) size which are composed of discrete atoms. The studied mono- and multipole moments of the CPPMs are comparable to those of globular proteins with similar size. We first characterize ion distributions and electrostatic potentials around a single CPPM. Although angle-resolved radial distribution functions reveal the expected local accumulation and depletion of counter- and co-ions around the patches, respectively, the orientation-averaged electrostatic potential shows only a small variation among the various CPPMs due to space charge cancellations. Furthermore, we study the orientation-averaged potential of mean force (PMF), the number of accumulated ions on the patches, as well as the CPPM orientations along the center-to-center distance of a pair of CPPMs. We compare the PMFs to the classical Derjaguin-Verwey-Landau-Overbeek theory and previously introduced orientation-averaged Debye-Hückel pair potentials including dipolar interactions. Our simulations confirm the adequacy of the theories in their respective regimes of validity, while low salt concentrations and large multipolar interactions remain a challenge for tractable theoretical descriptions.

  17. Average charge states of heavy and superheavy ions passing through a rarified gas : Theory and experiment

    NARCIS (Netherlands)

    Khuyagbaatar, J.; Shevelko, V. P.; Borschevsky, A.; Duellmann, Ch. E.; Tolstikhina, I. Yu.; Yakushev, A.

    2013-01-01

    The average charge states (q) over bar of heavy and superheavy ions (atomic numbers Z = 80-114) passing through He gas are studied experimentally and theoretically. Experimental data were measured at the gas-filled recoil separator, i.e., the TransActinide Separator and Chemistry Apparatus (TASCA) a

  18. Near-resonant versus nonresonant chemiluminescent charge-transfer reactions of atomic ions with HCl

    Science.gov (United States)

    Glenewinkel-Meyer, Th.; Ottinger, Ch.

    1994-01-01

    Charge-transfer reactions of C+, O+, F+, Ar+ and some other atomic ions with hydrogen chloride were investigated at collision energies between eVc.m.. This may be due to formation of a long-lived collision complex (Ar-HCl)+.

  19. Preparation of cold Mg{sup +}ion clouds for sympathetic cooling of highly charged ions at SPECTRAP

    Energy Technology Data Exchange (ETDEWEB)

    Cazan, Radu Mircea

    2012-02-15

    The bound electrons in hydrogen-like or lithium-like heavy ions experience extremely strong electric and magnetic fields in the surrounding of the nucleus. Laser spectroscopy of the ground-state hyperfine splitting in the lead region provides a sensitive tool to test strong-field quantum electro dynamics (QED), especially in the magnetic sector. Previous measurements on hydrogen-like systems performed in an electron-beam ion trap (EBIT) or at the experimental storage ring (ESR) were experimentally limited in accuracy due to statistics, the large Doppler broadening and the ion energy. The full potential of the QED test can only be exploited if measurements for hydrogen- and lithium-like ions are performed with accuracy improved by 2-3 orders of magnitude. Therefore, the new Penning trap setup SPECTRAP - dedicated for laser spectroscopy on trapped and cooled highly charged ions - is currently commissioned at GSI Darmstadt. Heavy highly charged ions will be delivered to this trap by the HITRAP facility in the future. SPECTRAP is a cylindrical Penning trap with axial access for external ion injection and radial optical access mounted inside a cold-bore superconducting Helmholtz-type split-coil magnet. To reach the targeted accuracy in laser spectroscopy, an efficient and fast cooling process for the highly charged ions must be employed. This can be realized by sympathetic cooling with a cloud of laser-cooled light ions. Within this thesis work, a laser system and an ion source for the production of such a {sup 24}Mg{sup +} ion cloud was developed and commissioned at SPECTRAP. An all-solid-state laser system for the generation of 279.6 nm light was designed and built. It consists of a fiber laser at 1118.5 nm followed by frequency quadrupling using two successive second-harmonic generation stages with actively stabilized ring resonators and nonlinear crystals. The laser system can deliver more than 15 mW of UV laser power under optimal conditions and requires little

  20. Surface modification of oxide layer on Si using highly charged ions

    Energy Technology Data Exchange (ETDEWEB)

    Sakurai, M., E-mail: msakurai@kobe-u.ac.jp [Department of Physics, Kobe University, Rokkodai, Nada-ku, Kobe 657-8501 (Japan); Liu, S.; Sakai, S. [Department of Physics, Kobe University, Rokkodai, Nada-ku, Kobe 657-8501 (Japan); Ohtani, S. [Institute for Laser Science, University of Electro-Communications, Chofu, Tokyo 182-8585 (Japan); Terui, T. [National Institute of Information and Communications Technology, Iwaoka, Nishi-ku, Kobe 651-2492 (Japan); Sakaue, H.A. [National Institute for Fusion Science, Oroshi-cho, Toki 509-5292 (Japan)

    2013-11-15

    Surface modification using highly charged ions is presented. The surface of a Si wafer which is covered with a native oxide layer is used as a sample. The sample was irradiated with Ar{sup 11+} ions at a fluence of 10{sup 13}–10{sup 14}/cm{sup 2}. The Ar{sup 11+} ions were obtained from an electron beam ion source (Kobe EBIS). The surface was investigated using secondary electron microscopy, X-ray photoelectron spectroscopy and high-resolution electron energy loss spectroscopy. The obtained results suggest that the native oxide layer is sputtered by the irradiation of Ar{sup 11+} ions and that the structural modification makes the density of the oxide layer lower and the electric conductivity higher.

  1. Multi-turn injection into a heavy-ion synchrotron in the presence of space charge

    CERN Document Server

    Appel, Sabrina

    2014-01-01

    For heavy-ion synchrotrons an efficient Multi-Turn Injection (MTI) from the injector linac is crucial in order to reach the specified currents using the available machine acceptance. The beam loss during the MTI must not exceed the limits determined by machine protection and by the vacuum requirements. Especially for low energy and intermediate charge state ions, the beam loss at the injection septum can cause a degradation of the vacuum and a corresponding reduction of the beam lifetime. In order to optimize the injection of intense beams a very detailed simulation model was developed. Besides the closed orbit bump, lattice errors, the position of the septum and other aperture limiting components the transverse space charge force is included self-consistently. The space charge force causes a characteristic shift of the optimum tunes and a smoothing of the phase space density.

  2. Charge exchange of medium energy H and He ions emerging from solid surfaces

    Science.gov (United States)

    Kitsudo, Y.; Shibuya, K.; Nishimura, T.; Hoshino, Y.; Vickridge, I.; Kido, Y.

    2009-02-01

    Charge exchange of medium energy H and He ions emerging from clean solid surfaces is studied extensively using a toroidal electrostatic analyzer with an excellent energy resolution. The charge distributions of He ions scattered from sub-monolayers near a surface are non-equilibrated, resulting in a surface peak even for poly-crystal solids. By solving simultaneous rate equations numerically, we derive electron capture and loss cross sections for Ni and Au surfaces. Based on a free electron gas model, non-equilibrated He+ fractions dependent on emerging angle reveals uniform electronic surfaces for metals and corrugated surfaces for Si and graphite with covalent bonds. It is also found that equilibrium charge fractions of H+ are independent of surface materials (Z2) and in contrast equilibrium He+ fractions depend pronouncedly on Z2. The data obtained are compared with semi-empirical formulas.

  3. The evolution of ion charge states in cathodic vacuum arc plasmas: a review

    Energy Technology Data Exchange (ETDEWEB)

    Anders, Andre

    2011-12-18

    Cathodic vacuum arc plasmas are known to contain multiply charged ions. 20 years after “Pressure Ionization: its role in metal vapour vacuum arc plasmas and ion sources” appeared in vol. 1 of Plasma Sources Science and Technology, it is a great opportunity to re-visit the issue of pressure ionization, a non-ideal plasma effect, and put it in perspective to the many other factors that influence observable charge state distributions, such as the role of the cathode material, the path in the density-temperature phase diagram, the “noise” in vacuum arc plasma as described by a fractal model approach, the effects of external magnetic fields and charge exchange collisions with neutrals. A much more complex image of the vacuum arc plasma emerges putting decades of experimentation and modeling in perspective.

  4. Laser acceleration of electrons to giga-electron-volt energies using highly charged ions.

    Science.gov (United States)

    Hu, S X; Starace, Anthony F

    2006-06-01

    The recent proposal to use highly charged ions as sources of electrons for laser acceleration [S. X. Hu and A. F. Starace, Phys. Rev. Lett. 88, 245003 (2002)] is investigated here in detail by means of three-dimensional, relativistic Monte Carlo simulations for a variety of system parameters, such as laser pulse duration, ionic charge state, and laser focusing spot size. Realistic laser focusing effects--e.g., the existence of longitudinal laser field components-are taken into account. Results of spatial averaging over the laser focus are also presented. These numerical simulations show that the proposed scheme for laser acceleration of electrons from highly charged ions is feasible with current or near-future experimental conditions and that electrons with GeV energies can be obtained in such experiments.

  5. Role of nonthermal electrons on dust ion acoustic double layer with variable dust charge

    Science.gov (United States)

    Borah, Prathana; Gogoi, Deepshikha; Das, Nilakshi

    2016-01-01

    The presence of nonthermal electron may play an important role in the formation of nonlinear structures in plasma. On the other hand, fluctuation of dust charge is an important and unique feature of complex plasma and it gives rise to a dissipative effect in the system leading to the formation of nonlinear structures due to the balance between nonlinearity and dissipation. In this paper, the propagation of nonlinear dust ion acoustic (DIA) wave in unmagnetized collisionless dusty plasma consisting of ions, nonthermal electrons and dust grains with variable negative charge has been investigated using the Sagdeev potential method. The existence domain of rarefactive double layer (DL) in the DIA wave has been investigated for the range of plasma parameters. The real potential has been obtained by numerically solving the Poisson equation and dust charging equation. It is observed that the presence of nonthermal electrons strengthens the DIA DL.

  6. Liquid-Gas Phase Transition in Nuclear Equation of State

    CERN Document Server

    Lee, S J

    1997-01-01

    A canonical ensemble model is used to describe a caloric curve of nuclear liquid-gas phase transition. Allowing a discontinuity in the freeze out density from one spinodal density to another for a given initial temperature, the nuclear liquid-gas phase transition can be described as first order. Averaging over various freeze out densities of all the possible initial temperatures for a given total reaction energy, the first order characteristics of liquid-gas phase transition is smeared out to a smooth transition. Two experiments, one at low beam energy and one at high beam energy show different caloric behaviors and are discussed.

  7. Development of diagnostic method for deep levels in semiconductors using charge induced by heavy ion microbeams

    Energy Technology Data Exchange (ETDEWEB)

    Kada, Wataru [Faculty of Science and Technology, Gunma University, Kiryu, Gunma 376-8515 (Japan); Kambayashi, Yuya [Faculty of Science and Technology, Gunma University, Kiryu, Gunma 376-8515 (Japan); Japan Atomic Energy Agency, 1233 Watanuki, Takasaki, Gunma 370-1292 (Japan); Iwamoto, Naoya; Onoda, Shinobu; Makino, Takahiro; Koka, Masashi; Kamiya, Tomihiro [Japan Atomic Energy Agency, 1233 Watanuki, Takasaki, Gunma 370-1292 (Japan); Hoshino, Norihiro; Tsuchida, Hidekazu [Central Research Institute of Electric Power Industry, 2-6-1 Nagasaka, Yokosuka, Kanagawa 240-0196 (Japan); Kojima, Kazutoshi [National Institute of Advanced Industrial Science and Technology, Tsukuba, Ibaraki 305-8568 (Japan); Hanaizumi, Osamu [Faculty of Science and Technology, Gunma University, Kiryu, Gunma 376-8515 (Japan); Ohshima, Takeshi, E-mail: ohshima.takeshi20@jaea.go.jp [Japan Atomic Energy Agency, 1233 Watanuki, Takasaki, Gunma 370-1292 (Japan)

    2015-04-01

    Highlights: •Charge Transient Spectroscopy using heavy ion microbeams (HIQTS) was developed. •HIQTS system is connected with 3 MeV Tandem accelerator at JAEA Takasaki. •Defects in 4H Silicon Carbide (SiC) Schottky diodes were evaluated using HIQTS. •6H-SiC pn diodes with partial damaged areas were also evaluated using HIQTS. -- Abstract: In order to study defects that create deep energy levels in semiconductors which act as carrier traps, Charge Transient Spectroscopy using heavy ion microbeams (HIQTS) was developed at JAEA Takasaki. The HIQTS system was connected with the heavy ion microbeam line of the 3 MV Tandem accelerator. Using the HIQTS system, deep levels in 4H-SiC Schottky barrier diodes irradiated with 3 MeV-protons were studied. As a result, a HIQTS peak with an activation energy of 0.73 eV was observed. In addition, local damage in 6H-SiC pn diodes partially irradiated with 12 MeV-O ion microbeams was studied using HIQTS. With increasing 12 MeV-O ion fluence, charge collection efficiency in locally damaged areas decreased and HIQTS signals increased.

  8. Laboratory measurements of K-shell transitions in highly charged iron ions

    Science.gov (United States)

    Steinbrügge, René; Rudolph, Jan K.; Bernitt, Sven; Crespo López-Urrutia, José R.

    2016-09-01

    The x-ray spectra of celestial sources show a plethora of features originating from highly charged ions. These can be used to determine the flow, temperatures, and abundances of elements in the star, which are needed to benchmark-stellar evolution models. However, the underlying atomic transition data of the ions are often only known by theoretical calculations, thus testing them in laboratory measurements is crucial. We present our measurements of energies, natural linewidths, radiative and Auger decay rates for K-shell transitions in He-like to F-like iron ions. In this experiments, an electron beam ion trap was used to create a target of highly charged ions, which were resonantly excited by monochromatic light from the PETRA III synchrotron radiation source. Fluorescence was observed while simultaneously detecting photoionization by the change in the ionic charge state. This method, combined with the high resolution of the monochromator used, yields uncertainties on the ppm-level for the excitation energies and below 10% for the linewidths and transition rates, thus providing a valuable benchmark for atomic theory.

  9. Thermodynamics of Ion Pair Formations Between Charged Poly(Amino Acid)s.

    Science.gov (United States)

    Petrauskas, Vytautas; Maximowitsch, Eglė; Matulis, Daumantas

    2015-09-17

    Electrostatic interactions between the positively and negatively charged amino acids in proteins play an important role in macromolecular stability, binding, and recognition. Numerous amino acids in proteins are ionizable and may exist in negatively (e.g., Glu, Asp, Cys, Tyr) or positively (e.g., Arg, Lys, His, Orn) charged form dependent on pH and their pKas. In this work, isothermal titration calorimetry was used to determine the average standard values of thermodynamic parameters (the Gibbs free energy, enthalpy, entropy, and the heat capacity) of interaction between the positively charged amino acid homopolymers (polyarginine, polylysine, and polyornithine) and the negatively charged homopolymers (polyaspartic and polyglutamic acids). These values are of potential use in the computational models of interacting proteins and other biological macromolecules. The study showed that oppositely charged poly(amino acid)s bound each other with the stoichiometry of one positive to one negative charge. Arginine bound to the negatively charged amino acids with exothermic enthalpy and higher affinity than lysine. This result also suggests that positive charges in proteins should not be considered entirely equivalent if carried by lysine or arginine. The difference in binding energy of arginine and lysine association with the negatively charged amino acids was attributed to the enthalpy of the second ionic hydrogen bond formation between the guanidine and carboxylic groups. Despite the favorable enthalpic contribution, all such ion pair formation reactions were largely entropy-driven. Consistent with previously observed ionic interactions, the positive heat capacity was always observed during the amino acid ion pair formation.

  10. On the formation of highly charged gaseous ions from unfolded proteins by electrospray ionization.

    Science.gov (United States)

    Konermann, Lars; Rodriguez, Antony D; Liu, Jiangjiang

    2012-08-07

    Electrospray ionization (ESI) of native proteins results in a narrow distribution of low protonation states. ESI for these folded species proceeds via the charged residue mechanism. In contrast, ESI of unfolded proteins yields a wide distribution of much higher charge states. The current work develops a model that can account for this effect. Recent molecular dynamics simulations revealed that ESI for unfolded polypeptide chains involves protein ejection from nanodroplets, representing a type of ion evaporation mechanism (IEM). We point out the analogies between this IEM, and the dissociation of gaseous protein complexes after collisional activation. The latter process commences with unraveling of a single subunit, in concert with Coulombically driven proton transfer. The subunit then separates from the residual complex as a highly charged ion. We propose that similar charge equilibration events accompany the IEM of unfolded proteins, thereby causing the formation of high ESI charge states. A bead chain model is used for examining how charge is partitioned as protein and droplet separate. It is shown that protein ejection from differently sized ESI droplets generates a range of protonation states. The predicted behavior agrees well with experimental data.

  11. Polarization measurement of dielectronic recombination transitions in highly charged krypton ions

    CERN Document Server

    Shah, Chintan; Bernitt, Sven; Dobrodey, Stepan; Steinbrügge, René; Beilmann, Christian; Amaro, Pedro; Hu, Zhimin; Weber, Sebastian; Fritzsche, Stephan; Surzhykov, Andrey; López-Urrutia, José R Crespo; Tashenov, Stanislav

    2016-01-01

    We report linear polarization measurements of x rays emitted due to dielectronic recombination into highly charged krypton ions. The ions in the He-like through O-like charge states were populated in an electron beam ion trap with the electron beam energy adjusted to recombination resonances in order to produce $K\\alpha$ x rays. The x rays were detected with a newly developed Compton polarimeter using a beryllium scattering target and 12 silicon x-ray detector diodes sampling the azimuthal distribution of the scattered x rays. The extracted degrees of linear polarization of several dielectronic recombination transitions agree with results of relativistic distorted--wave calculations. We also demonstrate a high sensitivity of the polarization to the Breit interaction, which is remarkable for a medium-$Z$ element like krypton. The experimental results can be used for polarization diagnostics of hot astrophysical and laboratory fusion plasmas.

  12. Ion Compensation for Space Charge in the Helical Electron Beams of Gyrotrons

    Science.gov (United States)

    Manuilov, V. N.; Semenov, V. E.

    2016-06-01

    We solve analytically the problem about ion compensation for the space charge of a helical electron beam in a gyrotron operated in the long-pulse regime. Elementary processes, which take place during ionization of residual gas in the tube under typical pressures of 10-6-10-7 mm Hg, are considered. It is shown that distribution of the space charge is affected mainly by the electrons of the initial beam and slow-moving ions produced by ionization of the residual gas. Steady-state density of ions in the operating space of the gyrotron after the end of the transitional processes is found, as well as the electron density profile in the channel of electron beam transportation. The results obtained allow us to evaluate the pitch-factor variations caused by partial compensations for the potential "sagging" in the gyrotron cavity, thus being useful for analysis of starting currents, efficiency, and mode competition in high-power gyrotrons.

  13. Energy and charge dependence of the rate of electron-ion recombination in cold magnetized plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Gao, H.; Schuch, R.; Zong, W.; Justiniano, E.; DeWitt, D.R.; Lebius, H.; Spies, W. [Stockholm Univ., Atomic Physics Dept., Stockholm (Sweden)

    1997-07-28

    We have measured electron-ion recombination rates for bare ions of D{sup +}, He{sup 2+}, N{sup 7+}, Ne{sup 10+} and Si{sup 14+} in a storage ring. For the multi-charged ions an unexpected energy dependence was found, showing a strong increase of the measured rates over the calculated radiative recombination rate for electron beam detuning energies below the electron beam transverse temperature. The measured enhanced rates increase approximately as Z{sup 2.8} with the charge state Z. A comparison of these rates with theoretical predictions for collisional-radiative recombination in the cold magnetized electron plasma, in particular three-body recombination including radiative de-excitation of electrons in Rydberg levels, is made. (author).

  14. Highly charged ions in a dilute plasma: an exact asymptotic solution involving strong coupling.

    Science.gov (United States)

    Brown, Lowell S; Dooling, David C; Preston, Dean L

    2006-05-01

    The ion sphere model introduced long ago by Salpeter is placed in a rigorous theoretical setting. The leading corrections to this model for very highly charged but dilute ions in thermal equilibrium with a weakly coupled, one-component background plasma are explicitly computed, and the subleading corrections shown to be negligibly small. This is done using the effective field theory methods advocated by Brown and Yaffe. Thus, corrections to nuclear reaction rates that such highly charged ions may undergo can be computed precisely. Moreover, their contribution to the equation of state can also be computed with precision. Such analytic results for very strong coupling are rarely available, and they can serve as benchmarks for testing computer models in this limit.

  15. EUV spectra of highly-charged ions W$^{54+}$-W$^{63+}$ relevant to ITER diagnostics

    CERN Document Server

    Ralchenko, Yu; Tan, J N; Gillaspy, J D; Pomeroy, J M; Reader, J; Feldman, U; Holland, G E

    2008-01-01

    We report the first measurements and detailed analysis of extreme ultraviolet (EUV) spectra (4 nm to 20 nm) of highly-charged tungsten ions W$^{54+}$ to W$^{63+}$ obtained with an electron beam ion trap (EBIT). Collisional-radiative modelling is used to identify strong electric-dipole and magnetic-dipole transitions in all ionization stages. These lines can be used for impurity transport studies and temperature diagnostics in fusion reactors, such as ITER. Identifications of prominent lines from several W ions were confirmed by measurement of isoelectronic EUV spectra of Hf, Ta, and Au. We also discuss the importance of charge exchange recombination for correct description of ionization balance in the EBIT plasma.

  16. Charge generation by heavy ions in power MOSFETs, burnout space predictions, and dynamic SEB sensitivity

    Science.gov (United States)

    Stassinopoulos, E. G.; Brucker, G. J.; Calvel, P.; Baiget, A.; Peyrotte, C.; Gaillard, R.

    1992-01-01

    The transport, energy loss, and charge production of heavy ions in the sensitive regions of IRF 150 power MOSFETs are described. The dependence and variation of transport parameters with ion type and energy relative to the requirements for single event burnout in this part type are discussed. Test data taken with this power MOSFET are used together with analyses by means of a computer code of the ion energy loss and charge production in the device to establish criteria for burnout and parameters for space predictions. These parameters are then used in an application to predict burnout rates in a geostationary orbit for power converters operating in a dynamic mode. Comparisons of rates for different geometries in simulating SEU (single event upset) sensitive volumes are presented.

  17. Molecular dynamics investigation into the electric charge effect on the operation of ion-based carbon nanotube oscillators

    Science.gov (United States)

    Ansari, R.; Ajori, S.; Sadeghi, F.

    2015-10-01

    The fabrication of nanoscale oscillators working in the gigahertz (GHz) range and beyond has now become the focal center of interest to many researchers. Motivated by this issue, this paper proposes a new type of nano-oscillators with enhanced operating frequency in which both the inner core and outer shell are electrically charged. To this end, molecular dynamics (MD) simulations are performed to investigate the mechanical oscillatory behavior of ions, and in particular chloride ion, tunneling through electrically charged carbon nanotubes (CNTs). It is assumed that the electric charges with similar sign and magnitude are evenly distributed on two ends of nanotube. The interatomic interactions between carbon atoms and van der Waals (vdW) interactions between ion and nanotube are respectively modeled by Tersoff-Brenner and Lennard-Jones (LJ) potential functions, whereas the electrostatic interactions between ion and electric charges are modeled by Coulomb potential function. A comprehensive study is conducted to get an insight into the effects of different parameters such as sign and magnitude of electric charges, nanotube radius, nanotube length and initial conditions (initial separation distance and velocity) on the oscillatory behavior of chloride ion-charged CNT oscillators. It is shown that, the chloride ion frequency inside negatively charged CNTs is lower than that inside positively charged ones with the same magnitude of electric charge, while it is higher than that inside uncharged CNTs. It is further observed that, higher frequencies are generated at higher magnitudes of electric charges distributed on the nanotube.

  18. MOLECULAR SPECTROSCPY AND REACTIONS OF ACTINIDES IN THE GAS PHASE AND CRYOGENIC MATRICES

    Energy Technology Data Exchange (ETDEWEB)

    Heaven, Michael C.; Gibson, John K.; Marcalo, Joaquim

    2009-02-01

    temperature or below. For many spectroscopic measurements, low temperatures have been achieved by co-condensing the actinide vapor in rare gas or inert molecule host matrices. Spectra recorded in matrices are usually considered to be minimally perturbed. Trapping the products from gas-phase reactions that occur when trace quantities of reactants are added to the inert host gas has resulted in the discovery of many new actinide species. Selected aspects of the matrix isolation data were discussed in chapter 17. In the present chapter we review the spectroscopic matrix data in terms of its relationship to gas-phase measurements, and update the description of the new reaction products found in matrices to reflect the developments that have occurred during the past two years. Spectra recorded in matrix environments are usually considered to be minimally perturbed, and this expectation is borne out for many closed shell actinide molecules. However, there is growing evidence that significant perturbations can occur for open shell molecules, resulting in geometric distortions and/or electronic state reordering. Studies of actinide reactions in the gas phase provide an opportunity to probe the relationship between electronic structure and reactivity. Much of this work has focused on the reactions of ionic species, as these may be selected and controlled using various forms of mass spectrometry. As an example of the type of insight derived from reaction studies, it has been established that the reaction barriers for An+ ions are determined by the promotion energies required to achieve the 5fn6d7s configuration. Gas-phase reaction studies also provide fundamental thermodynamic properties such as bond dissociation and ionization energies. In recent years, an increased number of gas-phase ion chemistry studies of bare (atomic) and ligated (molecular) actinide ions have appeared, in which relevant contributions to fundamental actinide chemistry have been made. These studies were initiated

  19. Soft-X-ray spectra of highly charged Os, Bi, Th, and U ions in an electron beam ion trap

    Energy Technology Data Exchange (ETDEWEB)

    Trabert, E; Beiersdorfer, P; Fournier, K B; Chen, M H

    2004-12-03

    Systematic variation of the electron-beam energy in an electron-beam ion trap has been employed to produce soft-X-ray spectra of Os, Bi, Th, and U with highest charge states ranging up to Ni-like ions. Guided by relativistic atomic structure calculations, the strongest lines have been identified with {Delta}n = 0 (n = 4 to n' = 4) transitions in Rb- to Cu-like ions. The rather weak 4p-4d transitions are much less affected by QED contributions than the dominant 4s-4p transitions. Our wavelength measurements consequently provide benchmarks with and (almost) without QED. Because the radiative corrections are not very sensitive to the number of electrons in the valence shell, our data, moreover, provide benchmarks for the evaluation of electron-electron interactions.

  20. Effect of duty-cycles on the air plasma gas-phase of dielectric barrier discharges

    Science.gov (United States)

    Barni, R.; Biganzoli, I.; Dell'Orto, E. C.; Riccardi, C.

    2015-10-01

    An experimental investigation concerning the effects of a duty-cycle in the supply of a dielectric barrier discharge in atmospheric pressure air has been performed. Electrical characteristics of the discharge have been measured, focusing mainly on the statistical properties of the current filaments and on dielectric surface charging, both affected by the frequent repetition of breakdown imposed by the duty-cycle. Information on the gas-phase composition was gathered too. In particular, a strong enhancement in the ozone formation rate is observed when suitable long pauses separate the active discharge phases. A simulation of the chemical kinetics in the gas-phase, based on a simplified discharge modeling, is briefly described in order to shed light on the observed increase in ozone production. The effect of a duty-cycle on surface modification of polymeric films in order to increase their wettability has been investigated too.

  1. Measurement of Gas-phase Acids in Diesel Exhaust

    Science.gov (United States)

    Wentzell, J. J.; Liggio, J.; Li, S.; Vlasenko, A. L.; Staebler, R. M.; Brook, J.; Lu, G.; Poitras, M.; Chan, T.

    2012-12-01

    Gas-phase acids were measured using chemical ionization mass spectrometry (CIMS) as part of the Diesel Engine Emission Research Experiment (DEERE). The CIMS technique, utilizing acetate ion (CH3COO-) as a reagent ion, proved to be a rapid (measurements on the order of seconds) and sensitive (several counts/pptv) method of quantifying the acid emissions. Diluted diesel exhaust measurements were made from a Constant Volume Sampling dilution tunnel using a light duty (1.9L turbocharged Volkswagen Jetta TDI) diesel engine equipped with an OEM diesel oxidation catalyst and exhaust gas recirculation, mounted on an engine dynamometer. Acids measured included isocyanic, nitrous, nitric, propionic and sum of lactic and oxalic, as well as other unidentified compounds. Complimentary measurements of CO, CO2, Total Hydrocarbon (THC), and NOx, were also performed. Several engine modes (different engine rpm and torque outputs) at steady state were examined to determine their effect on acid emissions. Emission rates with respect to NOx and fuel based emission factors were determined. Measurements of HONO fuel emission factors agree well with real-world measurements within a traffic tunnel.1 The first estimate of isocyanic acid emission factors from a diesel engine is reported, and suggests that the emission of this highly toxic compound in diesel exhaust should not be ignored. 1. Kurtenbach, R., Becker, K. H., Gomes, J. A. G., Kleffmann, J.,Lorzer, J. C., Spittler, M., Wiesen, P., Ackermann, R., Geyer, A.,and Platt, U.: Investigations of emissions and heterogeneous formation of HONO in a road traffic tunnel, Atmos. Environ., 35, 3385-3394, doi:10.1016/S1352-2310(01)00138-8, 2001.

  2. Projectile- and charge-state-dependent electron yields from ion penetration of solids as a probe of preequilibrium stopping power

    DEFF Research Database (Denmark)

    Rothard, H.; Schou, Jørgen; Groeneveld, K.-O.

    1992-01-01

    Kinetic electron-emission yields gamma from swift ion penetration of solids are proportional to the (electronic) stopping power gamma approximately Beta-S*, if the preequilibrium evolution of the charge and excitation states of the positively charged ions is taken into account. We show...... that the concept of the preequilibrium near-surface stopping S* can be applied successfully to describe the dependence of the ion-induced electron yields on the projectile atomic number Z(P) and on the charge states q(i) of the incoming ions. We discuss the implementation of this concept into Schou's transport...

  3. Charged Polymer-Coated Separators by Atmospheric Plasma-Induced Grafting for Lithium-Ion Batteries.

    Science.gov (United States)

    Han, Mina; Kim, Dong-Won; Kim, Yeong-Cheol

    2016-10-05

    A simple and fast method of atmospheric plasma-induced grafting was applied over a polyethylene membrane to enhance its performance as a separator for lithium-ion batteries. The process of grafting has formed a thin, durable, and uniform layer on the surface of the porous membrane. The charges of grafted polymers affected the performance of batteries in many ways besides the change of hydrophilicity. Negative charges in polymers improve the capacity retention of batteries and the uniformity of the SEI layer. On the other hand, the electrostatic attraction between different charges contributed to small increases of thermal stability and mechanical strength of separators. Polyampholyte was grafted by using the mixtures of monomers, and the composition of the grafted layer was optimized. The formation of stable uniform SEI layers and the marked improvement in capacity retention were observed in the full cell tests of the lithium battery with the polyampholyte-grafted separators when the polyampholyte has a negative net charge.

  4. Charge stripping of U238 ion beam by helium gas stripper

    Science.gov (United States)

    Imao, H.; Okuno, H.; Kuboki, H.; Yokouchi, S.; Fukunishi, N.; Kamigaito, O.; Hasebe, H.; Watanabe, T.; Watanabe, Y.; Kase, M.; Yano, Y.

    2012-12-01

    Development of a nondestructive, efficient electric-charge-stripping method is a key requirement for next-generation high-intensity heavy-ion accelerators such as the RIKEN Radioactive-Isotope Beam Factory. A charge stripper employing a low-Z gas is an important candidate applicable to high-intensity uranium beams for replacing carbon-foil strippers. In this study, a high-beam-transmission charge-stripping system employing helium gas for U238 beams injected at 10.8MeV/u was developed and demonstrated for the first time. The charge-state evolution measured using helium in a thickness range of 0.24-1.83mg/cm2 is compared with theoretical predictions. Energy attenuation and energy spread due to the helium stripper are also investigated.

  5. Prospects for advanced electron cyclotron resonance and electron beam ion source charge breeding methods for EURISOL

    Energy Technology Data Exchange (ETDEWEB)

    Delahaye, P.; Jardin, P.; Maunoury, L.; Traykov, E.; Varenne, F. [GANIL, CEA/DSM-CNRS/IN2P3, Bd. Becquerel, BP 55027, 14076 Caen Cedex 05 (France); Galata, A.; Porcellato, A. M.; Prete, G. F. [INFN-Laboratori Nazionali di Legnaro, Viale dell' Universita 2, 35020 Legnaro, Padova (Italy); Angot, J.; Lamy, T.; Sortais, P.; Thuillier, T. [LPSC Grenoble, 53, rue des Martyrs, 38026 Grenoble Cedex (France); Ban, G. [LPC Caen, 6 bd Marechal Juin, 14050 Caen Cedex (France); Celona, L.; Lunney, D. [INFN-Laboratori Nazionali del Sud, via S.Sofia 62, 95125 Catania (Italy); Choinski, J.; Gmaj, P.; Jakubowski, A.; Steckiewicz, O. [Heavy Ion Laboratory, University of Warsaw, ul. Pasteura 5a, 02 093 Warsaw (Poland); Kalvas, T. [Department of Physics, University of Jyvaeskylae, PB 35 (YFL) 40351 Jyvaeskylae (Finland); and others

    2012-02-15

    As the most ambitious concept of isotope separation on line (ISOL) facility, EURISOL aims at producing unprecedented intensities of post-accelerated radioactive isotopes. Charge breeding, which transforms the charge state of radioactive beams from 1+ to an n+ charge state prior to post-acceleration, is a key technology which has to overcome the following challenges: high charge states for high energies, efficiency, rapidity and purity. On the roadmap to EURISOL, a dedicated R and D is being undertaken to push forward the frontiers of the present state-of-the-art techniques which use either electron cyclotron resonance or electron beam ion sources. We describe here the guidelines of this R and D.

  6. High intensity high charge state ion beam production with an evaporative cooling magnet ECRIS

    Energy Technology Data Exchange (ETDEWEB)

    Lu, W., E-mail: luwang@impcas.ac.cn; Qian, C.; Sun, L. T.; Zhang, X. Z.; Feng, Y. C.; Ma, B. H.; Zhao, H. W.; Zhan, W. L. [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 73000 (China); Fang, X.; Guo, J. W.; Yang, Y. [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 73000 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Xiong, B.; Ruan, L. [Institute of Electrical Engineering, CAS, Beijing 100190 (China); Xie, D. [Nuclear Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)

    2016-02-15

    LECR4 (Lanzhou ECR ion source No. 4) is a room temperature electron cyclotron resonance ion source, designed to produce high current, high charge state ion beams for the SSC-LINAC injector (a new injector for sector separated cyclotron) at the Institute of Modern Physics. LECR4 also serves as a PoP machine for the application of evaporative cooling technology in accelerator field. To achieve those goals, LECR4 ECR ion source has been optimized for the operation at 18 GHz. During 2014, LECR4 ion source was commissioned at 18 GHz microwave of 1.6 kW. To further study the influence of injection stage to the production of medium and high charge state ion beams, in March 2015, the injection stage with pumping system was installed, and some optimum results were produced, such as 560 eμA of O{sup 7+}, 620 eμA of Ar{sup 11+}, 430 eμA of Ar{sup 12+}, 430 eμA of Xe{sup 20+}, and so on. The comparison will be discussed in the paper.

  7. Investigation of ion beam space charge compensation with a 4-grid analyzer

    Science.gov (United States)

    Ullmann, C.; Adonin, A.; Berezov, R.; Chauvin, N.; Delferrière, O.; Fils, J.; Hollinger, R.; Kester, O.; Senée, F.; Tuske, O.

    2016-02-01

    Experiments to investigate the space charge compensation of pulsed high-current heavy ion beams are performed at the GSI ion source text benches with a 4-grid analyzer provided by CEA/Saclay. The technical design of the 4-grid analyzer is revised to verify its functionality for measurements at pulsed high-current heavy ion beams. The experimental investigation of space charge compensation processes is needed to increase the performance and quality of current and future accelerator facilities. Measurements are performed directly downstream a triode extraction system mounted to a multi-cusp ion source at a high-current test bench as well as downstream the post-acceleration system of the high-current test injector (HOSTI) with ion energies up to 120 keV/u for helium and argon. At HOSTI, a cold or hot reflex discharge ion source is used to change the conditions for the measurements. The measurements were performed with helium, argon, and xenon and are presented. Results from measurements with single aperture extraction systems are shown.

  8. Investigation of ion beam space charge compensation with a 4-grid analyzer

    Energy Technology Data Exchange (ETDEWEB)

    Ullmann, C., E-mail: c.ullmann@gsi.de; Adonin, A.; Berezov, R.; Fils, J.; Hollinger, R.; Kester, O. [GSI, Darmstadt (Germany); Chauvin, N.; Delferrière, O.; Senée, F.; Tuske, O. [CEA, Saclay (France)

    2016-02-15

    Experiments to investigate the space charge compensation of pulsed high-current heavy ion beams are performed at the GSI ion source text benches with a 4-grid analyzer provided by CEA/Saclay. The technical design of the 4-grid analyzer is revised to verify its functionality for measurements at pulsed high-current heavy ion beams. The experimental investigation of space charge compensation processes is needed to increase the performance and quality of current and future accelerator facilities. Measurements are performed directly downstream a triode extraction system mounted to a multi-cusp ion source at a high-current test bench as well as downstream the post-acceleration system of the high-current test injector (HOSTI) with ion energies up to 120 keV/u for helium and argon. At HOSTI, a cold or hot reflex discharge ion source is used to change the conditions for the measurements. The measurements were performed with helium, argon, and xenon and are presented. Results from measurements with single aperture extraction systems are shown.

  9. Clean and highly ordered graphene synthesized in the gas phase.

    Science.gov (United States)

    Dato, Albert; Lee, Zonghoon; Jeon, Ki-Joon; Erni, Rolf; Radmilovic, Velimir; Richardson, Thomas J; Frenklach, Michael

    2009-10-28

    We report that the substrate-free gas-phase graphene synthesis method produces clean and highly ordered graphene sheets that are similar in quality to the graphene obtained through the mechanical exfoliation of highly oriented pyrolytic graphite.

  10. Revision of the gas-phase acidity scale below 300 kcal mol(-1).

    Science.gov (United States)

    Leito, Ivo; Raamat, Elin; Kütt, Agnes; Saame, Jaan; Kipper, Karin; Koppel, Ilmar A; Koppel, Ivar; Zhang, Min; Mishima, Masaaki; Yagupolskii, Lev M; Garlyauskayte, Romute Yu; Filatov, Andrey A

    2009-07-23

    The gas-phase acidity (GA) scale from (CF(3)CO)(2)NH to (C(2)F(5)SO(2))(2)NH--about a 24 kcal mol(-1) range of gas-phase acidities--was reexamined using the Fourier transform ion cyclotron resonance equilibrium measurement approach. Some additions and modifications to the standard methodology of GA measurements were introduced (estimation of partial pressures from mass spectra of the compounds, instead of the pressure gauge readings and use of long reaction times) to achieve higher reliability. Gas-phase acidities of 18 compounds were determined for the first time. The results reveal a contraction of the previously published values in this part of the scale. In particular, the GA values of (CF(3)SO(2))(2)NH and (C(2)F(5)SO(2))(2)NH (important components of lithium ion battery electrolytes and ionic liquids) were revised toward stronger acidities from 291.8 kcal mol(-1) to 286.5 kcal mol(-1) and from 289.4 kcal mol(-1) to 283.7 kcal mol(-1) (i.e., by 5.3 and 5.7 kcal mol(-1)), respectively. Experimental and computational evidence is presented in support of the current results.

  11. Charged Particle, Photon Multiplicity, and Transverse Energy Production in High-Energy Heavy-Ion Collisions

    Directory of Open Access Journals (Sweden)

    Raghunath Sahoo

    2015-01-01

    Full Text Available We review the charged particle and photon multiplicities and transverse energy production in heavy-ion collisions starting from few GeV to TeV energies. The experimental results of pseudorapidity distribution of charged particles and photons at different collision energies and centralities are discussed. We also discuss the hypothesis of limiting fragmentation and expansion dynamics using the Landau hydrodynamics and the underlying physics. Meanwhile, we present the estimation of initial energy density multiplied with formation time as a function of different collision energies and centralities. In the end, the transverse energy per charged particle in connection with the chemical freeze-out criteria is discussed. We invoke various models and phenomenological arguments to interpret and characterize the fireball created in heavy-ion collisions. This review overall provides a scope to understand the heavy-ion collision data and a possible formation of a deconfined phase of partons via the global observables like charged particles, photons, and the transverse energy measurement.

  12. Surface Disorder of GaN Irradiated by Highly Charged Arq+-Ions

    Institute of Scientific and Technical Information of China (English)

    ZHANG Li-Qing; ZHANG Chong-Hong; YANG Yi-Tao; YAO Cun-Feng; LI Bing-Sheng; SUN You-Mei; SONG Shu-Jian

    2009-01-01

    The surface damage to gallium nitride films irradiated by Arq+ (6 < q < 16) ions at room temperature is studied by the atomic force microscopy.It is found that when charge state exceeds a threshold value,significant swelling was turned into obvious erosion in the irradiated region.The surface change of the irradiated region strongly depends on the charge state and ion fluence.On the other hand,surface change is less dependent on the kinetic energy nearly in the present experimental range (120keV≤Ek≤220 keV).For q≤14,surface of the irradiated region is covered with an amorphous layer,rough and bulgy.A step-up appears between the irradiated and un-irradiated region. Moreover,the step height and the surface roughness are functions of the ion dose and charge state,and increase with the increase of dose and charge state.Especially at and near boundary,a sharp bump like ridges in irradiated areas is observed,and there appear characteristic grooves in un-irradiated areas.For q=16,surface of the irradiated region was etched and erased.

  13. Reliable operation of the Brookhaven EBIS for highly charged ion production for RHIC and NSRL

    Science.gov (United States)

    Beebe, E.; Alessi, J.; Binello, S.; Kanesue, T.; McCafferty, D.; Morris, J.; Okamura, M.; Pikin, A.; Ritter, J.; Schoepfer, R.

    2015-01-01

    An Electron Beam Ion Source for the Relativistic Heavy Ion Collider (RHIC EBIS) was commissioned at Brookhaven in September 2010 and since then it routinely supplies ions for RHIC and NASA Space Radiation Laboratory (NSRL) as the main source of highly charged ions from Helium to Uranium. Using three external primary ion sources for 1+ injection into the EBIS and an electrostatic injection beam line, ion species at the EBIS exit can be switched in 0.2 s. A total of 16 different ion species have been produced to date. The length and the capacity of the ion trap have been increased by 20% by extending the trap by two more drift tubes, compared with the original design. The fraction of Au32+ in the EBIS Au spectrum is approximately 12% for 70-80% electron beam neutralization and 8 pulses operation in a 5 Hertz train and 4-5 s super cycle. For single pulse per super cycle operation and 25% electron beam neutralization, the EBIS achieves the theoretical Au32+ fractional output of 18%. Long term stability has been very good with availability of the beam from RHIC EBIS during 2012 and 2014 RHIC runs approximately 99.8%.

  14. Reliable operation of the Brookhaven EBIS for highly charged ion production for RHIC and NSRL

    Energy Technology Data Exchange (ETDEWEB)

    Beebe, E., E-mail: beebe@bnl.gov; Alessi, J., E-mail: beebe@bnl.gov; Binello, S., E-mail: beebe@bnl.gov; Kanesue, T., E-mail: beebe@bnl.gov; McCafferty, D., E-mail: beebe@bnl.gov; Morris, J., E-mail: beebe@bnl.gov; Okamura, M., E-mail: beebe@bnl.gov; Pikin, A., E-mail: beebe@bnl.gov; Ritter, J., E-mail: beebe@bnl.gov; Schoepfer, R., E-mail: beebe@bnl.gov [Brookhaven National Laboratory, Upton, NY 11973 (United States)

    2015-01-09

    An Electron Beam Ion Source for the Relativistic Heavy Ion Collider (RHIC EBIS) was commissioned at Brookhaven in September 2010 and since then it routinely supplies ions for RHIC and NASA Space Radiation Laboratory (NSRL) as the main source of highly charged ions from Helium to Uranium. Using three external primary ion sources for 1+ injection into the EBIS and an electrostatic injection beam line, ion species at the EBIS exit can be switched in 0.2 s. A total of 16 different ion species have been produced to date. The length and the capacity of the ion trap have been increased by 20% by extending the trap by two more drift tubes, compared with the original design. The fraction of Au{sup 32+} in the EBIS Au spectrum is approximately 12% for 70-80% electron beam neutralization and 8 pulses operation in a 5 Hertz train and 4-5 s super cycle. For single pulse per super cycle operation and 25% electron beam neutralization, the EBIS achieves the theoretical Au{sup 32+} fractional output of 18%. Long term stability has been very good with availability of the beam from RHIC EBIS during 2012 and 2014 RHIC runs approximately 99.8%.

  15. Dust charging processes with a Cairns-Tsallis distribution function with negative ions

    Energy Technology Data Exchange (ETDEWEB)

    Abid, A. A., E-mail: abidaliabid1@hotmail.com [Applied Physics Department, Federal Urdu University of Arts, Science and Technology, Islamabad Campus, Islamabad 45320 (Pakistan); Khan, M. Z., E-mail: mzk-qau@yahoo.com [Applied Physics Department, Federal Urdu University of Arts, Science and Technology, Islamabad Campus, Islamabad 45320 (Pakistan); Plasma Technology Research Center, Department of Physics, Faculty of Science, University of Malaya, Kuala Lumpur 50603 (Malaysia); Yap, S. L. [Plasma Technology Research Center, Department of Physics, Faculty of Science, University of Malaya, Kuala Lumpur 50603 (Malaysia); Terças, H., E-mail: hugo.tercas@tecnico.ul.pt [Physics of Information Group, Instituto de Telecomunicações, Av. Rovisco Pais, Lisbon 1049-001 (Portugal); Mahmood, S. [Science Place, University of Saskatchewan, Saskatoon, Saskatchewan S7N5A2 (Canada)

    2016-01-15

    Dust grain charging processes are presented in a non-Maxwellian dusty plasma following the Cairns-Tsallis (q, α)–distribution, whose constituents are the electrons, as well as the positive/negative ions and negatively charged dust grains. For this purpose, we have solved the current balance equation for a negatively charged dust grain to achieve an equilibrium state value (viz., q{sub d} = constant) in the presence of Cairns-Tsallis (q, α)–distribution. In fact, the current balance equation becomes modified due to the Boltzmannian/streaming distributed negative ions. It is numerically found that the relevant plasma parameters, such as the spectral indexes q and α, the positive ion-to-electron temperature ratio, and the negative ion streaming speed (U{sub 0}) significantly affect the dust grain surface potential. It is also shown that in the limit q → 1 the Cairns-Tsallis reduces to the Cairns distribution; for α = 0 the Cairns-Tsallis distribution reduces to pure Tsallis distribution and the latter reduces to Maxwellian distribution for q → 1 and α = 0.

  16. Description and control of dissociation channels in gas-phase protein complexes

    Science.gov (United States)

    Thachuk, Mark; Fegan, Sarah K.; Raheem, Nigare

    2016-08-01

    Using molecular dynamics simulations of a coarse-grained model of the charged apo-hemoglobin protein complex, this work expands upon our initial report [S. K. Fegan and M. Thachuk, J. Am. Soc. Mass Spectrom. 25, 722-728 (2014)] about control of dissociation channels in the gas phase using specially designed charge tags. Employing a charge hopping algorithm and a range of temperatures, a variety of dissociation channels are found for activated gas-phase protein complexes. At low temperatures, a single monomer unfolds and becomes charge enriched. At higher temperatures, two additional channels open: (i) two monomers unfold and charge enrich and (ii) two monomers compete for unfolding with one eventually dominating and the other reattaching to the complex. At even higher temperatures, other more complex dissociation channels open with three or more monomers competing for unfolding. A model charge tag with five sites is specially designed to either attract or exclude charges. By attaching this tag to the N-terminus of specific monomers, the unfolding of those monomers can be decidedly enhanced or suppressed. In other words, using charge tags to direct the motion of charges in a protein complex provides a mechanism for controlling dissociation. This technique could be used in mass spectrometry experiments to direct forces at specific attachment points in a protein complex, and hence increase the diversity of product channels available for quantitative analysis. In turn, this could provide insight into the function of the protein complex in its native biological environment. From a dynamics perspective, this system provides an interesting example of cooperative behaviour involving motions with differing time scales.

  17. Imaging molecular structure through femtosecond photoelectron diffraction on aligned and oriented gas-phase molecules.

    Science.gov (United States)

    Boll, Rebecca; Rouzée, Arnaud; Adolph, Marcus; Anielski, Denis; Aquila, Andrew; Bari, Sadia; Bomme, Cédric; Bostedt, Christoph; Bozek, John D; Chapman, Henry N; Christensen, Lauge; Coffee, Ryan; Coppola, Niccola; De, Sankar; Decleva, Piero; Epp, Sascha W; Erk, Benjamin; Filsinger, Frank; Foucar, Lutz; Gorkhover, Tais; Gumprecht, Lars; Hömke, André; Holmegaard, Lotte; Johnsson, Per; Kienitz, Jens S; Kierspel, Thomas; Krasniqi, Faton; Kühnel, Kai-Uwe; Maurer, Jochen; Messerschmidt, Marc; Moshammer, Robert; Müller, Nele L M; Rudek, Benedikt; Savelyev, Evgeny; Schlichting, Ilme; Schmidt, Carlo; Scholz, Frank; Schorb, Sebastian; Schulz, Joachim; Seltmann, Jörn; Stener, Mauro; Stern, Stephan; Techert, Simone; Thøgersen, Jan; Trippel, Sebastian; Viefhaus, Jens; Vrakking, Marc; Stapelfeldt, Henrik; Küpper, Jochen; Ullrich, Joachim; Rudenko, Artem; Rolles, Daniel

    2014-01-01

    This paper gives an account of our progress towards performing femtosecond time-resolved photoelectron diffraction on gas-phase molecules in a pump-probe setup combining optical lasers and an X-ray free-electron laser. We present results of two experiments aimed at measuring photoelectron angular distributions of laser-aligned 1-ethynyl-4-fluorobenzene (C(8)H(5)F) and dissociating, laser-aligned 1,4-dibromobenzene (C(6)H(4)Br(2)) molecules and discuss them in the larger context of photoelectron diffraction on gas-phase molecules. We also show how the strong nanosecond laser pulse used for adiabatically laser-aligning the molecules influences the measured electron and ion spectra and angular distributions, and discuss how this may affect the outcome of future time-resolved photoelectron diffraction experiments.

  18. Hydration energies of deprotonated amino acids from gas phase equilibria measurements.

    Science.gov (United States)

    Wincel, Henryk

    2008-08-01

    Singly hydrated clusters of deprotonated amino acids were studied using an electrospray high-pressure mass spectrometer equipped with a pulsed ion-beam reaction chamber. Thermochemical data, DeltaH(o), DeltaS(o), and DeltaG(o), for the hydration reaction [AA - H](-) + H(2)O = [AA - H](-).(H(2)O) were obtained from gas-phase equilibria determinations for AA = Gly, Ala, Val, Pro, Phe, Lys, Met, Trp, Gln, Arg, and Asp. The hydration free-energy changes are found to depend significantly on the side-chain substituents. The water binding energy in [AA - H](-).(H(2)O) increases with the gas-phase acidity of AA. The anionic hydrogen bond strengths in [AA - H](-).(H(2)O) are compared with those of the cationic bonds in the corresponding AAH(+).(H(2)O) systems.

  19. Imaging Molecular Structure through Femtosecond Photoelectron Diffraction on Aligned and Oriented Gas-Phase Molecules

    CERN Document Server

    Boll, R; Adolph, M; Anielski, D; Aquila, A; Bari, S; Bomme, C; Bostedt, C; Bozek, J D; Chapman, H N; Christensen, L; Coffee, R; Coppola, N; De, S; Decleva, P; Epp, S W; Erk, B; Filsinger, F; Foucar, L; Gorkhover, T; Gumprecht, L; Hoemke, A; Holmegaard, L; Johnsson, P; Kienitz, J S; Kierspel, T; Krasniqi, F; Kuehnel, K -U; Maurer, J; Messerschmidt, M; Moshammer, R; Mueller, Nele L M; Rudek, B; Savelyev, E; Schlichting, I; Schmidt, C; Scholz, F; Schorb, S; Schulz, J; Seltmann, J; Stener, M; Stern, S; Techert, S; Thogersen, J; Trippel, S; Viefhaus, J; Vrakking, M; Stapelfeldt, H; Kuepper, J; Ullrich, J; Rudenko, A; Rolles, D

    2014-01-01

    This paper gives an account of our progress towards performing femtosecond time-resolved photoelectron diffraction on gas-phase molecules in a pump-probe setup combining optical lasers and an X-ray Free-Electron Laser. We present results of two experiments aimed at measuring photoelectron angular distributions of laser-aligned 1-ethynyl-4-fluorobenzene (C8H5F) and dissociating, laseraligned 1,4-dibromobenzene (C6H4Br2) molecules and discuss them in the larger context of photoelectron diffraction on gas-phase molecules. We also show how the strong nanosecond laser pulse used for adiabatically laser-aligning the molecules influences the measured electron and ion spectra and angular distributions, and discuss how this may affect the outcome of future time-resolved photoelectron diffraction experiments.

  20. HITRAP - a facility for experiments on heavy highly charged ions and on antiprotons

    Energy Technology Data Exchange (ETDEWEB)

    Andjelkovic, Z; Barth, W; Brantjes, N P M; Braeuning-Demian, A; Dahl, L; Herfurth, F; Kester, O; Kluge, H J; Koszudowski, S; Kozhuharov, C; Maero, G; Noertershaeuser, W [GSI, Darmstadt (Germany); Birkl, G [Technische Universitaet Darmstadt (Germany); Blank, I; Goetz, S [Universitaet Freiburg (Germany); Blaum, K [Max-Planck Institut fuer Kernphysik, Heidelberg (Germany); Bodewits, E; Hoekstra, R [KVI Groningen (Netherlands); Church, D [Texas AM University, Texas (United States); Pfister, J, E-mail: w.quint@gsi.d [Universitaet Frankfurt (Germany)

    2009-11-01

    HITRAP is a facility for very slow highly-charged heavy ions at GSI. HITRAP uses the GSI relativistic ion beams, the Experimental Storage Ring ESR for electron cooling and deceleration to 4 MeV/u, and consists of a combination of an interdigital H-mode (IH) structure with a radiofrequency quadrupole structure for further deceleration to 6 keV/u, and a Penning trap for accumulation and cooling to low temperatures. Finally, ion beams with low emittance will be delivered to a large variety of atomic and nuclear physics experiments. Presently, HITRAP is in the commissioning phase. The deceleration of heavy-ion beam from the ESR storage ring to an energy of 500 keV/u with the IH structure has been demonstrated and studied in detail. The commissioning of the RFQ structure and the cooler trap is ongoing.