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Sample records for sum-frequency generation spectroscopy

  1. Sum frequency generation for surface vibrational spectroscopy

    International Nuclear Information System (INIS)

    Hunt, J.H.; Guyot-Sionnest, P.; Shen, Y.R.

    1987-01-01

    Surface vibrational spectroscopy is one of the best means for characterizing molecular adsorbates. For this reason, many techniques have been developed in the past. However, most of them suffer from poor sensitivity, low spectral and temporal resolution, and applications limited to vacuum solid interfaces. Recently, the second harmonic generation (SHG) technique was proved repeatedly to be a simple but versatile surface probe. It is highly sensitive and surface specific; it is also capable of achieving high temporal, spatial, and spectral resolution. Being an optical technique, it can be applied to any interface accessible by light. The only serious drawback is its lack of molecular selectivity. An obvious remedy is the extension of the technique to IR-visible sum frequency generation (SFG). Surface vibrational spectroscopy with submonolayer sensitivity is then possible using SFG with the help of a tunable IR laser. The authors report here an SFG measurement of the C-H stretch vibration of monolayers of molecules at air-solid and air-liquid interfaces

  2. Sum Frequency Generation Vibrational Spectroscopy of Colloidal Platinum Nanoparticle Catalysts: Disordering versus Removal of Organic Capping

    KAUST Repository

    Krier, James M.; Michalak, William D.; Baker, L. Robert; An, Kwangjin; Komvopoulos, Kyriakos; Somorjai, Gabor A.

    2012-01-01

    Recent work with nanoparticle catalysts shows that size and shape control on the nanometer scale influences reaction rate and selectivity. Sum frequency generation (SFG) vibrational spectroscopy is a powerful tool for studying heterogeneous

  3. Probing a molecular electronic transition by two-colour sum-frequency generation spectroscopy

    International Nuclear Information System (INIS)

    Humbert, C.; Dreesen, L.; Nihonyanagi, S.; Masuda, T.; Kondo, T.; Mani, A.A.; Uosaki, K.; Thiry, P.A.; Peremans, A.

    2003-01-01

    We demonstrate that a new emerging technique, two-colour sum-frequency generation (SFG) spectroscopy, can be used to probe the molecular electronic properties of self-assembled monolayers (SAMs). In the CH spectral range (2800-3200 cm -1 ), we show that the sum-frequency generation signal of a porphyrin alkanethiol derivative adsorbed on Pt(1 1 1) reaches a maximum intensity at ∼435 nm SFG wavelength. This wavelength corresponds to the porphyrin moiety specific π-π* molecular electronic transition which is called the Soret or B band. This resonant behaviour is not observed for 1-dodecanethiol SAMs, which are devoid of molecular electronic transition in the investigated visible spectral range

  4. Theory of sum-frequency generation spectroscopy of adsorbed molecules using the density matrix method-broadband vibrational sum-frequency generation and applications

    International Nuclear Information System (INIS)

    Bonn, M; Ueba, H; Wolf, M

    2005-01-01

    A generalized theory of frequency- and time-resolved vibrational sum-frequency generation (SFG) spectroscopy of adsorbates at surfaces is presented using the density matrix formalism. Our theoretical treatment is specifically aimed at addressing issues that accompany the relatively novel SFG approach using broadband infrared pulses. The ultrashort duration of these pulses makes them ideally suited for time-resolved investigations, for which we present a complete theoretical treatment. A second key characteristic of these pulses is their large bandwidth and high intensity, which allow for highly non-linear effects, including vibrational ladder climbing of surface vibrations. We derive general expressions relating the density matrix to SFG spectra, and apply these expressions to specific experimental results by solving the coupled optical Bloch equations of the density matrix elements. Thus, we can theoretically reproduce recent experimentally demonstrated hot band SFG spectra using femtosecond broadband infrared excitation of carbon monoxide (CO) on a Ru(001) surface

  5. Quantitative Surface Chirality Detection with Sum Frequency Generation Vibrational Spectroscopy: Twin Polarization Angle Approach

    International Nuclear Information System (INIS)

    Wei, Feng; Xu, Yanyan; Guo, Yuan; Liu, Shi-lin; Wang, Hongfei

    2009-01-01

    Here we report a novel twin polarization angle (TPA) approach in the quantitative chirality detection with the surface sum-frequency generation vibrational spectroscopy (SFG-VS). Generally, the achiral contribution dominates the surface SFG-VS signal, and the pure chiral signal is usually two or three orders of magnitude smaller. Therefore, it has been difficult to make quantitative detection and analysis of the chiral contributions to the surface SFG-VS signal. In the TPA method, by varying together the polarization angles of the incoming visible light and the sum frequency signal at fixed s or p polarization of the incoming infrared beam, the polarization dependent SFG signal can give not only direct signature of the chiral contribution in the total SFG-VS signal, but also the accurate measurement of the chiral and achiral components in the surface SFG signal. The general description of the TPA method is presented and the experiment test of the TPA approach is also presented for the SFG-VS from the S- and R-limonene chiral liquid surfaces. The most accurate degree of chiral excess values thus obtained for the 2878 cm -1 spectral peak of the S- and R-limonene liquid surfaces are (23.7±0.4)% and (25.4±1.3)%, respectively.

  6. Circularly polarized infrared and visible sum-frequency-generation spectroscopy: Vibrational optical activity measurement

    International Nuclear Information System (INIS)

    Cheon, Sangheon; Cho, Minhaeng

    2005-01-01

    Vibrational optical activity spectroscopies utilizing either circularly polarized ir or circularly polarized visible beams were theoretically investigated by considering the infrared and visible sum-frequency-generation (IV-SFG) schemes. In addition to the purely electric dipole-allowed chiral component of the IV-SFG susceptibility, the polarizability-electric quadrupole hyperpolarizability term also contributes to the vibrationally resonant IV-SFG susceptibility. The circular-intensity-difference signal is shown to be determined by the interferences between the all-electric dipole-allowed chiral component and the polarizability-electric-dipole or electric-dipole-electric-quadrupole Raman optical activity tensor components. The circularly polarized SFG methods are shown to be potentially useful coherent spectroscopic tools for determining absolute configurations of chiral molecules in condensed phases

  7. Sum Frequency Generation Vibrational Spectroscopy of Colloidal Platinum Nanoparticle Catalysts: Disordering versus Removal of Organic Capping

    KAUST Repository

    Krier, James M.

    2012-08-23

    Recent work with nanoparticle catalysts shows that size and shape control on the nanometer scale influences reaction rate and selectivity. Sum frequency generation (SFG) vibrational spectroscopy is a powerful tool for studying heterogeneous catalysis because it enables the observation of surface intermediates during catalytic reactions. To control the size and shape of catalytic nanoparticles, an organic ligand was used as a capping agent to stabilize nanoparticles during synthesis. However, the presence of an organic capping agent presents two major challenges in SFG and catalytic reaction studies: it blocks a significant fraction of active surface sites and produces a strong signal that prevents the detection of reaction intermediates with SFG. Two methods for cleaning Pt nanoparticles capped with poly (vinylpyrrolidone) (PVP) are examined in this study: solvent cleaning and UV cleaning. Solvent cleaning leaves more PVP intact and relies on disordering with hydrogen gas to reduce the SFG signal of PVP. In contrast, UV cleaning depends on nearly complete removal of PVP to reduce SFG signal. Both UV and solvent cleaning enable the detection of reaction intermediates by SFG. However, solvent cleaning also yields nanoparticles that are stable under reaction conditions, whereas UV cleaning results in aggregation during reaction. The results of this study indicate that solvent cleaning is more advantageous for studying the effects of nanoparticle size and shape on catalytic selectivity by SFG vibrational spectroscopy. © 2012 American Chemical Society.

  8. Atmospheric pressure reaction cell for operando sum frequency generation spectroscopy of ultrahigh vacuum grown model catalysts

    Science.gov (United States)

    Roiaz, Matteo; Pramhaas, Verena; Li, Xia; Rameshan, Christoph; Rupprechter, Günther

    2018-04-01

    A new custom-designed ultrahigh vacuum (UHV) chamber coupled to a UHV and atmospheric-pressure-compatible spectroscopic and catalytic reaction cell is described, which allows us to perform IR-vis sum frequency generation (SFG) vibrational spectroscopy during catalytic (kinetic) measurements. SFG spectroscopy is an exceptional tool to study vibrational properties of surface adsorbates under operando conditions, close to those of technical catalysis. This versatile setup allows performing surface science, SFG spectroscopy, catalysis, and electrochemical investigations on model systems, including single crystals, thin films, and deposited metal nanoparticles, under well-controlled conditions of gas composition, pressure, temperature, and potential. The UHV chamber enables us to prepare the model catalysts and to analyze their surface structure and composition by low energy electron diffraction and Auger electron spectroscopy, respectively. Thereafter, a sample transfer mechanism moves samples under UHV to the spectroscopic cell, avoiding air exposure. In the catalytic cell, SFG spectroscopy and catalytic tests (reactant/product analysis by mass spectrometry or gas chromatography) are performed simultaneously. A dedicated sample manipulation stage allows the model catalysts to be examined from LN2 temperature to 1273 K, with gaseous reactants in a pressure range from UHV to atmospheric. For post-reaction analysis, the SFG cell is rapidly evacuated and samples are transferred back to the UHV chamber. The capabilities of this new setup are demonstrated by benchmark results of CO adsorption on Pt and Pd(111) single crystal surfaces and of CO adsorption and oxidation on a ZrO2 supported Pt nanoparticle model catalyst grown by atomic layer deposition.

  9. Sum frequency generation spectroscopy of tetraalkylphosphonium ionic liquids at the air-liquid interface

    Science.gov (United States)

    Peñalber-Johnstone, Chariz; Adamová, Gabriela; Plechkova, Natalia V.; Bahrami, Maryam; Ghaed-Sharaf, Tahereh; Ghatee, Mohammad Hadi; Seddon, Kenneth R.; Baldelli, Steven

    2018-05-01

    Sum frequency generation (SFG) spectroscopy is a nonlinear vibrational spectroscopic technique used in the study of interfaces, due to its unique ability to distinguish surface molecules that have preferential ordering compared to the isotropic bulk. Here, a series of alkyltrioctylphosphonium chloride ionic liquids, systematically varied by cation structure, were characterized at the air-liquid interface by SFG. The effect on surface structure resulting from molecular variation (i.e., addition of cyano- and methoxy-functional groups) of the cation alkyl chain was investigated. SFG spectra in the C—H stretching region (2750-3100 cm-1) for [P8 8 8 n][Cl], where n = 4, 5, 8, 10, 12, or 14, showed characteristic changes as the alkyl chain length was increased. Spectral profiles for n = 4, 5, 8, or 10 appeared similar; however, when the fourth alkyl chain was sufficiently long (as in the case of n = 12 or n = 14), abrupt changes occurred in the spectra. Molecular dynamics (MD) simulation of a slab of each ionic liquid (with n = 8, 10, or 12) confirmed gauche defects, with enhancement for the long alkyl chain and an abrupt increase of gauche occurrence from n = 8 to n = 10. A comparison of the tilt angle distribution from the simulation and the SFG analysis show a broad distribution of angles. Using experimental SFG spectra in conjunction with MD simulations, a comprehensive molecular picture at the surface of this unique class of liquids is presented.

  10. Structure and orientation of interfacial proteins determined by sum frequency generation vibrational spectroscopy: method and application.

    Science.gov (United States)

    Ye, Shuji; Wei, Feng; Li, Hongchun; Tian, Kangzhen; Luo, Yi

    2013-01-01

    In situ and real-time characterization of molecular structures and orientation of proteins at interfaces is essential to understand the nature of interfacial protein interaction. Such work will undoubtedly provide important clues to control biointerface in a desired manner. Sum frequency generation vibrational spectroscopy (SFG-VS) has been demonstrated to be a powerful technique to study the interfacial structures and interactions at the molecular level. This paper first systematically introduced the methods for the calculation of the Raman polarizability tensor, infrared transition dipole moment, and SFG molecular hyperpolarizability tensor elements of proteins/peptides with the secondary structures of α-helix, 310-helix, antiparallel β-sheet, and parallel β-sheet, as well as the methodology to determine the orientation of interfacial protein secondary structures using SFG amide I spectra. After that, recent progresses on the determination of protein structure and orientation at different interfaces by SFG-VS were then reviewed, which provides a molecular-level understanding of the structures and interactions of interfacial proteins, specially understanding the nature of driving force behind such interactions. Although this review has focused on analysis of amide I spectra, it will be expected to offer a basic idea for the spectral analysis of amide III SFG signals and other complicated molecular systems such as RNA and DNA. Copyright © 2013 Elsevier Inc. All rights reserved.

  11. Sum frequency generation (SFG) vibrational spectroscopy of planar phosphatidylethanolamine hybrid bilayer membranes under water.

    Science.gov (United States)

    Kett, Peter J N; Casford, Michael T L; Davies, Paul B

    2010-06-15

    Sum frequency generation (SFG) spectroscopy has been used to study the structure of phosphatidylethanolamine hybrid bilayer membranes (HBMs) under water at ambient temperatures. The HBMs were formed using a modified Langmuir-Schaefer technique and consisted of a layer of dipalmitoyl phosphatidylethanolamine (DPPE) physisorbed onto an octadecanethiol (ODT) self-assembled monolayer (SAM) at a series of surface pressures from 1 to 40 mN m(-1). The DPPE and ODT were selectively deuterated so that the contributions to the SFG spectra from the two layers could be determined separately. SFG spectra in both the C-H and C-D stretching regions confirmed that a monolayer of DPPE had been adsorbed to the ODT SAM and that there were gauche defects within the alkyl chains of the phospholipid. On adsorption of a layer of DPPE, methylene modes from the ODT SAM were detected, indicating that the phospholipid had partially disordered the alkanethiol monolayer. SFG spectra recorded in air indicated that removal of water from the surface of the HBM resulted in disruption of the DPPE layer and the formation of phospholipid bilayers.

  12. Sum-Frequency-Generation-Based Laser Sidebands for Tunable Femtosecond Raman Spectroscopy in the Ultraviolet

    Directory of Open Access Journals (Sweden)

    Liangdong Zhu

    2015-04-01

    Full Text Available Femtosecond stimulated Raman spectroscopy (FSRS is an emerging molecular structural dynamics technique for functional materials characterization typically in the visible to near-IR range. To expand its applications we have developed a versatile FSRS setup in the ultraviolet region. We use the combination of a narrowband, ~400 nm Raman pump from a home-built second harmonic bandwidth compressor and a tunable broadband probe pulse from sum-frequency-generation-based cascaded four-wave mixing (SFG-CFWM laser sidebands in a thin BBO crystal. The ground state Raman spectrum of a laser dye Quinolon 390 in methanol that strongly absorbs at ~355 nm is systematically studied as a standard sample to provide previously unavailable spectroscopic characterization in the vibrational domain. Both the Stokes and anti-Stokes Raman spectra can be collected by selecting different orders of SFG-CFWM sidebands as the probe pulse. The stimulated Raman gain with the 402 nm Raman pump is >21 times larger than that with the 550 nm Raman pump when measured at the 1317 cm−1 peak for the aromatic ring deformation and ring-H rocking mode of the dye molecule, demonstrating that pre-resonance enhancement is effectively achieved in the unique UV-FSRS setup. This added tunability in the versatile and compact optical setup enables FSRS to better capture transient conformational snapshots of photosensitive molecules that absorb in the UV range.

  13. Theoretical vibrational sum-frequency generation spectroscopy of water near lipid and surfactant monolayer interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Roy, S.; Gruenbaum, S. M.; Skinner, J. L. [Theoretical Chemistry Institute and Department of Chemistry, 1101 University Ave., University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States)

    2014-11-14

    Understanding the structure of water near cell membranes is crucial for characterizing water-mediated events such as molecular transport. To obtain structural information of water near a membrane, it is useful to have a surface-selective technique that can probe only interfacial water molecules. One such technique is vibrational sum-frequency generation (VSFG) spectroscopy. As model systems for studying membrane headgroup/water interactions, in this paper we consider lipid and surfactant monolayers on water. We adopt a theoretical approach combining molecular dynamics simulations and phase-sensitive VSFG to investigate water structure near these interfaces. Our simulated spectra are in qualitative agreement with experiments and reveal orientational ordering of interfacial water molecules near cationic, anionic, and zwitterionic interfaces. OH bonds of water molecules point toward an anionic interface leading to a positive VSFG peak, whereas the water hydrogen atoms point away from a cationic interface leading to a negative VSFG peak. Coexistence of these two interfacial water species is observed near interfaces between water and mixtures of cationic and anionic lipids, as indicated by the presence of both negative and positive peaks in their VSFG spectra. In the case of a zwitterionic interface, OH orientation is toward the interface on the average, resulting in a positive VSFG peak.

  14. Quantitative spectral and orientational analysis in surface sum frequency generation vibrational spectroscopy (SFG-VS)

    Science.gov (United States)

    Wang, Hong-Fei; Gan, Wei; Lu, Rong; Rao, Yi; Wu, Bao-Hua

    Sum frequency generation vibrational spectroscopy (SFG-VS) has been proven to be a uniquely effective spectroscopic technique in the investigation of molecular structure and conformations, as well as the dynamics of molecular interfaces. However, the ability to apply SFG-VS to complex molecular interfaces has been limited by the ability to abstract quantitative information from SFG-VS experiments. In this review, we try to make assessments of the limitations, issues and techniques as well as methodologies in quantitative orientational and spectral analysis with SFG-VS. Based on these assessments, we also try to summarize recent developments in methodologies on quantitative orientational and spectral analysis in SFG-VS, and their applications to detailed analysis of SFG-VS data of various vapour/neat liquid interfaces. A rigorous formulation of the polarization null angle (PNA) method is given for accurate determination of the orientational parameter D = /, and comparison between the PNA method with the commonly used polarization intensity ratio (PIR) method is discussed. The polarization and incident angle dependencies of the SFG-VS intensity are also reviewed, in the light of how experimental arrangements can be optimized to effectively abstract crucial information from the SFG-VS experiments. The values and models of the local field factors in the molecular layers are discussed. In order to examine the validity and limitations of the bond polarizability derivative model, the general expressions for molecular hyperpolarizability tensors and their expression with the bond polarizability derivative model for C3v, C2v and C∞v molecular groups are given in the two appendixes. We show that the bond polarizability derivative model can quantitatively describe many aspects of the intensities observed in the SFG-VS spectrum of the vapour/neat liquid interfaces in different polarizations. Using the polarization analysis in SFG-VS, polarization selection rules or

  15. Study of confinement and sliding friction of fluids using sum frequency generation spectroscopy

    Science.gov (United States)

    Nanjundiah, Kumar

    2007-12-01

    Friction and wear are important technologically. Tires on wet roads, windshield wipers and human joints are examples where nanometer-thick liquids are confined between flexible-rigid contact interfaces. Fundamental understanding of the structure of these liquids can assist in the design of products such as artificial joints and lubricants for Micro-electromechanical systems [MEMS]. Prior force measurements have suggested an increase in apparent viscosity of confined liquid and sometimes solid-like responses. But, these have not given the state of molecules under confinement. In the present study, we have used a surface sensitive, non-linear optical technique (infrared-visible sum frequency generation spectroscopy [SFG]) to investigate molecular structure at hidden interfaces. SFG can identify chemical groups, concentration and orientation of molecules at an interface. A friction cell was developed to study sliding of a smooth elastomeric lens against a sapphire surface. Experiments were done with dry sliding as well as lubricated sliding in the presence of linear alkane liquids. SFG spectra at the alkane/sapphire interface revealed ordering of the confined alkane molecules. These were more ordered than alkane liquid, but less ordered than alkane crystal. Cooling of the confined alkane below its melting temperature [TM] led to molecular orientation that was different from that of bulk crystal next to a sapphire surface. Molecules were oriented with their symmetry axis parallel to the surface normal. In addition, the melting temperature [Tconf] under confinement for a series of linear alkanes (n =15--27) showed a surprising trend. Intermediate molecular weights showed melting point depression. The T conf values suggested that melting started at the alkane/sapphire interface. In another investigation, confinement of water between an elastomeric PDMS lens and sapphire was studied. SFG spectra at the sapphire/water/PDMS interface revealed a heterogeneous morphology. The

  16. Effect of surface structure on catalytic reactions: A sum frequency generation surface vibrational spectroscopy study

    International Nuclear Information System (INIS)

    McCrea, Keith R.

    2001-01-01

    In the results discussed above, it is clear that Sum Frequency Generation (SFG) is a unique tool that allows the detection of vibrational spectra of adsorbed molecules present on single crystal surfaces under catalytic reaction conditions. Not only is it possible to detect active surface intermediates, it is also possible to detect spectator species which are not responsible for the measured turnover rates. By correlating high-pressure SFG spectra under reaction conditions and gas chromatography (GC) kinetic data, it is possible to determine which species are important under reaction intermediates. Because of the flexibility of this technique for studying surface intermediates, it is possible to determine how the structures of single crystal surfaces affect the observed rates of catalytic reactions. As an example of a structure insensitive reaction, ethylene hydrogenation was explored on both Pt(111) and Pt(100). The rates were determined to be essentially the same. It was observed that both ethylidyne and di-(sigma) bonded ethylene were present on the surface under reaction conditions on both crystals, although in different concentrations. This result shows that these two species are not responsible for the measured turnover rate, as it would be expected that one of the two crystals would be more active than the other, since the concentration of the surface intermediate would be different on the two crystals. The most likely active intermediates are weakly adsorbed molecules such as(pi)-bonded ethylene and ethyl. These species are not easily detected because their concentration lies at the detection limit of SFG. The SFG spectra and GC data essentially show that ethylene hydrogenation is structure insensitive for Pt(111) and Pt(100). SFG has proven to be a unique and excellent technique for studying adsorbed species on single crystal surfaces under high-pressure catalytic reactions. Coupled with kinetic data obtained from gas chromatography measurements, it can

  17. Characterization of polymer surface structure and surface mechanical behaviour by sum frequency generation surface vibrational spectroscopy and atomic force microscopy

    International Nuclear Information System (INIS)

    Opdahl, Aric; Koffas, Telly S; Amitay-Sadovsky, Ella; Kim, Joonyeong; Somorjai, Gabor A

    2004-01-01

    Sum frequency generation (SFG) vibrational spectroscopy and atomic force microscopy (AFM) have been used to study polymer surface structure and surface mechanical behaviour, specifically to study the relationships between the surface properties of polymers and their bulk compositions and the environment to which the polymer is exposed. The combination of SFG surface vibrational spectroscopy and AFM has been used to study surface segregation behaviour of polyolefin blends at the polymer/air and polymer/solid interfaces. SFG surface vibrational spectroscopy and AFM experiments have also been performed to characterize the properties of polymer/liquid and polymer/polymer interfaces, focusing on hydrogel materials. A method was developed to study the surface properties of hydrogel contact lens materials at various hydration conditions. Finally, the effect of mechanical stretching on the surface composition and surface mechanical behaviour of phase-separated polyurethanes, used in biomedical implant devices, has been studied by both SFG surface vibrational spectroscopy and AFM. (topical review)

  18. Sum Frequency Generation Vibrational Spectroscopy and Kinetic Study of 2-Methylfuran and 2,5-Dimethylfuran Hydrogenation over 7 nm Platinum Cubic Nanoparticles

    KAUST Repository

    Aliaga, Cesar; Tsung, Chia-Kuang; Alayoglu, Selim; Komvopoulos, Kyriakos; Yang, Peidong; Somorjai, Gabor A.

    2011-01-01

    Sum frequency generation vibrational spectroscopy and kinetic measurements obtained from gas chromatography were used to study the adsorption and hydrogenation of 2-methylfuran (MF) and 2,5-dimethylfuran (DMF) over cubic Pt nanoparticles of 7 nm

  19. Second harmonic generation and sum frequency generation

    International Nuclear Information System (INIS)

    Pellin, M.J.; Biwer, B.M.; Schauer, M.W.; Frye, J.M.; Gruen, D.M.

    1990-01-01

    Second harmonic generation and sum frequency generation are increasingly being used as in situ surface probes. These techniques are coherent and inherently surface sensitive by the nature of the mediums response to intense laser light. Here we will review these two techniques using aqueous corrosion as an example problem. Aqueous corrosion of technologically important materials such as Fe, Ni and Cr proceeds from a reduced metal surface with layer by layer growth of oxide films mitigated by compositional changes in the chemical makeup of the growing film. Passivation of the metal surface is achieved after growth of only a few tens of atomic layers of metal oxide. Surface Second Harmonic Generation and a related nonlinear laser technique, Sum Frequency Generation have demonstrated an ability to probe the surface composition of growing films even in the presence of aqueous solutions. 96 refs., 4 figs

  20. Salt Effects on Surface Structures of Polyelectrolyte Multilayers (PEMs) Investigated by Vibrational Sum Frequency Generation (SFG) Spectroscopy.

    Science.gov (United States)

    Ge, Aimin; Matsusaki, Michiya; Qiao, Lin; Akashi, Mitsuru; Ye, Shen

    2016-04-26

    Sum frequency generation (SFG) vibrational spectroscopy was employed to investigate the surface structures of polyelectrolyte multilayers (PEMs) constructed by sequentially alternating adsorption of poly(diallyldimethylammonium chloride) (PDDA) and poly(styrenesulfonate) (PSS). It was found that the surface structures and surface charge density of the as-deposited PEMs of PDDA/PSS significantly depend on the concentration of sodium chloride (NaCl) present in the polyelectrolyte solutions. Furthermore, it was found that the surface structure of the as-deposited PEMs is in a metastable state and will reach the equilibrium state by diffusion of the polyelectrolyte chain after an aging process, resulting in a polyelectrolyte mixture on the PEM surfaces.

  1. Quantification of crystalline cellulose in lignocellulosic biomass using sum frequency generation (SFG) vibration spectroscopy and comparison with other analytical methods.

    Science.gov (United States)

    Barnette, Anna L; Lee, Christopher; Bradley, Laura C; Schreiner, Edward P; Park, Yong Bum; Shin, Heenae; Cosgrove, Daniel J; Park, Sunkyu; Kim, Seong H

    2012-07-01

    The non-centrosymmetry requirement of sum frequency generation (SFG) vibration spectroscopy allows the detection and quantification of crystalline cellulose in lignocellulose biomass without spectral interferences from hemicelluloses and lignin. This paper shows a correlation between the amount of crystalline cellulose in biomass and the SFG signal intensity. Model biomass samples were prepared by mixing commercially available cellulose, xylan, and lignin to defined concentrations. The SFG signal intensity was found sensitive to a wide range of crystallinity, but varied non-linearly with the mass fraction of cellulose in the samples. This might be due to the matrix effects such as light scattering and absorption by xylan and lignin, as well as the non-linear density dependence of the SFG process itself. Comparison with other techniques such as XRD, FT-Raman, FT-IR and NMR demonstrate that SFG can be a complementary and sensitive tool to assess crystalline cellulose in biomass. Copyright © 2012 Elsevier Ltd. All rights reserved.

  2. Total internal reflection sum-frequency generation spectroscopy and dense gold nanoparticles monolayer: a route for probing adsorbed molecules

    International Nuclear Information System (INIS)

    Tourillon, Gerard; Dreesen, Laurent; Volcke, Cedric; Sartenaer, Yannick; Thiry, Paul A; Peremans, Andre

    2007-01-01

    We show that sum-frequency generation spectroscopy performed in the total internal reflection configuration (TIR-SFG) combined with a dense gold nanoparticles monolayer allows us to study, with an excellent signal to noise ratio and high signal to background ratio, the conformation of adsorbed molecules. Dodecanethiol (DDT) was used as probe molecules in order to assess the potentialities of the approach. An enhancement of more than one order of magnitude of the SFG signals arising from the adsorbed species is observed with the TIR geometry compared to the external reflection one while the SFG non-resonant contribution remains the same for both configurations. Although further work is required to fully understand the origin of the SFG process on nanoparticles, our work opens new possibilities for studying nanostructures

  3. Selective detection of crystalline cellulose in plant cell walls with sum-frequency-generation (SFG) vibration spectroscopy.

    Science.gov (United States)

    Barnette, Anna L; Bradley, Laura C; Veres, Brandon D; Schreiner, Edward P; Park, Yong Bum; Park, Junyeong; Park, Sunkyu; Kim, Seong H

    2011-07-11

    The selective detection of crystalline cellulose in biomass was demonstrated with sum-frequency-generation (SFG) vibration spectroscopy. SFG is a second-order nonlinear optical response from a system where the optical centrosymmetry is broken. In secondary plant cell walls that contain mostly cellulose, hemicellulose, and lignin with varying concentrations, only certain vibration modes in the crystalline cellulose structure can meet the noninversion symmetry requirements. Thus, SFG can be used to detect and analyze crystalline cellulose selectively in lignocellulosic biomass without extraction of noncellulosic species from biomass or deconvolution of amorphous spectra. The selective detection of crystalline cellulose in lignocellulosic biomass is not readily achievable with other techniques such as XRD, solid-state NMR, IR, and Raman analyses. Therefore, the SFG analysis presents a unique opportunity to reveal the cellulose crystalline structure in lignocellulosic biomass.

  4. Sum Frequency Generation Vibrational Spectroscopy of Adsorbed Amino Acids, Peptides and Proteins of Hydrophilic and Hydrophobic Solid-Water Interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Holinga IV, George Joseph [Univ. of California, Berkeley, CA (United States)

    2010-09-01

    Sum frequency generation (SFG) vibrational spectroscopy was used to investigate the interfacial properties of several amino acids, peptides, and proteins adsorbed at the hydrophilic polystyrene solid-liquid and the hydrophobic silica solid-liquid interfaces. The influence of experimental geometry on the sensitivity and resolution of the SFG vibrational spectroscopy technique was investigated both theoretically and experimentally. SFG was implemented to investigate the adsorption and organization of eight individual amino acids at model hydrophilic and hydrophobic surfaces under physiological conditions. Biointerface studies were conducted using a combination of SFG and quartz crystal microbalance (QCM) comparing the interfacial structure and concentration of two amino acids and their corresponding homopeptides at two model liquid-solid interfaces as a function of their concentration in aqueous solutions. The influence of temperature, concentration, equilibration time, and electrical bias on the extent of adsorption and interfacial structure of biomolecules were explored at the liquid-solid interface via QCM and SFG. QCM was utilized to quantify the biological activity of heparin functionalized surfaces. A novel optical parametric amplifier was developed and utilized in SFG experiments to investigate the secondary structure of an adsorbed model peptide at the solid-liquid interface.

  5. Vibrational sum-frequency generation spectroscopy of lipid bilayers at repetition rates up to 100 kHz

    Science.gov (United States)

    Yesudas, Freeda; Mero, Mark; Kneipp, Janina; Heiner, Zsuzsanna

    2018-03-01

    Broadband vibrational sum-frequency generation (BB-VSFG) spectroscopy has become a well-established surface analytical tool capable of identifying the orientation and structure of molecular layers. A straightforward way to boost the sensitivity of the technique could be to increase the laser repetition rate beyond that of standard BB-VSFG spectrometers, which rely on Ti:sapphire lasers operating at repetition rates of 1-5 kHz. Nevertheless, possible thermally induced artifacts in the vibrational spectra due to higher laser average powers are unexplored. Here, we discuss laser power induced temperature accumulation effects that distort the BB-VSFG spectra of 1,2-diacyl-sn-glycero-3-phosphocholine at an interface between two transparent phases at repetition rates of 5, 10, 50, and 100 kHz at constant pulse energy. No heat-induced distortions were found in the spectra, suggesting that the increase in the laser repetition rate provides a feasible route to an improved signal-to-noise ratio or shorter data acquisition times in BB-VSFG spectroscopy for thin films on transparent substrates. The results have implications for future BB-VSFG spectrometers pushing the detection limit for molecular layers with low surface coverage.

  6. Cooperative Effects of Zwitterionic-Ionic Surfactant Mixtures on the Interfacial Water Structure Revealed by Sum Frequency Generation Vibrational Spectroscopy.

    Science.gov (United States)

    Pan, Xuecong; Yang, Fangyuan; Chen, Shunli; Zhu, Xuefeng; Wang, Chuanyi

    2018-05-08

    Cooperative effects of a series of equimolar binary zwitterionic-ionic surfactant mixtures on the interfacial water structure at the air-water interfaces have been studied by sum frequency generation vibrational spectroscopy (SFG-VS). For zwitterionic surfactant palmityl sulfobetaine (SNC 16 ), anionic surfactant sodium hexadecyl sulfate (SHS), and cationic surfactant cetyltrimethylammonium bromide (CTAB) with the same length of alkyl chain, significantly enhanced ordering of interfacial water molecules was observed for the zwitterionic-anionic surfactant mixtures SNC 16 -SHS, indicating that SNC 16 interacts more strongly with SHS than with CTAB because of the strong headgroup-headgroup electrostatic attraction for SNC 16 -SHS. Meanwhile, the SFG amplitude ratio of methyl and methylene symmetric stretching modes was used to verify the stronger interaction between SNC 16 and SHS. The conformational order indicator increased from 0.64 for SNC 16 to 7.17 for SNC 16 -SHS but only 0.94 for SNC 16 -CTAB. In addition, another anionic surfactant sodium dodecyl sulfate (SDS) was introduced to study the influence of chain-chain interaction. Decreased SFG amplitude of interfacial water molecules for SNC 16 -SDS was observed. Therefore, both the headgroup-headgroup electrostatic interaction and chain-chain van der Waals attractive interaction of the surfactants play an important role in enhancing the ordering of interfacial water molecules. The results provided experimental and theoretical bases for practical applications of the surfactants.

  7. Nonlinear optical response of a gold surface in the visible range: A study by two-color sum-frequency generation spectroscopy. I. Experimental determination.

    Science.gov (United States)

    Dalstein, L; Revel, A; Humbert, C; Busson, B

    2018-04-07

    We experimentally determine the effective nonlinear second-order susceptibility of gold over the visible spectral range. To reach that goal, we probe by vibrational two-color sum-frequency generation spectroscopy the methyl stretching region of a dodecanethiol self-assembled monolayer adsorbed on a gold film. The sum-frequency generation spectra show a remarkable shape reversal when the visible probe wavelength is tuned from 435 to 705 nm. After correcting from Fresnel effects, the methyl stretching vibrations serve as an internal reference, allowing to extract the dispersion of the absolute phase and relative amplitude of the effective nonlinear optical response of gold in the visible range.

  8. Nanoscale chemical and mechanical characterization of thin films:sum frequency generation (SFG) vibrational spectroscopy at buriedinterfaces

    Energy Technology Data Exchange (ETDEWEB)

    Kweskin, Sasha Joseph [Univ. of California, Berkeley, CA (United States)

    2006-01-01

    Sum frequency generation (SFG) surface vibrational spectroscopy was used to characterize interfaces pertinent to current surface engineering applications, such as thin film polymers and novel catalysts. An array of advanced surface science techniques like scanning probe microscopy (SPM), x-ray photoelectron spectroscopy (XPS), gas chromatography (GC) and electron microscopy were used to obtain experimental measurements complementary to SFG data elucidating polymer and catalyst surface composition, surface structure, and surface mechanical behavior. Experiments reported in this dissertation concentrate on three fundamental questions: (1) How does the interfacial molecular structure differ from that of the bulk in real world applications? (2) How do differences in chemical environment affect interface composition or conformation? (3) How do these changes correlate to properties such as mechanical or catalytic performance? The density, surface energy and bonding at a solid interface dramatically alter the polymer configuration, physics and mechanical properties such as surface glass transition, adhesion and hardness. The enhanced sensitivity of SFG at the buried interface is applied to three systems: a series of acrylates under compression, the compositions and segregation behavior of binary polymer polyolefin blends, and the changes in surface structure of a hydrogel as a function of hydration. In addition, a catalytically active thin film of polymer coated nanoparticles is investigated to evaluate the efficacy of SFG to provide in situ information for catalytic reactions involving small mass adsorption and/or product development. Through the use of SFG, in situ total internal reflection (TIR) was used to increase the sensitivity of SFG and provide the necessary specificity to investigate interfaces of thin polymer films and nanostructures previously considered unfeasible. The dynamic nature of thin film surfaces is examined and it is found that the non

  9. Surface and buried interfacial structures of epoxy resins used as underfills studied by sum frequency generation vibrational spectroscopy.

    Science.gov (United States)

    Vázquez, Anne V; Holden, Brad; Kristalyn, Cornelius; Fuller, Mike; Wilkerson, Brett; Chen, Zhan

    2011-05-01

    Flip chip technology has greatly improved the performance of semiconductor devices, but relies heavily on the performance of epoxy underfill adhesives. Because epoxy underfills are cured in situ in flip chip semiconductor devices, understanding their surface and interfacial structures is critical for understanding their adhesion to various substrates. Here, sum frequency generation (SFG) vibrational spectroscopy was used to study surface and buried interfacial structures of two model epoxy resins used as underfills in flip chip devices, bisphenol A digylcidyl ether (BADGE) and 1,4-butanediol diglycidyl ether (BDDGE). The surface structures of these epoxies were compared before and after cure, and the orientations of their surface functional groups were deduced to understand how surface structural changes during cure may affect adhesion properties. Further, the effect of moisture exposure, a known cause of adhesion failure, on surface structures was studied. It was found that the BADGE surface significantly restructured upon moisture exposure while the BDDGE surface did not, showing that BADGE adhesives may be more prone to moisture-induced delamination. Lastly, although surface structure can give some insight into adhesion, buried interfacial structures more directly correspond to adhesion properties of polymers. SFG was used to study buried interfaces between deuterated polystyrene (d-PS) and the epoxies before and after moisture exposure. It was shown that moisture exposure acted to disorder the buried interfaces, most likely due to swelling. These results correlated with lap shear adhesion testing showing a decrease in adhesion strength after moisture exposure. The presented work showed that surface and interfacial structures can be correlated to adhesive strength and may be helpful in understanding and designing optimized epoxy underfill adhesives.

  10. Sum Frequency Generation Vibrational Spectroscopy of 1,3-Butadiene Hydrogenation on 4 nm Pt@SiO 2 , Pd@SiO 2 , and Rh@SiO 2 Core–Shell Catalysts

    KAUST Repository

    Krier, James M.; Michalak, William D.; Cai, Xiaojun; Carl, Lindsay; Komvopoulos, Kyriakos; Somorjai, Gabor A.

    2015-01-01

    NPs (Stöber encapsulation) prepared by colloidal synthesis. Sum frequency generation (SFG) vibrational spectroscopy was performed to correlate surface intermediates observed in situ with reaction selectivity. It is shown that calcination is effective

  11. Catalyzed hydrogenation of nitrogen and ethylene on metal (Fe, Pt) single crystal surfaces and effects of coadsorption: A sum frequency generation vibrational spectroscopy study

    Energy Technology Data Exchange (ETDEWEB)

    Westerberg, Staffan Per Gustav [Univ. of California, Berkeley, CA (United States)

    2004-01-01

    High-pressure catalytic reactions and associated processes, such as adsorption have been studied on a molecular level on single crystal surfaces. Sum Frequency Generation (SFG) vibrational spectroscopy together with Auger Electron Spectroscopy (AES), Temperature Programmed Desorption (TPD) and Gas Chromatography (GC) were used to investigate the nature of species on catalytic surfaces and to measure the catalytic reaction rates. Special attention has been directed at studying high-pressure reactions and in particular, ammonia synthesis in order to identify reaction intermediates and the influence of adsorbates on the surface during reaction conditions. The adsorption of gases N2, H2, O2 and NH3 that play a role in ammonia synthesis have been studied on the Fe(111) crystal surface by sum frequency generation vibrational spectroscopy using an integrated Ultra-High Vacuum (UHV)/high-pressure system. SFG spectra are presented for the dissociation intermediates, NH2 (~3325 cm-1) and NH (~3235 cm-1) under high pressure of ammonia (200 Torr) on the clean Fe(111) surface. Addition of 0.5 Torr of oxygen to 200 Torr of ammonia does not significantly change the bonding of dissociation intermediates to the surface. However, it leads to a phase change of nearly 180° between the resonant and non-resonant second order non-linear susceptibility of the surface, demonstrated by the reversal of the SFG spectral features. Heating the surface in the presence of 200 Torr ammonia and 0.5 Torr oxygen reduces the oxygen coverage, which can be seen from the SFG spectra as another relative phase change of 180°. The reduction of the oxide is also supported by Auger electron spectroscopy. The result suggests that the phase change of the spectral features could serve as a sensitive indicator of the chemical environment of the adsorbates.

  12. Intrinsic Chirality and Prochirality at Air/R-(+)- and S-(-)-Limonene Interfaces: Spectral Signatures with Interference Chiral Sum-Frequency Generation Vibrational Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Fu, Li; Zhang, Yun; Wei, Zhehao; Wang, Hongfei

    2014-06-04

    We report in this work detailed measurements on the chiral and achiral sum-frequency vibrational spectra in the C-H stretching vibration region (2800-3050cm-1) of the air/liquid interfaces of R-limonene and S-limonene, using the recently developed high-resolution broadband sum-frequency generation vibrational spectroscopy (HR-BB-SFG-VS). The achiral SFG spectra of R-limonene and S-limonene, as well as the equal amount (50/50) racemic mixture show that the enantiomers are with the same interfacial orientations. The interference chiral SFG spectra of the limonene enantiomers exhibit spectral signature from chiral response of the Cα-H stretching mode, and spectral signature from prochiral response of the CH2 asymmetric stretching mode, respectively. The chiral spectral feature of the Cα-H stretching mode changes sign from R-limonene to S-limonene, and disappears for the 50/50 racemic mixture. While the prochiral spectral feature of the CH2 asymmetric stretching mode is the same for R-limonene and S-limonene, and also surprisingly remains the same for the 50/50 racemic mixture. These results provided detail information in understanding the structure and chirality of molecular interfaces, and demonstrated the sensitivity and potential of SFG-VS as unique spectroscopic tool for chirality characterization and chiral recognition at the molecular interface.

  13. Efficient yellow beam generation by intracavity sum frequency ...

    Indian Academy of Sciences (India)

    2014-02-06

    Feb 6, 2014 ... We present our studies on dual wavelength operation using a single Nd:YVO4 crystal and its intracavity sum frequency generation by considering the influence of the thermal lensing effect on the performance of the laser. A KTP crystal cut for type-II phase matching was used for intracavity sum frequency ...

  14. Sum frequency generation vibrational spectroscopy (SFG-VS) for complex molecular surfaces and interfaces: Spectral lineshape measurement and analysis plus some controversial issues

    Science.gov (United States)

    Wang, Hong-Fei

    2016-12-01

    Sum-frequency generation vibrational spectroscopy (SFG-VS) was first developed in the 1980s and it has been proven a uniquely sensitive and surface/interface selective spectroscopic probe for characterization of the structure, conformation and dynamics of molecular surfaces and interfaces. In recent years, there have been many progresses in the development of methodology and instrumentation in the SFG-VS toolbox that have significantly broadened the application to complex molecular surfaces and interfaces. In this review, after presenting a unified view on the theory and methodology focusing on the SFG-VS spectral lineshape, as well as the new opportunities in SFG-VS applications with such developments, some of the controversial issues that have been puzzling the community are discussed. The aim of this review is to present to the researchers and students interested in molecular surfaces and interfacial sciences up-to-date perspectives complementary to the existing textbooks and reviews on SFG-VS.

  15. Sum Frequency Generation Vibrational Spectroscopy and Kinetic Study of 2-Methylfuran and 2,5-Dimethylfuran Hydrogenation over 7 nm Platinum Cubic Nanoparticles

    KAUST Repository

    Aliaga, Cesar

    2011-04-28

    Sum frequency generation vibrational spectroscopy and kinetic measurements obtained from gas chromatography were used to study the adsorption and hydrogenation of 2-methylfuran (MF) and 2,5-dimethylfuran (DMF) over cubic Pt nanoparticles of 7 nm average size, synthesized by colloidal methods and cleaned by ultraviolet light and ozone treatment. Reactions carried out at atmospheric pressure in the temperature range of 20-120 °C produced dihydro and tetrahydro species, as well as ring-opening products (alcohols) and ring-cracking products, showing high selectivity toward ring opening throughout the entire temperature range. The aromatic rings (MF and DMF) adsorbed parallel to the nanoparticle surface. Results yield insight into various surface reaction intermediates and the reason for the significantly lower selectivity for ring cracking in DMF hydrogenation compared to MF hydrogenation. © 2011 American Chemical Society.

  16. Sum-Frequency Generation from Chiral Media and Interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Ji, Na [Univ. of California, Berkeley, CA (United States)

    2006-02-13

    Sum frequency generation (SFG), a second-order nonlinear optical process, is electric-dipole forbidden in systems with inversion symmetry. As a result, it has been used to study chiral media and interfaces, systems intrinsically lacking inversion symmetry. This thesis describes recent progresses in the applications of and new insights into SFG from chiral media and interfaces. SFG from solutions of chiral amino acids is investigated, and a theoretical model explaining the origin and the strength of the chiral signal in electronic-resonance SFG spectroscopy is discussed. An interference scheme that allows us to distinguish enantiomers by measuring both the magnitude and the phase of the chiral SFG response is described, as well as a chiral SFG microscope producing chirality-sensitive images with sub-micron resolution. Exploiting atomic and molecular parity nonconservation, the SFG process is also used to solve the Ozma problems. Sum frequency vibrational spectroscopy is used to obtain the adsorption behavior of leucine molecules at air-water interfaces. With poly(tetrafluoroethylene) as a model system, we extend the application of this surface-sensitive vibrational spectroscopy to fluorine-containing polymers.

  17. Sum-Frequency Generation from Chiral Media and Interfaces

    International Nuclear Information System (INIS)

    Ji, Na

    2006-01-01

    Sum frequency generation (SFG), a second-order nonlinear optical process, is electric-dipole forbidden in systems with inversion symmetry. As a result, it has been used to study chiral media and interfaces, systems intrinsically lacking inversion symmetry. This thesis describes recent progresses in the applications of and new insights into SFG from chiral media and interfaces. SFG from solutions of chiral amino acids is investigated, and a theoretical model explaining the origin and the strength of the chiral signal in electronic-resonance SFG spectroscopy is discussed. An interference scheme that allows us to distinguish enantiomers by measuring both the magnitude and the phase of the chiral SFG response is described, as well as a chiral SFG microscope producing chirality-sensitive images with sub-micron resolution. Exploiting atomic and molecular parity nonconservation, the SFG process is also used to solve the Ozma problems. Sum frequency vibrational spectroscopy is used to obtain the adsorption behavior of leucine molecules at air-water interfaces. With poly(tetrafluoroethylene) as a model system, we extend the application of this surface-sensitive vibrational spectroscopy to fluorine-containing polymers

  18. Studies of Heterogeneously Catalyzed Liquid-Phase Alcohol Oxidation on Platinum bySum-frequency Generation Vibrational Spectroscopy and Reaction Rate Measurements

    Energy Technology Data Exchange (ETDEWEB)

    Thompson, Christopher [Univ. of California, Berkeley, CA (United States)

    2014-05-15

    Compared to many branches of chemistry, the molecular level study of catalytically active surfaces is young. Only with the invention of ultrahigh vacuum technology in the past half century has it been possible to carry out experiments that yield useful molecular information about the reactive occurrences at a surface. The reason is two-fold: low pressure is necessary to keep a surface clean for an amount of time long enough to perform an experiment, and most atomic scale techniques that are surface speci c (x-ray photoelectron spectroscopy, electron energy loss spectroscopy, Auger electron spectroscopy, etc.) cannot be used at ambient pressures, because electrons, which act as chemical probes in these techniques, are easily scattered by molecules. Sum-frequency generation (SFG) vibrational spectroscopy is one technique that can provide molecular level information from the surface without the necessity for high vacuum. Since the advent of SFG as a surface spectroscopic tool it has proved its worth in the studies of surface catalyzed reactions in the gas phase, with numerous reactions in the gas phase having been investigated on a multitude of surfaces. However, in situ SFG characterization of catalysis at the solid-liquid interface has yet to be thoroughly pursued despite the broad interest in the use of heterogeneous catalysts in the liquid phase as replacements for homogeneous counterparts. This work describes an attempt to move in that direction, applying SFG to study the solid-liquid interface under conditions of catalytic alcohol oxidation on platinum.

  19. Adding a dimension to the infrared spectra of interfaces using heterodyne detected 2D sum-frequency generation (HD 2D SFG) spectroscopy.

    Science.gov (United States)

    Xiong, Wei; Laaser, Jennifer E; Mehlenbacher, Randy D; Zanni, Martin T

    2011-12-27

    In the last ten years, two-dimensional infrared spectroscopy has become an important technique for studying molecular structures and dynamics. We report the implementation of heterodyne detected two-dimensional sum-frequency generation (HD 2D SFG) spectroscopy, which is the analog of 2D infrared (2D IR) spectroscopy, but is selective to noncentrosymmetric systems such as interfaces. We implement the technique using mid-IR pulse shaping, which enables rapid scanning, phase cycling, and automatic phasing. Absorptive spectra are obtained, that have the highest frequency resolution possible, from which we extract the rephasing and nonrephasing signals that are sometimes preferred. Using this technique, we measure the vibrational mode of CO adsorbed on a polycrystalline Pt surface. The 2D spectrum reveals a significant inhomogenous contribution to the spectral line shape, which is quantified by simulations. This observation indicates that the surface conformation and environment of CO molecules is more complicated than the simple "atop" configuration assumed in previous work. Our method can be straightforwardly incorporated into many existing SFG spectrometers. The technique enables one to quantify inhomogeneity, vibrational couplings, spectral diffusion, chemical exchange, and many other properties analogous to 2D IR spectroscopy, but specifically for interfaces.

  20. Intrinsic chirality and prochirality at Air/R-(+)- and S-(-)-limonene interfaces: spectral signatures with interference chiral sum-frequency generation vibrational spectroscopy.

    Science.gov (United States)

    Fu, Li; Zhang, Yun; Wei, Zhe-Hao; Wang, Hong-Fei

    2014-09-01

    We report in this work detailed measurements of the chiral and achiral sum-frequency vibrational spectra in the C-H stretching vibration region (2800-3050 cm(-1)) of the air/liquid interfaces of R-(+)-limonene and S-(-)-limonene, using the recently developed high-resolution broadband sum-frequency generation vibrational spectroscopy (HR-BB-SFG-VS). The achiral SFG spectra of R-limonene and S-limonene, as well as the RS racemic mixture (50/50 equal amount mixture), show that the corresponding molecular groups of the R and S enantiomers are with the same interfacial orientations. The interference chiral SFG spectra of the limonene enantiomers exhibit a spectral signature from the chiral response of the Cα-H stretching mode, and a spectral signature from the prochiral response of the CH(2) asymmetric stretching mode, respectively. The chiral spectral feature of the Cα-H stretching mode changes sign from R-(+)-limonene to S-(-)-limonene surfaces, and disappears for the RS racemic mixture surface. While the prochiral spectral feature of the CH(2) asymmetric stretching mode is the same for R-(+)-limonene and S-(-)-limonene surfaces, and also surprisingly remains the same for the RS racemic mixture surface. Therefore, the structures of the R-(+)-limonene and the S-(-)-limonene at the liquid interfaces are nevertheless not mirror images to each other, even though the corresponding groups have the same tilt angle from the interfacial normal, i.e., the R-(+)-limonene and the S-(-)-limonene at the surface are diastereomeric instead of enantiomeric. These results provide detailed information in understanding the structure and chirality of molecular interfaces and demonstrate the sensitivity and potential of SFG-VS as a unique spectroscopic tool for chirality characterization and chiral recognition at the molecular interface. © 2014 Wiley Periodicals, Inc.

  1. Support Effects in Catalysis Studied by in-situ Sum Frequency Generation Vibrational Spectroscopy and in-situ X-Ray Spectroscopies

    Science.gov (United States)

    Kennedy, Griffin John

    Kinetic measurements are paired with in-situ spectroscopic characterization tools to investigate colloidally based, supported Pt catalytic model systems in order to elucidate the mechanisms by which metal and support work in tandem to dictate activity and selectivity. The results demonstrate oxide support materials, while inactive in absence of Pt nanoparticles, possess unique active sites for the selective conversion of gas phase molecules when paired with an active metal catalyst. In order to establish a paradigm for metal-support interactions using colloidally synthesized Pt nanoparticles the ability of the organic capping agent to inhibit reactivity and interaction with the support must first be assessed. Pt nanoparticles capped by poly(vinylpyrrolidone) (PVP), and those from which the PVP is removed by UV light exposure, are investigated for two reactions, the hydrogenation of ethylene and the oxidation of methanol. It is shown that prior to PVP removal the particles are moderately active for both reactions. Following removal, the activity for the two reactions diverges, the ethylene hydrogenation rate increases 10-fold, while the methanol oxidation rate decreases 3-fold. To better understand this effect the capping agent prior to, and the residual carbon remaining after UV treatment are probed by sum frequency generation vibrational spectroscopy. Prior to removal no major differences are observed when the particles are exposed to alternating H2 and O2 environments. When the PVP is removed, carbonaceous fragments remain on the surface that dynamically restructure in H2 and O2. These fragments create a tightly bound shell in an oxygen environment and a porous coating of hydrogenated carbon in the hydrogen environment. Reaction rate measurements of thermally cleaned PVP and oleic acid capped particles show this effect to be independent of cleaning method or capping agent. In all this demonstrates the ability of the capping agent to mediate nanoparticle catalysis

  2. Sum Frequency Generation Studies of Hydrogenation Reactions on Platinum Nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Krier, James M. [Univ. of California, Berkeley, CA (United States)

    2013-08-31

    Sum Frequency Generation (SFG) vibrational spectroscopy is used to characterize intermediate species of hydrogenation reactions on the surface of platinum nanoparticle catalysts. In contrast to other spectroscopy techniques which operate in ultra-high vacuum or probe surface species after reaction, SFG collects information under normal conditions as the reaction is taking place. Several systems have been studied previously using SFG on single crystals, notably alkene hydrogenation on Pt(111). In this thesis, many aspects of SFG experiments on colloidal nanoparticles are explored for the first time. To address spectral interference by the capping agent (PVP), three procedures are proposed: UV cleaning, H2 induced disordering and calcination (core-shell nanoparticles). UV cleaning and calcination physically destroy organic capping while disordering reduces SFG signal through a reversible structural change by PVP.

  3. Low energy electron diffraction (LEED) and sum frequency generation (SFG) vibrational spectroscopy studies of solid-vacuum, solid-air and solid-liquid interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Hoffer, Saskia [Univ. of California, Berkeley, CA (United States)

    2002-01-01

    Electron based surface probing techniques can provide detailed information about surface structure or chemical composition in vacuum environments. The development of new surface techniques has made possible in situ molecular level studies of solid-gas interfaces and more recently, solid-liquid interfaces. The aim of this dissertation is two-fold. First, by using novel sample preparation, Low Energy Electron Diffraction (LEED) and other traditional ultra high vacuum (UHV) techniques are shown to provide new information on the insulator/vacuum interface. The surface structure of the classic insulator NaCl has been determined using these methods. Second, using sum frequency generation (SFG) surface specific vibrational spectroscopy studies were performed on both the biopolymer/air and electrode/electrolyte interfaces. The surface structure and composition of polyetherurethane-silicone copolymers were determined in air using SFG, atomic force microscopy (AFM), and X-ray photoelectron spectroscopy (XPS). SFG studies of the electrode (platinum, gold and copper)/electrolyte interface were performed as a function of applied potential in an electrochemical cell.

  4. Self-assembled organic monolayers on gold nanoparticles: A study by sum-frequency generation combined with UV-vis spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Humbert, C. [LURE, CNRS-UMR 130, Centre Universitaire Paris-Sud, Ba-hat t. 209D, B.P. 34, 91898 Orsay Cedex (France) and Laboratoire de Spectroscopie Moleculaire de Surface, University of Namur, 61 Rue de Bruxelles, B-5000 Namur (Belgium)]. E-mail: christophe.humbert@fundp.ac.be; Busson, B. [LURE, CNRS-UMR 130, Centre Universitaire Paris-Sud, Ba-hat t. 209D, B.P. 34, 91898 Orsay Cedex (France); Abid, J.-P. [Ecole Polytechnique Federale de Lausanne, Laboratoire d' Electrochimie Physique et Analytique, CH-1015 Lausanne (Switzerland); Six, C. [LURE, CNRS-UMR 130, Centre Universitaire Paris-Sud, Ba-hat t. 209D, B.P. 34, 91898 Orsay Cedex (France); Girault, H.H. [Ecole Polytechnique Federale de Lausanne, Laboratoire d' Electrochimie Physique et Analytique, CH-1015 Lausanne (Switzerland); Tadjeddine, A. [LURE, CNRS-UMR 130, Centre Universitaire Paris-Sud, Ba-hat t. 209D, B.P. 34, 91898 Orsay Cedex (France)

    2005-05-20

    We use sum-frequency generation spectroscopy (SFG) in the infrared 2800-3000 cm{sup -1} spectral range and UV-vis spectroscopy (transmission) in the 450-650 nm spectral range in order to characterize vibrational and electronic properties of various interfaces composed of organic monolayers adsorbed on gold nanoparticles (AuNPs) with 19 nm average diameter. SFG signal is observed for AuNPs films deposited on glass substrates using the following silane intermediates: 3-(aminopropyl) triethoxysilane and 3-(mercaptopropyl) trimethoxysilane. The density of AuNPs and their aggregates are measured with a scanning electron microscope. For the samples showing a strong well-defined surface plasmon resonance (SPR), we also observe an enhancement of their non-linear optical properties. Furthermore, the SFG measurements show that 1-dodecanethiol films are rather well ordered on specific AuNPs substrates. In this way, the presence of the SFG signal, which comes from both the bulk electronic s-d interband transition and the vibrational states of the adsorbed molecules, depends on a SPR process. This phenomenon is evidenced on the AuNPs by the incident visible beam located at 532 nm, i.e. near the SPR energy maximum of these interfaces. These results open the door to experiments involving macromolecular and biological materials networks deposited on ultrathin metal electrodes in a controlled electrochemical environment.

  5. Synthesis and characterization of aromatic self-assembled monolayers containing methylene and ethyleneglycol entities by means of sum-frequency generation spectroscopy

    International Nuclear Information System (INIS)

    Dreesen, L.; Sartenaer, Y.; Peremans, A.; Thiry, P.A.; Humbert, C.; Grugier, J.; Marchand-Brynaert, J.

    2006-01-01

    We use infrared-visible sum-frequency generation (SFG) spectroscopy in order to investigate the adsorption properties on Pt(111) of molecules having CH 3 -C 6 H 4 -(O-CH 2 -CH 2 ) n -O-(CH 2 ) m -SH as general chemical formula. We synthesized three molecules defined by the values m = 5 n = 4, m = 11 n = 4, m = 11 n = 8 and characterized them by Nuclear Magnetic Resonance spectroscopy. Thanks to spectroscopic measurements, we show that these molecules build self-assembled monolayers on Pt(111). First, the weak SFG signals arising from the ad-layer indicate low order and surface coverage of the substrate by these molecules. Next, the vibrational fingerprints of the aforementioned molecules are determined between 2825 and 3125 cm - 1 and the observed SFG spectral features are ascribed on the basis of the analysis of shorter and simpler molecules (1-dodecanethiol, 4-methylbenzenethiol and CH 3 -C 6 H 4 -O-(CH 2 ) 11 -SH) also adsorbed on Pt(111). The occurrence of methylene vibration modes indicates a significant amount of chain defects whatever the n and m numbers are. Finally, the identification of a particular vibration mode, characteristic of the aromatic ring, enables us to qualitatively discuss the effect of the number of methylene and ethylene glycol entities on its orientation. More precisely, higher these numbers, more tilted (with respect to the substrate normal) the aromatic ring plane is

  6. Water Orientation at Ceramide/Water Interfaces Studied by Heterodyne-Detected Vibrational Sum Frequency Generation Spectroscopy and Molecular Dynamics Simulation

    KAUST Repository

    Adhikari, Aniruddha

    2016-10-10

    Lipid/water interaction is essential for many biological processes. The water structure at the nonionic lipid interface remains little known, and there is no scope of a priori prediction of water orientation at nonionic interfaces, either. Here, we report our study combining advanced nonlinear spectroscopy and molecular dynamics simulation on the water orientation at the ceramide/water interface. We measured χ spectrum in the OH stretch region of ceramide/isotopically diluted water interface using heterodyne-detected vibrational sum-frequency generation spectroscopy and found that the interfacial water prefers an overall hydrogen-up orientation. Molecular dynamics simulation indicates that this preferred hydrogen-up orientation of water is determined by a delicate balance between hydrogen-up and hydrogen-down orientation induced by lipid-water and intralipid hydrogen bonds. This mechanism also suggests that water orientation at neutral lipid interfaces depends highly on the chemical structure of the lipid headgroup, in contrast to the charged lipid interfaces where the net water orientation is determined solely by the charge of the lipid headgroup.

  7. Self-assembled organic monolayers on gold nanoparticles: A study by sum-frequency generation combined with UV-vis spectroscopy

    International Nuclear Information System (INIS)

    Humbert, C.; Busson, B.; Abid, J.-P.; Six, C.; Girault, H.H.; Tadjeddine, A.

    2005-01-01

    We use sum-frequency generation spectroscopy (SFG) in the infrared 2800-3000 cm -1 spectral range and UV-vis spectroscopy (transmission) in the 450-650 nm spectral range in order to characterize vibrational and electronic properties of various interfaces composed of organic monolayers adsorbed on gold nanoparticles (AuNPs) with 19 nm average diameter. SFG signal is observed for AuNPs films deposited on glass substrates using the following silane intermediates: 3-(aminopropyl) triethoxysilane and 3-(mercaptopropyl) trimethoxysilane. The density of AuNPs and their aggregates are measured with a scanning electron microscope. For the samples showing a strong well-defined surface plasmon resonance (SPR), we also observe an enhancement of their non-linear optical properties. Furthermore, the SFG measurements show that 1-dodecanethiol films are rather well ordered on specific AuNPs substrates. In this way, the presence of the SFG signal, which comes from both the bulk electronic s-d interband transition and the vibrational states of the adsorbed molecules, depends on a SPR process. This phenomenon is evidenced on the AuNPs by the incident visible beam located at 532 nm, i.e. near the SPR energy maximum of these interfaces. These results open the door to experiments involving macromolecular and biological materials networks deposited on ultrathin metal electrodes in a controlled electrochemical environment

  8. Phase transition behaviors of the supported DPPC bilayer investigated by sum frequency generation (SFG) vibrational spectroscopy and atomic force microscopy (AFM).

    Science.gov (United States)

    Wu, Heng-Liang; Tong, Yujin; Peng, Qiling; Li, Na; Ye, Shen

    2016-01-21

    The phase transition behaviors of a supported bilayer of dipalmitoylphosphatidyl-choline (DPPC) have been systematically evaluated by in situ sum frequency generation (SFG) vibrational spectroscopy and atomic force microscopy (AFM). By using an asymmetric bilayer composed of per-deuterated and per-protonated monolayers, i.e., DPPC-d75/DPPC and a symmetric bilayer of DPPC/DPPC, we were able to probe the molecular structural changes during the phase transition process of the lipid bilayer by SFG spectroscopy. It was found that the DPPC bilayer is sequentially melted from the top (adjacent to the solution) to bottom leaflet (adjacent to the substrate) over a wide temperature range. The conformational ordering of the supported bilayer does not decrease (even slightly increases) during the phase transition process. The conformational defects in the bilayer can be removed after the complete melting process. The phase transition enthalpy for the bottom leaflet was found to be approximately three times greater than that for the top leaflet, indicating a strong interaction of the lipids with the substrate. The present SFG and AFM observations revealed similar temperature dependent profiles. Based on these results, the temperature-induced structural changes in the supported lipid bilayer during its phase transition process are discussed in comparison with previous studies.

  9. Hydrogenation of the alpha,beta-Unsaturated Aldehydes Acrolein, Crotonaldehyde, and Prenal over Pt Single Crystals: A Kinetic and Sum-Frequency Generation Vibrational Spectroscopy Study

    Energy Technology Data Exchange (ETDEWEB)

    Kliewer, C.J.; Somorjai, G.A.

    2008-11-26

    Sum-frequency generation vibrational spectroscopy (SFG-VS) and kinetic measurements using gas chromatography have been used to study the surface reaction intermediates during the hydrogenation of three {alpha},{beta}-unsaturated aldehydes, acrolein, crotonaldehyde, and prenal, over Pt(111) at Torr pressures (1 Torr aldehyde, 100 Torr hydrogen) in the temperature range of 295K to 415K. SFG-VS data showed that acrolein has mixed adsorption species of {eta}{sub 2}-di-{sigma}(CC)-trans, {eta}{sub 2}-di-{sigma}(CC)-cis as well as highly coordinated {eta}{sub 3} or {eta}{sub 4} species. Crotonaldehyde adsorbed to Pt(111) as {eta}{sub 2} surface intermediates. SFG-VS during prenal hydrogenation also suggested the presence of the {eta}{sub 2} adsorption species, and became more highly coordinated as the temperature was raised to 415K, in agreement with its enhanced C=O hydrogenation. The effect of catalyst surface structure was clarified by carrying out the hydrogenation of crotonaldehyde over both Pt(111) and Pt(100) single crystals while acquiring the SFG-VS spectra in situ. Both the kinetics and SFG-VS showed little structure sensitivity. Pt(100) generated more decarbonylation 'cracking' product while Pt(111) had a higher selectivity for the formation of the desired unsaturated alcohol, crotylalcohol.

  10. Two-dimensional sum-frequency generation (2D SFG) spectroscopy: summary of principles and its application to amyloid fiber monolayers.

    Science.gov (United States)

    Ghosh, Ayanjeet; Ho, Jia-Jung; Serrano, Arnaldo L; Skoff, David R; Zhang, Tianqi; Zanni, Martin T

    2015-01-01

    By adding a mid-infrared pulse shaper to a sum-frequency generation (SFG) spectrometer, we have built a 2D SFG spectrometer capable of measuring spectra analogous to 2D IR spectra but with monolayer sensitivity and SFG selection rules. In this paper, we describe the experimental apparatus and provide an introduction to 2D SFG spectroscopy to help the reader interpret 2D SFG spectra. The main aim of this manuscript is to report 2D SFG spectra of the amyloid forming peptide FGAIL. FGAIL is a critical segment of the human islet amyloid polypeptide (hIAPP or amylin) that aggregates in people with type 2 diabetes. FGAIL is catalyzed into amyloid fibers by many types of surfaces. Here, we study the structure of FGAIL upon deposition onto a gold surface covered with a self-assembled monolayer of methyl-4-mercaptobenzoate (MMB) that produces an ester coating. FGAIL deposited on bare gold does not form ordered layers. The measured 2D SFG spectrum is consistent with amyloid fiber formation, exhibiting both the parallel (a+) and perpendicular (a-) symmetry modes associated with amyloid β-sheets. Cross peaks are observed between the ester stretches of the coating and the FGAIL peptides. Simulations are presented for two possible structures of FGAIL amyloid β-sheets that illustrate the sensitivity of the 2D SFG spectra to structure and orientation. These results provide some of the first molecular insights into surface catalyzed amyloid fiber structure.

  11. Adsorption of 1- and 2-butylimidazoles at the copper/air and steel/air interfaces studied by sum frequency generation vibrational spectroscopy.

    Science.gov (United States)

    Casford, Michael T L; Davies, Paul B

    2012-07-24

    The structure of thin films of 1- and 2-butylimidazoles adsorbed on copper and steel surfaces under air was examined using sum frequency generation (SFG) vibrational spectroscopy in the ppp and ssp polarizations. Additionally, the SFG spectra of both isomers were recorded at 55 °C at the liquid imidazole/air interface for reference. Complementary bulk infrared, reflection-absorption infrared spectroscopy (RAIRS), and Raman spectra of both imidazoles were recorded for assignment purposes. The SFG spectra in the C-H stretching region at the liquid/air interface are dominated by resonances from the methyl end group of the butyl side chain of the imidazoles, indicating that they are aligned parallel or closely parallel to the surface normal. These are also the most prominent features in the SFG spectra on copper and steel. In addition, both the ppp and ssp spectra on copper show resonances from the C-H stretching modes of the imidazole ring for both isomers. The ring C-H resonances are completely absent from the spectra on steel and at the liquid/air interface. The relative intensities of the SFG spectra can be interpreted as showing that, on copper, under air, both butylimidazoles are adsorbed with their butyl side chains perpendicular to the interface and with the ring significantly inclined away from the surface plane and toward the surface normal. The SFG spectra of both imidazoles on steel indicate an orientation where the imidazole rings are parallel or nearly parallel to the surface. The weak C-H resonances from the ring at the liquid/air interface suggest that the tilt angle of the ring from the surface normal at this interface is significantly greater than it is on copper.

  12. Sum-frequency generation spectroscopy on metals, oxides, and oxide-supported metal particles; Summenfrequenzerzeugungsspektroskopie an Metallen, Oxiden und oxidgetraegerten Metallpartikeln

    Energy Technology Data Exchange (ETDEWEB)

    Aumer, Andreas

    2010-06-21

    This thesis focuses on 4 different model systems of surface science. The experimental techniques used for the measurements include sum frequency generation (SFG), thermal desorption spectroscopy (TDS), low energy electron diffraction (LEED), Auger electron spectroscopy (AES), infrared adsorption spectrosocopy (IRAS) and scanning tunneling microscopy (STM). By using SFG, measurements could be performed up to a pressure of 50 mbar. The systems under investigation were: CO on Pt(111), water on Ag(001) and on MgO/Ag(001), CO on Au/MgO/Ag(001), and CO on Au-Pd/MgO/Ag(001). The system of CO on Pt(111) exhibits a two peak-pattern under certain pressure and temperature conditions which has not been studied so far. Various experiments helped to elucidate the origin of this distinct behaviour. The measurements of water on Ag(001) and MgO/Ag(001) show that on MgO, water first adsorbs as a monolayer with a following multilayer, whereas on Ag(001) it adsorbs as a multilayer from the beginning. The monolayer can be studied below the multilayer and some resonances can be identified. For the case of Au/MgO/Ag(001), STM shows that the growth mode of Au depends on the thickness of the supporting MgO film, which can not be seen with spectroscopic methods. For mixed Au-Pd particles on MgO/Ag(001) a clear difference in the adsorption behaviour between pure metal particles and mixed particles can be seen, which is explained by an interaction between these metals. Annealing the mixed particles to 600 K leads to a segregation of the metals, where the Au atoms diffuse to the shell and the Pd atoms make up the core. The results of all these measurements are discussed in the light of recent publications. (orig.)

  13. Hydration of Sulphobetaine (SB) and Tetra(ethylene glycol) (EG4)-Terminated Self-Assembled Monolayers Studied by Sum Frequency Generation (SFG) Vibrational Spectroscopy

    Science.gov (United States)

    Stein, M. Jeanette; Weidner, Tobias; McCrea, Keith; Castner, David G.; Ratner, Buddy D.

    2010-01-01

    Sum frequency generation (SFG) vibrational spectroscopy is used to study the surface and the underlying substrate of both homogeneous and mixed self-assembled monolayers (SAMs) of 11-mercaptoundecyl-1-sulphobetainethiol (HS(CH2)11N+(CH3)2(CH2)3SO3−, SB) and 1-mercapto-11-undecyl tetra(ethylene glycol) (HS(CH2)11O(CH2CH2O)4OH, EG4) with an 11-mercapto-1-undecanol (HS(CH2)11OH, MCU) diluent. SFG results on the C–H region of the dry and hydrated SAMs gave an in situ look into the molecular orientation and suggested an approach to maximize signal-to-noise ratio on these difficult to analyze hydrophilic SAMs. Vibrational fingerprint studies in the 3000–3600 cm−1 spectral range for the SAMs exposed serially to air, water, and deuterated water revealed that a layer of tightly-bound structured water was associated with the surface of a non-fouling monolayer but was not present on a hydrophobic N-undecylmercaptan (HS(CH2)10CH3, UnD) control. The percentage of water retained upon submersion in D2O correlated well with the relative amount of protein that was previously shown to absorb onto the monolayers. These results provide evidence supporting the current theory regarding the role of a tightly-bound vicinal water layer in the protein resistance of a non-fouling group. PMID:19639981

  14. Discovery of deep and shallow trap states from step structures of rutile TiO2 vicinal surfaces by second harmonic and sum frequency generation spectroscopy

    International Nuclear Information System (INIS)

    Takahashi, Hiroaki; Watanabe, Ryosuke; Miyauchi, Yoshihiro; Mizutani, Goro

    2011-01-01

    In this report, local electronic structures of steps and terraces on rutile TiO 2 single crystal faces were studied by second harmonic and sum frequency generation (SHG/SFG) spectroscopy. We attained selective measurement of the local electronic states of the step bunches formed on the vicinal (17 18 1) and (15 13 0) surfaces using a recently developed step-selective probing technique. The electronic structures of the flat (110)-(1x1) (the terrace face of the vicinal surfaces) and (011)-(2x1) surfaces were also discussed. The SHG/SFG spectra showed that step structures are mainly responsible for the formation of trap states, since significant resonances from the trap states were observed only from the vicinal surfaces. We detected deep hole trap (DHT) states and shallow electron trap (SET) states selectively from the step bunches on the vicinal surfaces. Detailed analysis of the SHG/SFG spectra showed that the DHT and SET states are more likely to be induced at the top edges of the step bunches than on their hillsides. Unlike the SET states, the DHT states were observed only at the step bunches parallel to [1 1 1][equivalent to the step bunches formed on the (17 18 1) surface]. Photocatalytic activity for each TiO 2 sample was also measured through methylene blue photodegradation reactions and was found to follow the sequence: (110) < (17 18 1) < (15 13 0) < (011), indicating that steps along [0 0 1] are more reactive than steps along [1 1 1]. This result implies that the presence of the DHT states observed from the step bunches parallel to [1 1 1] did not effectively contribute to the methylene blue photodegradation reactions.

  15. Sum Frequency Generation Vibrational Spectroscopy Studies on ModelPeptide Adsorption at the Hydrophobic Solid-Water and HydrophilicSolid-Water Interfaces

    Energy Technology Data Exchange (ETDEWEB)

    York, Roger L. [Univ. of California, Berkeley, CA (United States)

    2007-01-01

    Sum frequency generation (SFG) vibrational spectroscopy has been used to study the interfacial structure of several polypeptides and amino acids adsorbed to hydrophobic and hydrophilic surfaces under a variety of experimental conditions. Peptide sequence, peptide chain length, peptide hydrophobicity, peptide side-chain type, surface hydrophobicity, and solution ionic strength all affect an adsorbed peptide's interfacial structure. Herein, it is demonstrated that with the choice of simple, model peptides and amino acids, surface specific SFG vibrational spectroscopy can be a powerful tool to elucidate the interfacial structure of these adsorbates. Herein, four experiments are described. In one, a series of isosequential amphiphilic peptides are synthesized and studied when adsorbed to both hydrophobic and hydrophilic surfaces. On hydrophobic surfaces of deuterated polystyrene, it was determined that the hydrophobic part of the peptide is ordered at the solid-liquid interface, while the hydrophilic part of the peptide appears to have a random orientation at this interface. On a hydrophilic surface of silica, it was determined that an ordered peptide was only observed if a peptide had stable secondary structure in solution. In another experiment, the interfacial structure of a model amphiphilic peptide was studied as a function of the ionic strength of the solution, a parameter that could change the peptide's secondary structure in solution. It was determined that on a hydrophobic surface, the peptide's interfacial structure was independent of its structure in solution. This was in contrast to the adsorbed structure on a hydrophilic surface, where the peptide's interfacial structure showed a strong dependence on its solution secondary structure. In a third experiment, the SFG spectra of lysine and proline amino acids on both hydrophobic and hydrophilic surfaces were obtained by using a different experimental geometry that increases the SFG signal

  16. Correlation of molecular conformation with adhesion at AlOx/poly (ethylene terephthalate) interface studied by sum-frequency generation spectroscopy

    International Nuclear Information System (INIS)

    Miyamae, Takayuki; Nozoye, Hisakazu

    2004-01-01

    The interface between AlO x and poly(ethylene terephthalate) has been investigated by sum-frequency generation (SFG). A considerable improvement in adhesion strength was achieved by short time Ar plasma modification. The increase of the adhesion strength shows good correlation with the increase of the SFG peak strength. By depositing AlO x , the increase of SFG intensities and appearance of a new peak are observed, indicating the formation of a C=O···Al bond at the interface. Surface-modification and interfacial adhesion property are discussed

  17. Sum-frequency generation echo and grating from interface

    International Nuclear Information System (INIS)

    Volkov, Victor

    2014-01-01

    The work addresses spectroscopy of fourth-order Sum Frequency Generation Echo and Grating responses as an experimental tool to study structure and dynamics at interfaces. First, it addresses experimental geometry to extract background-free fourth-order Echo and Grating responses. Further, the article provides the analytical expressions of the response functions for these nonlinearities. The derived expressions are used to model the χ (4) two-dimensional spectral responses of a hydrated methyl acetate, which resembles a hydrated carbonyl moiety at the polar outer side of a phospholipid membrane. Orientation, transition dipole moments, and Raman tensors are obtained from the results of classical and quantum calculations, respectively. The numerical studies for the nonlinear responses under different polarization schemes and timings suggest the possibility of securely factoring of spectral contributions of χ YYYZX and χ YYYZY macroscopic susceptibilities. As such, the nonlinearities provide an experimental perspective on orientation of a generic (low-symmetry) molecular system at interfaces. Besides, the spectral properties of the tensors may reflect correlations of the in-plane and out-of-plane field components specific to the interface. For the case of a phospholipid membrane, the experiment would address in-plane and out-of-plane anisotropy of hydrogen bonding and related dynamics

  18. Sum-frequency generation echo and grating from interface

    Energy Technology Data Exchange (ETDEWEB)

    Volkov, Victor [Bereozovaya 2A, Konstantinovo, Moscow Region 140207 (Russian Federation)

    2014-10-14

    The work addresses spectroscopy of fourth-order Sum Frequency Generation Echo and Grating responses as an experimental tool to study structure and dynamics at interfaces. First, it addresses experimental geometry to extract background-free fourth-order Echo and Grating responses. Further, the article provides the analytical expressions of the response functions for these nonlinearities. The derived expressions are used to model the χ{sup (4)} two-dimensional spectral responses of a hydrated methyl acetate, which resembles a hydrated carbonyl moiety at the polar outer side of a phospholipid membrane. Orientation, transition dipole moments, and Raman tensors are obtained from the results of classical and quantum calculations, respectively. The numerical studies for the nonlinear responses under different polarization schemes and timings suggest the possibility of securely factoring of spectral contributions of χ{sub YYYZX} and χ{sub YYYZY} macroscopic susceptibilities. As such, the nonlinearities provide an experimental perspective on orientation of a generic (low-symmetry) molecular system at interfaces. Besides, the spectral properties of the tensors may reflect correlations of the in-plane and out-of-plane field components specific to the interface. For the case of a phospholipid membrane, the experiment would address in-plane and out-of-plane anisotropy of hydrogen bonding and related dynamics.

  19. Characterization of the molecular structure and mechanical properties of polymer surfaces and protein/polymer interfaces by sum frequency generation vibrational spectroscopy and atomic force microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Koffas, Telly Stelianos [Univ. of California, Berkeley, CA (United States)

    2004-01-01

    Sum frequency generation (SFG) vibrational spectroscopy, atomic force microscopy (AFM), and other complementary surface-sensitive techniques have been used to study the surface molecular structure and surface mechanical behavior of biologically-relevant polymer systems. SFG and AFM have emerged as powerful analytical tools to deduce structure/property relationships, in situ, for polymers at air, liquid and solid interfaces. The experiments described in this dissertation have been performed to understand how polymer surface properties are linked to polymer bulk composition, substrate hydrophobicity, changes in the ambient environment (e.g., humidity and temperature), or the adsorption of macromolecules. The correlation of spectroscopic and mechanical data by SFG and AFM can become a powerful methodology to study and engineer materials with tailored surface properties. The overarching theme of this research is the interrogation of systems of increasing structural complexity, which allows us to extend conclusions made on simpler model systems. We begin by systematically describing the surface molecular composition and mechanical properties of polymers, copolymers, and blends having simple linear architectures. Subsequent chapters focus on networked hydrogel materials used as soft contact lenses and the adsorption of protein and surfactant at the polymer/liquid interface. The power of SFG is immediately demonstrated in experiments which identify the chemical parameters that influence the molecular composition and ordering of a polymer chain's side groups at the polymer/air and polymer/liquid interfaces. In general, side groups with increasingly greater hydrophobic character will be more surface active in air. Larger side groups impose steric restrictions, thus they will tend to be more randomly ordered than smaller hydrophobic groups. If exposed to a hydrophilic environment, such as water, the polymer chain will attempt to orient more of its hydrophilic groups to

  20. Sum frequency generation for studying plasma-wall interactions

    International Nuclear Information System (INIS)

    Roke, Sylvie

    2010-01-01

    Interaction of a plasma with a surface results in chemical and physical restructuring of the surface as well as the plasma in the vicinity of the surface. Studying such a reorganization of the atoms and molecules in the surface layer requires optical tools that can penetrate the plasma environment. At the same time, surface specificity is required. Sum Frequency Generation (SFG) is an optical method that fulfills these requirements. SFG has been developed into a surface specific probe during the eighties and nineties. Nowadays SFG is routinely applied in the research of complex interfaces. In such experiments, liquid/gas, solid/gas, solid/liquid, or liquid/liquid interfaces are probed, and the chemical surface composition, orientational distribution, order and chirality can be retrieved. An application to investigate plasma-wall interactions is feasible too.

  1. Vibrational sum frequency generation (SFG) spectroscopic study of crystalline cellulose in biomass

    Science.gov (United States)

    Kim, Seong H.; Lee, Christopher M.; Kafle, Kabindra; Park, Yong Bum; Xi, Xiaoning

    2013-09-01

    The noncentrosymmetry requirement of sum frequency generation (SFG) spectroscopy allows selective detection of crystalline cellulose in plant cell walls and lignocellulose biomass without spectral interferences from hemicelluloses and lignin. In addition, the phase synchronization requirement of the SFG process allows noninvasive investigation of spatial arrangement of crystalline cellulose microfibrils in the sample. This paper reviews how these principles are applied to reveal structural information of crystalline cellulose in plant cell walls and biomass.

  2. Efficient yellow beam generation by intracavity sum frequency ...

    Indian Academy of Sciences (India)

    2014-02-06

    Feb 6, 2014 ... petition leading to instability in the output sum frequency power and ... Nd:YVO4 crystal has been identified as one of the promising laser materials for diode ... very important to achieve small laser mode size as well as proper ...

  3. The structure of oleamide films at the aluminum/oil interface and aluminum/air interface studied by Sum Frequency Generation (SFG) vibrational spectroscopy and Reflection Absorption Infrared Spectroscopy (RAIRS).

    Science.gov (United States)

    Casford, Michael T L; Davies, Paul B

    2009-08-01

    The structure of oleamide (cis-9-octadecenamide) films on aluminum has been investigated by sum frequency generation vibrational spectroscopy (SFG) and reflection absorption infrared spectroscopy (RAIRS). Three different film deposition strategies were investigated: (i) films formed by equilibrium adsorption from oleamide solutions in oil, (ii) Langmuir-Blodgett films cast at 1 and 25 mN m(-1), (iii) thick spin-cast films. Both L-B and spin-cast films were examined in air and under oil. The adsorbate formed in the 1 mN m(-1) film in air showed little orientational order. For this film, the spectroscopic results and the ellipsometric thickness point to a relatively conformationally disordered monolayer that is oriented principally in the plane of the interface. Direct adsorption to the metal interface from oil results in SFG spectra of oleamide that are comparable to those observed for the 1 mN m(-1) L-B film in air. In contrast, SFG and RAIRS results for the 25 mN m(-1) film in air and SFG spectra of the spin-cast film in air both show strong conformational ordering and orientational alignment normal to the interface. The 25 mN m(-1) film has an ellipsometric thickness almost twice that of the 1 mN m(-1) L-B film. Taken in combination with the spectroscopic results, this is indicative of a well packed monolayer in air in which the hydrocarbon chain is in an essentially defect-free extended conformation with the methyl terminus oriented away from the surface. A similar structure is also deduced for the surface of the spin-cast film in air. Upon immersion of the 25 mN m(-1) L-B film in oil the SFG spectra show that this film rapidly adopts a relatively disordered structure similar to that seen for the 1 mN m(-1) L-B film in air. Immersion of the spin-cast film in oil results in the gradual disordering of the amide film over a period of several days until the observed spectra become essentially identical to those observed for direct adsorption of oleamide from oil.

  4. Combined IR-Raman vs vibrational sum-frequency heterospectral correlation spectroscopy

    Science.gov (United States)

    Roy, Sandra; Beutier, Clémentine; Hore, Dennis K.

    2018-06-01

    Vibrational sum-frequency generation spectroscopy is a valuable probe of surface structure, particularly when the same molecules are present in one of the adjacent bulk solid or solution phases. As a result of the non-centrosymmetric requirement of SFG, the signal generated is a marker of the extent to which the molecules are ordered in an arrangement that breaks the up-down symmetry at the surface. In cases where the accompanying changes in the bulk are of interest in understanding and interpreting the surface structure, simultaneous analysis of the bulk IR absorption or bulk Raman scattering is helpful, and may be used in heterospectral surface-bulk two-dimensional correlation. We demonstrate that, in such cases, generating a new type of bulk spectrum that combines the IR and Raman amplitudes is a better candidate than the individual IR and Raman spectra for the purpose of correlation with the SFG signal.

  5. Sum Frequency Generation Vibrational Spectroscopy of 1,3-Butadiene Hydrogenation on 4 nm Pt@SiO 2 , Pd@SiO 2 , and Rh@SiO 2 Core–Shell Catalysts

    KAUST Repository

    Krier, James M.

    2015-01-14

    © 2014 American Chemical Society. 1,3-Butadiene (1,3-BD) hydrogenation was performed on 4 nm Pt, Pd, and Rh nanoparticles (NPs) encapsulated in SiO2 shells at 20, 60, and 100 °C. The core-shells were grown around polyvinylpyrrolidone (PVP) coated NPs (Stöber encapsulation) prepared by colloidal synthesis. Sum frequency generation (SFG) vibrational spectroscopy was performed to correlate surface intermediates observed in situ with reaction selectivity. It is shown that calcination is effective in removing PVP, and the SFG signal can be generated from the metal surface. Using SFG, it is possible to compare the surface vibrational spectrum of Pt@SiO2 (1,3-BD is hydrogenated through multiple paths and produces butane, 1-butene, and cis/trans-2-butene) to Pd@SiO2 (1,3-BD favors one path and produces 1-butene and cis/trans-2-butene). In contrast to Pt@SiO2 and Pd@SiO2, SFG and kinetic experiments of Rh@SiO2 show a permanent accumulation of organic material.

  6. Implementation of bright six-partite entanglement by coupled intracavity sum frequency generation

    Science.gov (United States)

    Wang, Junfeng; Liu, Le; Liu, Yuzhu; Zhang, Yanan; Wu, Hongyan; Gong, Chengxuan; Zhang, Ruofan; Zhang, Houyuan; Fan, JingYu

    2018-04-01

    Bright six-partite continuous-variable (CV) entanglement generated by the coupled intracavity sum frequency generation is investigated. The entanglement characteristics of reflected pump fields and the output sum frequency fields are discussed theoretically in symmetric and asymmetric cases by applying van Loock and Furusawa criteria for multipartite CV entanglement. Such compact tunable multipartite CV entanglement, generated from an experimentally feasible coupled system, could be used in integrated quantum communication and networks.

  7. In Situ Adsorption Studies at the Solid/Liquid Interface: Characterization of Biological Surfaces and Interfaces Using Sum Frequency Generation Vibrational Spectroscopy, Atomic Force Microscopy, and Quartz Crystal Microbalance

    International Nuclear Information System (INIS)

    Phillips, D.C.

    2006-01-01

    Sum frequency generation (SFG) vibrational spectroscopy, atomic force microscopy (AFM), and quartz crystal microbalance (QCM) have been used to study the molecular surface structure, surface topography and mechanical properties, and quantitative adsorbed amount of biological molecules at the solid-liquid interface. The molecular-level behavior of designed peptides adsorbed on hydrophobic polystyrene and hydrophilic silica substrates has been examined as a model of protein adsorption on polymeric biomaterial surfaces. Proteins are such large and complex molecules that it is difficult to identify the features in their structure that lead to adsorption and interaction with solid surfaces. Designed peptides which possess secondary structure provide simple model systems for understanding protein adsorption. Depending on the amino acid sequence of a peptide, different secondary structures (α-helix and β-sheet) can be induced at apolar (air/liquid or air/solid) interfaces. Having a well-defined secondary structure allows experiments to be carried out under controlled conditions, where it is possible to investigate the affects of peptide amino acid sequence and chain length, concentration, buffering effects, etc. on adsorbed peptide structure. The experiments presented in this dissertation demonstrate that SFG vibrational spectroscopy can be used to directly probe the interaction of adsorbing biomolecules with a surface or interface. The use of well designed model systems aided in isolation of the SFG signal of the adsorbing species, and showed that surface functional groups of the substrate are sensitive to surface adsorbates. The complementary techniques of AFM and QCM allowed for deconvolution of the effects of surface topography and coverage from the observed SFG spectra. Initial studies of biologically relevant surfaces are also presented: SFG spectroscopy was used to study the surface composition of common soil bacteria for use in bioremediation of nuclear waste

  8. In Situ Adsorption Studies at the Solid/Liquid Interface:Characterization of Biological Surfaces and Interfaces Using SumFrequency Generation Vibrational Spectroscopy, Atomic Force Microscopy,and Quartz Crystal Microbalance

    Energy Technology Data Exchange (ETDEWEB)

    Phillips, Diana Christine [Univ. of California, Berkeley, CA (United States)

    2006-01-01

    Sum frequency generation (SFG) vibrational spectroscopy, atomic force microscopy (AFM), and quartz crystal microbalance (QCM) have been used to study the molecular surface structure, surface topography and mechanical properties, and quantitative adsorbed amount of biological molecules at the solid-liquid interface. The molecular-level behavior of designed peptides adsorbed on hydrophobic polystyrene and hydrophilic silica substrates has been examined as a model of protein adsorption on polymeric biomaterial surfaces. Proteins are such large and complex molecules that it is difficult to identify the features in their structure that lead to adsorption and interaction with solid surfaces. Designed peptides which possess secondary structure provide simple model systems for understanding protein adsorption. Depending on the amino acid sequence of a peptide, different secondary structures (α-helix and β-sheet) can be induced at apolar (air/liquid or air/solid) interfaces. Having a well-defined secondary structure allows experiments to be carried out under controlled conditions, where it is possible to investigate the affects of peptide amino acid sequence and chain length, concentration, buffering effects, etc. on adsorbed peptide structure. The experiments presented in this dissertation demonstrate that SFG vibrational spectroscopy can be used to directly probe the interaction of adsorbing biomolecules with a surface or interface. The use of well designed model systems aided in isolation of the SFG signal of the adsorbing species, and showed that surface functional groups of the substrate are sensitive to surface adsorbates. The complementary techniques of AFM and QCM allowed for deconvolution of the effects of surface topography and coverage from the observed SFG spectra. Initial studies of biologically relevant surfaces are also presented: SFG spectroscopy was used to study the surface composition of common soil bacteria for use in bioremediation of nuclear waste.

  9. Toward a simple molecular understanding of sum frequency generation at air-water interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Noah-Vanhoucke, Joyce; Smith, Jared D.; Geissler, Phillip L.

    2009-01-13

    Second-order vibrational spectroscopies successfully isolate signals from interfaces, but they report on intermolecular structure in a complicated and indirect way. Here we adapt a perspective on vibrational response developed for bulk spectroscopies to explore the microscopic fluctuations to which sum frequency generation (SFG), a popular surface-specific measurement, is most sensitive. We focus exclusively on inhomogeneous broadening of spectral susceptibilities for OH stretching of HOD as a dilute solute in D{sub 2}O. Exploiting a simple connection between vibrational frequency shifts and an electric field variable, we identify several functions of molecular orientation whose averages govern SFG. The frequency-dependence of these quantities is well captured by a pair of averages, involving alignment of OH and OD bonds with the surface normal at corresponding values of the electric field. The approximate form we obtain for SFG susceptibility highlights a dramatic sensitivity to the way a simulated liquid slab is partitioned for calculating second-order response.

  10. Broader energy distribution of CO adsorbed at polycrystalline Pt electrode in comparison with that at Pt(111) electrode in H_2SO_4 solution confirmed by potential dependent IR/visible double resonance sum frequency generation spectroscopy

    International Nuclear Information System (INIS)

    Yang, Shuo; Noguchi, Hidenori; Uosaki, Kohei

    2017-01-01

    Highlights: • Electrochemical SFG spectroscopy is an efficient in situ probe of electronic structure at electrochemical interface. • Electrooxidation performances of CO adsorbed on polycrystalline Pt and Pt(111) electrodes were compared. • The enhanced SFG signal of CO on Pt electrodes was observed due to a vibrational-electronic double resonance effect. • The broader energy distribution of 5sa state of CO on polycrystalline Pt than on Pt(111) is proved by SFG results. - Abstract: Electrochemical cyclic voltammetry and potential dependent double resonance sum frequency generation (DR-SFG) spectroscopy were performed on CO adsorbed on polycrystalline Pt and Pt(111) electrodes in H_2SO_4 solution to examine the effect of substrate on the electronic structure of CO. The dependence of SFG intensity on potential and visible energy for atop CO band was observed on both polycrystalline and single crystalline Pt electrodes. Enhancement of the SFG intensity was determined to be a direct result of a surface electronic resonance of the visible/SF light with the electronic transition from Fermi level of Pt to the 5σ_a anti-bonding state of adsorbed CO, in agreement with previous results. Interestingly, when compared to the Pt(111) electrode, the distribution width of the intensity enhancement region on polycrystalline Pt is broader than on Pt(111). This suggests that the energy distribution of the 5σ_a state of CO on polycrystalline Pt surface is broader than that on Pt(111) due to the complex surface structure of the polycrystalline Pt electrode.

  11. Sum-frequency nonlinear Cherenkov radiation generated on the boundary of bulk medium crystal.

    Science.gov (United States)

    Wang, Xiaojing; Cao, Jianjun; Zhao, Xiaohui; Zheng, Yuanlin; Ren, Huaijin; Deng, Xuewei; Chen, Xianfeng

    2015-12-14

    We demonstrated experimentally a method to generate the sum-frequency Nonlinear Cherenkov radiation (NCR) on the boundary of bulk medium by using two synchronized laser beam with wavelength of 1300 nm and 800 nm. It is also an evidence that the polarization wave is always confined to the boundary. Critical conditions of surface sum-frequency NCR under normal and anomalous dispersion condition is discussed.

  12. Highly efficient deep ultraviolet generation by sum-frequency mixing ...

    Indian Academy of Sciences (India)

    Ultraviolet laser radiation; walk-off compensation; third harmonic generation; nonlinear optical material. ... Because of its large birefringence, BBO crystal permits the generation of UV radiation near 200 nm by THG ... A, B and C are three different configurations for THG, A – Single crystal, B – two crystals (B2 and B3 in.

  13. Capturing inhomogeneous broadening of the -CN stretch vibration in a Langmuir monolayer with high-resolution spectra and ultrafast vibrational dynamics in sum-frequency generation vibrational spectroscopy (SFG-VS)

    Science.gov (United States)

    Velarde, Luis; Wang, Hong-fei

    2013-08-01

    While in principle the frequency-domain and time-domain spectroscopic measurements should generate identical information for a given molecular system, the inhomogeneous character of surface vibrations in sum-frequency generation vibrational spectroscopy (SFG-VS) studies has only been studied with time-domain SFG-VS by mapping the decay of the vibrational polarization using ultrafast lasers, this due to the lack of SFG vibrational spectra with high enough spectral resolution and accurate enough lineshape. Here, with the recently developed high-resolution broadband SFG-VS (HR-BB-SFG-VS) technique, we show that the inhomogeneous lineshape can be obtained in the frequency-domain for the anchoring CN stretch of the 4-n-octyl-4'-cyanobiphenyl (8CB) Langmuir monolayer at the air-water interface, and that an excellent agreement with the time-domain SFG free-induction-decay can be established. We found that the 8CB CN stretch spectrum consists of a single peak centered at 2234.00 ± 0.01 cm-1 with a total linewidth of 10.9 ± 0.3 cm-1 at half maximum. The Lorentzian contribution accounts only for 4.7 ± 0.4 cm-1 to this width and the Gaussian (inhomogeneous) broadening for as much as 8.1 ± 0.2 cm-1. Polarization analysis of the -CN spectra showed that the -CN group is tilted 57° ± 2° from the surface normal. The large heterogeneity in the -CN spectrum is tentatively attributed to the -CN group interactions with the interfacial water molecules penetrated/accommodated into the 8CB monolayer, a unique phenomenon for the nCB Langmuir monolayers reported previously.

  14. Singly-resonant sum frequency generation of visible light in a semiconductor disk laser

    DEFF Research Database (Denmark)

    Andersen, Martin Thalbitzer; Schlosser, P.J.; Hastie, J.E.

    2009-01-01

    In this paper a generic approach for visible light generation is presented. It is based on sum frequency generation between a semiconductor disk laser and a solid-state laser, where the frequency mixing is achieved within the cavity of the semiconductor disk laser using a singlepass of the solid......-state laser light. This exploits the good beam quality and high intra-cavity power present in the semiconductor disk laser to achieve high conversion efficiency. Combining sum frequency mixing and semiconductor disk lasers in this manner allows in principle for generation of any wavelength within the visible...

  15. In-situ Studies of the Reactions of Bifunctional and Heterocyclic Molecules over Noble Metal Single Crystal and Nanoparticle Catalysts Studied with Kinetics and Sum-Frequency Generation Vibrational Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Kliewer, Christopher J. [Univ. of California, Berkeley, CA (United States)

    2009-06-30

    Sum frequency generation surface vibrational spectroscopy (SFG-VS) in combination with gas chromatography (GC) was used in-situ to monitor surface bound reaction intermediates and reaction selectivities for the hydrogenation reactions of pyrrole, furan, pyridine, acrolein, crotonaldehyde, and prenal over Pt(111), Pt(100), Rh(111), and platinum nanoparticles under Torr reactant pressures and temperatures of 300K to 450K. The focus of this work is the correlation between the SFG-VS observed surface bound reaction intermediates and adsorption modes with the reaction selectivity, and how this is affected by catalyst structure and temperature. Pyrrole hydrogenation was investigated over Pt(111) and Rh(111) single crystals at Torr pressures. It was found that pyrrole adsorbs to Pt(111) perpendicularly by cleaving the N-H bond and binding through the nitrogen. However, over Rh(111) pyrrole adsorbs in a tilted geometry binding through the {pi}-aromatic orbitals. A surface-bound pyrroline reaction intermediate was detected over both surfaces with SFG-VS. It was found that the ring-cracking product butylamine is a reaction poison over both surfaces studied. Furan hydrogenation was studied over Pt(111), Pt(100), 10 nm cubic platinum nanoparticles and 1 nm platinum nanoparticles. The product distribution was observed to be highly structure sensitive and the acquired SFG-VS spectra reflected this sensitivity. Pt(100) exhibited more ring-cracking to form butanol than Pt(111), while the nanoparticles yielded higher selectivities for the partially saturated ring dihydrofuran. Pyridine hydrogenation was investigated over Pt(111) and Pt(100). The α-pyridyl surface adsorption mode was observed with SFG-VS over both surfaces. 1,4-dihydropyridine was seen as a surface intermediate over Pt(100) but not Pt(111). Upon heating the surfaces to 350K, the adsorbed pyridine changes to a flat-lying adsorption mode. No evidence was found for the pyridinium cation. The hydrogenation of the

  16. Sum frequency and second harmonic generation from the surface of a liquid microjet

    Energy Technology Data Exchange (ETDEWEB)

    Smolentsev, Nikolay; Chen, Yixing; Roke, Sylvie, E-mail: sylvie.roke@epfl.ch [Laboratory for Fundamental Biophotonics (LBP), Institute of Bioengineering (IBI), School of Engineering STI, École Polytechnique Fédérale de Lausanne EPFL, 1015 Lausanne (Switzerland); Jena, Kailash C. [Laboratory for Fundamental Biophotonics (LBP), Institute of Bioengineering (IBI), School of Engineering STI, École Polytechnique Fédérale de Lausanne EPFL, 1015 Lausanne (Switzerland); Department of Physics, Indian Institute of Technology Ropar, Rupnagar, 140001 (India); Brown, Matthew A. [Laboratory for Surface Science and Technology, Department of Materials, ETH Zürich, CH-8093 Zurich (Switzerland)

    2014-11-14

    The use of a liquid microjet as a possible source of interest for Second Harmonic Generation (SHG) and Sum Frequency Generation (SFG) spectroscopy is examined. We measured non-resonant SHG scattering patterns from the air/water interface of a microjet of pure water and observe a strong enhancement of the SHG signal for certain scattering angles. These enhancements can be explained by the optical properties and the shape of the liquid microjet. SFG experiments at the surface of a liquid microjet of ethanol in air show that it is also possible to measure the coherent vibrational SFG spectrum of the ethanol/air interface in this way. Our findings are useful for future far-UV or X-ray based nonlinear optical surface experiments on liquid jets. In addition, combined X-ray photoelectron spectroscopy and SHG/SFG measurements are feasible, which will be very useful in improving our understanding of the molecular foundations of electrostatic and chemical surface properties and phenomena.

  17. Sum frequency and second harmonic generation from the surface of a liquid microjet

    Science.gov (United States)

    Smolentsev, Nikolay; Chen, Yixing; Jena, Kailash C.; Brown, Matthew A.; Roke, Sylvie

    2014-11-01

    The use of a liquid microjet as a possible source of interest for Second Harmonic Generation (SHG) and Sum Frequency Generation (SFG) spectroscopy is examined. We measured non-resonant SHG scattering patterns from the air/water interface of a microjet of pure water and observe a strong enhancement of the SHG signal for certain scattering angles. These enhancements can be explained by the optical properties and the shape of the liquid microjet. SFG experiments at the surface of a liquid microjet of ethanol in air show that it is also possible to measure the coherent vibrational SFG spectrum of the ethanol/air interface in this way. Our findings are useful for future far-UV or X-ray based nonlinear optical surface experiments on liquid jets. In addition, combined X-ray photoelectron spectroscopy and SHG/SFG measurements are feasible, which will be very useful in improving our understanding of the molecular foundations of electrostatic and chemical surface properties and phenomena.

  18. Sum frequency and second harmonic generation from the surface of a liquid microjet

    International Nuclear Information System (INIS)

    Smolentsev, Nikolay; Chen, Yixing; Roke, Sylvie; Jena, Kailash C.; Brown, Matthew A.

    2014-01-01

    The use of a liquid microjet as a possible source of interest for Second Harmonic Generation (SHG) and Sum Frequency Generation (SFG) spectroscopy is examined. We measured non-resonant SHG scattering patterns from the air/water interface of a microjet of pure water and observe a strong enhancement of the SHG signal for certain scattering angles. These enhancements can be explained by the optical properties and the shape of the liquid microjet. SFG experiments at the surface of a liquid microjet of ethanol in air show that it is also possible to measure the coherent vibrational SFG spectrum of the ethanol/air interface in this way. Our findings are useful for future far-UV or X-ray based nonlinear optical surface experiments on liquid jets. In addition, combined X-ray photoelectron spectroscopy and SHG/SFG measurements are feasible, which will be very useful in improving our understanding of the molecular foundations of electrostatic and chemical surface properties and phenomena

  19. Studies of Interfacial Regions by Sum-Frequency Generation with a Free-Electron Laser

    NARCIS (Netherlands)

    Eliel, E. R.; van der Ham, E. W. M.; Vrehen, Q. H. F.; Thooft, G. W.; Barmentlo, M.; Auerhammer, J. M.; van der Meer, A. F. G.; van Amersfoort, P. W.

    1995-01-01

    The use of a Free-Electron Laser (FEL) allows the study of (non)linear optical properties of materials over unsurpassed large spectral intervals. As an example, we report on the use of a FEL as the infrared source in spectroscopic infrared-visible Sum-Frequency Generation (SFG). Employing the

  20. Elucidation of Compression-Induced Surface Crystallization in Amorphous Tablets Using Sum Frequency Generation (SFG) Microscopy.

    Science.gov (United States)

    Mah, Pei T; Novakovic, Dunja; Saarinen, Jukka; Van Landeghem, Stijn; Peltonen, Leena; Laaksonen, Timo; Isomäki, Antti; Strachan, Clare J

    2017-05-01

    To investigate the effect of compression on the crystallization behavior in amorphous tablets using sum frequency generation (SFG) microscopy imaging and more established analytical methods. Tablets containing neat amorphous griseofulvin with/without excipients (silica, hydroxypropyl methylcellulose acetate succinate (HPMCAS), microcrystalline cellulose (MCC) and polyethylene glycol (PEG)) were prepared. They were analyzed upon preparation and storage using attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy, scanning electron microscopy (SEM) and SFG microscopy. Compression-induced crystallization occurred predominantly on the surface of the neat amorphous griseofulvin tablets, with minimal crystallinity being detected in the core of the tablets. The presence of various types of excipients was not able to mitigate the compression-induced surface crystallization of the amorphous griseofulvin tablets. However, the excipients affected the crystallization rate of amorphous griseofulvin in the core of the tablet upon compression and storage. SFG microscopy can be used in combination with ATR-FTIR spectroscopy and SEM to understand the crystallization behaviour of amorphous tablets upon compression and storage. When selecting excipients for amorphous formulations, it is important to consider the effect of the excipients on the physical stability of the amorphous formulations.

  1. Highly efficient single-pass sum frequency generation by cascaded nonlinear crystals

    DEFF Research Database (Denmark)

    Hansen, Anders Kragh; Andersen, Peter E.; Jensen, Ole Bjarlin

    2015-01-01

    , despite differences in the phase relations of the involved fields. An unprecedented 5.5 W of continuous-wave diffraction-limited green light is generated from the single-pass sum frequency mixing of two diode lasers in two periodically poled nonlinear crystals (conversion efficiency 50%). The technique......The cascading of nonlinear crystals has been established as a simple method to greatly increase the conversion efficiency of single-pass second-harmonic generation compared to a single-crystal scheme. Here, we show for the first time that the technique can be extended to sum frequency generation...... is generally applicable and can be applied to any combination of fundamental wavelengths and nonlinear crystals....

  2. Small Molecules and Sum Frequency Generation Probes of Nanoparticulate TiO2

    Science.gov (United States)

    Shultz, Mary Jane

    2006-03-01

    Anatase TiO2 is known to photo catalytically mineralize a wide variety of pollutants and pathogens, both airborne and in aqueous solution. One of the major benefits of basing water treatment systems on TiO2 is that it is environmentally benign and so non toxic that it is used as a colorant in creamy salad dressing. The primary impediment to wide spread implementation of a TiO2 based system for water decontamination is that the quantum efficiency in contact with condense phase water is less than 5%. Since the quantum efficiency for destruction of airborne materials is greater than 80%, the potential for increased efficiency is very real. To convert the potential to practice, the oxidation mechanism needs to be more fully understood. We will report on the results of using a nonlinear optical spectroscopy, sum frequency generation (SFG) as an in situ probe of interactions at the TiO2 surface. Results suggest that the dominant oxidation mechanism converts from a direct to an indirect mechanism as the water content (vapor pressure) increases. This presentation will discuss the probe technique as well as the results.

  3. Orientations of nonlocal vibrational modes from combined experimental and theoretical sum frequency spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Chase, Hilary M.; Chen, Shunli; Fu, Li; Upshur, Mary Alice; Rudshteyn, Benjamin; Thomson, Regan J.; Wang, Hong-Fei; Batista, Victor S.; Geiger, Franz M.

    2017-09-01

    Inferring molecular orientations from vibrational sum frequency generation (SFG) spectra is challenging in polarization combinations that result in low signal intensities, or when the local point group symmetry approximation fails. While combining experiments with density functional theory (DFT) could overcome this problem, the scope of the combined method has yet to be established. Here, we assess its feasibility of determining the distributions of molecular orientations for one monobasic ester, two epoxides and three alcohols at the vapor/fused silica interface. We find that molecular orientations of nonlocal vibrational modes cannot be determined using polarization-resolved SFG measurements alone.

  4. Sum frequency generation image reconstruction: Aliphatic membrane under spherical cap geometry

    Energy Technology Data Exchange (ETDEWEB)

    Volkov, Victor [Bereozovaya 2A, Konstantinovo, Moscow Region 140207 (Russian Federation)

    2014-10-07

    The article explores an opportunity to approach structural properties of phospholipid membranes using Sum Frequency Generation microscopy. To establish the principles of sum frequency generation image reconstruction in such systems, at first approach, we may adopt an idealistic spherical cap uniform assembly of hydrocarbon molecules. Quantum mechanical studies for decanoic acid (used here as a representative molecular system) provide necessary information on transition dipole moments and Raman tensors of the normal modes specific to methyl terminal – a typical moiety in aliphatic (and phospholipid) membranes. Relative degree of localization and frequencies of the normal modes of methyl terminals make nonlinearities of this moiety to be promising in structural analysis using Sum Frequency Generation imaging. Accordingly, the article describes derivations of relevant macroscopic nonlinearities and suggests a mapping procedure to translate amplitudes of the nonlinearities onto microscopy image plane according to geometry of spherical assembly, local molecular orientation, and optical geometry. Reconstructed images indicate a possibility to extract local curvature of bilayer envelopes of spherical character. This may have practical implications for structural extractions in membrane systems of practical relevance.

  5. Theoretical study of sum-frequency vibrational spectroscopy on limonene surface

    International Nuclear Information System (INIS)

    Zheng, Ren-Hui; Liu, Hao; Jing, Yuan-Yuan; Wang, Bo-Yang; Shi, Qiang; Wei, Wen-Mei

    2014-01-01

    By combining molecule dynamics (MD) simulation and quantum chemistry computation, we calculate the surface sum-frequency vibrational spectroscopy (SFVS) of R-limonene molecules at the gas-liquid interface for SSP, PPP, and SPS polarization combinations. The distributions of the Euler angles are obtained using MD simulation, the ψ-distribution is between isotropic and Gaussian. Instead of the MD distributions, different analytical distributions such as the δ-function, Gaussian and isotropic distributions are applied to simulate surface SFVS. We find that different distributions significantly affect the absolute SFVS intensity and also influence on relative SFVS intensity, and the δ-function distribution should be used with caution when the orientation distribution is broad. Furthermore, the reason that the SPS signal is weak in reflected arrangement is discussed

  6. Theoretical study of sum-frequency vibrational spectroscopy on limonene surface

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Ren-Hui, E-mail: zrh@iccas.ac.cn; Liu, Hao; Jing, Yuan-Yuan; Wang, Bo-Yang; Shi, Qiang [Beijing National Laboratory for Molecular Sciences, State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Institute of Chemistry, Chinese Academy of Sciences, Zhongguancun, Beijing 100190 (China); Wei, Wen-Mei [Department of Chemistry, College of Basic Medicine, Anhui Medical University, Hefei, Anhui 230032 (China)

    2014-03-14

    By combining molecule dynamics (MD) simulation and quantum chemistry computation, we calculate the surface sum-frequency vibrational spectroscopy (SFVS) of R-limonene molecules at the gas-liquid interface for SSP, PPP, and SPS polarization combinations. The distributions of the Euler angles are obtained using MD simulation, the ψ-distribution is between isotropic and Gaussian. Instead of the MD distributions, different analytical distributions such as the δ-function, Gaussian and isotropic distributions are applied to simulate surface SFVS. We find that different distributions significantly affect the absolute SFVS intensity and also influence on relative SFVS intensity, and the δ-function distribution should be used with caution when the orientation distribution is broad. Furthermore, the reason that the SPS signal is weak in reflected arrangement is discussed.

  7. Combining total internal reflection sum frequency spectroscopy spectral imaging and confocal fluorescence microscopy.

    Science.gov (United States)

    Allgeyer, Edward S; Sterling, Sarah M; Gunewardene, Mudalige S; Hess, Samuel T; Neivandt, David J; Mason, Michael D

    2015-01-27

    Understanding surface and interfacial lateral organization in material and biological systems is critical in nearly every field of science. The continued development of tools and techniques viable for elucidation of interfacial and surface information is therefore necessary to address new questions and further current investigations. Sum frequency spectroscopy (SFS) is a label-free, nonlinear optical technique with inherent surface specificity that can yield critical organizational information on interfacial species. Unfortunately, SFS provides no spatial information on a surface; small scale heterogeneities that may exist are averaged over the large areas typically probed. Over the past decade, this has begun to be addressed with the advent of SFS microscopy. Here we detail the construction and function of a total internal reflection (TIR) SFS spectral and confocal fluorescence imaging microscope directly amenable to surface investigations. This instrument combines, for the first time, sample scanning TIR-SFS imaging with confocal fluorescence microscopy.

  8. Photon wave function formalism for analysis of Mach–Zehnder interferometer and sum-frequency generation

    Energy Technology Data Exchange (ETDEWEB)

    Ritboon, Atirach, E-mail: atirach.3.14@gmail.com [School of Physics and Astronomy, University of Glasgow, Glasgow, G12 8QQ (United Kingdom); Department of Physics, Faculty of Science, Prince of Songkla University, Hat Yai 90112 (Thailand); Daengngam, Chalongrat, E-mail: chalongrat.d@psu.ac.th [Department of Physics, Faculty of Science, Prince of Songkla University, Hat Yai 90112 (Thailand); Pengpan, Teparksorn, E-mail: teparksorn.p@psu.ac.th [Department of Physics, Faculty of Science, Prince of Songkla University, Hat Yai 90112 (Thailand)

    2016-08-15

    Biakynicki-Birula introduced a photon wave function similar to the matter wave function that satisfies the Schrödinger equation. Its second quantization form can be applied to investigate nonlinear optics at nearly full quantum level. In this paper, we applied the photon wave function formalism to analyze both linear optical processes in the well-known Mach–Zehnder interferometer and nonlinear optical processes for sum-frequency generation in dispersive and lossless medium. Results by photon wave function formalism agree with the well-established Maxwell treatments and existing experimental verifications.

  9. Photon wave function formalism for analysis of Mach–Zehnder interferometer and sum-frequency generation

    International Nuclear Information System (INIS)

    Ritboon, Atirach; Daengngam, Chalongrat; Pengpan, Teparksorn

    2016-01-01

    Biakynicki-Birula introduced a photon wave function similar to the matter wave function that satisfies the Schrödinger equation. Its second quantization form can be applied to investigate nonlinear optics at nearly full quantum level. In this paper, we applied the photon wave function formalism to analyze both linear optical processes in the well-known Mach–Zehnder interferometer and nonlinear optical processes for sum-frequency generation in dispersive and lossless medium. Results by photon wave function formalism agree with the well-established Maxwell treatments and existing experimental verifications.

  10. Efficient generation of 509 nm light by sum-frequency mixing between two tapered diode lasers

    DEFF Research Database (Denmark)

    Tawfieq, Mahmoud; Jensen, Ole Bjarlin; Hansen, Anders Kragh

    2015-01-01

    We demonstrate a concept for visible laser sources based on sum-frequency generation of beam com- bined tapered diode lasers. In this specific case, a 1.7 W sum-frequency generated green laser at 509 nm is obtained, by frequency adding of 6.17 W from a 978 nm tapered diode laser with 8.06 W from...... a 1063 nm tapered diode laser, inside a periodically poled MgO doped lithium niobate crystal. This corresponds to an optical to optical conversion ef fi ciency of 12.1%. As an example of potential applica- tions, the generated nearly diffraction-limited green light is used for pumping a Ti:sapphire laser......, thus demonstrating good beam quality and power stability. The maximum output powers achieved when pumping the Ti:sapphire laser are 226 mW (CW) and 185 mW (mode-locked) at 1.7 W green pump power. The optical spectrum emitted by the mode-locked Ti:sapphire laser shows a spectral width of about 54 nm...

  11. Conformation, orientation and interaction in molecular monolayers: A surface second harmonic and sum frequency generation study

    International Nuclear Information System (INIS)

    Superfine, R.; Huang, J.Y.; Shen, Y.R.

    1988-12-01

    We have used sum frequency generation (SFG) to study the order in a silane monolayer before and after the deposition of a coadsorbed liquid crystal monolayer. We observe an increase in the order of the chain of the silane molecule induced by the interpenetration of the liquid crystal molecules. By using second harmonic generation (SHG) and SFG, we have studied the orientation and conformation of the liquid crystal molecule on clean and silane coated glass surfaces. On both surfaces, the biphenyl group is tilted by 70 degree with the alkyl chain end pointing away from the surface. The shift in the C-H stretch frequencies in the coadsorbed system indicates a significant interaction between molecules. 9 refs., 3 figs

  12. Optical sum-frequency generation in a whispering-gallery-mode resonator

    International Nuclear Information System (INIS)

    Strekalov, Dmitry V; Kowligy, Abijith S; Huang, Yu-Ping; Kumar, Prem

    2014-01-01

    We demonstrate sum-frequency generation between a telecom wavelength and the Rb D2 line, achieved through natural phase matching in a nonlinear whispering gallery mode resonator. Due to the strong optical field confinement and ultra high Q of the cavity, the process saturates already at sub-mW pump peak power, at least two orders of magnitude lower than in existing waveguide-based devices. The experimental data are in agreement with the nonlinear dynamics and phase matching theory based on spherical geometry. Our experimental and theoretical results point toward a new platform for manipulating the color and quantum states of light waves for applications such as atomic memory based quantum networking and logic operations with optical signals. (paper)

  13. Sum frequency generation of CO on (III) and polycrystalline platinum electrode surfaces: Evidence for SFG invisible surface CO

    Energy Technology Data Exchange (ETDEWEB)

    Baldelli, S.; Markovic, N.; Ross, P.; Shen, Y.R.; Somorjai, G.

    1999-10-21

    The vibrational spectroscopy sum frequency generation (SFG) is used to investigate the adsorption of carbon monoxide on the single crystal (111) and polycrystalline platinum surfaces. By varying the frequency and polarization of the light beams, different surface species of CO species are probed. SFG signal intensities for different polarization indicate that adsorbed CO polarizability is significantly perturbed from the gas-phase molecule. The SFG signal of CO disappears well below the main oxidation potential of CO to CO{sub 2}. The disappearance of the CO signal is interpreted as a transformation in the CO layer to a state which is invisible to SFG. The invisible state is suggested to be CO with the bond axis nearly parallel to the platinum surface.

  14. Wetting effect on optical sum frequency generation (SFG) spectra of D-glucose, D-fructose, and sucrose

    Science.gov (United States)

    Hieu, Hoang Chi; Li, Hongyan; Miyauchi, Yoshihiro; Mizutani, Goro; Fujita, Naoko; Nakamura, Yasunori

    2015-03-01

    We report a sum frequency generation (SFG) spectroscopy study of D-glucose, D-fructose and sucrose in the Csbnd H stretching vibration regime. Wetting effect on the SFG spectra was investigated. The SFG spectrum of D-glucose changed from that of α-D-glucose into those of α-D-glucose monohydrate by wetting. The SFG spectra showed evidence of a small change of β-D-fructopyranose into other anomers by wetting. SFG spectra of sucrose did not change by wetting. Assignments of the vibrational peaks in the SFG spectra of the three sugars in the dry and wet states were performed in the Csbnd H stretching vibration region near 3000 cm-1.

  15. Generation and tunable enhancement of a sum-frequency signal in lithium niobate nanowires

    Science.gov (United States)

    Sergeyev, Anton; Reig Escalé, Marc; Grange, Rachel

    2017-02-01

    Recent developments in the fabrication of lithium niobate (LiNbO3) structures down to the nanoscale opens up novel applications of this versatile material in nonlinear optics. Current nonlinear optical studies in sub-micron waveguides are mainly restricted to the generation of second and third harmonics. In this work, we demonstrate the generation and waveguiding of the sum-frequency generation (SFG) signal in a single LiNbO3 nanowire with a cross-section of 517 nm  ×  654 nm. Furthermore, we enhance the guided SFG signal 17.9 times by means of modal phase matching. We also display tuning of the phase-matched wavelength by varying the nanowire cross-section and changing the polarization of the incident laser. The results prove that LiNbO3 nanowires can be successfully used for nonlinear wave-mixing applications and assisting the miniaturization of optical devices. , which features invited work from the best early-career researchers working within the scope of J Phys D. This project is part of the Journal of Physics series’ 50th anniversary celebrations in 2017. Rachel Grange was selected by the Editorial Board of J Phys D as an Emerging Leader.

  16. Broadband short pulse measurement by autocorrelation with a sum-frequency generation set-up

    International Nuclear Information System (INIS)

    Glotin, F.; Jaroszynski, D.; Marcouille, O.

    1995-01-01

    Previous spectral and laser pulse length measurements carried out on the CLIO FEL at wavelength λ=8.5 μm suggested that very short light pulses could be generated, about 500 fs wide (FWHM). For these measurements a Michelson interferometer with a Te crystal, as a non-linear detector, was used as a second order autocorrelation device. More recent measurements in similar conditions have confirmed that the laser pulses observed are indeed single: they are not followed by other pulses distant by the slippage length Nλ. As the single micropulse length is likely to depend on the slippage, more measurements at different wavelengths would be useful. This is not directly possible with our actual interferometer set-up, based on a phase-matched non-linear crystal. However, we can use the broadband non-linear medium provided by one of our users' experiments: Sum-Frequency Generation over surfaces. With such autocorrelation set-up, interference fringes are no more visible, but this is largely compensated by the frequency range provided. First tests at 8 μm have already been performed to validate the technic, leading to results similar to those obtained with our previous Michelson set-up

  17. Study of the Imidazolium-Based Ionic Liquid - ag Electrified Interface on the CO_{2} Electroreduction by Sum Frequency Spectroscopy.

    Science.gov (United States)

    Garcia Rey, Natalia; Dlott, Dana

    2017-06-01

    Imidazolium based ionic liquids (ILs) have been used as a promising system to improve the CO_{2} electroreduction at lower overpotential than other organic or aqueous electrolytes^{1}. Although the detailed mechanism of the CO_{2} electroreduction on Ag has not been elucidated yet, we have developed a methodology to study the electrified interface during the CO_{2} electroreduction using sum frequency generation (SFG) spectroscopy in combination with cyclic voltammetry^{2}. In this work, we tuned the composition of imidazolium-based ILs by exchanging the anion or the functional groups of the imidazolium. We use the nonresonant SFG (NR-SFG) to study the IL-Ag interface and resonant SFG (RES-SFG) to identify the CO adsorbed on the electrode and monitor the Stark shift as a function of cell potential. In previous studies on CO_{2} electroreduction in the IL: 1-ethyl-3-methylimidazolium tetrafluorborate (EMIM-BF_{4}) on Ag, we showed three events occurred at the same potential (-1.33 V vs. Ag/AgCl): the current associated with CO_{2} electroreduction increased, the Stark shift of the adsorbed atop CO doubled in magnitude and the EMIM-BF_{4} underwent a structural transition^{3}. In addition, we also observed how the structural transition of the EMIM-BF_{4} electrolyte shift to lower potentials when the IL is mixed with water. It is known that water enhances the CO_{2} electroreduction producing more CO^{4}. Moreover, the CO is adsorbed in multi-bonded and in atop sites when more water is present in the electrolyte. ^{1}Lau, G. P. S.; Schreier, M.; Vasilyev, D.; Scopelliti, R.; Grätzel, M.; Dyson, P. J., New Insights into the Role of Imidazolium-Based Promoters for the Electroreduction of CO_{2} on a Silver Electrode. J. Am. Chem. Soc. 2016, 138, 7820-7823. ^{2}Garcia Rey, N.; Dlott, D. D., Studies of Electrochemical Interfaces by Broadband Sum Frequency Generation. J. Electroanal. Chem. 2016. DOI:10.1016/j.jelechem.2016.12.023. ^{3}Garcia Rey, N.; Dlott, D. D

  18. Efficient generation of continuous-wave yellow-orange light using sum-frequency in periodically poled KTP

    DEFF Research Database (Denmark)

    Janousek, Jiri; Johansson, Sandra; Tidemand-Lichtenberg, Peter

    We present highly efficient sum-frequency generation between two CW 1064 and 1342 nm laser lines of two Nd:YVO4 lasers using periodically poled KTP. This is an all solid-state light source in the yellow-orange spectral range....

  19. Determining In Situ Protein Conformation and Orientation from the Amide-I Sum-Frequency Generation Spectrum: Theory and Experiment

    NARCIS (Netherlands)

    Roeters, S.J.; van Dijk, C.N.; Torres Knoop, A.; Backus, E.H.G.; Campen, R.K.; Bonn, M.; Woutersen, S.

    2013-01-01

    Vibrational sum-frequency generation (VSFG) spectra of the amide-I band of proteins can give detailed insight into biomolecular processes near membranes. However, interpreting these spectra in terms of the conformation and orientation of a protein can be difficult, especially in the case of complex

  20. Multimodal Broadband Vibrational Sum Frequency Generation (MM-BB-V-SFG) Spectrometer and Microscope.

    Science.gov (United States)

    Lee, Christopher M; Kafle, Kabindra; Huang, Shixin; Kim, Seong H

    2016-01-14

    A broadband sum frequency generation (BB-SFG) spectrometer with multimodal (MM) capabilities was constructed, which could be routinely reconfigured for tabletop experiments in reflection, transmission, and total internal reflection (TIR) geometries, as well as microscopic imaging. The system was constructed using a Ti:sapphire amplifier (800 nm, pulse width = 85 fs, repetition rate = 2 kHz), an optical parameter amplification (OPA) system for production of broadband IR pulses tunable between 1000 and 4000 cm(-1), and two Fabry-Pérot etalons arranged in series for production of narrowband 800 nm pulses. The key feature allowing the MM operation was the nearly collinear alignment of the visible (fixed, 800 nm) and infrared (tunable, 1000-4000 cm(-1)) pulses which were spatially separated. Physical insights discussed in this paper include the comparison of spectral bandwidth produced with 40 and 85 fs pump beams, the improvement of spectral resolution using etalons, the SFG probe volume in bulk analysis, the normalization of SFG signals, the stitching of multiple spectral segments, and the operation in different modes for air/liquid and adsorbate/solid interfaces, bulk samples, as well as spectral imaging combined with principle component analysis (PCA). The SFG spectral features obtained with the MM-BB-SFG system were compared with those obtained with picosecond-scanning-SFG system and high-resolution BB-SFG system (HR-BB-SFG) for dimethyl sulfoxide, α-pinene, and various samples containing cellulose (purified commercial products, Cladophora cell wall, cotton and flax fibers, and onion epidermis cell wall).

  1. Effects of cations and cholesterol with sphingomyelin membranes investigated by high-resolution broadband sum frequency vibrational spectroscopy

    Science.gov (United States)

    Zhang, Zhen; Feng, Rong-juan; Li, Yi-yi; Liu, Ming-hua; Guo, Yuan

    2017-08-01

    Sphingomyelin(SM) is specifically enriched in the plasma membrane of mammalian cells. Its molecular structure is compose by N-acyl-Derythro-sphingosylphosphorylcholine. The function of the SM related to membrane signaling and protein trafficking are relied on the interactions of the SM, cations, cholesterol and proteins. In this report, the interaction of three different nature SMs, cations and cholesterol at air/aqueous interfaces studied by high-resolution broadband sum frequency vibrational spectroscopy, respectively. Our results shed lights on understanding the relationship between SMs monolayer, cholesterol and Cations.

  2. Two-dimensional sum-frequency generation (2D SFG) reveals structure and dynamics of a surface-bound peptide

    Science.gov (United States)

    Laaser, Jennifer E.; Skoff, David R.; Ho, Jia-Jung; Joo, Yongho; Serrano, Arnaldo L.; Steinkruger, Jay D.; Gopalan, Padma; Gellman, Samuel H.; Zanni, Martin T.

    2014-01-01

    Surface-bound polypeptides and proteins are increasingly used to functionalize inorganic interfaces such as electrodes, but their structural characterization is exceedingly difficult with standard technologies. In this paper, we report the first two-dimensional sum-frequency generation (2D SFG) spectra of a peptide monolayer, which is collected by adding a mid-IR pulse shaper to a standard femtosecond SFG spectrometer. On a gold surface, standard FTIR spectroscopy is inconclusive about the peptide structure because of solvation-induced frequency shifts, but the 2D lineshapes, anharmonic shifts, and lifetimes obtained from 2D SFG reveal that the peptide is largely α-helical and upright. Random coil residues are also observed, which do not themselves appear in SFG spectra due to their isotropic structural distribution, but which still absorb infrared light and so can be detected by cross-peaks in 2D SFG spectra. We discuss these results in the context of peptide design. Because of the similar way in which the spectra are collected, these 2D SFG spectra can be directly compared to 2D IR spectra, thereby enabling structural interpretations of surface-bound peptides and biomolecules based on the well-studied structure/2D IR spectra relationships established from soluble proteins. PMID:24372101

  3. Direct comparison of phase-sensitive vibrational sum frequency generation with maximum entropy method: case study of water.

    Science.gov (United States)

    de Beer, Alex G F; Samson, Jean-Sebastièn; Hua, Wei; Huang, Zishuai; Chen, Xiangke; Allen, Heather C; Roke, Sylvie

    2011-12-14

    We present a direct comparison of phase sensitive sum-frequency generation experiments with phase reconstruction obtained by the maximum entropy method. We show that both methods lead to the same complex spectrum. Furthermore, we discuss the strengths and weaknesses of each of these methods, analyzing possible sources of experimental and analytical errors. A simulation program for maximum entropy phase reconstruction is available at: http://lbp.epfl.ch/. © 2011 American Institute of Physics

  4. All-solid-state quasi-CW yellow laser with intracavity self-Raman conversion and sum frequency generation

    International Nuclear Information System (INIS)

    Kananovich, A; Grabtchikov, A; Orlovich, V; Demidovich, A; Danailov, M

    2010-01-01

    Quasi continuous-wave (qCW) yellow emission (pulse duration 5 ms, repetition rate 20 Hz) at 559 nm is demonstrated through intracavity sum frequency generation (SFG) of Stokes and fundamental fields in Nd:YVO 4 diode pumped self-Raman laser for the first time. Average in pulse output power at 559 nm was 0.47 W for 22 W of pump power, which corresponds to 2.1% of diode-to-yellow efficiency. The pulsed mode of operation was due to diode pump modulation and was used to reduce thermal stress of the crystal

  5. Sum frequency generation and catalytic reaction studies of the removal of the organic capping agents from Pt nanoparticles by UV-ozone treatment

    Energy Technology Data Exchange (ETDEWEB)

    Aliaga, Cesar; Park, Jeong Y.; Yamada, Yusuke; Lee, Hyun Sook; Tsung, Chia-Kuang; Yang, Peidong; Somorjai, Gabor A.

    2009-12-10

    We report the structure of the organic capping layers of platinum colloid nanoparticles and their removal by UV-ozone exposure. Sum frequency generation vibrational spectroscopy (SFGVS) studies identify the carbon-hydrogen stretching modes on poly(vinylpyrrolidone) (PVP) and tetradecyl tributylammonium bromide (TTAB)-capped platinum nanoparticles. We found that the UV-ozone treatment technique effectively removes the capping layer on the basis of several analytical measurements including SFGVS, X-ray photoelectron spectroscopy, and diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). The overall shape of the nanoparticles was preserved after the removal of capping layers, as confirmed by transmission electron microscopy (TEM). SFGVS of ethylene hydrogenation on the clean platinum nanoparticles demonstrates the existence of ethylidyne and di-{sigma}-bonded species, indicating the similarity between single-crystal and nanoparticle systems.

  6. Facet-specific interaction between methanol and TiO2 probed by sum-frequency vibrational spectroscopy.

    Science.gov (United States)

    Yang, Deheng; Li, Yadong; Liu, Xinyi; Cao, Yue; Gao, Yi; Shen, Y Ron; Liu, Wei-Tao

    2018-04-24

    The facet-specific interaction between molecules and crystalline catalysts, such as titanium dioxides (TiO 2 ), has attracted much attention due to possible facet-dependent reactivity. Using surface-sensitive sum-frequency vibrational spectroscopy, we have studied how methanol interacts with different common facets of crystalline TiO 2 , including rutile(110), (001), (100), and anatase(101), under ambient temperature and pressure. We found that methanol adsorbs predominantly in the molecular form on all of the four surfaces, while spontaneous dissociation into methoxy occurs preferentially when these surfaces become defective. Extraction of Fermi resonance coupling between stretch and bending modes of the methyl group in analyzing adsorbed methanol spectra allows determination of the methanol adsorption isotherm. The isotherms obtained for the four surfaces are nearly the same, yielding two adsorbed Gibbs free energies associated with two different adsorption configurations singled out by ab initio calculations. They are ( i ) ∼-20 kJ/mol for methanol with its oxygen attached to a low-coordinated surface titanium, and ( ii ) ∼-5 kJ/mol for methanol hydrogen-bonded to a surface oxygen and a neighboring methanol molecule. Despite similar adsorption energetics, the Fermi resonance coupling strength for adsorbed methanol appears to depend sensitively on the surface facet and coverage.

  7. Highly efficient deep ultraviolet generation by sum-frequency mixing ...

    Indian Academy of Sciences (India)

    Generation of deep ultraviolet radiation at 210 nm by Type-I third harmonic generation is achieved in a pair of BBO crystals with conversion efficiency as high as 36%. The fundamental source is the dye laser radiation pumped by the second harmonic of a Q-switched Nd : YAG laser. A walk-off compensated configuration ...

  8. Sum-frequency generation from molecular monolayers using 14 μm radiation from the FELIX free-electron laser

    International Nuclear Information System (INIS)

    Van der Ham, E.W.M.; Vrehen, Q.H.F.; Eliel, E.R.

    1995-01-01

    Sum-frequency generation (SFG) has developed into a widely applied tool for study of surfaces and interfaces where molecules are present. It combines the surface specificity of a second-order nonlinear optical technique with the power of a spectroscopic method, and it can be used under widely varying experimental conditions ranging from UHV to electrochemical cells. The important characteristic of SFG is that it allows one to study the average spatial orientation of a molecular bond in a monolayer of molecules at an interface. Until recently SFG measurements were confined to the frequency interval Y μ > 1700 cm -1 because of a lack of suitable laser sources at wave-lengths λ > 6 μm. So for most molecules only a few vibrational modes and thus intramolecular bonds can be studied. We have developed a universal sum-frequency spectrometer around the FELIX free-electron law that covers the complete molecular fingerprint since we can generate any IR wavelength between 2.75 and 110 fμ at the FELIX facility. We have used this setup for a series of exploratory SFG experiments in a frequency range that was hitherto unexplored in the study of molecular monolayers. We have studied thiol monolayers chemisorbed on a variety of noble metals (Au, Ag, Pt) where we focussed on the C-S stretch vibration at ν = 702 cm -1 (λ = 14.3 μm). We have found spectroscopic features revealing the presence of both the trane and gauche conformers of the adsorbed molecules. The present measurements open a whole new wavelength range for nonlinear optical studies of interfaces

  9. Second-harmonic and sum-frequency generation for surface studies

    International Nuclear Information System (INIS)

    Hunt, J.H.; Guyot-Sionnest, P.; Shen, Y.R.

    1987-07-01

    Second harmonic generation (SHG) has now been well established as a versatile surface-sensitive probe. It has been used to study electrochemical processes at electrode surfaces, molecular adsorption and desorption at metal and semiconductor surfaces, orientational phase transition of molecular monolayers on water, surface reconstruction and epitaxial growth, and so on. More recently, it has been employed as a tool to monitor monolayer polymerization and other surface reactions, to probe polar order of molecules at interfaces, and to measure molecular nonlinearity. While most surface techniques are restricted to the solid/vacuum environment, SHG is applicable to nearly all interfaces as long as the interfaces are accessible by light. In addition, SHG has the advantages of being capable of in-situ measurements with high temporal, spatial, and spectral resolutions

  10. Efficient concept for generation of diffraction-limited green light by sum-frequency generation of spectrally combined tapered diode lasers

    DEFF Research Database (Denmark)

    Müller, André; Jensen, Ole Bjarlin; Hasler, Karl-Heinz

    2012-01-01

    In order to increase the power of visible diode laser systems in an efficient manner, we propose spectral beam combining with subsequent sum-frequency generation. We show that this approach, in comparison with second harmonic generation of single emitters, can enhance the available power signific......In order to increase the power of visible diode laser systems in an efficient manner, we propose spectral beam combining with subsequent sum-frequency generation. We show that this approach, in comparison with second harmonic generation of single emitters, can enhance the available power...... significantly. By combining two distributed Bragg reflector tapered diode lasers we achieve a 2.5–3.2 fold increase in power and a maximum of 3.9 W of diffraction-limited green light. At this power level, green diode laser systems have a high application potential, e.g., within the biomedical field. Our concept...

  11. Characterisation of the membrane affinity of an isoniazide peptide conjugate by tensiometry, atomic force microscopy and sum-frequency vibrational spectroscopy, using a phospholipid Langmuir monolayer model.

    Science.gov (United States)

    Hill, Katalin; Pénzes, Csanád Botond; Schnöller, Donát; Horváti, Kata; Bosze, Szilvia; Hudecz, Ferenc; Keszthelyi, Tamás; Kiss, Eva

    2010-10-07

    Tensiometry, sum-frequency vibrational spectroscopy, and atomic force microscopy were employed to assess the cell penetration ability of a peptide conjugate of the antituberculotic agent isoniazide. Isoniazide was conjugated to peptide (91)SEFAYGSFVRTVSLPV(106), a functional T-cell epitope of the immunodominant 16 kDa protein of Mycobacterium tuberculosis. As a simple but versatile model of the cell membrane a phospholipid Langmuir monolayer at the liquid/air interface was used. Changes induced in the structure of the phospholipid monolayer by injection of the peptide conjugate into the subphase were followed by tensiometry and sum-frequency vibrational spectroscopy. The drug penetrated lipid films were transferred to a solid support by the Langmuir-Blodgett technique, and their structures were characterized by atomic force microscopy. Peptide conjugation was found to strongly enhance the cell penetration ability of isoniazide.

  12. In situ speciation of the functional groups at mineral/electrolyte interfaces by sum frequency vibrational spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Floersheimer, M.; Kruse, K.; Klenze, R.; Kim, J.I. [Institut fuer Nukleare Entsorgung, Forschungszentrum Karlsruhe, Postfach 3640, D-76021 Karlsruhe (Germany); Fanghaenel, Th. [Institut fuer Nukleare Entsorgung, Forschungszentrum Karlsruhe, Postfach 3640, D-76021 Karlsruhe (Germany); Physikalisch-Chemisches Institut, Ruprecht-Karls-Universitaet Heidelberg, Im Neuenheimer Feld 253, D-69120, Heidelberg (Germany)

    2005-07-01

    Full text of publication follows: In order to describe surface reactivity and adsorption/desorption processes on the molecular level, a large number of functional groups has been postulated. In most cases, however, a direct proof for the existence of these species in real aquatic environment is lacking because it is difficult to obtain chemical analytical information in situ under electrolyte with interface selectivity. Here we apply interface selective sum frequency (SF) vibrational spectroscopy to study the (001) and (110) surfaces of sapphire ({alpha}-Al{sub 2}O{sub 3}) under water between pH 4 and 12. This work is part of an ongoing fundamental study of the sorption mechanism of actinides on single crystals faces of sapphire by various experimental and theoretical techniques. Sapphire is used as a simple model for natural clay minerals and related iron phases. In the O-H stretch region of the infrared spectrum between 2800 and 4000 cm{sup -1}, we observe a surprisingly large number of 8 SF bands in total. Two of them are due to the polar ordered water film near the mineral surface which is well known from various aquatic interfaces. The other bands originate from up to 6 different aluminol species or from specifically [1] bound water molecules. The prominent peak of the (001) surface (SF intensity maximum at 3690 cm{sup -1}), we attribute to an OH species bridging two [1-4] aluminium atoms. At the (110) surface, the concentration of this species is considerably smaller. Another aluminol species that can be detected at the (001) and the (110) surface (signal maximum near 3450 cm{sup -1}) exhibits O-H bonds which are almost parallel to the interface plane. This species is probably the in-plane aluminol group predicted in recent molecular dynamics calculations [4]. SF spectroscopy allows us also to measure the absolute polar orientation of the water molecules adjacent to the mineral surface. The inversion of the molecules polar orientation upon alteration of the p

  13. Single-frequency blue light generation by single-pass sum-frequency generation in a coupled ring cavity tapered laser

    DEFF Research Database (Denmark)

    Jensen, Ole Bjarlin; Petersen, Paul Michael

    2013-01-01

    A generic approach for generation of tunable single frequency light is presented. 340 mW of near diffraction limited, single-frequency, and tunable blue light around 459 nm is generated by sum-frequency generation (SFG) between two tunable tapered diode lasers. One diode laser is operated in a ring...... cavity and another tapered diode laser is single-passed through a nonlinear crystal which is contained in the coupled ring cavity. Using this method, the single-pass conversion efficiency is more than 25%. In contrast to SFG in an external cavity, the system is entirely self-stabilized with no electronic...

  14. Coupled-cluster sum-frequency generation nonlinear susceptibilities of methyl (CH3) and methylene (CH2) groups.

    Science.gov (United States)

    Tetsassi Feugmo, Conrard Giresse; Liégeois, Vincent; Champagne, Benoît

    2017-11-15

    The first vibrational sum frequency generation (SFG) spectra based on molecular properties calculated at the coupled cluster singles and doubles (CCSD) level of approximation have been simulated for interfacial model alkyl chains, providing benchmark data for comparisons with approximate methods, including density functional theory (DFT). The approach proceeds in three steps. In the first two steps, the molecular spectral properties are determined: the vibrational normal modes and frequencies and then the derivatives of the dipole moment and of the polarizability with respect to the normal coordinates. These derivatives are evaluated with a numerical differentiation approach, of which the accuracy was monitored using Romberg's procedure. Then, in the last step, a three-layer model is employed to evaluate the macroscopic second-order nonlinear optical responses and thereby the simulated SFG spectra of the alkyl interface. Results emphasize the following facts: (i) the dipole and polarizability derivatives calculated at the DFT level with the B3LYP exchange-correlation functional can differ, with respect to CCSD, by as much as ±10 to 20% and ±20 to 50% for the CH 3 and CH 2 vibrations, respectively; (ii) these differences are enhanced when considering the SFG intensities as well as their variations as a function of the experimental configuration (ppp versus ssp) and as a function of the tilt and rotation angles, defining the orientation of the alkyl chain at the interface; (iii) these differences originate from both the vibrational normal coordinates and the Cartesian derivatives of the dipole moment and polarizability; (iv) freezing the successive fragments of the alkyl chain strongly modifies the SFG spectrum and enables highlighting the delocalization effects between the terminal CH 3 group and its neighboring CH 2 units; and finally (v) going from the free chain to the free methyl model, and further to C 3v constraints on leads to large variations of two ratios

  15. Vibrational Dynamics of Interfacial Water by Free Induction Decay Sum Frequency Generation (FID-SFG) at the Al2O3(1120)/H2O Interface.

    Science.gov (United States)

    Boulesbaa, Abdelaziz; Borguet, Eric

    2014-02-06

    The dephasing dynamics of a vibrational coherence may reveal the interactions of chemical functional groups with their environment. To investigate this process at a surface, we employ free induction decay sum frequency generation (FID-SFG) to measure the time that it takes for free OH stretch oscillators at the charged (pH ≈ 13, KOH) interface of alumina/water (Al2O3/H2O) to lose their collective coherence. By employing noncollinear optical parametric amplification (NOPA) technology and nonlinear vibrational spectroscopy, we showed that the single free OH peak actually corresponds to two distinct oscillators oriented opposite to each other and measured the total dephasing time, T2, of the free OH stretch modes at the Al2O3/H2O interface with a sub-40 fs temporal resolution. Our results suggested that the free OH oscillators associated with interfacial water dephase on the time scale of 89.4 ± 6.9 fs, whereas the homogeneous dephasing of interfacial alumina hydroxyls is an order of magnitude slower.

  16. Spectrally- and Time-Resolved Sum Frequency Generation (STiR-SFG): a new tool for ultrafast hydrogen bond dynamics at interfaces.

    Science.gov (United States)

    Benderskii, Alexander; Bordenyuk, Andrey; Weeraman, Champika

    2006-03-01

    The recently developed spectrally- and time-resolved Sum Frequency Generation (STiR-SFG) is a surface-selective 3-wave mixing (IR+visible) spectroscopic technique capable of measuring ultrafast spectral evolution of vibrational coherences. A detailed description of this measurement will be presented, and a noniterative method or deconvolving the laser pulses will be introduced to obtain the molecular response function. STiR-SFG, combined with the frequency-domain SFG spectroscopy, was applied to study hydrogen bonding dynamics at aqueous interfaces (D2O/CaF2). Spectral dynamics of the OD-stretch on the 50-150 fs time scale provides real-time observation of ultrafast H-bond rearrangement. Tuning the IR wavelength to the blue or red side of the OD-stretch transition, we selectively monitor the dynamics of different sub-ensembles in the distribution of the H-bond structures. The blue-side excitation (weaker H-bonding) shows monotonic red-shift of the OD-frequency. In contrast, the red-side excitation (stronger H-bonding structures) produces a blue-shift and a recursion, which may indicate the presence of an underdamped intermolecular mode of interfacial water. Effect of electrolyte concentration on the H-bond dynamics will be discussed.

  17. Experimental evidence for an optical interference model for vibrational sum frequency generation on multilayer organic thin film systems. I. Electric dipole approximation

    International Nuclear Information System (INIS)

    O’Brien, Daniel B.; Massari, Aaron M.

    2015-01-01

    In the field of vibrational sum frequency generation spectroscopy (VSFG) applied to organic thin film systems, a significant challenge to data analysis is in the accurate description of optical interference effects. Herein, we provide experimental evidence that a model recently developed in our lab provides an accurate description of this phenomenon. We studied the organic small molecule N,N′-dioctyl-3,4,9,10-perylenedicarboximide vapor deposited as a thickness gradient on silicon wafer substrates with two oxide thicknesses and two surface preps. VSFG data were obtained using the ssp and the sps polarization combinations in the imide carbonyl stretching region as a function of organic thickness. In this first of two reports, the data are modeled and interpreted within the ubiquitous electric dipole approximation for VSFG. The intrinsic sample responses are parameterized during the fitting routines while optical interference effects are simply calculated from the model using known refractive indices, thin film thicknesses, and beam angles. The results indicate that the thin film model provides a good description of optical interferences, indicating that interfacial terms are significant. Inconsistencies between the fitting results within the bounds of the electric dipole response motivate deliberation for additional effects to be considered in the second report

  18. Experimental evidence for an optical interference model for vibrational sum frequency generation on multilayer organic thin film systems. I. Electric dipole approximation.

    Science.gov (United States)

    O'Brien, Daniel B; Massari, Aaron M

    2015-01-14

    In the field of vibrational sum frequency generation spectroscopy (VSFG) applied to organic thin film systems, a significant challenge to data analysis is in the accurate description of optical interference effects. Herein, we provide experimental evidence that a model recently developed in our lab provides an accurate description of this phenomenon. We studied the organic small molecule N,N'-dioctyl-3,4,9,10-perylenedicarboximide vapor deposited as a thickness gradient on silicon wafer substrates with two oxide thicknesses and two surface preps. VSFG data were obtained using the ssp and the sps polarization combinations in the imide carbonyl stretching region as a function of organic thickness. In this first of two reports, the data are modeled and interpreted within the ubiquitous electric dipole approximation for VSFG. The intrinsic sample responses are parameterized during the fitting routines while optical interference effects are simply calculated from the model using known refractive indices, thin film thicknesses, and beam angles. The results indicate that the thin film model provides a good description of optical interferences, indicating that interfacial terms are significant. Inconsistencies between the fitting results within the bounds of the electric dipole response motivate deliberation for additional effects to be considered in the second report.

  19. Experimental evidence for an optical interference model for vibrational sum frequency generation on multilayer organic thin film systems. I. Electric dipole approximation

    Energy Technology Data Exchange (ETDEWEB)

    O’Brien, Daniel B.; Massari, Aaron M., E-mail: massari@umn.edu [Department of Chemistry, University of Minnesota—Twin Cities, 207 Pleasant Street SE, Minneapolis, Minnesota 55455 (United States)

    2015-01-14

    In the field of vibrational sum frequency generation spectroscopy (VSFG) applied to organic thin film systems, a significant challenge to data analysis is in the accurate description of optical interference effects. Herein, we provide experimental evidence that a model recently developed in our lab provides an accurate description of this phenomenon. We studied the organic small molecule N,N′-dioctyl-3,4,9,10-perylenedicarboximide vapor deposited as a thickness gradient on silicon wafer substrates with two oxide thicknesses and two surface preps. VSFG data were obtained using the ssp and the sps polarization combinations in the imide carbonyl stretching region as a function of organic thickness. In this first of two reports, the data are modeled and interpreted within the ubiquitous electric dipole approximation for VSFG. The intrinsic sample responses are parameterized during the fitting routines while optical interference effects are simply calculated from the model using known refractive indices, thin film thicknesses, and beam angles. The results indicate that the thin film model provides a good description of optical interferences, indicating that interfacial terms are significant. Inconsistencies between the fitting results within the bounds of the electric dipole response motivate deliberation for additional effects to be considered in the second report.

  20. Continuous-wave sodium D2 resonance radiation generated in single-pass sum-frequency generation with periodically poled lithium niobate.

    Science.gov (United States)

    Yue, J; She, C-Y; Williams, B P; Vance, J D; Acott, P E; Kawahara, T D

    2009-04-01

    With two cw single-mode Nd:YAG lasers at 1064 and 1319 nm and a periodically poled lithium niobate crystal, 11 mW of 2 kHz/100 ms bandwidth single-mode tunable 589 nm cw radiation has been detected using single-pass sum-frequency generation. The demonstrated conversion efficiency is approximately 3.2%[W(-1) cm(-1)]. This compact solid-state light source has been used in a solid-state-dye laser hybrid sodium fluorescence lidar transmitter to measure temperatures and winds in the upper atmosphere (80-105 km); it is being implemented into the transmitter of a mobile all-solid-state sodium temperature and wind lidar under construction.

  1. 2D heterodyne-detected sum frequency generation study on the ultrafast vibrational dynamics of H{sub 2}O and HOD water at charged interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Inoue, Ken-ichi; Singh, Prashant C. [Molecular Spectroscopy Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Nihonyanagi, Satoshi; Tahara, Tahei, E-mail: tahei@riken.jp [Molecular Spectroscopy Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Ultrafast Spectroscopy Research Team, RIKEN Center for Advanced Photonics, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Yamaguchi, Shoichi [Molecular Spectroscopy Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Department of Applied Chemistry, Saitama University, 255 Shimo-Okubo, Saitama 338-8570 (Japan)

    2015-06-07

    Two-dimensional heterodyne-detected vibrational sum-frequency generation (2D HD-VSFG) spectroscopy is applied to study the ultrafast vibrational dynamics of water at positively charged aqueous interfaces, and 2D HD-VSFG spectra of cetyltrimethylammonium bromide (CTAB)/water interfaces in the whole hydrogen-bonded OH stretch region (3000 cm{sup −1} ≤ ω{sub pump} ≤ 3600 cm{sup −1}) are measured. 2D HD-VSFG spectrum of the CTAB/isotopically diluted water (HOD-D{sub 2}O) interface exhibits a diagonally elongated bleaching lobe immediately after excitation, which becomes round with a time constant of ∼0.3 ps due to spectral diffusion. In contrast, 2D HD-VSFG spectrum of the CTAB/H{sub 2}O interface at 0.0 ps clearly shows two diagonal peaks and their cross peaks in the bleaching region, corresponding to the double peaks observed at 3230 cm{sup −1} and 3420 cm{sup −1} in the steady-state HD-VSFG spectrum. Horizontal slices of the 2D spectrum show that the relative intensity of the two peaks of the bleaching at the CTAB/H{sub 2}O interface gradually change with the change of the pump frequency. We simulate the pump-frequency dependence of the bleaching feature using a model that takes account of the Fermi resonance and inhomogeneity of the OH stretch vibration, and the simulated spectra reproduce the essential features of the 2D HD-VSFG spectra of the CTAB/H{sub 2}O interface. The present study demonstrates that heterodyne detection of the time-resolved VSFG is critically important for studying the ultrafast dynamics of water interfaces and for unveiling the underlying mechanism.

  2. Amine Chemistry at Aqueous Interfaces: The Study of Organic Amines in Neutralizing Acidic Gases at an Air/Water Surface Using Vibrational Sum Frequency Spectroscopy

    Science.gov (United States)

    McWilliams, L.; Wren, S. N.; Valley, N. A.; Richmond, G.

    2014-12-01

    Small organic bases have been measured in atmospheric samples, with their sources ranging from industrial processing to animal husbandry. These small organic amines are often highly soluble, being found in atmospheric condensed phases such as fogwater and rainwater. Additionally, they display acid-neutralization ability often greater than ammonia, yet little is known regarding their kinetic and thermodynamic properties. This presentation will describe the molecular level details of a model amine system at the vapor/liquid interface in the presence of acidic gas. We find that this amine system shows very unique properties in terms of its bonding, structure, and orientation at aqueous surfaces. The results of our studies using a combination of computation, vibrational sum frequency spectroscopy, and surface tension will report the properties inherent to these atmospherically relevant species at aqueous surfaces.

  3. A Tunable CW Orange Laser Based on a Cascaded MgO:PPLN Single-Pass Sum-Frequency Generation Module

    OpenAIRE

    Dismas K. Choge; Huai-Xi Chen; Bao-Lu Tian; Yi-Bin Xu; Guang-Wei Li; Wan-Guo Liang

    2018-01-01

    We report an all-solid-state continuous wave (CW) tunable orange laser based on cascaded single-pass sum-frequency generation with fundamental wavelengths at 1545.7 and 975.2 nm using two quasi-phase-matched (QPM) MgO-doped periodically poled lithium niobate (MgO:PPLN) crystals. Up to 10 mW of orange laser is generated in the cascaded module corresponding to a 10.4%/W nonlinear conversion efficiency. The orange output showed a temperature tuning rate of ~0.05 nm/°C, and the beam quality (M2) ...

  4. Observation of sum-frequency-generation-induced cascaded four-wave mixing using two crossing femtosecond laser pulses in a 0.1 mm beta-barium-borate crystal.

    Science.gov (United States)

    Liu, Weimin; Zhu, Liangdong; Fang, Chong

    2012-09-15

    We demonstrate the simultaneous generation of multicolor femtosecond laser pulses spanning the wavelength range from UV to near IR in a 0.1 mm Type I beta-barium borate crystal from 800 nm fundamental and weak IR super-continuum white light (SCWL) pulses. The multicolor broadband laser pulses observed are attributed to two concomitant cascaded four-wave mixing (CFWM) processes as corroborated by calculation: (1) directly from the two incident laser pulses; (2) by the sum-frequency generation (SFG) induced CFWM process (SFGFWM). The latter signal arises from the interaction between the frequency-doubled fundamental pulse (400 nm) and the SFG pulse generated in between the fundamental and IR-SCWL pulses. The versatility and simplicity of this spatially dispersed multicolor self-compressed laser pulse generation offer compact and attractive methods to conduct femtosecond stimulated Raman spectroscopy and time-resolved multicolor spectroscopy.

  5. IR visible sum-frequency vibrational spectroscopy of Biphenyl-3 methylene thiol monolayer on gold and silver: effect of the visible wavelength on the SFG spectrum

    Science.gov (United States)

    Humbert, C.; Dreesen, L.; Mani, A. A.; Caudano, Y.; Lemaire, J.-J.; Thiry, P. A.; Peremans, A.

    2002-04-01

    We measured IR-visible sum-frequency generation spectra of CH 3-(C 6H 4) 2-(CH 2) 3-S-H (Biphenyl-3) self-assembled monolayers on a silver and a gold substrate. For the latter substrate, we observed different interference patterns between the resonant signal of the CH vibration and the non-resonant contribution of the substrate as a function of the visible beam wavelength. The non-linear response of the gold substrate is enhanced around 480 nm corresponding to the s-d interband transition. Such effect is not observed for the silver substrate the interband transition of which is located out of the investigated visible spectral range of 450-700 nm.

  6. High-Pressure Catalytic Reactions of C6 Hydrocarbons on PlatinumSingle-Crystals and nanoparticles: A Sum Frequency Generation VibrationalSpectroscopic and Kinetic Study

    Energy Technology Data Exchange (ETDEWEB)

    Bratlie, Kaitlin [Univ. of California, Berkeley, CA (United States)

    2007-01-01

    Catalytic reactions of cyclohexene, benzene, n-hexane, 2-methylpentane, 3-methylpentane, and 1-hexene on platinum catalysts were monitored in situ via sum frequency generation (SFG) vibrational spectroscopy and gas chromatography (GC). SFG is a surface specific vibrational spectroscopic tool capable of monitoring submonolayer coverages under reaction conditions without gas-phase interference. SFG was used to identify the surface intermediates present during catalytic processes on Pt(111) and Pt(100) single-crystals and on cubic and cuboctahedra Pt nanoparticles in the Torr pressure regime and at high temperatures (300K-450K). At low pressures (<10-6 Torr), cyclohexene hydrogenated and dehydrogenates to form cyclohexyl (C6H11) and π-allyl C6H9, respectively, on Pt(100). Increasing pressures to 1.5 Torr form cyclohexyl, π-allyl C6H9, and 1,4-cyclohexadiene, illustrating the necessity to investigate catalytic reactions at high-pressures. Simultaneously, GC was used to acquire turnover rates that were correlated to reactive intermediates observed spectroscopically. Benzene hydrogenation on Pt(111) and Pt(100) illustrated structure sensitivity via both vibrational spectroscopy and kinetics. Both cyclohexane and cyclohexene were produced on Pt(111), while only cyclohexane was formed on Pt(100). Additionally, π-allyl c-C6H9 was found only on Pt(100), indicating that cyclohexene rapidly dehydrogenates on the (100) surface. The structure insensitive production of cyclohexane was found to exhibit a compensation effect and was analyzed using the selective energy transfer (SET) model. The SET model suggests that the Pt-H system donates energy to the E2u mode of free benzene, which leads to catalysis. Linear C6 (n-hexane, 2-methylpentane, 3-methylpentane, and 1-hexene) hydrocarbons were also investigated in the presence and absence of excess hydrogen on Pt

  7. NOLM-based all-optical 40 Gbit/s format conversion through sum-frequency generation (SFG) in a PPLN waveguide

    Science.gov (United States)

    Wang, Jian; Sun, Junqiang

    2005-11-01

    A novel all-optical format conversion scheme from NRZ to RZ based on sum-frequency generation (SFG) in a periodically poled LiNbO 3 (PPLN) waveguide is proposed, using a nonlinear optical loop mirror (NOLM). The conversion mechanism relies on the combination of attenuation and nonlinear phase shift induced on the clockwise signal field during the SFG process. The SFG between pump, and co- and counter- propagating signals in the PPLN waveguide are numerically studied, showing that counter-propagating SFG can be ignored when quasi-phase matching (QPM) for SFG during co-propagating interaction. The nonlinear phase shift induced on the clockwise signal field is analyzed in detail, showing that it is more effective to yield large values for nonlinear phase shift when appropriately phase mismatched for the SFG process. Two tuning schemes are proposed depend on whether the sum-frequency wavelength is variable or fixed. It is found that the latter has a rather wide 3dB signal conversion bandwidth approximately 154nm. Finally, the influence of reversible process of SFG is discussed and the optimum arrangement of pump and signal peak powers is theoretically demonstrated. The result shows that proper power arrangement, pump width, and waveguide length are necessary for achieving a good conversion effect.

  8. A new approach to sum frequency generation of single-frequency blue light in a coupled ring cavity

    DEFF Research Database (Denmark)

    Jensen, Ole Bjarlin; Petersen, Paul Michael

    2014-01-01

    We present a generic approach for the generation of tunable single-frequency light and demonstrate generation of more than 300 mW tunable light around 460 nm. One tapered diode laser is operated in a coupled ring cavity containing the nonlinear crystal and another tapered diode laser is sent thro...... through the nonlinear crystal in a single pass. A high conversion efficiency of more than 25 % of the single-pass laser is enabled by the high circulating power in the coupled cavity. The system is entirely self-stabilized with no need for electronic locking....

  9. Quantum Mechanical Calculations of Vibrational Sum-Frequency-Generation (SFG) Spectra of Cellulose: Dependence of the CH and OH Peak Intensity on the Polarity of Cellulose Chains within the SFG Coherence Domain.

    Science.gov (United States)

    Lee, Christopher M; Chen, Xing; Weiss, Philip A; Jensen, Lasse; Kim, Seong H

    2017-01-05

    Vibrational sum-frequency-generation (SFG) spectroscopy is capable of selectively detecting crystalline biopolymers interspersed in amorphous polymer matrices. However, the spectral interpretation is difficult due to the lack of knowledge on how spatial arrangements of crystalline segments influence SFG spectra features. Here we report time-dependent density functional theory (TD-DFT) calculations of cellulose crystallites in intimate contact with two different polarities: parallel versus antiparallel. TD-DFT calculations reveal that the CH/OH intensity ratio is very sensitive to the polarity of the crystallite packing. Theoretical calculations of hyperpolarizability tensors (β abc ) clearly show the dependence of SFG intensities on the polarity of crystallite packing within the SFG coherence length, which provides the basis for interpretation of the empirically observed SFG features of native cellulose in biological systems.

  10. Interpreting intensities in vibrational sum frequency generation (SFG) spectroscopy: CO adsorption on Pd surfaces

    Science.gov (United States)

    Morkel, M.; Unterhalt, H.; Klüner, T.; Rupprechter, G.; Freund, H.-J.

    2005-07-01

    The lineshape and intensity of SFG signals of CO adsorbed on supported Pd nanoparticles and Pd(1 1 1) are analyzed. For CO/Pd(1 1 1) nearly symmetric lorentzian lineshapes were observed. Applying two different visible wavelengths for excitation, asymmetric lineshapes observed for the CO/Pd/Al 2O 3/NiAl(1 1 0) system are explained by a lower resonant and a higher non-resonant SFG signal and a change in the phase between resonant and non-resonant signals, most likely originating from an interband transition in the NiAl substrate. The relative intensity of different CO species (hollow, bridge, on-top) was modeled by DFT calculations of IR transition moments and Raman activities. While the (experimental) sensitivity of SFG towards different CO species strongly varies, the calculated IR and Raman activities are rather similar. The inability to exactly reproduce experimental SFG intensities suggests a strong coverage dependence of Raman activities or that non-linear effects occur that can currently not be properly accounted for.

  11. Tunable, continuous-wave, ultraviolet source based on intracavity sum-frequency-generation in an optical parametric oscillator using BiB₃O₆.

    Science.gov (United States)

    Devi, Kavita; Kumar, S Chaitanya; Ebrahim-Zadeh, M

    2013-10-21

    We report a continuous-wave (cw) source of tunable radiation across 333-345 nm in the ultraviolet (UV) using bismuth triborate, BiB₃O₆ (BIBO) as the nonlinear gain material. The source is based on internal sum-frequency-generation (SFG) in a cw singly-resonant optical parametric oscillator (OPO) pumped at 532 nm. The compact tunable source employs a 30-mm-long MgO:sPPLT crystal as the OPO gain medium and a 5-mm-long BIBO crystal for intracavity SFG of the signal and pump, providing up to 21.6 mW of UV power at 339.7 nm, with >15 mW over 64% of the SFG tuning range. The cw OPO is also tunable across 1158-1312 nm in the idler, delivering as much as 1.7 W at 1247 nm, with >1W over 65% of the tuning range. The UV output at maximum power exhibits passive power stability better than 3.4% rms and frequency stability of 193 GHz over more than one minute.

  12. Femtosecond nonlinear spectroscopy at surfaces: Second-harmonic probing of hole burning at the Si(111)7x7 surface and Fourier-transform sum-frequency vibrational spectroscopy

    International Nuclear Information System (INIS)

    McGuire, John Andrew

    2004-01-01

    The high temporal resolution and broad bandwidth of a femtosecond laser system are exploited in a pair of nonlinear optical studies of surfaces. The dephasing dynamics of resonances associated with the adatom dangling bonds of the Si(111)7 x 7 surface are explored by transient second-harmonic hole burning, a process that can be described as a fourth-order nonlinear optical process. Spectral holes produced by a 100 fs pump pulse at about 800 nm are probed by the second harmonic signal of a 100 fs pulse tunable around 800 nm. The measured spectral holes yield homogeneous dephasing times of a few tens of femtoseconds. Fits with a Lorentzian spectral hole centered at zero probe detuning show a linear dependence of the hole width on pump fluence, which suggests that charge carrier-carrier scattering dominates the dephasing dynamics at the measured excitation densities. Extrapolation of the deduced homogeneous dephasing times to zero excitation density yields an intrinsic dephasing time of ∼ 70 fs. The presence of a secondary spectral hole indicates that scattering of the surface electrons with surface optical phonons at 570 cm -1 occurs within the first 200 fs after excitation. The broad bandwidth of femtosecond IR pulses is used to perform IR-visible sum frequency vibrational spectroscopy. By implementing a Fourier-transform technique, we demonstrate the ability to obtain sub-laser-bandwidth spectral resolution. FT-SFG yields a greater signal when implemented with a stretched visible pulse than with a femtosecond visible pulse. However, when compared with multichannel spectroscopy using a femtosecond IR pulse but a narrowband visible pulse, Fourier-transform SFG is found to have an inferior signal-to-noise ratio. A mathematical analysis of the signal-to-noise ratio illustrates the constraints on the Fourier-transform approach

  13. Femtosecond nonlinear spectroscopy at surfaces: Second-harmonic probing of hole burning at the Si(111)7x7 surface and fourier-transform sum-frequency vibrational spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    McGuire, John Andrew [Univ. of California, Berkeley, CA (United States)

    2004-11-24

    The high temporal resolution and broad bandwidth of a femtosecond laser system are exploited in a pair of nonlinear optical studies of surfaces. The dephasing dynamics of resonances associated with the adatom dangling bonds of the Si(111)7 x 7 surface are explored by transient second-harmonic hole burning, a process that can be described as a fourth-order nonlinear optical process. Spectral holes produced by a 100 fs pump pulse at about 800 nm are probed by the second harmonic signal of a 100 fs pulse tunable around 800 nm. The measured spectral holes yield homogeneous dephasing times of a few tens of femtoseconds. Fits with a Lorentzian spectral hole centered at zero probe detuning show a linear dependence of the hole width on pump fluence, which suggests that charge carrier-carrier scattering dominates the dephasing dynamics at the measured excitation densities. Extrapolation of the deduced homogeneous dephasing times to zero excitation density yields an intrinsic dephasing time of {approx} 70 fs. The presence of a secondary spectral hole indicates that scattering of the surface electrons with surface optical phonons at 570 cm-1 occurs within the first 200 fs after excitation. The broad bandwidth of femtosecond IR pulses is used to perform IR-visible sum frequency vibrational spectroscopy. By implementing a Fourier-transform technique, we demonstrate the ability to obtain sub-laser-bandwidth spectral resolution. FT-SFG yields a greater signal when implemented with a stretched visible pulse than with a femtosecond visible pulse. However, when compared with multichannel spectroscopy using a femtosecond IR pulse but a narrowband visible pulse, Fourier-transform SFG is found to have an inferior signal-to-noise ratio. A mathematical analysis of the signal-to-noise ratio illustrates the constraints on the Fourier-transform approach.

  14. Blue and Orange Two-Color CW Laser Based on Single-Pass Second-Harmonic and Sum-Frequency Generation in MgO:PPLN

    Directory of Open Access Journals (Sweden)

    Dismas K. Choge

    2018-04-01

    Full Text Available We demonstrate a compact blue and orange-two color continuous wave laser source emitting at 487 nm and from 597.4 to 600.3 nm, respectively. The temperature tunable coherent orange radiation is achieved by frequency mixing 974 nm laser diode (LD and a C-band amplified spontaneous emission laser source while the temperature insensitive blue radiation is generated by second-order quasi-phase-matching frequency doubling of 974 nm LD. We implement the simultaneous nonlinear processes in a single magnesium oxide doped periodically poled lithium niobate bulk crystal without the need of an aperiodic design.

  15. Alkyl chain interaction at the surface of room temperature ionic liquids: systematic variation of alkyl chain length (R = C(1)-C(4), C(8)) in both cation and anion of [RMIM][R-OSO(3)] by sum frequency generation and surface tension.

    Science.gov (United States)

    Santos, Cherry S; Baldelli, Steven

    2009-01-29

    The gas-liquid interface of halide-free 1,3-dialkylimidazolium alkyl sulfates [RMIM][R-OSO(3)] with R chain length from C(1)-C(4) and C(8) has been studied systematically using the surface-specific sum frequency generation (SFG) vibrational spectroscopy and surface tension measurements. From the SFG spectra, vibrational modes from the methyl group of both cation and anion are observed for all ionic liquid samples considered in the present study. These results suggest the presence of both ions at the gas-liquid interface, which is further supported by surface tension measurements. Surface tension data show a decreasing trend as the alkyl chain in the imidazolium cation is varied from methyl to butyl chain, with a specific anion. A similar trend is observed when the alkyl chain of the anion is modified and the cation is fixed.

  16. Support effects in catalysis studied by in-situ sum frequency generation vibrational spectroscopy and in-situ x-ray spectroscopies

    Energy Technology Data Exchange (ETDEWEB)

    Kennedy, Griffin John [Univ. of California, Berkeley, CA (United States)

    2017-04-14

    Here, kinetic measurements are paired with in-situ spectroscopic characterization tools to investigate colloidally based, supported Pt catalytic model systems in order to elucidate the mechanisms by which metal and support work in tandem to dictate activity and selectivity. The results demonstrate oxide support materials, while inactive in absence of Pt nanoparticles, possess unique active sites for the selective conversion of gas phase molecules when paired with an active metal catalyst.

  17. Unidirectional ring-laser operation using sum-frequency mixing

    DEFF Research Database (Denmark)

    Tidemand-Lichtenberg, Peter; Cheng, Haynes Pak Hay; Pedersen, Christian

    2010-01-01

    A technique enforcing unidirectional operation of ring lasers is proposed and demonstrated. The approach relies on sum-frequency mixing between a single-pass laser and one of the two counterpropagating intracavity fields of the ring laser. Sum-frequency mixing introduces a parametric loss for the...... where lossless second-order nonlinear materials are available. Numerical modeling and experimental demonstration of parametric-induced unidirectional operation of a diode-pumped solid-state 1342 nm cw ring laser are presented.......A technique enforcing unidirectional operation of ring lasers is proposed and demonstrated. The approach relies on sum-frequency mixing between a single-pass laser and one of the two counterpropagating intracavity fields of the ring laser. Sum-frequency mixing introduces a parametric loss...

  18. Giant enhancement of sum-frequency yield by surface-plasmon excitation

    NARCIS (Netherlands)

    van der Ham, E. W. M.; Vrehen, Q. H. F.; Eliel, E. R.; Yakovlev, V. A.; Valieva, E. V.; Kuzik, L. A.; Petrov, J. E.; Sychugov, V. A.; van der Meer, A. F. G.

    1999-01-01

    We show experimentally that the radiation generated in infrared-visible sum-frequency mixing at an air-silver interface can be greatly enhanced when the visible input beam excites a surface plasmon-polariton at the interface. With either a prism or a grating used to couple the visible radiation with

  19. Water Orientation at Ceramide/Water Interfaces Studied by Heterodyne-Detected Vibrational Sum Frequency Generation Spectroscopy and Molecular Dynamics Simulation

    KAUST Repository

    Adhikari, Aniruddha; Re, Suyong; Nishima, Wataru; Ahmed, Mohammed; Nihonyanagi, Satoshi; Klauda, Jeffery B.; Sugita, Yuji; Tahara, Tahei

    2016-01-01

    Lipid/water interaction is essential for many biological processes. The water structure at the nonionic lipid interface remains little known, and there is no scope of a priori prediction of water orientation at nonionic interfaces, either. Here, we

  20. Polarization entanglement of sum-frequency photons: A tool to probe the Markovian limit

    Science.gov (United States)

    Volkov, Victor; Chelli, Riccardo

    2015-06-01

    The article addresses the possibility of entanglement-specific infrared-visible sum-frequency generation spectroscopy. In the case of an anisotropic interface, it is possible to employ SSS and PSS polarizations to detect responses not only specific to χY Y Y and χX Y Y nonlinearities, but also to higher-order χ(Y Y Y )(X Y Y ) and χ(X Y Y )(Y Y Y ) nonlinearities. Using quantum mechanical studies of the rhenium complex [Re (OH) 3(CO) 3] as a molecular model, we demonstrate that if such complexes would form an anisotropic orientational distribution at a surface, under the considered geometry and the polarization settings, we may prepare quantum correlated C =O vibrational states to emit polarization-entangled photons. Accordingly, we explore the possibility of a polarization-measurement protocol to extract spectral signatures of the entangled states. The response would be informative on intramolecular interactions. As a result, we discuss the possible practical implications in probing dynamics at interfaces, and different opportunities in the preparation of entangled vibrational states of quantified fidelity.

  1. Nonlinear beam clean-up using resonantly enhanced sum-frequency mixing

    DEFF Research Database (Denmark)

    Karamehmedovic, Emir; Pedersen, Christian; Jensen, Ole Bjarlin

    2009-01-01

    We investigate the possibility of improving the beam quality and obtaining high conversion efficiency in nonlinear sum-frequency generation. A 765 nm beam from an external cavity tapered diode laser is single-passed through a nonlinear crystal situated in the high intracavity field of a 1342 nm N......:YVO4 laser, generating a SFG beam at 488 nm. The ECDL have MH^2=1.9 and MV^2=2.4 and the solid-state laser has M^2...

  2. Sensibility to Changes of Vibrational Modes of Excited Electron: Sum Frequency Signals Versus Difference Frequency Signals

    International Nuclear Information System (INIS)

    Gu Anna; Liang Xianting

    2011-01-01

    In this paper, we investigate a two electronic level system with vibrational modes coupled to a Brownian oscillator bath. The difference frequency generation (DFG) signals and sum frequency generation (SFG) signals are calculated. It is shown that, for the same model, the SFG signals are more sensitive than the DFG signals to the changes of the vibrational modes of the electronic two-level system. Because the SFG conversion efficiency can be improved by using the time-delay method, the findings in this paper predict that the SFG spectrum may probe the changes of the microstructure more effectively. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

  3. All-solid-state continuous-wave doubly resonant all-intracavity sum-frequency mixer.

    Science.gov (United States)

    Kretschmann, H M; Heine, F; Huber, G; Halldórsson, T

    1997-10-01

    A new resonator design for doubly resonant continuous-wave intracavity sum-frequency mixing is presented. We generated 212 mW of coherent radiation at 618 nm by mixing the radiation of a 1080-nm Nd(3+):YAlO(3) laser and a 1444-nm Nd(3+):YAG laser. Two different mixing resonator setups and several nonlinear-optical crystals were investigated. So far output is limited by unequal performance of the two fundamental lasers and coating problems of the nonlinear crystals.

  4. Sum-frequency spectroscopic studies: I. Surface melting of ice, II. Surface alignment of polymers

    Energy Technology Data Exchange (ETDEWEB)

    Wei, Xing [Univ. of California, Berkeley, CA (United States)

    2000-01-01

    Surface vibrational spectroscopy via infrared-visible sum-frequency generation (SFG) has been established as a useful tool to study the structures of different kinds of surfaces and interfaces. This technique was used to study the (0001) face of hexagonal ice (Ih). SFG spectra in the O-H stretch frequency range were obtained at various sample temperatures. For the vapor(air)/ice interface, the degree of orientational order of the dangling OH bonds at the surface was measured as a function of temperature. Disordering sets in around 200 K and increases dramatically with temperature, which is strong evidence of surface melting of ice. For the other ice interfaces (silica/OTS/ice and silica/ice), a similar temperature dependence of the hydrogen bonded OH stretch peak was observed; the free OH stretch mode, however, appears to be different from that of the vapor (air)/ice interface due to interactions at the interfaces. The technique was also used to measure the orientational distributions of the polymer chains on a rubbed polyvinyl alcohol surface. Results show that the polymer chains at the surface appear to be well aligned by rubbing, and the adsorbed liquid crystal molecules are aligned, in turn, by the surface polymer chains. A strong correlation exists between the orientational distributions of the polymer chains and the liquid crystal molecules, indicating that the surface-induced bulk alignment of a liquid crystal film by rubbed polymer surfaces is via an orientational epitaxy-like mechanism. This thesis also contains studies on some related issues that are crucial to the above applications. An experiment was designed to measure SFG spectra in both reflection and transmission. The result confirms that SFG in reflection is generally dominated by the surface contribution. Another issue is the motional effect due to fast orientational motion of molecules at a surface or interface. Calculations show that the effect is significant if the molecular orientation varies

  5. Efficient near diffraction limited blue light source by sum-frequency mixing of a BAL and a solid-state laser

    DEFF Research Database (Denmark)

    Sørensen, Knud Palmelund; Tidemand-Lichtenberg, Peter; Pedersen, Christian

    2011-01-01

    and slow axis of the diode, respectively. The BAL output beam is single-passed through a periodically poled KTiOPO4 (PPKTP) crystal placed in an intra-cavity beam waist of a 1064 nm Nd:YVO4 laser, resulting in 100 mW of sum-frequency generated blue output power. This corresponds to a power conversion......Sum-frequency mixing of an 808 nm broad area laser (BAL) with a build-in grating structure for spectral control and a 1064 nm solid-state laser is experimentally investigated. The spectrally improved 20 mu m wide BAL can deliver up to 700 mW of output power with an M-2 of 1.4 and 5.3 in the fast...

  6. Up to 30 mW of broadly tunable CW green-to-orange light, based on sum-frequency mixing of Cr4+:forsterite and Nd:YVO4 lasers

    DEFF Research Database (Denmark)

    Mortensen, Jesper Liltorp; McWilliam, Allan; G. Leburn, Christopher

    2006-01-01

    Efficient generation of continuous-wave (CW) tunable light in the yellow region is reported. The method is based on sum-frequency mixing of a tunable Cr4+:forsterite laser with a Nd:YVO4 laser. A periodically poled lithium niobate crystal was placed intra-cavity in a Nd:YVO4 laser, and the Cr4...

  7. Self-assembled organic and fullerene monolayers characterisation by two-colour SFG spectroscopy: a pathway to meet doubly resonant SFG process

    International Nuclear Information System (INIS)

    Humbert, C.; Caudano, Y.; Dreesen, L.; Sartenaer, Y.; Mani, A.A.; Silien, C.; Lemaire, J.-J.; Thiry, P.A.; Peremans, A.

    2004-01-01

    Two-colour sum-frequency generation (two-colour SFG) spectroscopy was used to probe both vibrational and electronic properties of 1-dodecanethiol/Ag(1 1 1), Au(1 1 1), and Pt(1 1 1), of 5-[p-(6-mercaptohexoxy)-phenyl]-10,15,20-triphenylporphin/Pt(1 1 1), and of C 60 /Ag(1 1 1). The role of the various physical parameters determining the sum-frequency generation (SFG) intensity equation is highlighted. The enhancement of the non-linear second order susceptibility in the aforementioned interfaces is explained in terms of metal interband transition, molecular electronic transition and of electron-phonon coupling, respectively

  8. Self-assembled organic and fullerene monolayers characterisation by two-colour SFG spectroscopy: a pathway to meet doubly resonant SFG process

    Science.gov (United States)

    Humbert, C.; Caudano, Y.; Dreesen, L.; Sartenaer, Y.; Mani, A. A.; Silien, C.; Lemaire, J.-J.; Thiry, P. A.; Peremans, A.

    2004-10-01

    Two-colour sum-frequency generation (two-colour SFG) spectroscopy was used to probe both vibrational and electronic properties of 1-dodecanethiol/Ag(1 1 1), Au(1 1 1), and Pt(1 1 1), of 5-[ p-(6-mercaptohexoxy)-phenyl]-10,15,20-triphenylporphin/Pt(1 1 1), and of C 60/Ag(1 1 1). The role of the various physical parameters determining the sum-frequency generation (SFG) intensity equation is highlighted. The enhancement of the non-linear second order susceptibility in the aforementioned interfaces is explained in terms of metal interband transition, molecular electronic transition and of electron-phonon coupling, respectively.

  9. Self-assembled organic and fullerene monolayers characterisation by two-colour SFG spectroscopy: a pathway to meet doubly resonant SFG process

    OpenAIRE

    Humbert, C.; Caudano, Y.; Dreesen, Laurent; Sartenaer, Y.; Mani, A. A.; Silien, C.; Lemaire, J.-J.; Thiry, P. A.; Peremans, A.

    2004-01-01

    Two-colour sum-frequency generation (two-colour SFG) spectroscopy was used to probe both vibrational and electronic properties of 1-dodecanethiol/Ag(1 1 1), Au(1 1 1), and Pt(1 1 1), of 5-[p-(6-mercaptohexoxy)-phenyl]-10,15,20-triphenylporphin/Pt(1 1 1), and of C60/Ag(1 1 1). The role of the various physical parameters determining the sum-frequency generation (SFG) intensity equation is highlighted. The enhancement of the non-linear second order susceptibility in the aforementioned interfaces...

  10. Generation of continuous coherent radiation at Lyman-alpha and 1S-2P Spectroscopy of atomic hydrogen

    NARCIS (Netherlands)

    Pahl, A.; Fendel, P.; Henrich, B.R.; Walz, J.; Hansch, T.W.; Eikema, K.S.E.

    2005-01-01

    Continuous coherent radiation from wavelengths from 121 to 123 nm in the vacuum ultraviolet (VUV) was generated by four-wave sum-frequency mixing in mercury vapor. A yield of 20 nW at Lyman-alpha (121.57 nm) was achieved. We describe the experimental setup in detail and present a calculation of the

  11. Second Harmonic Generation, Sum Frequency Generation, and χ(3): Dissecting Environmental Interfaces with a Nonlinear Optical Swiss Army Knife

    Science.gov (United States)

    Geiger, Franz M.

    2009-05-01

    This review discusses recent advances in the nonlinear optics of environmental interfaces. We discuss the quantitative aspects of the label-free approaches presented here and demonstrate that nonlinear optics has now assumed the role of a Swiss Army knife that can be used to dissect, with molecular detail, the fundamental and practical aspects of environmental interfaces and heterogeneous geochemical environments. In this work, nonlinear optical methods are applied to complex organic molecules, such as veterinary antibiotics, and to small inorganic anions and cations, such as nitrate and chromate, or cadmium, zinc, and manganese. The environmental implications of the thermodynamic, kinetic, spectroscopic, structural, and electrochemical data are discussed.

  12. In-Situ Measurement of Chirality of Molecules and Molecular Assemblies with Surface Nonlinear Spectroscopy

    International Nuclear Information System (INIS)

    Wang, Hongfei

    2012-01-01

    Developments in quantitative measurement and analysis in nonlinear surface spectroscopy, namely, second harmonic generation linear dichroism (SHG-LD) and sum frequency generation vibrational spectroscopy linear dichroism (SFG-VS-LD), provide new opportunities for probing the surface chirality of monolayers and thin films. In this book chapter, the up-to-date theoretical background and experimental methodology, as well as examples and future perspectives on the developments with surface nonlinear spectroscopy in surface chirality studies are to be summarized and outlined for general readers.

  13. SFG spectroscopy from 10 -8 to 1000 mbar: less-ordered CO structures and coadsorption on Pd (1 1 1)

    Science.gov (United States)

    Morkel, Matthias; Unterhalt, Holger; Salmeron, Miquel; Rupprechter, Günther; Freund, Hans-Joachim

    2003-06-01

    Vibrational sum frequency generation spectroscopy was employed to study "less-ordered" phases resulting from low-temperature CO exposure on Pd(1 1 1). Such imperfect structures may also occur under catalytic reaction conditions up to 1000 mbar and originate from the superposition of ordered structures when the CO mobility and flux were insufficient. The effect of coadsorbed hydrogen and water was also examined.

  14. Analysis Tools for Next-Generation Hadron Spectroscopy Experiments

    Science.gov (United States)

    Battaglieri, M.; Briscoe, B. J.; Celentano, A.; Chung, S.-U.; D'Angelo, A.; De Vita, R.; Döring, M.; Dudek, J.; Eidelman, S.; Fegan, S.; Ferretti, J.; Filippi, A.; Fox, G.; Galata, G.; García-Tecocoatzi, H.; Glazier, D. I.; Grube, B.; Hanhart, C.; Hoferichter, M.; Hughes, S. M.; Ireland, D. G.; Ketzer, B.; Klein, F. J.; Kubis, B.; Liu, B.; Masjuan, P.; Mathieu, V.; McKinnon, B.; Mitchel, R.; Nerling, F.; Paul, S.; Peláez, J. R.; Rademacker, J.; Rizzo, A.; Salgado, C.; Santopinto, E.; Sarantsev, A. V.; Sato, T.; Schlüter, T.; [Silva]da Silva, M. L. L.; Stankovic, I.; Strakovsky, I.; Szczepaniak, A.; Vassallo, A.; Walford, N. K.; Watts, D. P.; Zana, L.

    The series of workshops on New Partial-Wave Analysis Tools for Next-Generation Hadron Spectroscopy Experiments was initiated with the ATHOS 2012 meeting, which took place in Camogli, Italy, June 20-22, 2012. It was followed by ATHOS 2013 in Kloster Seeon near Munich, Germany, May 21-24, 2013. The third, ATHOS3, meeting is planned for April 13-17, 2015 at The George Washington University Virginia Science and Technology Campus, USA. The workshops focus on the development of amplitude analysis tools for meson and baryon spectroscopy, and complement other programs in hadron spectroscopy organized in the recent past including the INT-JLab Workshop on Hadron Spectroscopy in Seattle in 2009, the International Workshop on Amplitude Analysis in Hadron Spectroscopy at the ECT*-Trento in 2011, the School on Amplitude Analysis in Modern Physics in Bad Honnef in 2011, the Jefferson Lab Advanced Study Institute Summer School in 2012, and the School on Concepts of Modern Amplitude Analysis Techniques in Flecken-Zechlin near Berlin in September 2013. The aim of this document is to summarize the discussions that took place at the ATHOS 2012 and ATHOS 2013 meetings. We do not attempt a comprehensive review of the field of amplitude analysis, but offer a collection of thoughts that we hope may lay the ground for such a document.

  15. Analysis Tools for Next-Generation Hadron Spectroscopy Experiments

    International Nuclear Information System (INIS)

    Battaglieri, Marco; Briscoe, William; Celentano, Andrea; Chung, Suh-Urk; D'Angelo, Annalisa; De Vita, Rafaella; Döring, Michael; Dudek, Jozef; Eidelman, S.; Fegan, Stuart; Ferretti, J.; Filippi, A.; Fox, G.; Galata, G.; Garcia-Tecocoatzi, H.; Glazier, Derek; Grube, B.; Hanhart, C.; Hoferichter, M.; Hughes, S. M.; Ireland, David G.; Ketzer, B.; Klein, Franz J.; Kubis, B.; Liu, B.; Masjuan, P.; Mathieu, Vincent; McKinnon, Brian; Mitchel, R.; Nerling, F.; Paul, S.; Peláez, J. R.; Rademacker, J.; Rizzo, Alessandro; Salgado, Carlos; Santopinto, E.; Sarantsev, Andrey V.; Sato, Toru; Schlüter, T.; Da Silva, M. L.L.; Stankovic, I.; Strakovsky, Igor; Szczepaniak, Adam; Vassallo, A.; Walford, Natalie K.; Watts, Daniel P.

    2015-01-01

    The series of workshops on New Partial-Wave Analysis Tools for Next-Generation Hadron Spectroscopy Experiments was initiated with the ATHOS 2012 meeting, which took place in Camogli, Italy, June 20-22, 2012. It was followed by ATHOS 2013 in Kloster Seeon near Munich, Germany, May 21-24, 2013. The third, ATHOS3, meeting is planned for April 13-17, 2015 at The George Washington University Virginia Science and Technology Campus, USA. The workshops focus on the development of amplitude analysis tools for meson and baryon spectroscopy, and complement other programs in hadron spectroscopy organized in the recent past including the INT-JLab Workshop on Hadron Spectroscopy in Seattle in 2009, the International Workshop on Amplitude Analysis in Hadron Spectroscopy at the ECT*-Trento in 2011, the School on Amplitude Analysis in Modern Physics in Bad Honnef in 2011, the Jefferson Lab Advanced Study Institute Summer School in 2012, and the School on Concepts of Modern Amplitude Analysis Techniques in Flecken-Zechlin near Berlin in September 2013. The aim of this document is to summarize the discussions that took place at the ATHOS 2012 and ATHOS 2013 meetings. We do not attempt a comprehensive review of the field of amplitude analysis, but offer a collection of thoughts that we hope may lay the ground for such a document

  16. Generation of narrow peaks in spectroscopy of charged particles

    Energy Technology Data Exchange (ETDEWEB)

    Dubbers, Dirk, E-mail: dubbers@physi.uni-heidelberg.de; Schmidt, Ulrich, E-mail: ulrich.schmidt@physi.uni-heidelberg.de

    2016-11-21

    In spectroscopy of charged particles, narrow peaks may appear in continuous spectra if magnetic transport of the particles is involved. These artefacts, which so far have escaped the attention of investigators, can develop whenever geometric detection efficiency is less than 100%. As such peaks may be misinterpreted as new physics, their generation is investigated, both analytically and experimentally, for various detector configurations, including those used in searches for the spontaneous decay of the vacuum in heavy-ion collisions.

  17. Detection of elemental mercury by multimode diode laser correlation spectroscopy.

    Science.gov (United States)

    Lou, Xiutao; Somesfalean, Gabriel; Svanberg, Sune; Zhang, Zhiguo; Wu, Shaohua

    2012-02-27

    We demonstrate a method for elemental mercury detection based on correlation spectroscopy employing UV laser radiation generated by sum-frequency mixing of two visible multimode diode lasers. Resonance matching of the multimode UV laser is achieved in a wide wavelength range and with good tolerance for various operating conditions. Large mode-hops provide an off-resonance baseline, eliminating interferences from other gas species with broadband absorption. A sensitivity of 1 μg/m3 is obtained for a 1-m path length and 30-s integration time. The performance of the system shows promise for mercury monitoring in industrial applications.

  18. Second harmonic generation spectroscopy on Si surfaces and interfaces

    DEFF Research Database (Denmark)

    Pedersen, Kjeld

    2010-01-01

    Optical second harmonic generation (SHG) spectroscopy studies of Si(111) surfaces and interfaces are reviewed for two types of systems: (1) clean 7 x 7 and root 3 x root 3-Ag reconstructed surfaces prepared under ultra-high vacuum conditions where surface states are excited and (2) interfaces...... in silicon-on-insulator (SOI) structures and thin metal films on Si surfaces where several interfaces contribute to the SHG. In all the systems resonances are seen at interband transitions near the bulk critical points E-1 and E-2. On the clean surfaces a number of resonances appear below the onset of bulk...

  19. Self-assembled organic and fullerene monolayers characterisation by two-colour SFG spectroscopy: a pathway to meet doubly resonant SFG process

    Energy Technology Data Exchange (ETDEWEB)

    Humbert, C.; Caudano, Y.; Dreesen, L.; Sartenaer, Y.; Mani, A.A.; Silien, C.; Lemaire, J.-J.; Thiry, P.A.; Peremans, A

    2004-10-15

    Two-colour sum-frequency generation (two-colour SFG) spectroscopy was used to probe both vibrational and electronic properties of 1-dodecanethiol/Ag(1 1 1), Au(1 1 1), and Pt(1 1 1), of 5-[p-(6-mercaptohexoxy)-phenyl]-10,15,20-triphenylporphin/Pt(1 1 1), and of C{sub 60}/Ag(1 1 1). The role of the various physical parameters determining the sum-frequency generation (SFG) intensity equation is highlighted. The enhancement of the non-linear second order susceptibility in the aforementioned interfaces is explained in terms of metal interband transition, molecular electronic transition and of electron-phonon coupling, respectively.

  20. Difference frequency generation spectroscopy as a vibrational optical activity measurement tool.

    Science.gov (United States)

    Cheon, Sangheon; Cho, Minhaeng

    2009-03-19

    Vibrational optical activity (VOA) of chiral molecules in condensed phases can be studied by using vibrational circular dichroism and Raman optical activity measurement techniques. Recently, IR-vis sum frequency generation has shown to be an alternative VOA measurement method. Such a three-wave-mixing method employing a polarization modulation technique can be a potentially useful VOA measurement tool. Here, a theoretical description of difference frequency generation (DFG) employing circularly polarized visible radiations is presented. Frequency scanning to obtain a VOA-DFG spectrum is achieved by controlling the difference between the two electronically nonresonant incident radiation frequencies. If the two incident beams are linearly polarized and their polarization directions are perpendicular to each other, one can selectively measure the all-electric-dipole-allowed chiral component of the DFG susceptibility. In addition, by using circularly polarized beams and taking the DFG difference intensity signal, which is defined as the difference between left and right circularly polarized DFG signals, additional chiral susceptibility components originating from the electric quadrupole transition can be measured. The DFG as a novel VOA measurement technique for solution samples containing chiral molecules will therefore be a useful coherent spectroscopic tool for determining absolute configuration of chiral molecules in condensed phases.

  1. CW light sources at the 589 nm sodium D2 line by sum-frequency mixing of diode pumped neodymium lasers

    International Nuclear Information System (INIS)

    Lü, Y F; Lu, J; Xu, L J; Sun, G C; Zhao, Z M; Gao, X; Lin, J Q

    2010-01-01

    We present a laser architecture to obtain continuous-wave (CW) light sources at the 589 nm sodium D2 line. A 808 nm diode-pumped a Nd:YLiF 4 (Nd:YLF) crystal emitting at 1053 nm. A part of the pump power was then absorbed by the Nd:YLF crystal. The remaining was used to pump a Nd:YAG crystal emitting at 1338 nm. Intracavity sum-frequency mixing at 1053 and 1338 nm was then realized in a LiB 3 O 5 (LBO) crystal to reach the yellow-orange radiation. We obtained a CW output power of 235 mW at 589 nm with a pump laser diode emitting 17.8 W at 808 nm

  2. Diode-pumped quasi-three-level Nd:GdV O4–Nd:YAG sum-frequency laser at 464 nm

    International Nuclear Information System (INIS)

    Lu, Jie

    2014-01-01

    We report a laser architecture to obtain continuous-wave (cw) blue radiation at 464 nm. A 808 nm diode pumped a Nd:GdV O 4 crystal emitting at 912 nm. A part of the pump power was then absorbed by the Nd:GdV O 4 crystal. The remainder was used to pump a Nd:YAG crystal emitting at 946 nm. Intracavity sum-frequency mixing at 912 and 946 nm was then realized in a LiB 3 O 5 (LBO) crystal to produce blue radiation. We obtained a cw output power of 1.52 W at 464 nm with a pump laser diode emitting 18.4 W at 808 nm. (letter)

  3. Over 8 W high peak power UV laser with a high power Q-switched Nd:YVO4 oscillator and the compact extra-cavity sum-frequency mixing

    International Nuclear Information System (INIS)

    Yan, X P; Liu, Q; Gong, M; Wang, D S; Fu, X

    2009-01-01

    A 8.2 W UV laser was reported with the compact extra-cavity sum-frequency mixing. The IR fundamental frequency source was a high power and high beam quality Q-switched Nd:YVO 4 oscillator. 38 W fundamental frequency laser at 1064 nm was obtained at the pulse repetition rate of 450 kHz with the beam quality factors of M 2 x = 1.27, M 2 y = 1.21. The type I and type II phase-matched LBO crystals were used as the extra-cavity frequency doubling and mixing crystals respectively. At 38 kHz, 8.2 W UV laser at 355 nm was achieved with the pulse duration of 8 ns corresponding to the pulse peak power as high as 27 kW, and the optical-optical conversion efficiency from IR to UV was 25.6%. The output characteristics of the IR and the harmonic generations varying with the pulse repetition rate were also investigated detailedly

  4. Studies on the substrate mediated vibrational excitation of CO/Si(100) by means of SFG spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Han, Xu; Lass, Kristian; Balgar, Thorsten; Hasselbrink, Eckart [Universitaet Duisburg-Essen, Fachbereich Chemie, 45117 Essen (Germany)

    2009-07-01

    Vibrational excitations of adsorbates play an important role in chemical reaction dynamics. In the past decade CO on solid surfaces was chosen as adequate model system for studying vibrational relaxation dynamics. Our work is focused on the energy dissipation of vibrationally excited CO adsorbed on a silicon surface by means of IR/Vis sum frequency generation (SFG) spectroscopy. Here we present studies on substrate mediated excitation of vibrational modes of CO on Si(100) induced by UV radiation. We suppose the observation of highly excited internal stretch vibrations of CO caused by hot electrons generated within the silicon substrate.

  5. Interfacial structure of soft matter probed by SFG spectroscopy.

    Science.gov (United States)

    Ye, Shen; Tong, Yujin; Ge, Aimin; Qiao, Lin; Davies, Paul B

    2014-10-01

    Sum frequency generation (SFG) vibrational spectroscopy, an interface-specific technique in contrast to, for example, attenuated total reflectance spectroscopy, which is only interface sensitive, has been employed to investigate the surface and interface structure of soft matter on a molecular scale. The experimental arrangement required to carry out SFG spectroscopy, with particular reference to soft matter, and the analytical methods developed to interpret the spectra are described. The elucidation of the interfacial structure of soft matter systems is an essential prerequisite in order to understand and eventually control the surface properties of these important functional materials. Copyright © 2014 The Chemical Society of Japan and Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. WEAVE: the next generation wide-field spectroscopy facility for the William Herschel Telescope : The next generation wide-field spectroscopy facility for the William Herschel Telescope

    NARCIS (Netherlands)

    Dalton, Gavin; Trager, Scott C.; Abrams, Don Carlos; Carter, David; Bonifacio, Piercarlo; Aguerri, J. Alfonso L.; MacIntosh, Mike; Evans, Chris; Lewis, Ian; Navarro, Ramon; Agocs, Tibor; Dee, Kevin; Rousset, Sophie; Tosh, Ian; Middleton, Kevin; Pragt, Johannes; Terrett, David; Brock, Matthew; Benn, Chris; Verheijen, Marc; Cano Infantes, Diego; Bevil, Craige; Steele, Iain; Mottram, Chris; Bates, Stuart; Gribbin, Francis J.; Rey, Jürg; Rodriguez, Luis Fernando; Delgado, Jose Miguel; Guinouard, Isabelle; Walton, Nic; Irwin, Michael J.; Jagourel, Pascal; Stuik, Remko; Gerlofsma, Gerrit; Roelfsma, Ronald; Skillen, Ian; Ridings, Andy; Balcells, Marc; Daban, Jean-Baptiste; Gouvret, Carole; Venema, Lars; Girard, Paul

    We present the preliminary design of the WEAVE next generation spectroscopy facility for the William Herschel Telescope (WHT), principally targeting optical ground-based follow up of upcoming ground-based (LOFAR) and spacebased (Gaia) surveys. WEAVE is a multi-object and multi-IFU facility utilizing

  7. High-temperature laser induced spectroscopy in nuclear steam generators

    International Nuclear Information System (INIS)

    Allmon, W.E.; Berthold, J.W.

    1990-01-01

    This patent describes an apparatus for conducting optical spectroscopy in a hostile environment. It comprises: a source of high intensity light; an optical fiber connected to the source of high intensity light for transmitting light therefrom. The optical fiber having an end for discharging light onto a material to be spectroscopically analyzed; a sheath defining a space around at least a part of the optical fiber carrying the end of the optical fiber for shielding the optical fiber from the hostile environment; a window in the sheath for closing the space and for passing light transmitted through the end of the optical fiber out of the sheath; light detector means for detecting and spectroscopically analyzing emitted light from the material; an optical fiber means for transmitting the emitted light from the material to the light detector means; a standardization module for containing a sample having a known composition and being exposed to known temperature and pressure conditions; an additional optical fiber connected to the module for transmitting light to the sample in the module; multiplexer means; and additional optical fiber means for returning light from the module to the detector through the multiplexer means

  8. Corrosion of steam generator pipelines analysed using Moessbauer spectroscopy

    International Nuclear Information System (INIS)

    Slugen, V.; Lipka, J.; Toth, I.; Hascik, J.; Hinca, R.; Lehota, M.

    2003-01-01

    The variability of the properties and the composition of the corrosion products of the stainless CrNi and mild steels in dependence on the conditions (temperature, acidity, etc.) is of such range that, in practice, it is impossible to determine the properties of the corrosion products for an actual case from the theoretical data only. Since the decontamination processes for the materials of the water-cooled reactor (VVER-440) secondary circuits are in the progress of development, it is necessary to draw the needed information by the measurement and analysis of the real specimens. The corrosion layers was separated by scraping the rust off the surface and the powder samples were studied by transmission Moessbauer spectroscopy. It should be noted that the gamma spectroscopic measurements give no evidence of the presence of low-energy gamma radiation emitted from the samples. The scraped specimen powder was homogenised (using a 50 μm sieve) and fixed into a special holder. The 57 Co in Rh matrix was used as the radioactive Moessbauer source. Measured spectra were fitted using program NORMOS SITE. According to the results obtained from Moessbauer spectra, it is possible to establish that the main component of secondary circuit's corrosion products is magnetite Fe 3 O 4 . Next components are hematite α-Fe 2 O 3 and hydroxide akagenite β-FeOOH, which is characterised by significant paramagnetic doublet in the middle of spectra. The sextets corresponding to base materials (martensite and austenite steels) were identified in all measured spectra. (author)

  9. Femtosecond Coherent Anti-Stokes Raman Spectroscopy (CARS) As Next Generation Nonlinear LIDAR Spectroscopy and Microscopy

    International Nuclear Information System (INIS)

    Ooi, C. H. Raymond

    2009-01-01

    Nonlinear spectroscopy using coherent anti-Stokes Raman scattering and femtosecond laser pulses has been successfully developed as powerful tools for chemical analysis and biological imaging. Recent developments show promising possibilities of incorporating CARS into LIDAR system for remote detection of molecular species in airborne particles. The corresponding theory is being developed to describe nonlinear scattering of a mesoscopic particle composed of complex molecules by laser pulses with arbitrary shape and spectral content. Microscopic many-body transform theory is used to compute the third order susceptibility for CARS in molecules with known absorption spectrum and vibrational modes. The theory is combined with an integral scattering formula and Mie-Lorentz formulae, giving a rigorous formalism which provides powerful numerical experimentation of CARS spectra, particularly on the variations with the laser parameters and the direction of detection.

  10. Mobile charge generation dynamics in P3HT: PCBM observed by time-resolved terahertz spectroscopy

    DEFF Research Database (Denmark)

    Cooke, D. G.; Krebs, Frederik C; Jepsen, Peter Uhd

    2012-01-01

    Ultra-broadband time-resolved terahertz spectroscopy is used to examine the sub-ps conductivity dynamics of a conjugated polymer bulk heterojunction film P3HT:PCBM. We directly observe mobile charge generation dynamics on a sub-100 fs time scale.......Ultra-broadband time-resolved terahertz spectroscopy is used to examine the sub-ps conductivity dynamics of a conjugated polymer bulk heterojunction film P3HT:PCBM. We directly observe mobile charge generation dynamics on a sub-100 fs time scale....

  11. Adding a dimension to the infrared spectra of interfaces: 2D SFG spectroscopy via mid-IR pulse shaping

    Science.gov (United States)

    Zanni, Martin

    2012-02-01

    Sum-frequency generation spectroscopy provides an infrared spectrum of interfaces and thus has widespread use in the materials and chemical sciences. In this presentation, I will present our recent work in developing a 2D pulse sequence to generate 2D SFG spectra of interfaces, in analogy to 2D infrared spectra used to measure bulk species. To develop this spectroscopy, we have utilized many of the tricks-of-the-trade developed in the 2D IR and 2D Vis communities in the last decade, including mid-IR pulse shaping. With mid-IR pulse shaping, the 2D pulse sequence is manipulated by computer programming in the desired frequency resolution, rotating frame, and signal pathway. We believe that 2D SFG will become an important tool in the interfacial sciences in an analogous way that 2D IR is now being used in many disciplines.

  12. Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Hellman, Hal

    1968-01-01

    This booklet discusses spectroscopy, the study of absorption of radiation by matter, including X-ray, gamma-ray, microwave, mass spectroscopy, as well as others. Spectroscopy has produced more fundamental information to the study of the detailed structure of matter than any other tools.

  13. Spectroscopy

    CERN Document Server

    Walker, S

    1976-01-01

    The three volumes of Spectroscopy constitute the one comprehensive text available on the principles, practice and applications of spectroscopy. By giving full accounts of those spectroscopic techniques only recently introduced into student courses - such as Mössbauer spectroscopy and photoelectron spectroscopy - in addition to those techniques long recognised as being essential in chemistry teaching - sucha as e.s.r. and infrared spectroscopy - the book caters for the complete requirements of undergraduate students and at the same time provides a sound introduction to special topics for graduate students.

  14. Ultrafast spectroscopy of model biological membranes

    NARCIS (Netherlands)

    Ghosh, Avishek

    2009-01-01

    In this PhD thesis, I have described the novel time-resolved sum-frequency generation (TR-SFG) spectroscopic technique that I developed during the course of my PhD research and used it study the ultrafast vibrational, structural and orientational dynamics of water molecules at model biological

  15. High-resolution broadband terahertz spectroscopy via electronic heterodyne detection of photonically generated terahertz frequency comb.

    Science.gov (United States)

    Pavelyev, D G; Skryl, A S; Bakunov, M I

    2014-10-01

    We report an alternative approach to the terahertz frequency-comb spectroscopy (TFCS) based on nonlinear mixing of a photonically generated terahertz pulse train with a continuous wave signal from an electronic synthesizer. A superlattice is used as a nonlinear mixer. Unlike the standard TFCS technique, this approach does not require a complex double-laser system but retains the advantages of TFCS-high spectral resolution and wide bandwidth.

  16. An efficient continuous-wave 591 nm light source based on sum-frequency mixing of a diode pumped Nd:GdVO4–Nd:CNGG laser

    International Nuclear Information System (INIS)

    Zhao, Y D; Liu, J H

    2013-01-01

    We report a laser architecture to obtain continuous-wave (CW) yellow-orange light sources at the 591 nm wavelength. An 808 nm diode pumped a Nd:GdVO 4 crystal emitting at 1063 nm. A part of the pump power was then absorbed by the Nd:CNGG crystal. The remaining pump power was used to pump a Nd:CNGG crystal emitting at 1329 nm. Intracavity sum-frequency mixing at 1063 and 1329 nm was then realized in a LiB 3 O 5 (LBO) crystal to reach the yellow-orange radiation. We obtained a CW output power of 494 mW at 591 nm with a pump laser diode emitting 17.8 W at 808 nm. (paper)

  17. Raman spectroscopy for in-situ characterisation of steam generator deposits

    International Nuclear Information System (INIS)

    Rochefort, P.A.; Guzonas, D.A.; Turner, C.W.

    1997-12-01

    This report describes the effort to develop in-situ characterisation of steam generator deposits using remote raman spectroscopy to determine the chemical composition and semi-quantitative measurement of their concentrations. Information on the composition of the deposits is necessary in order to establish the optimal cleaning conditions and procedures. Furthermore, the composition of the deposits also provides information on the conditions that exist within the steam generator and the feedtrain. The raman spectra of the three most common iron oxide phases found in the CANDU deposits (hematite, magnetite and nickel ferrite) are shown

  18. Spectroscopy

    DEFF Research Database (Denmark)

    Berg, Rolf W.

    This introductory booklet covers the basics of molecular spectroscopy, infrared and Raman methods, instrumental considerations, symmetry analysis of molecules, group theory and selection rules, as well as assignments of fundamental vibrational modes in molecules.......This introductory booklet covers the basics of molecular spectroscopy, infrared and Raman methods, instrumental considerations, symmetry analysis of molecules, group theory and selection rules, as well as assignments of fundamental vibrational modes in molecules....

  19. DEVELOPMENT OF NEXT-GENERATION DETECTORS AND INSTRUMENTATION FOR PHOTOELECTRON SPECTROSCOPY, DIFFRACTION AND HOLOGRAPHY

    International Nuclear Information System (INIS)

    Charles S. Fadley, Principal Investigator

    2005-01-01

    We have developed a new multichannel detector for use in photoelectron spectroscopy (as well as other types of high-count-rate spectroscopy) that will operate at rates of up to 1 GHz. Such detectors are crucial to the full utilization of the high-brightness radiation generated by third-generation synchrotron radiation sources. In addition, new software and hardware has been developed to permit rapidly and accurately scanning photoelectron spectra that will be accumulated in as little as a 200 micros. A versatile next-generation sample goniometer permitting equally rapid scanning of specimen angles or photon energies for angle-resolved photoemission studies, photoelectron diffraction, and photoelectron holography measurements, and cooling to below 10K has also been designed and constructed. These capabilities have been incorporated into a unique photoelectron spectrometer/diffractometer at the Advanced Light Source of the Lawrence Berkeley National Laboratory; this experimental system includes ultrahigh energy resolution, in situ rotation, variable polarization, and optional spin detection. This overall system is now being used in studies of a variety of problems including magnetic metals and oxides; metal/metal, metal/metal oxide, and metal-oxide/metal-oxide multilayers; and systems exhibiting giant and colossal magnetoresistance

  20. spectroscopy

    African Journals Online (AJOL)

    Aghomotsegin

    2015-10-14

    Oct 14, 2015 ... characterized by using phenotypic, API and Fourier transform infrared (FTIR) spectroscopy methods. One hundred and fifty-seven (157) strains were isolated from 13 cheese samples, and identification test was performed for 83 strains. At the end of the study, a total of 22 Lactococcus sp., 36 Enterecoccus ...

  1. Quantitative detection of plasma-generated radicals in liquids by electron paramagnetic resonance spectroscopy

    International Nuclear Information System (INIS)

    Tresp, H; Hammer, M U; Winter, J; Reuter, S; Weltmann, K-D

    2013-01-01

    In this paper the qualitative and quantitative detection of oxygen radicals in liquids after plasma treatment with an atmospheric pressure argon plasma jet by electron paramagnetic resonance spectroscopy is investigated. Absolute values for · OH and O 2 ·- radical concentration and their net production rate in plasma-treated liquids are determined without the use of additional scavenging chemicals such as superoxide dismutase (SOD) or mannitol (D-MAN). The main oxygen-centred radical generation in PBS was found to originate from the superoxide radical. It is shown that hidden parameters such as the manufacturer of chemical components could have a big influence on the comparability and reproducibility of the results. Finally, the effect of a shielding gas device for the investigated plasma jet with a shielding gas composition of varying oxygen-to-nitrogen ratio on radical generation after plasma treatment of phosphate-buffered saline solution was investigated. (paper)

  2. High Harmonic Generation XUV Spectroscopy for Studying Ultrafast Photophysics of Coordination Complexes

    Science.gov (United States)

    Ryland, Elizabeth S.; Lin, Ming-Fu; Benke, Kristin; Verkamp, Max A.; Zhang, Kaili; Vura-Weis, Josh

    2017-06-01

    Extreme ultraviolet (XUV) spectroscopy is an inner shell technique that probes the M_{2,3}-edge excitation of atoms. Absorption of the XUV photon causes a 3p→3d transition, the energy and shape of which is directly related to the element and ligand environment. This technique is thus element-, oxidation state-, spin state-, and ligand field specific. A process called high-harmonic generation (HHG) enables the production of ultrashort (˜20fs) pulses of collimated XUV photons in a tabletop instrument. This allows transient XUV spectroscopy to be conducted as an in-lab experiment, where it was previously only possible at accelerator-based light sources. Additionally, ultrashort pulses provide the capability for unprecedented time resolution (˜50fs IRF). This technique has the capacity to serve a pivotal role in the study of electron and energy transfer processes in materials and chemical biology. I will present the XUV transient absorption instrument we have built, along with ultrafast transient M_{2,3}-edge absorption data of a series of small inorganic molecules in order to demonstrate the high specificity and time resolution of this tabletop technique as well as how our group is applying it to the study of ultrafast electronic dynamics of coordination complexes.

  3. Multiphoton electronic-spin generation and transmission spectroscopy in n-type GaAs

    Energy Technology Data Exchange (ETDEWEB)

    Idrish Miah, M., E-mail: m.miah@griffith.edu.a [Department of Physics, University of Chittagong, Chittagong 4331 (Bangladesh)

    2011-01-17

    Multiphoton electronic-spin generation in semiconductors was investigated using differential transmission spectroscopy. The generation of the electronic spins in the semiconductor samples were achieved by multiphoton pumping with circularly polarized light beam and was probed by the spin-resolved transmission of the samples. The electronic spin-polarization of conduction band was estimated and was found to depend on the delay of the probe beam, temperature as well as on the multiphoton pumping energy. The temperature dependence showed a decrease of the spin-polarization with increasing temperature. The electronic spin-polarization was found to depolarize rapidly for multiphoton pumping energy larger than the energy gap of the split-off band to the conduction band. The results were compared with those obtained in one-photon pumping, which shows that an enhancement of the electronic spin-polarization was achieved in multiphoton pumping. The findings resulting from this investigation might have potential applications in opto-spintronics, where the generation of highly polarized electronic spins is required.

  4. Multiphoton electronic-spin generation and transmission spectroscopy in n-type GaAs

    International Nuclear Information System (INIS)

    Idrish Miah, M.

    2011-01-01

    Multiphoton electronic-spin generation in semiconductors was investigated using differential transmission spectroscopy. The generation of the electronic spins in the semiconductor samples were achieved by multiphoton pumping with circularly polarized light beam and was probed by the spin-resolved transmission of the samples. The electronic spin-polarization of conduction band was estimated and was found to depend on the delay of the probe beam, temperature as well as on the multiphoton pumping energy. The temperature dependence showed a decrease of the spin-polarization with increasing temperature. The electronic spin-polarization was found to depolarize rapidly for multiphoton pumping energy larger than the energy gap of the split-off band to the conduction band. The results were compared with those obtained in one-photon pumping, which shows that an enhancement of the electronic spin-polarization was achieved in multiphoton pumping. The findings resulting from this investigation might have potential applications in opto-spintronics, where the generation of highly polarized electronic spins is required.

  5. Influences on the Emissions of Bacterial Plasmas Generated through Nanosecond Laser-Induced Breakdown Spectroscopy

    Science.gov (United States)

    Malenfant, Dylan J.

    In the past decade, laser-induced breakdown spectroscopy has been shown to provide compositional data that can be used for discrimination between bacterial specimens at the strain level. This work demonstrates the viability of this technique in a clinical setting. Studies were conducted to investigate the impact of emissions generated by a nitrocellulose filter paper background on the classification of four species: E. coli, S. epidermidis, M. smegmatis, and P. aeruginosa. Limits of detection were determined as 48+/-12 kCFU per ablation event for new mounting procedures using standard diagnostic laboratory techniques, and a device for centrifuge filtration was designed for sampling from low-titer bacterial suspensions. Plasma emissions from samples grown at biological levels of magnesium, zinc, and glucose were shown not to deviate from controls. A limit of detection for environmental zinc was found to be 11 ppm. Discrimination with heat-killed samples was demonstrated, providing a sterile diagnostic environment.

  6. Extremely short light pulses: generation; diagnostics, and application in attosecond spectroscopy

    International Nuclear Information System (INIS)

    Iakovlev, V.

    2003-06-01

    The scope of the thesis includes the design of chirped mirrors, as well as theoretical investigations in the fields of high-harmonic generation and laser-dressed Auger decay, the unifying aspect being the presence of extremely short light pulses and physical processes taking place on a femtosecond scale. The main results of the research are the following: 1) It was shown that efficient global optimization of chirped mirrors is possible with an adapted version of the memetic algorithm (also known as hybrid genetic algorithm). 2) The analysis of high-harmonic spectra generated by a few-cycle laser pulse can reveal the electric field of the pulse in the vicinity of its envelope peak. The method developed for this purpose can also be regarded as a method to measure the carrier-envelope phase of laser pulses, which is more robust and has a larger range of applicability compared to the simple analysis of the cut-off region of high-harmonic spectra. 3) A quantum theory of time-resolved Auger spectroscopy was developed. Based on the essential states method, closed-form expressions for probability amplitudes were derived. The theory lays the foundation for the interpretation of experiments that probe electronic motion during atomic excitation, deexcitation, and ionization. (author)

  7. Mobile Charge Generation Dynamics in P3HT:PCBM Observed by Time-Resolved Terahertz Spectroscopy

    DEFF Research Database (Denmark)

    Cooke, D. G.; Krebs, Frederik C; Jepsen, Peter Uhd

    2012-01-01

    Ultra-broadband time-resolved terahertz spectroscopy is used to examine the sub-ps conductivity dynamics of a conjugated polymer bulk heterojunction film P3HT:PCBM. We directly observe mobile charge generation dynamics on a sub-100 fs time scale.......Ultra-broadband time-resolved terahertz spectroscopy is used to examine the sub-ps conductivity dynamics of a conjugated polymer bulk heterojunction film P3HT:PCBM. We directly observe mobile charge generation dynamics on a sub-100 fs time scale....

  8. Generation of Electricity at Graphene Interface Governed by Underlying Surface Dipole Induced Ion Adsorption

    Science.gov (United States)

    Yang, Shanshan; Su, Yudan; Wu, Qiong; Zhang, Yuanbo; Tian, Chuanshan

    Aqueous droplet moving along graphene surface can produce electricity This interesting phenomenon provided environment-friendly means to harvest energy from graphene interface in contact with sea wave or rain droplets. However, microscopically, the nature of charge adsorption at the graphene interface is still unclear. Here, utilizing sum-frequency spectroscopy in combined with measurement of electrical power generation, the origin of charge adsorption on graphene was investigated. It was found that the direct ion-graphene interaction is negligibly small, contrary to the early speculation, but the ordered surface dipole from the supporting substrate, such as PET, is responsible for ion adsorption at the interface. Graphene serves as a conductive layer with mild screening of Coulomb interaction when aqueous droplet slips over the surface. These results pave the way for optimization of energy harvesting efficiency of graphene-based device.

  9. Time-domain SFG spectroscopy using mid-IR pulse shaping: practical and intrinsic advantages.

    Science.gov (United States)

    Laaser, Jennifer E; Xiong, Wei; Zanni, Martin T

    2011-03-24

    Sum-frequency generation (SFG) spectroscopy is a ubiquitous tool in the surface sciences. It provides infrared transition frequencies and line shapes that probe the structure and environment of molecules at interfaces. In this article, we apply techniques learned from the multidimensional spectroscopy community to SFG spectroscopy. We implement balanced heterodyne detection to remove scatter and the local oscillator background. Heterodyning also separates the resonant and nonresonant signals by acquiring both the real and imaginary parts of the spectrum. We utilize mid-IR pulse shaping to control the phase and delay of the mid-IR pump pulse. Pulse shaping allows phase cycling for data collection in the rotating frame and additional background subtraction. We also demonstrate time-domain data collection, which is a Fourier transform technique, and has many advantages in signal throughput, frequency resolution, and line shape accuracy over existing frequency domain methods. To demonstrate time-domain SFG spectroscopy, we study an aryl isocyanide on gold, and find that the system has an inhomogeneous structural distribution, in agreement with computational results, but which was not resolved by previous frequency-domain SFG studies. The ability to rapidly and actively manipulate the mid-IR pulse in an SFG pules sequence makes possible new experiments and more accurate spectra. © 2011 American Chemical Society

  10. Final design and progress of WEAVE : the next generation wide-field spectroscopy facility for the William Herschel Telescope

    NARCIS (Netherlands)

    Dalton, Gavin; Trager, Scott; Abrams, Don Carlos; Bonifacio, Piercarlo; Aguerri, J. Alfonso L.; Middleton, Kevin; Benn, Chris; Dee, Kevin; Sayède, Frédéric; Lewis, Ian; Pragt, Johannes; Pico, Sergio; Walton, Nic; Rey, Jeurg; Allende Prieto, Carlos; Peñate, José; Lhome, Emilie; Agócs, Tibor; Alonso, José; Terrett, David; Brock, Matthew; Gilbert, James; Schallig, Ellen; Ridings, Andy; Guinouard, Isabelle; Verheijen, Marc; Tosh, Ian; Rogers, Kevin; Lee, Martin; Steele, Iain; Stuik, Remko; Tromp, Niels; Jaskó, Attila; Carrasco, Esperanza; Farcas, Szigfrid; Kragt, Jan; Lesman, Dirk; Kroes, Gabby; Mottram, Chris; Bates, Stuart; Rodriguez, Luis Fernando; Gribbin, Frank; Delgado, José Miguel; Herreros, José Miguel; Martin, Carlos; Cano, Diego; Navarro, Ramon; Irwin, Mike; Lewis, Jim; Gonzalez Solares, Eduardo; Murphy, David; Worley, Clare; Bassom, Richard; O'Mahoney, Neil; Bianco, Andrea; Zurita, Christina; ter Horst, Rik; Molinari, Emilio; Lodi, Marcello; Guerra, José; Martin, Adrian; Vallenari, Antonella; Salasnich, Bernardo; Baruffolo, Andrea; Jin, Shoko; Hill, Vanessa; Smith, Dan; Drew, Janet; Poggianti, Bianca; Pieri, Mat; Dominquez Palmero, Lillian; Farina, Cecilia

    2016-01-01

    We present the Final Design of the WEAVE next-generation spectroscopy facility for the William Herschel Telescope (WHT), together with a status update on the details of manufacturing, integration and the overall project schedule now that all the major fabrication contracts are in place. We also

  11. Final design and progress of WEAVE: the next generation wide-field spectroscopy facility for the William Herschel Telescope

    NARCIS (Netherlands)

    Dalton, Gavin; Trager, Scott; Abrams, Don Carlos; Bonifacio, Piercarlo; Aguerri, J. Alfonso L.; Middleton, Kevin; Benn, Chris; Dee, Kevin; Sayède, Frédéric; Lewis, Ian; Pragt, Johannes; Pico, Sergio; Walton, Nic; Rey, Jeurg; Allende Prieto, Carlos; Peñate, José; Lhome, Emilie; Agócs, Tibor; Alonso, José; Terrett, David; Brock, Matthew; Gilbert, James; Schallig, Ellen; Ridings, Andy; Guinouard, Isabelle; Verheijen, Marc; Tosh, Ian; Rogers, Kevin; Lee, Martin; Steele, Iain; Stuik, Remko; Tromp, Niels; Jaskó, Attila; Carrasco, Esperanza; Farcas, Szigfrid; Kragt, Jan; Lesman, Dirk; Kroes, Gabby; Mottram, Chris; Bates, Stuart; Rodriguez, Luis Fernando; Gribbin, Frank; Delgado, José Miguel; Herreros, José Miguel; Martin, Carlos; Cano, Diego; Navarro, Ramon; Irwin, Mike; Lewis, Jim; Gonzalez Solares, Eduardo; Murphy, David; Worley, Clare; Bassom, Richard; O'Mahoney, Neil; Bianco, Andrea; Zurita, Christina; ter Horst, Rik; Molinari, Emilio; Lodi, Marcello; Guerra, José; Martin, Adrian; Vallenari, Antonella; Salasnich, Bernardo; Baruffolo, Andrea; Jin, Shoko; Hill, Vanessa; Smith, Dan; Drew, Janet; Poggianti, Bianca; Pieri, Mat; Dominquez Palmero, Lillian; Farina, Cecilia

    2016-01-01

    We present the Final Design of the WEAVE next-generation spectroscopy facility for the William Herschel Telescope (WHT), together with a status update on the details of manufacturing, integration and the overall project schedule now that all the major fabrication contracts are in place. We also

  12. Project overview and update on WEAVE: the next generation wide-field spectroscopy facility for the William Herschel Telescope

    NARCIS (Netherlands)

    Dalton, Gavin; Trager, Scott; Abrams, Don Carlos; Bonifacio, Piercarlo; López Aguerri, J. Alfonso; Middleton, Kevin; Benn, Chris; Dee, Kevin; Sayède, Frédéric; Lewis, Ian; Pragt, Johan; Pico, Sergio; Walton, Nic; Rey, Juerg; Allende Prieto, Carlos; Peñate, José; Lhome, Emilie; Agócs, Tibor; Alonso, José; Terrett, David; Brock, Matthew; Gilbert, James; Ridings, Andy; Guinouard, Isabelle; Verheijen, Marc A.W.; Tosh, Ian; Rogers, Kevin; Steele, Iain; Stuik, Remko; Tromp, Neils; Jasko, Attila; Kragt, Jan; Lesman, Dirk; Mottram, Chris; Bates, Stuart; Gribbin, Frank; Rodriguez, Luis Fernando; Delgado, José M.; Martin, Carlos; Cano, Diego; Navarro, Ramón; Irwin, Mike; Lewis, Jim; Gonzalez Solares, Eduardo; O'Mahony, Neil; Bianco, Andrea; Zurita, Christina; ter Horst, Rik; Molinari, Emilio; Lodi, Marcello; Guerra, José; Vallenari, Antonella; Baruffolo, Andrea

    We present an overview of and status report on the WEAVE next-generation spectroscopy facility for the William Herschel Telescope (WHT). WEAVE principally targets optical ground-based follow up of upcoming ground-based (LOFAR) and space-based (Gaia) surveys. WEAVE is a multi-object and multi-IFU

  13. Generation of Small Single Domain Nanobody Binders for Sensitive Detection of Testosterone by Electrochemical Impedance Spectroscopy.

    Science.gov (United States)

    Li, Guanghui; Zhu, Min; Ma, Lu; Yan, Junrong; Lu, Xiaoling; Shen, Yanfei; Wan, Yakun

    2016-06-08

    A phage display library of variable domain of the heavy chain only antibody or nanobody (Nb) was constructed after immunizing a bactrian camel with testosterone. With the smaller molecular size (15 kDa), improved solubility, good stability, high affinity, specificity, and lower immunogenicity, Nbs are a promising tool in the next generation of diagnosis and medical applications. Testosterone is a reproductive hormone, playing an important role in normal cardiac function and being the highly predictive marker for many diseases. Herein, a simple and sensitive immunosensor based on electrochemical impedance spectroscopy (EIS) and Nbs was successfully developed for the determination of testosterone. We successfully isolated the antitestosterone Nbs from an immune phage display library. Moreover, one of the Nbs was biotinylated according to in vivo BirA system, which showed the highest production yield and the most stable case. Further, the EIS immunosensor was set up for testosterone detection by applying the biotinylated antitestosterone Nb. As a result, the biosensor exhibited a linear working range from 0.05 to 5 ng mL(-1) with a detection limit of 0.045 ng mL(-1). In addition, the proposed immunosensor was successfully applied in determining testosterone in serum samples. In conclusion, the proposed immunosensor revealed high specificity of testosterone detection and showed as a potential approach for sensitive and accurate diagnosis of testosterone.

  14. Charge generation in organic solar cell materials studied by terahertz spectroscopy

    KAUST Repository

    Scarongella, M.

    2015-09-09

    We have investigated the photophysics in neat films of conjugated polymer PBDTTPD and its blend with PCBM using terahertz time-domain spectroscopy. This material has very high efficiency when used in organic solar cells. We were able to identify a THz signature for bound excitons in neat PBDTTPD films, pointing to important delocalization in those excitons. Then, we investigated the nature and local mobility (orders of magnitude higher than bulk mobility) of charges in the PBDTTPPD:PCBM blend as a function of excitation wavelength, fluence and pump-probe time delay. At low pump fluence (no bimolecular recombination phenomena), we were able to observe prompt and delayed charge generation components, the latter originating from excitons created in neat polymer domains which, thanks to delocalization, could reach the PCBM interface and dissociate to charges on a time scale of 1 ps. The nature of the photogenerated charges did not change between 0.5 ps and 800 ps after photo-excitation, which indicated that the excitons split directly into relatively free charges on an ultrafast time scale. © (2015) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.

  15. Probing electronic and vibrational properties at the electrochemical interface using SFG spectroscopy: Methanol electro-oxidation on Pt(1 1 0)

    Science.gov (United States)

    Vidal, F.; Busson, B.; Tadjeddine, A.

    2005-02-01

    We report the study of methanol electro-oxidation on Pt(1 1 0) using infrared-visible sum-frequency generation (SFG) vibrational spectroscopy. The use of this technique enables to probe the vibrational and electronic properties of the interface simultaneously in situ. We have investigated the vibrational properties of the interface in the CO ads internal stretch spectral region (1700-2150 cm -1) over a wide range of potentials. The analysis of the evolution of the C-O stretch line shape, which is related to the interference between the vibrational and electronic parts of the non-linear response, with the potential allows us to show that the onset of bulk methanol oxidation corresponds to the transition from a negatively to a positively charged surface.

  16. Applications of photon-in, photon-out spectroscopy with third-generation, synchrotron-radiation sources

    International Nuclear Information System (INIS)

    Lindle, D.W.; Perera, R.C.C.

    1991-01-01

    This report discusses the following topics: Mother nature's finest test probe; soft x-ray emission spectroscopy with high-brightness synchrotron radiation sources; anisotropy and polarization of x-ray emission from atoms and molecules; valence-hole fluorescence from molecular photoions as a probe of shape-resonance ionization: progress and prospects; structural biophysics on third-generation synchrotron sources; ultra-soft x-ray fluorescence-yield XAFS: an in situ photon-in, photon-out spectroscopy; and x-ray microprobe: an analytical tool for imaging elemental composition and microstructure

  17. Generation of pulsed far-infrared radiation and its application for far-infrared time-resolved spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Kondo, Yasuhiro [Tohoku Univ., Sendai (Japan). Faculty of Engineering

    1996-07-01

    So-called time-resolved spectroscopy technique has been used from old time as the means for studying the dynamic optical property, light-induced reaction and so on of matters. As an example, there is the method called pump and probe, and here, the wavelength of this probe light is the problem. If the object energy region is limited to about 0.1 eV, fast time-resolved spectroscopy is feasible relatively easily. However, energy region is extended to low energy region, the light source which is available as the pulsed probe light having sufficient intensity is limited. In this paper, the attempt of time-resolved spectroscopy utilizing coherent radiation, which has ended in failure, and the laser pulse-induced far-infrared radiation which can be utilized as new far-infrared probe light are reported. The reason why far-infrared radiation is used is explained. The attempt of time-resolved spectroscopy using NaCl crystals is reported on the equipment, the method of measuring absorption spectra and the results. Laser pulse-induced far-infrared radiation and the method of generating it are described. The multi-channel detector for far-infrared radiation which was made for trial is shown. (K.I.)

  18. Next generation laser-based standoff spectroscopy techniques for Mars exploration.

    Science.gov (United States)

    Gasda, Patrick J; Acosta-Maeda, Tayro E; Lucey, Paul G; Misra, Anupam K; Sharma, Shiv K; Taylor, G Jeffrey

    2015-01-01

    In the recent Mars 2020 Rover Science Definition Team Report, the National Aeronautics and Space Administration (NASA) has sought the capability to detect and identify elements, minerals, and most importantly, biosignatures, at fine scales for the preparation of a retrievable cache of samples. The current Mars rover, the Mars Science Laboratory Curiosity, has a remote laser-induced breakdown spectroscopy (LIBS) instrument, a type of quantitative elemental analysis, called the Chemistry Camera (ChemCam) that has shown that laser-induced spectroscopy instruments are not only feasible for space exploration, but are reliable and complementary to traditional elemental analysis instruments such as the Alpha Particle X-Ray Spectrometer. The superb track record of ChemCam has paved the way for other laser-induced spectroscopy instruments, such as Raman and fluorescence spectroscopy. We have developed a prototype remote LIBS-Raman-fluorescence instrument, Q-switched laser-induced time-resolved spectroscopy (QuaLITy), which is approximately 70 000 times more efficient at recording signals than a commercially available LIBS instrument. The increase in detection limits and sensitivity is due to our development of a directly coupled system, the use of an intensified charge-coupled device image detector, and a pulsed laser that allows for time-resolved measurements. We compare the LIBS capabilities of our system with an Ocean Optics spectrometer instrument at 7 m and 5 m distance. An increase in signal-to-noise ratio of at least an order of magnitude allows for greater quantitative analysis of the elements in a LIBS spectrum with 200-300 μm spatial resolution at 7 m, a Raman instrument capable of 1 mm spatial resolution at 3 m, and bioorganic fluorescence detection at longer distances. Thus, the new QuaLITy instrument fulfills all of the NASA expectations for proposed instruments.

  19. A trough for improved SFG spectroscopy of lipid monolayers

    Science.gov (United States)

    Franz, Johannes; van Zadel, Marc-Jan; Weidner, Tobias

    2017-05-01

    Lipid monolayers are indispensable model systems for biological membranes. The main advantage over bilayer model systems is that the surface pressure within the layer can be directly and reliably controlled. The sensitive interplay between surface pressure and temperature determines the molecular order within a model membrane and consequently determines the membrane phase behavior. The lipid phase is of crucial importance for a range of membrane functions such as protein interactions and membrane permeability. A very reliable method to probe the structure of lipid monolayers is sum frequency generation (SFG) vibrational spectroscopy. Not only is SFG extremely surface sensitive but it can also directly access critical parameters such as lipid order and orientation, and it can provide valuable information about protein interactions along with interfacial hydration. However, recent studies have shown that temperature gradients caused by high power laser beams perturb the lipid layers and potentially obscure the spectroscopic results. Here we demonstrate how the local heating problem can be effectively reduced by spatially distributing the laser pulses on the sample surface using a translating Langmuir trough for SFG experiments at lipid monolayers. The efficiency of the trough is illustrated by the detection of enhanced molecular order due to reduced heat load.

  20. Interaction of nanodiamond with in situ generated sp-carbon chains probed by Raman spectroscopy

    Czech Academy of Sciences Publication Activity Database

    Kavan, Ladislav; Zukalová, Markéta; Kalbáč, Martin; Osawa, E.; Dunsch, L.

    2006-01-01

    Roč. 44, č. 14 (2006), s. 3113-3116 ISSN 0008-6223 R&D Projects: GA AV ČR IAA4040306; GA MŠk LC510 Grant - others:NEDO International Grant(XE) 20041T081 Institutional research plan: CEZ:AV0Z40400503 Keywords : carbyne * diamond * Raman spectroscopy Subject RIV: CG - Electrochemistry Impact factor: 3.884, year: 2006

  1. X-ray absorption spectroscopy in the keV range with laser generated high harmonic radiation

    International Nuclear Information System (INIS)

    Seres, Enikoe; Seres, Jozsef; Spielmann, Christian

    2006-01-01

    By irradiating He and Ne atoms with 3 mJ, 12 fs, near infrared laser pulses from a tabletop laser system, the authors generated spatially and temporally coherent x rays up to a photon energy of 3.5 keV. With this source it is possible to use high-harmonic radiation for x-ray absorption spectroscopy in the keV range. They were able to clearly resolve the L absorption edges of titanium and copper and the K edges of aluminum and silicon. From the fine structure of the x-ray absorption they estimated the interatomic distances

  2. Conformational order of n-dodecanethiol and n-dodecaneselenol monolayers on polycrystalline copper investigated by PM-IRRAS and SFG spectroscopy

    Science.gov (United States)

    Fonder, G.; Cecchet, F.; Peremans, A.; Thiry, P. A.; Delhalle, J.; Mekhalif, Z.

    2009-08-01

    Self-assembled monolayers (SAMs) of n-dodecanethiol (C 12H 25SH) and n-dodecaneselenol (C 12H 25SeH) on polycrystalline copper have been elaborated with the purpose of achieving densely packed and crystalline-like assemblies. By combining the surface sensitivity of polarization modulation infrared reflection absorption spectroscopy (PM-IRRAS) and sum-frequency generation spectroscopy (SFG), the effect of the self-assembly time (15 min, 30 min, 1 h, 2 h and 24 h) on the formation of n-dodecanethiol and n-dodecaneselenol monolayers on untreated and electrochemically reduced polycrystalline copper has been investigated. On electrochemically reduced copper, PM-IRRAS spectroscopy shows that both molecules are able to form well organized layers. SFG spectroscopy indicates that the C 12H 25SeH SAMs are slightly better ordered than those achieved with C 12H 25SH. On untreated copper, the two molecules lead to different film organizations. Both PM-IRRAS and SFG indicate that C 12H 25SH SAMs are of the same film quality as those obtained on electrochemically reduced copper. On the contrary, C 12H 25SeH monolayers are invariably poorly organized at the molecular level.

  3. High-resolution inner-shell spectroscopies of free atoms and molecules using soft-x-ray beamlines at the third-generation synchrotron radiation sources

    International Nuclear Information System (INIS)

    Ueda, Kiyoshi

    2003-01-01

    This article reviews the current status of inner-shell spectroscopies of free atoms and molecules using high-resolution soft-x-ray monochromators installed in the soft-x-ray beamlines at the third-generation synchrotron radiation facilities. Beamlines and endstations devoted to atomic and molecular inner-shell spectroscopies and various types of experimental techniques, such as ion yield spectroscopy, resonant photoemission spectroscopy and multiple-coincidence momentum imaging, are described. Experimental results for K-shell excitation of Ne, O K-shell excitation of H 2 O and CO 2 , C K-shell excitation and ionization of CO 2 and B K-shell excitation of BF 3 , obtained at beamline 27SU of SPring-8 in Japan, are discussed as examples of atomic and molecular inner-shell spectroscopies using the third-generation synchrotron radiation sources. (topical review)

  4. In situ fluorescence spectroscopy correlates ionomer degradation to reactive oxygen species generation in an operating fuel cell.

    Science.gov (United States)

    Prabhakaran, Venkateshkumar; Arges, Christopher G; Ramani, Vijay

    2013-11-21

    The rate of generation of reactive oxygen species (ROS) within the polymer electrolyte membrane (PEM) of an operating proton exchange member fuel cell (PEMFC) was monitored using in situ fluorescence spectroscopy. A modified barrier layer was introduced between the PEM and the electrocatalyst layer to eliminate metal-dye interactions and fluorescence resonance energy transfer (FRET) effects during measurements. Standard fuel cell operating parameters (temperature, relative humidity, and electrode potential) were systematically varied to evaluate their influence on the rate of ROS generation during PEMFC operation. Independently, the macroscopic rate of PEM degradation was measured by monitoring the fluoride ion emission rate (FER) in the effluent stream at each operating condition. The ROS generation reaction rate constant (estimated from the in situ fluorescence experiments) correlated perfectly with the measured FER across all conditions, demonstrating unequivocally for the first time that a direct correlation exists between in situ ROS generation and PEM macroscopic degradation. The activation energy for ROS generation within the PEM was estimated to be 12.5 kJ mol(-1).

  5. IL 6: 2D-IR spectroscopy: chemistry and biophysics in real time

    International Nuclear Information System (INIS)

    Bredenbeck, Jens

    2010-01-01

    Pulsed multidimensional experiments, daily business in the field of NMR spectroscopy, have been demonstrated only relatively recently in IR spectroscopy. Similar as nuclear spins in multidimensional NMR, molecular vibrations are employed in multidimensional IR experiments as probes of molecular structure and dynamics, albeit with femtosecond time resolution. Different types of multidimensional IR experiments have been implemented, resembling basic NMR experiments such as NOESY, COSY and EXSY. In contrast to one-dimensional linear spectroscopy, such multidimensional experiments reveal couplings and correlations of vibrations, which are closely linked to molecular structure and its change in time. The use of mixed IR/VIS pulse sequences further extends the potential of multidimensional IR spectroscopy, enabling studies of ultrafast non-equilibrium processes as well as surface specific, highly sensitive experiments. A UV/VIS pulse preceding the IR pulse sequence can be used to prepare the system under study in a non-equilibrium state. 2D-IR snapshots of the evolving non-equilibrium system are then taken, for example during a photochemical reaction or during the photo-cycle of a light sensitive protein. Preparing the system in a non-equilibrium state by UV/Vis excitation during the IR pulse sequence allows for correlating states of reactant and product of the light triggered process via their 2D-IR cross peaks - a technique that has been used to map the connectivity between different binding sites of a ligand as it migrates through a protein. Introduction of a non-resonant VIS pulse at the end of the IR part of the experiment allows to selectively up-convert the infrared signal of interfacial molecules to the visible spectral range by sum frequency generation. In this way, femtosecond interfacial 2D-IR spectroscopy can be implemented, achieving sub-monolayer sensitivity. (author)

  6. Second-harmonic generation circular dichroism spectroscopy from tripod-like chiral molecular films

    International Nuclear Information System (INIS)

    Wang Xiao-Ou; Chen Li-An; Chen Li-Xue; Sun Xiu-Dong; Li Jun-Qing; Li Chun-Fei

    2010-01-01

    The second-harmonic generation (SHG) circular dichroism in the light of reflection from chiral films of tripod-like chiral molecules is investigated. The expressions of the second-harmonic generation circular dichroism are derived from our presented three-coupled-oscillator model for the tripod-like chiral molecules. Spectral dependence of the circular dichroism of SHG from film surface composed of tripod-like chiral molecules is simulated numerically and analysed. Influence of chiral parameters on the second-harmonic generation circular dichroism spectrum in chiral films is studied. The result shows that the second-harmonic generation circular dichroism is a sensitive method of detecting chirality compared with the ordinary circular dichroism in linear optics. All of our work indicates that the classical molecular models are very effective to explain the second-harmonic generation circular dichroism of chiral molecular system. The classical molecular model theory can give us a clear physical picture and brings us very instructive information about the link between the molecular configuration and the nonlinear processes

  7. Dense electro-optic frequency comb generated by two-stage modulation for dual-comb spectroscopy.

    Science.gov (United States)

    Wang, Shuai; Fan, Xinyu; Xu, Bingxin; He, Zuyuan

    2017-10-01

    An electro-optic frequency comb enables frequency-agile comb-based spectroscopy without using sophisticated phase-locking electronics. Nevertheless, dense electro-optic frequency combs over broad spans have yet to be developed. In this Letter, we propose a straightforward and efficient method for electro-optic frequency comb generation with a small line spacing and a large span. This method is based on two-stage modulation: generating an 18 GHz line-spacing comb at the first stage and a 250 MHz line-spacing comb at the second stage. After generating an electro-optic frequency comb covering 1500 lines, we set up an easily established mutually coherent hybrid dual-comb interferometer, which combines the generated electro-optic frequency comb and a free-running mode-locked laser. As a proof of concept, this hybrid dual-comb interferometer is used to measure the absorption and dispersion profiles of the molecular transition of H 13 CN with a spectral resolution of 250 MHz.

  8. Investigation of the generation of singlet oxygen in ensembles of photoexcited silicon nanocrystals by electron paramagnetic resonance spectroscopy

    International Nuclear Information System (INIS)

    Konstantinova, E. A.; Demin, V. A.; Timoshenko, V. Yu.

    2008-01-01

    The generation of singlet oxygen is investigated and its concentration upon photoexcitation of silicon nanocrystals in porous silicon layers is determined using electron paramagnetic resonance spectroscopy. The relaxation times of spin centers, i.e., silicon dangling bonds, in vacuum and in an oxygen atmosphere in the dark and under illumination of the samples are measured for the first time. It is revealed that the spin-lattice relaxation in porous silicon is retarded as compared to that in a single-crystal substrate. From analyzing experimental data, a microscopic model is proposed for interaction of oxygen molecules in the triplet state and spin centers at the surface of silicon nanocrystals. The results obtained have demonstrated that porous silicon holds promise for the use as a photosensitizer of molecular oxygen in biomedical applications

  9. Second harmonic generation spectroscopy in the Reststrahl band of SiC using an infrared free-electron laser

    Energy Technology Data Exchange (ETDEWEB)

    Paarmann, Alexander, E-mail: alexander.paarmann@fhi-berlin.mpg.de; Razdolski, Ilya; Melnikov, Alexey; Gewinner, Sandy; Schöllkopf, Wieland; Wolf, Martin [Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin (Germany)

    2015-08-24

    The Reststrahl spectral region of silicon carbide has recently attracted much attention owing to its potential for mid-infrared nanophotonic applications based on surface phonon polaritons (SPhPs). Studies of optical phonon resonances responsible for surface polariton formation, however, have so far been limited to linear optics. In this Letter, we report the first nonlinear optical investigation of the Reststrahl region of SiC, employing an infrared free-electron laser to perform second harmonic generation (SHG) spectroscopy. We observe two distinct resonance features in the SHG spectra, one attributed to resonant enhancement of the nonlinear susceptibility χ{sup (2)} and the other due to a resonance in the Fresnel transmission. Our work clearly demonstrates high sensitivity of mid-infrared SHG to phonon-driven phenomena and opens a route to studying nonlinear effects in nanophotonic structures based on SPhPs.

  10. Ultrashort Generation Regimes in the All-Fiber Kerr Mode-Locked Erbium-Doped Fiber Ring Laser for Terahertz Pulsed Spectroscopy

    Directory of Open Access Journals (Sweden)

    V. S. Voropaev

    2015-01-01

    Full Text Available Many femtosecond engineering applications require for a stable generation of ultrashort pulses. Thus, in the terahertz pulsed spectroscopy a measurement error in the refractive index is strongly dependent on the pulse duration stability with allowable variation of few femtoseconds. The aim of this work is to study the ultrashort pulses (USP regimes stability in the all – fiber erbium doped ring laser with Kerr mode-locking. The study was conducted at several different values of the total resonator intra-cavity dispersion. Three laser schemes with the intra-cavity dispersion values from -1.232 ps2 to +0.008 ps2 have been studied. In the experiment there were two regimes of generation observed: the stretched pulse generation and ordinary soliton generation. Main attention is focused on the stability of regimes under study. The most stable regime was that of the stretched pulse generation with a spectrum form of sech2 , possible pulse duration of 490 fs at least, repetition rate of 2.9 MHz, and average output power of 17 mW. It is worth noting, that obtained regimes had characteristics suitable for the successful use in the terahertz pulsed spectroscopy. The results may be useful in the following areas of science and technology: a high-precision spectroscopy, optical frequency standards, super-continuum generation, and terahertz pulsed spectroscopy. The future system development is expected to stabilize duration and repetition rate of the obtained regime of ultra-short pulse generation.

  11. Catheter based mid-infrared reflectance and reflectance generated absorption spectroscopy

    Science.gov (United States)

    Holman, Hoi-Ying N

    2013-10-29

    A method of characterizing conditions in a tissue, by (a) providing a catheter that has a light source that emits light in selected wavenumbers within the range of mid-IR spectrum; (b) directing the light from the catheter to an area of tissue at a location inside a blood vessel of a subject; (c) collecting light reflected from the location and generating a reflectance spectra; and (d) comparing the reflectance spectra to a reference spectra of normal tissue, whereby a location having an increased number of absorbance peaks at said selected wavenumbers indicates a tissue inside the blood vessel containing a physiological marker for atherosclerosis.

  12. Electron Spin Resonance Spectroscopy for Studying the Generation and Scavenging of Reactive Oxygen Species by Nanomaterials

    Science.gov (United States)

    Yin, Jun-Jie; Zhao, Baozhong; Xia, Qingsu; Fu, Peter P.

    2013-09-01

    One fundamental mechanism widely described for nanotoxicity involves oxidative damage due to generation of free radicals and other reactive oxygen species. Indeed, the ability of nanoscale materials to facilitate the transfer of electrons, and thereby promote oxidative damage or in some instances provide antioxidant protection, may be a fundamental property of these materials. Any assessment of a nanoscale material's safety must therefore consider the potential for toxicity arising from oxidative damage. Therefore, rapid and predictive methods are needed to assess oxidative damage elicited by nanoscale materials. The use of electron spin resonance (ESR) to study free radical related bioactivity of nanomaterials has several advantages for free radical determination and identification. Specifically it can directly assess antioxidant quenching or prooxidant generation of relevant free radicals and reactive oxygen species. In this chapter, we have reported some nonclassical behaviors of the electron spin relaxation properties of unpaired electrons in different fullerenes and the investigation of anti/prooxidant activity by various types of nanomaterials using ESR. In addition, we have reviewed the mechanisms of free radical formation photosensitized by different nanomaterials. This chapter also included the use of spin labels, spin traps and ESR oximetry to systematically examine the enzymatic mimetic activities of nanomaterials.

  13. Non-invasive vibrational SFG spectroscopy reveals that bacterial adhesion can alter the conformation of grafted "brush" chains on SAM.

    Science.gov (United States)

    Bulard, Emilie; Guo, Ziang; Zheng, Wanquan; Dubost, Henri; Fontaine-Aupart, Marie-Pierre; Bellon-Fontaine, Marie-Noëlle; Herry, Jean-Marie; Briandet, Romain; Bourguignon, Bernard

    2011-04-19

    Understanding bacterial adhesion on a surface is a crucial step to design new materials with improved properties or to control biofilm formation and eradication. Sum Frequency Generation (SFG) vibrational spectroscopy has been employed to study in situ the conformational response of a self-assembled monolayer (SAM) of octadecanethiol (ODT) on a gold film to the adhesion of hydrophilic and hydrophobic ovococcoid model bacteria. The present work highlights vibrational SFG spectroscopy as a powerful and unique non-invasive biophysical technique to probe and control bacteria interaction with ordered surfaces. Indeed, the SFG vibrational spectral changes reveal different ODT SAM conformations in air and upon exposure to aqueous solution or bacterial adhesion. Furthermore, this effect depends on the bacterial cell surface properties. The SFG spectral modeling demonstrates that hydrophobic bacteria flatten the ODT SAM alkyl chain terminal part, whereas the hydrophilic ones raise this ODT SAM terminal part. Microorganism-induced alteration of grafted chains can thus affect the desired interfacial functionality, a result that should be considered for the design of new reactive materials. © 2011 American Chemical Society

  14. Optical spectroscopy of vacancy related defects in silicon carbide generated by proton irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Kasper, C.; Sperlich, A.; Simin, D.; Astakhov, G.V. [Experimental Physics VI, Julius Maximilian University of Wuerzburg (Germany); Kraus, H. [Japan Atomic EnergyAgency, Takasaki, Gunma (Japan); Experimental Physics VI, Julius Maximilian University of Wuerzburg (Germany); Makino, T.; Sato, S.I.; Ohshima, T. [Japan Atomic EnergyAgency, Takasaki, Gunma (Japan); Dyakonov, V. [Experimental Physics VI, Julius Maximilian University of Wuerzburg (Germany); ZAE Bayern, Wuerzburg (Germany)

    2016-07-01

    Defects in silicon carbide (SiC) received growing attention in recent years, because they are promising candidates for spin based quantum information processing. In this study we examine silicon vacancies in 4H-SiC crystals generated by proton irradiation. By the use of confocal microscopy the implantation depth of Si vacancies for varying proton energies can be verified. An important issue is to ascertain the nature and distribution of the defects. For this purpose, we use the characteristic photoluminescence spectrum of Si vacancies, whose intensity is proportional to the defect density. Using xyz-scans, where the photoluminescence at each mapping point is recorded, one can thus determine the vacancies nature and their distribution in the SiC crystal. Additionally we verify the nature of the examined defects by measuring their uniquely defined zero-field-splitting by using ODMR associated with defect spins.

  15. Characterization of an Atmospheric-Pressure Argon Plasma Generated by 915 MHz Microwaves Using Optical Emission Spectroscopy

    Directory of Open Access Journals (Sweden)

    Robert Miotk

    2017-01-01

    Full Text Available The paper presents the investigations of an atmospheric-pressure argon plasma generated at 915 MHz microwaves using the optical emission spectroscopy (OES. The 915 MHz microwave plasma was inducted and sustained in a waveguide-supplied coaxial-line-based nozzleless microwave plasma source. The aim of presented investigations was to estimate parameters of the generated plasma, that is, excitation temperature of electrons Texc, temperature of plasma gas Tg, and concentration of electrons ne. Assuming that excited levels of argon atoms are in local thermodynamic equilibrium, Boltzmann method allowed in determining the Texc temperature in the range of 8100–11000 K. The temperature of plasma gas Tg was estimated by comparing the simulated spectra of the OH radical to the measured one in LIFBASE program. The obtained Tg temperature ranged in 1200–2800 K. Using a method based on Stark broadening of the Hβ line, the concentration of electrons ne was determined in the range from 1.4 × 1015 to 1.7 × 1015 cm−3, depending on the power absorbed by the microwave plasma.

  16. Next-Generation Microshutter Arrays for Large-Format Imaging and Spectroscopy

    Science.gov (United States)

    Moseley, Samuel; Kutyrev, Alexander; Brown, Ari; Li, Mary

    2012-01-01

    A next-generation microshutter array, LArge Microshutter Array (LAMA), was developed as a multi-object field selector. LAMA consists of small-scaled microshutter arrays that can be combined to form large-scale microshutter array mosaics. Microshutter actuation is accomplished via electrostatic attraction between the shutter and a counter electrode, and 2D addressing can be accomplished by applying an electrostatic potential between a row of shutters and a column, orthogonal to the row, of counter electrodes. Microelectromechanical system (MEMS) technology is used to fabricate the microshutter arrays. The main feature of the microshutter device is to use a set of standard surface micromachining processes for device fabrication. Electrostatic actuation is used to eliminate the need for macromechanical magnet actuating components. A simplified electrostatic actuation with no macro components (e.g. moving magnets) required for actuation and latching of the shutters will make the microshutter arrays robust and less prone to mechanical failure. Smaller-size individual arrays will help to increase the yield and thus reduce the cost and improve robustness of the fabrication process. Reducing the size of the individual shutter array to about one square inch and building the large-scale mosaics by tiling these smaller-size arrays would further help to reduce the cost of the device due to the higher yield of smaller devices. The LAMA development is based on prior experience acquired while developing microshutter arrays for the James Webb Space Telescope (JWST), but it will have different features. The LAMA modular design permits large-format mosaicking to cover a field of view at least 50 times larger than JWST MSA. The LAMA electrostatic, instead of magnetic, actuation enables operation cycles at least 100 times faster and a mass significantly smaller compared to JWST MSA. Also, standard surface micromachining technology will simplify the fabrication process, increasing

  17. Non-linear optical studies of adsorbates: Spectroscopy and dynamics

    International Nuclear Information System (INIS)

    Zhu, Xiangdong.

    1989-08-01

    In the first part of this thesis, we have established a systematic procedure to apply the surface optical second-harmonic generation (SHG) technique to study surface dynamics of adsorbates. In particular, we have developed a novel technique for studies of molecular surface diffusions. In this technique, the laser-induced desorption with two interfering laser beams is used to produce a monolayer grating of adsorbates. The monolayer grating is detected with diffractions of optical SHG. By monitoring the first-order second-harmonic diffraction, we can follow the time evolution of the grating modulation from which we are able to deduce the diffusion constant of the adsorbates on the surface. We have successfully applied this technique to investigate the surface diffusion of CO on Ni(111). The unique advantages of this novel technique will enable us to readily study anisotropy of a surface diffusion with variable grating orientation, and to investigate diffusion processes of a large dynamic range with variable grating spacings. In the second part of this work, we demonstrate that optical infrared-visible sum-frequency generation (SFG) from surfaces can be used as a viable surface vibrational spectroscopic technique. We have successfully recorded the first vibrational spectrum of a monolayer of adsorbates using optical infrared-visible SFG. The qualitative and quantitative correlation of optical SFG with infrared absorption and Raman scattering spectroscopies are examined and experimentally demonstrated. We have further investigated the possibility to use transient infrared-visible SFG to probe vibrational transients and ultrafast relaxations on surfaces. 146 refs

  18. Non-linear optical studies of adsorbates: Spectroscopy and dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Xiangdong.

    1989-08-01

    In the first part of this thesis, we have established a systematic procedure to apply the surface optical second-harmonic generation (SHG) technique to study surface dynamics of adsorbates. In particular, we have developed a novel technique for studies of molecular surface diffusions. In this technique, the laser-induced desorption with two interfering laser beams is used to produce a monolayer grating of adsorbates. The monolayer grating is detected with diffractions of optical SHG. By monitoring the first-order second-harmonic diffraction, we can follow the time evolution of the grating modulation from which we are able to deduce the diffusion constant of the adsorbates on the surface. We have successfully applied this technique to investigate the surface diffusion of CO on Ni(111). The unique advantages of this novel technique will enable us to readily study anisotropy of a surface diffusion with variable grating orientation, and to investigate diffusion processes of a large dynamic range with variable grating spacings. In the second part of this work, we demonstrate that optical infrared-visible sum-frequency generation (SFG) from surfaces can be used as a viable surface vibrational spectroscopic technique. We have successfully recorded the first vibrational spectrum of a monolayer of adsorbates using optical infrared-visible SFG. The qualitative and quantitative correlation of optical SFG with infrared absorption and Raman scattering spectroscopies are examined and experimentally demonstrated. We have further investigated the possibility to use transient infrared-visible SFG to probe vibrational transients and ultrafast relaxations on surfaces. 146 refs.

  19. Orientational Analysis of Dodecanethiol and P-Nitrothiophenol SAMs on Metals with Polarisation - dependent SFG spectroscopy

    International Nuclear Information System (INIS)

    Manea, A.

    2011-01-01

    Polarisation-dependent sum frequency generation (SFG) spectroscopy is used to investigate the orientation of molecules on metallic surfaces. In particular, self-assembled monolayers (SAMs) of dodecanethiol (DDT) and of p-nitro thiophenol (p-NTP), grown on Pt and on Au, have been chosen as models to highlight the ability of combining ppp and ssp polarizations sets (representing the polarisation of the involved beams in the conventional order of SFG, Vis and IR beam) to infer orientational information at metallic interfaces. Indeed, using only the ppp set of data, as it is usually done for metallic surfaces, is not sufficient to determine the full molecular orientation. We show here that simply combining ppp and ssp polarizations enables both the tilt and rotation angles of methyl groups in DDT SAMs to be determined. Moreover, for p-NTP, while the SFG active vibrations detected with the ppp polarisation alone provide no orientational information, however, the combination with ssp spectra enables to retrieve the tilt angle of the p-NTP 1,4 axis. Though orientational information obtained by polarisation-dependent measurements has been extensively used at insulating interfaces, we report here their first application to metallic surfaces. (author)

  20. An optical emission spectroscopy study of the plasma generated in the DC HF CVD nucleation of diamond

    Energy Technology Data Exchange (ETDEWEB)

    Larijani, M.M. [Nuclear Research Centre for Agriculture and Medicine, AEOI, P.O. Box 31485-498, Karaj (Iran, Islamic Republic of)]. E-mail: mmojtahedzadeh@nrcam.org; Le Normand, F. [Groupe Surfaces-Interfaces, IPCMS, UMR 7504 CNRS, BP 20, 67037 Strasbourg Cedex 2 (France); Cregut, O. [Groupe Surfaces-Interfaces, IPCMS, UMR 7504 CNRS, BP 20, 67037 Strasbourg Cedex 2 (France)

    2007-02-15

    Optical emission spectroscopy (OES) was used to study the plasma generated by the activation of the gas phase CH{sub 4} + H{sub 2} both by hot filaments and by a plasma discharge (DC HF CVD) during the nucleation of CVD diamond. The effects of nucleation parameters, such as methane concentration and extraction potential, on the plasma chemistry near the surface were investigated. The density of the diamond nucleation and the quality of the diamond films were studied by scanning electron microscopy (SEM) and Raman scattering, respectively. The OES results showed that the methane concentration influenced strongly the intensity ratio of H{sub {beta}}-H{sub {alpha}} implying an increase of electron mean energy, as well as CH, CH{sup +}, C{sub 2}. A correlation between the relative increase of CH{sup +} and the diamond nucleation density was found, conversely the increase of C{sub 2} contributed to the introduction of defects in the diamond nuclei.

  1. Generation of a new spectral format, the lifetime synchronous spectrum (LiSS), using phase-resolved fluorescence spectroscopy

    International Nuclear Information System (INIS)

    Shaver, J.M.; McGown, L.B.

    1994-01-01

    A new fluorescence spectral format is introduced in which fluorescence lifetime is shown as a function of synchronously scanned wavelength to generate a Lifetime Synchronous Spectrum (LiSS). Lifetimes are determined in the frequency domain with the use of Phase-Resolved Fluorescence Spectroscopy (PRFS) to obtain the phase of the fluorescence signal. Theory and construction of the LiSS are presented and experimental results are shown for solutions of single components and simple binary and ternary mixtures. These results show how the lifetime information in the LiSS augments the steady-state intensity information of a standard synchronous spectrum, providing unique information for identification of components and resolution of overlapping spectral peaks. The LiSS technique takes advantage of noise reduction inherent in the extraction of lifetime from PRFS in addition to standard spectral smoothing techniques. The precision of phase determination through PRFS is found to be comparable to that of direct phase measurements at normal fluorescence intensities and superior for low-intensity signals

  2. Probing Surface-Adlayer Conjugation on Organic-Modified Si(111) Surfaces with Microscopy, Scattering, Spectroscopy, and Density Functional Theory

    International Nuclear Information System (INIS)

    Kellar, Joshua A.; Lin, Jui-Ching; Kim, Jun-Hyun; Yoder, Nathan L.; Bevan, Kirk H.; Stokes, Grace Y.; Geiger, Franz M.; Nguyen, SonBinh T.; Bedzyk, Michael J.; Hersam, Mark C.

    2009-01-01

    Highly conjugated molecules bound to silicon are promising candidates for organosilicon electronic devices and sensors. In this study, 1-bromo-4-ethynylbenzene was synthesized and reacted with a hydrogen-passivated Si(111) surface via ultraviolet irradiation. Through an array of characterization and modeling tools, the binding configuration and morphology of the reacted molecule were thoroughly analyzed. Atomic force microscopy confirmed an atomically flat surface morphology following reaction, while X-ray photoelectron spectroscopy verified reaction to the surface via the terminal alkyne moiety. In addition, synchrotron X-ray characterization, including X-ray reflectivity, X-ray fluorescence, and X-ray standing wave measurements, enabled sub-angstrom determination of the position of the bromine atom with respect to the silicon lattice. This structural characterization was quantitatively compared with density functional theory (DFT) calculations, thus enabling the π-conjugation of the terminal carbon atoms to be deduced. The X-ray and DFT results were additionally corroborated with the vibrational spectrum of the organic adlayer, which was measured with sum frequency generation. Overall, these results illustrate that the terminal carbon atoms in 1-bromo-4-ethynylbenzene adlayers on Si(111) retain π-conjugation, thus revealing alkyne molecules as promising candidates for organosilicon electronics and sensing.

  3. Orientational analysis of dodecanethiol and p-nitrothiophenol SAMs on metals with polarisation-dependent SFG spectroscopy.

    Science.gov (United States)

    Cecchet, Francesca; Lis, Dan; Guthmuller, Julien; Champagne, Benoît; Caudano, Yves; Silien, Christophe; Mani, Alaa Addin; Thiry, Paul A; Peremans, André

    2010-02-22

    Polarisation-dependent sum frequency generation (SFG) spectroscopy is used to investigate the orientation of molecules on metallic surfaces. In particular, self-assembled monolayers (SAMs) of dodecanethiol (DDT) and of p-nitrothiophenol (p-NTP), grown on Pt and on Au, have been chosen as models to highlight the ability of combining ppp and ssp polarisations sets (representing the polarisation of the involved beams in the conventional order of SFG, Vis and IR beam) to infer orientational information at metallic interfaces. Indeed, using only the ppp set of data, as it is usually done for metallic surfaces, is not sufficient to determine the full molecular orientation. We show here that simply combining ppp and ssp polarisations enables both the tilt and rotation angles of methyl groups in DDT SAMs to be determined. Moreover, for p-NTP, while the SFG active vibrations detected with the ppp polarisation alone provide no orientational information, however, the combination with ssp spectra enables to retrieve the tilt angle of the p-NTP 1,4 axis. Though orientational information obtained by polarisation-dependent measurements has been extensively used at insulating interfaces, we report here their first application to metallic surfaces.

  4. Membrane interaction of antimicrobial peptides using E. coli lipid extract as model bacterial cell membranes and SFG spectroscopy.

    Science.gov (United States)

    Soblosky, Lauren; Ramamoorthy, Ayyalusamy; Chen, Zhan

    2015-04-01

    Supported lipid bilayers are used as a convenient model cell membrane system to study biologically important molecule-lipid interactions in situ. However, the lipid bilayer models are often simple and the acquired results with these models may not provide all pertinent information related to a real cell membrane. In this work, we use sum frequency generation (SFG) vibrational spectroscopy to study molecular-level interactions between the antimicrobial peptides (AMPs) MSI-594, ovispirin-1 G18, magainin 2 and a simple 1,2-dipalmitoyl-d62-sn-glycero-3-phosphoglycerol (dDPPG)/1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoglycerol (POPG) bilayer. We compared such interactions to those between the AMPs and a more complex dDPPG/Escherichia coli (E. coli) polar lipid extract bilayer. We show that to fully understand more complex aspects of peptide-bilayer interaction, such as interaction kinetics, a heterogeneous lipid composition is required, such as the E. coli polar lipid extract. The discrepancy in peptide-bilayer interaction is likely due in part to the difference in bilayer charge between the two systems since highly negative charged lipids can promote more favorable electrostatic interactions between the peptide and lipid bilayer. Results presented in this paper indicate that more complex model bilayers are needed to accurately analyze peptide-cell membrane interactions and demonstrates the importance of using an appropriate lipid composition to study AMP interaction properties. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  5. Non-invasive SFG spectroscopy: a tool to reveal the conformational change of grafted chains due to bacterial adhesion

    Science.gov (United States)

    Bulard, Emilie; Dubost, Henri; Fontaine-Aupart, Marie-Pierre; Zheng, Wanquan; Herry, Jean-Marie; Bellon-Fontaine, Marie-No"lle; Briandet, Romain; Bourguignon, Bernard

    2011-07-01

    In many fields such as biomedical or food industry, surface colonization by micro-organisms leads to biofilms formation that are tridimentional biostructures highly resistant to the action of antimicrobials, by mechanisms still unclear. In order to deepen our understanding of the initial interaction of bacteria cells with a solid surface, we analyze by in situ vibrational Sum Frequency Generation (SFG) spectroscopy the effect of the adhesion of hydrophilic Lactoccocus lactis bacteria and its hydrophobic mutants in distilled water on a self-assembled monolayer (SAM) of octadecanethiol (ODT) on a gold film. When a homogeneous bacterial monolayer is deposited on this ordered surface, SFG spectrum of the ODT SAM shows significant intensity changes from that in air or in water. Its modelling as a function of conformation allows to distinguish optical effects due to the water solution surrounding bacteria from conformational changes of the ODT SAM due to the presence of the bacteria cells. Futhermore, bacterial adhesion induces different measurable effects on the ODT SAM conformation, depending on the hydrophobic / hydrophilic character of the bacterial surface. Such a result deserves to be taken into account for the design of new materials with improved properties or to control biofilm formation.

  6. Model Catalysis of Ammonia Synthesis ad Iron-Water Interfaces - ASum Frequency Generation Vibrational Spectroscopic Study of Solid-GasInterfaces and Anion Photoelectron Spectroscopic Study of Selected Anionclusters

    Energy Technology Data Exchange (ETDEWEB)

    Ferguson, Michael James [Univ. of California, Berkeley, CA (United States)

    2005-01-01

    The ammonia synthesis reaction has been studied using single crystal model catalysis combined with sum frequency generation (SFG) vibrational spectroscopy. The adsorption of gases N2, H2, O2 and NH3 that play a role in ammonia synthesis have been studied on the Fe(111) crystal surface by sum frequency generation vibrational spectroscopy using an integrated Ultra-High Vacuum (UHV)/high-pressure system. SFG spectra are presented for the dissociation intermediates, NH2 (~3325 cm-1) and NH (~3235 cm-1) under high pressure of ammonia or equilibrium concentrations of reactants and products on Fe(111) surfaces. Special attention was paid to understand how potassium promotion of the iron catalyst affects the intermediates of ammonia synthesis. An Fe(111) surface promoted with 0.2 monolayers of potassium red shifts the vibrational frequencies of the reactive surface intermediates, NH and NH2, providing evidence for weakened the nitrogen-hydrogen bonds relative to clean Fe(111). Spectral features of these surface intermediates persisted to higher temperatures for promoted iron surfaces than for clean Fe(111) surfaces implying that nitrogen-iron bonds are stronger for the promoted surface. The ratio of the NH to NH2 signal changed for promoted surfaces in the presence of equilibrium concentrations of reactants and products. The order of adding oxygen and potassium to promoted surfaces does not alter the spectra indicating that ammonia induces surface reconstruction of the catalyst to produce the same surface morphology. When oxygen is co-adsorbed with nitrogen, hydrogen, ammonia or potassium on Fe(111), a relative phase shift of the spectra occurs as compared to the presence of adsorbates on clean iron surfaces. Water adsorption on iron was also probed using SFG vibrational spectroscopy. For both H2O and D2O, the only spectral feature was in the range of

  7. Efficient 525 nm laser generation in single or double resonant cavity

    Science.gov (United States)

    Liu, Shilong; Han, Zhenhai; Liu, Shikai; Li, Yinhai; Zhou, Zhiyuan; Shi, Baosen

    2018-03-01

    This paper reports the results of a study into highly efficient sum frequency generation from 792 and 1556 nm wavelength light to 525 nm wavelength light using either a single or double resonant ring cavity based on a periodically poled potassium titanyl phosphate crystal (PPKTP). By optimizing the cavity's parameters, the maximum power achieved for the resultant 525 nm laser was 263 and 373 mW for the single and double resonant cavity, respectively. The corresponding quantum conversion efficiencies were 8 and 77% for converting 1556 nm photons to 525 nm photons with the single and double resonant cavity, respectively. The measured intra-cavity single pass conversion efficiency for both configurations was about 5%. The performances of the sum frequency generation in these two configurations was studied and compared in detail. This work will provide guidelines for optimizing the generation of sum frequency generated laser light for a variety of configurations. The high conversion efficiency achieved in this work will help pave the way for frequency up-conversion of non-classical quantum states, such as the squeezed vacuum and single photon states. The proposed green laser source will be used in our future experiments, which includes a plan to generate two-color entangled photon pairs and achieve the frequency down-conversion of single photons carrying orbital angular momentum.

  8. IR and SFG vibrational spectroscopy of the water bend in the bulk liquid and at the liquid-vapor interface, respectively

    Energy Technology Data Exchange (ETDEWEB)

    Ni, Yicun; Skinner, J. L. [Theoretical Chemistry Institute and Department of Chemistry, University of Wisconsin, Madison, Wisconsin 53706 (United States)

    2015-07-07

    Vibrational spectroscopy of the water bending mode has been investigated experimentally to study the structure of water in condensed phases. In the present work, we calculate the theoretical infrared (IR) and sum-frequency generation (SFG) spectra of the HOH bend in liquid water and at the water liquid/vapor interface using a mixed quantum/classical approach. Classical molecular dynamics simulation is performed by using a recently developed water model that explicitly includes three-body interactions and yields a better description of the water surface. Ab-initio-based transition frequency, dipole, polarizability, and intermolecular coupling maps are developed for the spectral calculations. The calculated IR and SFG spectra show good agreement with the experimental measurements. In the theoretical imaginary part of the SFG susceptibility for the water liquid/vapor interface, we find two features: a negative band centered at 1615 cm{sup −1} and a positive band centered at 1670 cm{sup −1}. We analyze this spectrum in terms of the contributions from molecules in different hydrogen-bond classes to the SFG spectral density and also compare to SFG results for the OH stretch. SFG of the water bending mode provides a complementary picture of the heterogeneous hydrogen-bond configurations at the water surface.

  9. CO dissociation and CO hydrogenation on smooth and ion-bombarded Pd(1 1 1): SFG and XPS spectroscopy at mbar pressures

    Science.gov (United States)

    Rupprechter, G.; Kaichev, V. V.; Unterhalt, H.; Morkel, M.; Bukhtiyarov, V. I.

    2004-07-01

    The CO dissociation probability on transition metals is often invoked to explain the product distribution (selectivity) of catalytic CO hydrogenation. Along these lines, we have investigated CO adsorption and dissociation on smooth and ion-bombarded Pd(1 1 1) at pressures up to 1 mbar using vibrational sum frequency generation (SFG) and X-ray photoelectron spectroscopy (XPS). Under high pressure, CO adsorbate structures were observed that were identical to high-coverage structures in UHV. On ion-bombarded surfaces an additional species was detected which was attributed to CO bridge bonded to defect (low-coordinated) sites. On both surfaces, no indications of CO dissociation were found even after hours of 0.1 mbar CO exposure. However, exposing CO/H 2 mixtures to ion-bombarded Pd(1 1 1) produced carbonaceous deposits suggesting CH xO species as precursors for CO bond cleavage and that the formation of CH xO is facilitated by surface defects. The relevance of the observations for CO hydrogenation on Pd catalysts is discussed.

  10. IR and SFG vibrational spectroscopy of the water bend in the bulk liquid and at the liquid-vapor interface, respectively

    Science.gov (United States)

    Ni, Yicun; Skinner, J. L.

    2015-07-01

    Vibrational spectroscopy of the water bending mode has been investigated experimentally to study the structure of water in condensed phases. In the present work, we calculate the theoretical infrared (IR) and sum-frequency generation (SFG) spectra of the HOH bend in liquid water and at the water liquid/vapor interface using a mixed quantum/classical approach. Classical molecular dynamics simulation is performed by using a recently developed water model that explicitly includes three-body interactions and yields a better description of the water surface. Ab-initio-based transition frequency, dipole, polarizability, and intermolecular coupling maps are developed for the spectral calculations. The calculated IR and SFG spectra show good agreement with the experimental measurements. In the theoretical imaginary part of the SFG susceptibility for the water liquid/vapor interface, we find two features: a negative band centered at 1615 cm-1 and a positive band centered at 1670 cm-1. We analyze this spectrum in terms of the contributions from molecules in different hydrogen-bond classes to the SFG spectral density and also compare to SFG results for the OH stretch. SFG of the water bending mode provides a complementary picture of the heterogeneous hydrogen-bond configurations at the water surface.

  11. CO dissociation and CO hydrogenation on smooth and ion-bombarded Pd(1 1 1): SFG and XPS spectroscopy at mbar pressures

    Energy Technology Data Exchange (ETDEWEB)

    Rupprechter, G.; Kaichev, V.V.; Unterhalt, H.; Morkel, M.; Bukhtiyarov, V.I

    2004-07-31

    The CO dissociation probability on transition metals is often invoked to explain the product distribution (selectivity) of catalytic CO hydrogenation. Along these lines, we have investigated CO adsorption and dissociation on smooth and ion-bombarded Pd(1 1 1) at pressures up to 1 mbar using vibrational sum frequency generation (SFG) and X-ray photoelectron spectroscopy (XPS). Under high pressure, CO adsorbate structures were observed that were identical to high-coverage structures in UHV. On ion-bombarded surfaces an additional species was detected which was attributed to CO bridge bonded to defect (low-coordinated) sites. On both surfaces, no indications of CO dissociation were found even after hours of 0.1 mbar CO exposure. However, exposing CO/H{sub 2} mixtures to ion-bombarded Pd(1 1 1) produced carbonaceous deposits suggesting CH{sub x}O species as precursors for C---O bond cleavage and that the formation of CH{sub x}O is facilitated by surface defects. The relevance of the observations for CO hydrogenation on Pd catalysts is discussed.

  12. Angle-resolved photoemission spectroscopy with 9-eV photon-energy pulses generated in a gas-filled hollow-core photonic crystal fiber

    OpenAIRE

    Bromberger, H.; Ermolov, A.; Belli, F.; Liu, H.; Calegari, F.; Chavez-Cervantes, M.; Li, M. T.; Lin, C. T.; Abdolvand, A.; Russell, P. St. J.; Cavalleri, A.; Travers, J. C.; Gierz, I.

    2015-01-01

    A recently developed source of ultraviolet radiation, based on optical soliton propagation in a gas-filled hollow-core photonic crystal fiber, is applied here to angle-resolved photoemission spectroscopy (ARPES). Near-infrared femtosecond pulses of only few {\\mu}J energy generate vacuum ultraviolet (VUV) radiation between 5.5 and 9 eV inside the gas-filled fiber. These pulses are used to measure the band structure of the topological insulator Bi2Se3 with a signal to noise ratio comparable to ...

  13. Exploring Fluorescent Dyes at Biomimetic Interfaces with Second Harmonic Generation and Molecular Dynamics

    Czech Academy of Sciences Publication Activity Database

    Licari, G.; Cwiklik, Lukasz; Jungwirth, Pavel; Vauthey, E.

    2017-01-01

    Roč. 33, č. 14 (2017), s. 3373-3383 ISSN 0743-7463 R&D Projects: GA ČR(CZ) GBP208/12/G016 Institutional support: RVO:61388955 ; RVO:61388963 Keywords : sum-frequency generation * excited-state dynamics * air-water-interface * density-functional theory Subject RIV: CF - Physical ; Theoretical Chemistry OBOR OECD: Physical chemistry Impact factor: 3.833, year: 2016

  14. Exploring Fluorescent Dyes at Biomimetic Interfaces with Second Harmonic Generation and Molecular Dynamics

    Czech Academy of Sciences Publication Activity Database

    Licari, G.; Cwiklik, Lukasz; Jungwirth, Pavel; Vauthey, E.

    2017-01-01

    Roč. 33, č. 14 (2017), s. 3373-3383 ISSN 0743-7463 R&D Projects: GA ČR(CZ) GBP208/12/G016 Institutional support: RVO:61388955 ; RVO:61388963 Keywords : sum -frequency generation * excited-state dynamics * air-water-interface * density-functional theory Subject RIV: CF - Physical ; Theoretical Chemistry OBOR OECD: Physical chemistry Impact factor: 3.833, year: 2016

  15. Heterogeneous Amyloid β-Sheet Polymorphs Identified on Hydrogen Bond Promoting Surfaces Using 2D SFG Spectroscopy.

    Science.gov (United States)

    Ho, Jia-Jung; Ghosh, Ayanjeet; Zhang, Tianqi O; Zanni, Martin T

    2018-02-08

    Two-dimensional sum-frequency generation spectroscopy (2D SFG) is used to study the structures of the pentapeptide FGAIL on hydrogen bond promoting surfaces. FGAIL is the most amyloidogenic portion of the human islet amyloid polypeptide (hIAPP or amylin). In the presence of a pure gold surface, FGAIL does not form ordered structures. When the gold is coated with a self-assembled monolayer of mercaptobenzoic acid (MBA), 2D SFG spectra reveal features associated with β-sheets. Also observed are cross peaks between the FGAIL peptides and the carboxylic acid groups of the MBA monolayer, indicating that the peptides are in close contact with the surface headgroups. In the second set of samples, FGAIL peptides chemically ligated to the MBA monolayer also exhibited β-sheet features but with a much simpler spectrum. From simulations of the experiments, we conclude that the hydrogen bond promoting surface catalyzes the formation of both parallel and antiparallel β-sheet structures with several different orientations. When ligated, parallel sheets with only a single orientation are the primary structure. Thus, this hydrogen bond promoting surface creates a heterogeneous distribution of polymorph structures, consistent with a concentration effect that allows nucleation of many different amyloid seeding structures. A single well-defined seed favors one polymorph over the others, showing that the concentrating influence of a membrane can be counterbalanced by factors that favor directed fiber growth. These experiments lay the foundation for the measurement and interpretation of β-sheet structures with heterodyne-detected 2D SFG spectroscopy. The results of this model system suggest that a heterogeneous distribution of polymorphs found in nature are an indication of nonselective amyloid aggregation whereas a narrow distribution of polymorph structures is consistent with a specific protein or lipid interaction that directs fiber growth.

  16. High-order nonlinear optical processes in ablated carbon-containing materials: Recent approaches in development of the nonlinear spectroscopy using harmonic generation in the extreme ultraviolet range

    Science.gov (United States)

    Ganeev, R. A.

    2017-08-01

    The nonlinear spectroscopy using harmonic generation in the extreme ultraviolet range became a versatile tool for the analysis of the optical, structural and morphological properties of matter. The carbon-contained materials have shown the advanced properties among other studied species, which allowed both the definition of the role of structural properties on the nonlinear optical response and the analysis of the fundamental features of carbon as the attractive material for generation of coherent short-wavelength radiation. We review the studies of the high-order harmonic generation by focusing ultrashort pulses into the plasmas produced during laser ablation of various organic compounds. We discuss the role of ionic transitions of ablated carbon-containing molecules on the harmonic yield. We also show the similarities and distinctions of the harmonic and plasma spectra of organic compounds and graphite. We discuss the studies of the generation of harmonics up to the 27th order (λ = 29.9 nm) of 806 nm radiation in the boron carbide plasma and analyze the advantages and disadvantages of this target compared with the ingredients comprising B4C (solid boron and graphite) by comparing plasma emission and harmonic spectra from three species. We also show that the coincidence of harmonic and plasma emission wavelengths in most cases does not cause the enhancement or decrease of the conversion efficiency of this harmonic.

  17. Three-photon excited PL spectroscopy and photo-generated Frenkel defects in wide-bandgap layered CdI2 semiconductors

    International Nuclear Information System (INIS)

    Miah, M. Idrish

    2009-01-01

    We performed a three-photon excitation nonlinear photoluminescence (PL) spectroscopy in single crystals of wide-bandgap semiconductors (WBSs). The crystal temperature (T L )-dependent PL emission intensity (I PL ) excited with different excitation power density (P) was measured. The PL emissions showed characteristics I PL with their maxima at around 520 nm. The I PL might be due to the presence of the photo-generated Frenkel defects (FDs) in WBSs. A detailed analysis of the PL spectra showed a third-order power law dependence of the maximum I PL on P for all the crystal temperature T L . The I PL was found to increase with decreasing T L . The results demonstrated the existence of the self-trapped excitons resulting from the presence of the FDs in the crystals.

  18. Three-photon excited PL spectroscopy and photo-generated Frenkel defects in wide-bandgap layered CdI{sub 2} semiconductors

    Energy Technology Data Exchange (ETDEWEB)

    Miah, M. Idrish, E-mail: m.miah@griffith.edu.a [Qeensland Micro- and Nanotechnology Centre, Griffith University, Nathan, Brisbane, QLD 4111 (Australia)] [School of Biomolecular and Physical Sciences, Griffith University, Nathan, Brisbane, QLD 4111 (Australia)] [Department of Physics, University of Chittagong, Chittagong-4331 (Bangladesh)

    2009-12-14

    We performed a three-photon excitation nonlinear photoluminescence (PL) spectroscopy in single crystals of wide-bandgap semiconductors (WBSs). The crystal temperature (T{sub L})-dependent PL emission intensity (I{sub PL}) excited with different excitation power density (P) was measured. The PL emissions showed characteristics I{sub PL} with their maxima at around 520 nm. The I{sub PL} might be due to the presence of the photo-generated Frenkel defects (FDs) in WBSs. A detailed analysis of the PL spectra showed a third-order power law dependence of the maximum I{sub PL} on P for all the crystal temperature T{sub L}. The I{sub PL} was found to increase with decreasing T{sub L}. The results demonstrated the existence of the self-trapped excitons resulting from the presence of the FDs in the crystals.

  19. Angle-resolved photoemission spectroscopy with 9-eV photon-energy pulses generated in a gas-filled hollow-core photonic crystal fiber

    Science.gov (United States)

    Bromberger, H.; Ermolov, A.; Belli, F.; Liu, H.; Calegari, F.; Chávez-Cervantes, M.; Li, M. T.; Lin, C. T.; Abdolvand, A.; Russell, P. St. J.; Cavalleri, A.; Travers, J. C.; Gierz, I.

    2015-08-01

    A recently developed source of ultraviolet radiation, based on optical soliton propagation in a gas-filled hollow-core photonic crystal fiber, is applied here to angle-resolved photoemission spectroscopy (ARPES). Near-infrared femtosecond pulses of only few μJ energy generate vacuum ultraviolet radiation between 5.5 and 9 eV inside the gas-filled fiber. These pulses are used to measure the band structure of the topological insulator Bi2Se3 with a signal to noise ratio comparable to that obtained with high order harmonics from a gas jet. The two-order-of-magnitude gain in efficiency promises time-resolved ARPES measurements at repetition rates of hundreds of kHz or even MHz, with photon energies that cover the first Brillouin zone of most materials.

  20. Angle-resolved photoemission spectroscopy with 9-eV photon-energy pulses generated in a gas-filled hollow-core photonic crystal fiber

    International Nuclear Information System (INIS)

    Bromberger, H.; Liu, H.; Chávez-Cervantes, M.; Gierz, I.; Ermolov, A.; Belli, F.; Abdolvand, A.; Russell, P. St. J.; Travers, J. C.; Calegari, F.; Li, M. T.; Lin, C. T.; Cavalleri, A.

    2015-01-01

    A recently developed source of ultraviolet radiation, based on optical soliton propagation in a gas-filled hollow-core photonic crystal fiber, is applied here to angle-resolved photoemission spectroscopy (ARPES). Near-infrared femtosecond pulses of only few μJ energy generate vacuum ultraviolet radiation between 5.5 and 9 eV inside the gas-filled fiber. These pulses are used to measure the band structure of the topological insulator Bi 2 Se 3 with a signal to noise ratio comparable to that obtained with high order harmonics from a gas jet. The two-order-of-magnitude gain in efficiency promises time-resolved ARPES measurements at repetition rates of hundreds of kHz or even MHz, with photon energies that cover the first Brillouin zone of most materials

  1. Angle-resolved photoemission spectroscopy with 9-eV photon-energy pulses generated in a gas-filled hollow-core photonic crystal fiber

    Energy Technology Data Exchange (ETDEWEB)

    Bromberger, H., E-mail: Hubertus.Bromberger@mpsd.mpg.de; Liu, H.; Chávez-Cervantes, M.; Gierz, I. [Max Planck Institute for the Structure and Dynamics of Matter, Luruper Chaussee 149, 22761 Hamburg (Germany); Ermolov, A.; Belli, F.; Abdolvand, A.; Russell, P. St. J.; Travers, J. C. [Max Planck Institute for the Science of Light, Günther-Scharowsky-Str. 1, 91058 Erlangen (Germany); Calegari, F. [Max Planck Institute for the Structure and Dynamics of Matter, Luruper Chaussee 149, 22761 Hamburg (Germany); Institute for Photonics and Nanotechnologies, IFN-CNR, Piazza Leonardo da Vinci 32, I-20133 Milano (Italy); Li, M. T.; Lin, C. T. [Max Planck Institute for Solid State Research, Heisenbergstr. 1, 70569 Stuttgart (Germany); Cavalleri, A. [Max Planck Institute for the Structure and Dynamics of Matter, Luruper Chaussee 149, 22761 Hamburg (Germany); Clarendon Laboratory, Department of Physics, University of Oxford, Parks Rd. Oxford OX1 3PU (United Kingdom)

    2015-08-31

    A recently developed source of ultraviolet radiation, based on optical soliton propagation in a gas-filled hollow-core photonic crystal fiber, is applied here to angle-resolved photoemission spectroscopy (ARPES). Near-infrared femtosecond pulses of only few μJ energy generate vacuum ultraviolet radiation between 5.5 and 9 eV inside the gas-filled fiber. These pulses are used to measure the band structure of the topological insulator Bi{sub 2}Se{sub 3} with a signal to noise ratio comparable to that obtained with high order harmonics from a gas jet. The two-order-of-magnitude gain in efficiency promises time-resolved ARPES measurements at repetition rates of hundreds of kHz or even MHz, with photon energies that cover the first Brillouin zone of most materials.

  2. Determination of total inorganic arsenic in potable water through spectroscopy of atomic absorption with generation of hydride

    International Nuclear Information System (INIS)

    Rodriguez Roman, Susan; Barquero, M.

    2000-01-01

    Arsenic is an element that has been studied in the analysis of environmental samples for its toxicity showed in very low concentrations. The objective of this work is the validation of a method for the determination of total inorganic arsenic in drinking water. Through the spectrophotometric technique of atomic absorption an automatic system of flow injection for the generation of hydrides is used. The prereduction of Arsenic was made with potasium iodide 1,5% m/v and ascorbic acid 0.25% m/v dissolved in hydrochloric acid 3,7% m/v. The recuperation percentage of the method was 97 ± 3% in a dynamic range to 30 μg/L. The detection limit was 0,7 μg/L established over 0,5 mL of sample. The samples analyzed were found under the set limits of normative in Costa Rica of 10 μg/L. (author) [es

  3. Spin-resolved photoelectron spectroscopy using femtosecond extreme ultraviolet light pulses from high-order harmonic generation

    Energy Technology Data Exchange (ETDEWEB)

    Plötzing, M.; Adam, R., E-mail: r.adam@fz-juelich.de; Weier, C.; Plucinski, L.; Schneider, C. M. [Forschungszentrum Jülich GmbH, Peter Grünberg Institut (PGI-6), 52425 Jülich (Germany); Eich, S.; Emmerich, S.; Rollinger, M.; Aeschlimann, M. [University of Kaiserslautern and Research Center OPTIMAS, 67663 Kaiserslautern (Germany); Mathias, S. [Georg-August-Universität Göttingen, I. Physikalisches Institut, 37077 Göttingen (Germany)

    2016-04-15

    The fundamental mechanism responsible for optically induced magnetization dynamics in ferromagnetic thin films has been under intense debate since almost two decades. Currently, numerous competing theoretical models are in strong need for a decisive experimental confirmation such as monitoring the triggered changes in the spin-dependent band structure on ultrashort time scales. Our approach explores the possibility of observing femtosecond band structure dynamics by giving access to extended parts of the Brillouin zone in a simultaneously time-, energy- and spin-resolved photoemission experiment. For this purpose, our setup uses a state-of-the-art, highly efficient spin detector and ultrashort, extreme ultraviolet light pulses created by laser-based high-order harmonic generation. In this paper, we present the setup and first spin-resolved spectra obtained with our experiment within an acquisition time short enough to allow pump-probe studies. Further, we characterize the influence of the excitation with femtosecond extreme ultraviolet pulses by comparing the results with data acquired using a continuous wave light source with similar photon energy. In addition, changes in the spectra induced by vacuum space-charge effects due to both the extreme ultraviolet probe- and near-infrared pump-pulses are studied by analyzing the resulting spectral distortions. The combination of energy resolution and electron count rate achieved in our setup confirms its suitability for spin-resolved studies of the band structure on ultrashort time scales.

  4. Determination of total inorganic arsenic in potable water through spectroscopy of atomic absorption with generation of hydride

    International Nuclear Information System (INIS)

    Rodriguez Roman, S.

    1997-01-01

    This study developed a method for the cuantitative analysis of arsenic in potable water , through the spectrophotometric technique of atomic absorption. It used an automatic system of injection of flux for the generation of hydrides. It studied the effect produced by reducer agents, in the prereduction of arsenic in water, obtaining the best result with the use of potasium iodide 1.5% and ascorbic acid 0.25% in hydrochloric acid 3.7%, for the direct determination of total inorganic arsenic. It observed the effect produced by cadmium and selenium to the half of the concentration of arsenic, chromium, lead and silver at the same concentration, and barium at a ten times higher concentration, in the recuperation of total inorganic arsenic. It also used sodium borohydride 0.3% in sodium hydroxide 0.05% (5mL/min), for the formation of the volatile hydrides. It used hydrochloric acid 3.7% (12 mL/min) as disolution of transport; argon as inert gas, and a flame air-acetylene, for the atomization of the hydrides. This method was applied to 19 samples of potable water, and the result was no detectable for all of them. (S. Grainger)

  5. Electron spectroscopy

    International Nuclear Information System (INIS)

    Hegde, M.S.

    1979-01-01

    An introduction to the various techniques in electron spectroscopy is presented. These techniques include: (1) UV Photoelectron spectroscopy, (2) X-ray Photoelectron spectroscopy, (3) Auger electron spectroscopy, (4) Electron energy loss spectroscopy, (5) Penning ionization spectroscopy and (6) Ion neutralization spectroscopy. The radiations used in each technique, the basis of the technique and the special information obtained in structure determination in atoms and molecules by each technique are summarised. (A.K.)

  6. Time-resolved study of formate on Ni( 1 1 1 ) by picosecond SFG spectroscopy

    Science.gov (United States)

    Kusafuka, K.; Noguchi, H.; Onda, K.; Kubota, J.; Domen, K.; Hirose, C.; Wada, A.

    2002-04-01

    Time-resolved vibrational measurements were carried out on formate (HCOO) adsorbed on Ni(1 1 1) surface by combining the sum-frequency generation method and picosecond laser system (time resolution of 6 ps). Rapid intensity decrease (within the time resolution) followed by intensity recovery (time constant of several tens of ps) of CH stretching signal was observed when picosecond 800 nm pulse was irradiated on the sample surface. From the results of temperature and pump fluence dependences of temporal behaviour of signal intensity, we concluded that the observed intensity change was induced by non-thermal process. Mechanism of the temporal intensity change was discussed.

  7. Site-specific Orientation of an α-helical Peptide Ovispirin-1 from Isotope Labeled SFG Spectroscopy

    Science.gov (United States)

    Ding, Bei; Laaser, Jennifer E.; Liu, Yuwei; Wang, Pengrui; Zanni, Martin T.; Chen, Zhan

    2013-01-01

    Sum-frequency generation (SFG) vibrational spectroscopy is often used to probe the backbone structures and orientations of polypeptides at surfaces. Using the ovispirin-1 polypeptide at the solid/liquid interface of polystyrene, we demonstrate for the first time that SFG can probe the polarization response of a single isotope labeled residue. To interpret the spectral intensities, we simulated the spectra using an excitonic Hamiltonian approach. We show that the polarization dependence of either the label or the unlabeled amide I band alone does not provide sufficient structural constraints to obtain both the tilt and the twist of the ovispirin helix at a solid/liquid interface, but that both can be determined from the polarization dependence of the complete spectrum. For ovispirin, the detailed analysis of the polarized SFG experimental data shows that the helix axis is tilted at roughly 138 degrees from the surface normal, and the transition dipole of the isotope labeled C=O group is tilted at 23 degrees from the surface normal, with the hydrophobic region facing the polystyrene surface. We further demonstrated that the Hamiltonian approach is able to address the coupling effect and the structural disorder. For comparison, we also collected the FTIR spectrum of ovispirin under similar conditions, which reveals the enhanced sensitivity of SFG for structural studies of single monolayer peptide surfaces. Our study provides insight into how structural and environmental effects appear in SFG spectra of the amide I band and establishes that SFG of isotope labeled peptides will be a powerful technique for elucidating secondary structures with residue-by-residue resolution. PMID:24228619

  8. Site-specific orientation of an α-helical peptide ovispirin-1 from isotope-labeled SFG spectroscopy.

    Science.gov (United States)

    Ding, Bei; Laaser, Jennifer E; Liu, Yuwei; Wang, Pengrui; Zanni, Martin T; Chen, Zhan

    2013-11-27

    Sum-frequency generation (SFG) vibrational spectroscopy is often used to probe the backbone structures and orientations of polypeptides at surfaces. Using the ovispirin-1 polypeptide at the solid/liquid interface of polystyrene, we demonstrate for the first time that SFG can probe the polarization response of a single-isotope-labeled residue. To interpret the spectral intensities, we simulated the spectra using an excitonic Hamiltonian approach. We show that the polarization dependence of either the label or the unlabeled amide I band alone does not provide sufficient structural constraints to obtain both the tilt and the twist of the ovispirin helix at a solid/liquid interface, but that both can be determined from the polarization dependence of the complete spectrum. For ovispirin, the detailed analysis of the polarized SFG experimental data shows that the helix axis is tilted at roughly 138° from the surface normal, and the transition dipole of the isotope-labeled C═O group is tilted at 23° from the surface normal, with the hydrophobic region facing the polystyrene surface. We further demonstrate that the Hamiltonian approach is able to address the coupling effect and the structural disorder. For comparison, we also collected the FTIR spectrum of ovispirin under similar conditions, which reveals the enhanced sensitivity of SFG for structural studies of single monolayer peptide surfaces. Our study provides insight into how structural and environmental effects appear in SFG spectra of the amide I band and establishes that SFG of isotope-labeled peptides will be a powerful technique for elucidating secondary structures with residue-by-residue resolution.

  9. Understanding fifth-harmonic generation in CLBO

    Science.gov (United States)

    Patankar, S.; Yang, S. T.; Moody, J. D.; Bayramian, A. J.; Swadling, G. F.; Barker, D.; Datte, P.; Mennerat, G.; Norton, M.; Carr, C. W.; Begishev, I. A.; Bromage, J.; Ross, J. S.

    2018-02-01

    We report on results of fifth harmonic generation in Cesium Lithium Borate (CLBO) using a three-crystal cascaded frequency conversion scheme designed to study the energy balance of the final sum frequency generation stage. The experimental setup independently combines the first and fourth harmonic of a Nd:Glass laser in a 5mm thick CLBO crystal. Energy balance between the incoming and output energy is close to unity when the CLBO is out of phase matching and approximately 80% when the crystal is in phase matching. A detailed analysis of the residual fundamental and fourth harmonic energy indicates 5th harmonic light is being generated but only 26% is unaccounted for. We attribute the missing light to linear transmission loss in the CLBO oven. The ratio of the output to input energy is unity when the missing 5th harmonic is incorporated into the calculations. Two-dimensional plane wave mixing simulations show agreement with the results at lower intensities.

  10. Efficient plasma and bubble generation underwater by an optimized laser excitation and its application for liquid analyses by laser-induced breakdown spectroscopy

    International Nuclear Information System (INIS)

    Lazic, Violeta; Jovicevic, Sonja; Fantoni, Roberta; Colao, Francesco

    2007-01-01

    Laser-induced breakdown spectroscopy (LIBS) measurements were performed on bulk water solutions by applying a double-pulse excitation from a Q-Switched (QS) Nd:YAG laser emitting at 1064 nm. In order to optimize the LIBS signal, laser pulse energies were varied through changing of the QS trigger delays with respect to the flash-lamp trigger. We had noted that reduction of the first pulse energy from 92 mJ to 72 mJ drastically improves the signal, although the second pulse energy was also lowered from 214 mJ to 144 mJ. With lower pulse energies, limit of detection (LOD) for Mg in pure water was reduced for one order of magnitude (34 ppb instead of 210 ppb). In order to explain such a phenomenon, we studied the dynamics of the gas bubble generated after the first laser pulse through measurements of the HeNe laser light scattered on the bubble. The influence of laser energy on underwater bubble and plasma formation and corresponding plasma emission intensity were also studied by photographic technique. From the results obtained, we conclude that the optimal first pulse energy should be kept close to the plasma elongation threshold, in our case about 65 mJ, where the gas bubble has its maximum lateral expansion and the secondary plasma is still well-localized. The importance of a multi-pulse sequence on the LIBS signal was also analyzed, where the pulse sequence after the first QS aperture was produced by operating the laser close to the lasing threshold, with the consequent generation of relaxation oscillations. Low-energy multi-pulses might keep the bubble expansion large prior to the probing pulse, but preventing the formation of secondary weak plasmas in multiple sites, which reduces the LIBS signal. The short interval between the pre-pulses and the probing pulse is another reason for the observed LIBS signal enhancement

  11. Modeling of low-temperature plasmas generated using laser-induced breakdown spectroscopy: the ChemCam diagnostic tool on the Mars Science Laboratory Rover

    Science.gov (United States)

    Colgan, James

    2016-05-01

    We report on efforts to model the low-temperature plasmas generated using laser-induced breakdown spectroscopy (LIBS). LIBS is a minimally invasive technique that can quickly and efficiently determine the elemental composition of a target and is employed in an extremely wide range of applications due to its ease of use and fast turnaround. In particular, LIBS is the diagnostic tool used by the ChemCam instrument on the Mars Science Laboratory rover Curiosity. In this talk, we report on the use of the Los Alamos plasma modeling code ATOMIC to simulate LIBS plasmas, which are typically at temperatures of order 1 eV and electron densities of order 10 16 - 17 cm-3. At such conditions, these plasmas are usually in local-thermodynamic equilibrium (LTE) and normally contain neutral and singly ionized species only, which then requires that modeling must use accurate atomic structure data for the element under investigation. Since LIBS devices are often employed in a very wide range of applications, it is therefore desirable to have accurate data for most of the elements in the periodic table, ideally including actinides. Here, we discuss some recent applications of our modeling using ATOMIC that have explored the plasma physics aspects of LIBS generated plasmas, and in particular discuss the modeling of a plasma formed from a basalt sample used as a ChemCam standard1. We also highlight some of the more general atomic physics challenges that are encountered when attempting to model low-temperature plasmas. The Los Alamos National Laboratory is operated by Los Alamos National Security, LLC for the National Nuclear Security Administration of the U.S. Department of Energy under Contract No. DE-AC5206NA25396. Work performed in conjunction with D. P. Kilcrease, H. M. Johns, E. J. Judge, J. E. Barefield, R. C. Wiens, S. M. Clegg.

  12. Rapid analysis of effluents generated by the dairy industry for fat determination by preconcentration in nylon membranes and attenuated total reflectance infrared spectroscopy measurement.

    Science.gov (United States)

    Moliner Martínez, Y; Muñoz-Ortuño, M; Herráez-Hernández, R; Campíns-Falcó, P

    2014-02-01

    This paper describes a new approach for the determination of fat in the effluents generated by the dairy industry which is based on the retention of fat in nylon membranes and measurement of the absorbances on the membrane surface by ATR-IR spectroscopy. Different options have been evaluated for retaining fat in the membranes using milk samples of different origin and fat content. Based on the results obtained, a method is proposed for the determination of fat in effluents which involves the filtration of 1 mL of the samples through 0.45 µm nylon membranes of 13 mm diameter. The fat content is then determined by measuring the absorbance of band at 1745 cm(-1). The proposed method can be used for the direct estimation of fat at concentrations in the 2-12 mg/L interval with adequate reproducibility. The intraday precision, expressed as coefficients of variation CVs, were ≤ 11%, whereas the interday CVs were ≤ 20%. The method shows a good tolerance towards conditions typically found in the effluents generated by the dairy industry. The most relevant features of the proposed method are simplicity and speed as the samples can be characterized in a few minutes. Sample preparation does not involve either additional instrumentation (such as pumps or vacuum equipment) or organic solvents or other chemicals. Therefore, the proposed method can be considered a rapid, simple and cost-effective alternative to gravimetric methods for controlling fat content in these effluents during production or cleaning processes. © 2013 Published by Elsevier B.V.

  13. Corrosion evaluation of heat recovery steam generator superheater tube in two methods of testing: Tafel polarization and electrochemical impedance spectroscopy (EIS)

    Science.gov (United States)

    Santoso, Rio Pudjidarma; Riastuti, Rini

    2018-05-01

    The purpose of this research is to evaluate the corrosion process which occurs on the water side of Heat Recovery Steam Generator (HRSG) superheater tube. The tube was 13CrMo44 and divided into 3 types of specimen: new tube, used tube (with oxide layer on surface), cleaned-used tube (without oxide layer on surface). The evaluation of corrosion parameters wasperformed using deaerated ultra-high purity water (boiler feed water) in two methods of testing: Tafel polarization and Electrochemical Impedance Spectroscopy (EIS). Tafel polarization was excellent as its capability to show the value of corrosion current and the corrosion rate explicitly, on the other hand, EIS was excellent as its capability to explain for corrosion mechanism on metal interface in detail. Both methods showed that the increase of electrolyte temperature from 25°C to 55°C would increase the corrosion rate with the mechanism of decreasing polarization resistance due to thinning out the passive film thickness and enlarge the area of reduction reaction of cathode. Magnetite oxide scale which is laid on the surface of used tube specimen shows protective nature to reduce the corrosion rate, and clear up this oxide would increase the corrosion rate back as new tube.

  14. Uranium, radium and thorium in soils with high-resolution gamma spectroscopy, MCNP-generated efficiencies, and VRF non-linear full-spectrum nuclide shape fitting

    Directory of Open Access Journals (Sweden)

    Metzger Robert

    2017-01-01

    Full Text Available A new method for analysis of uranium and radium in soils by gamma spectroscopy has been developed using VRF (“Visual RobFit” which, unlike traditional peak-search techniques, fits full-spectrum nuclide shapes with non-linear least-squares minimization of the chi-squared statistic. Gamma efficiency curves were developed for a 500 mL Marinelli beaker geometry as a function of soil density using MCNP. Collected spectra were then analyzed using the MCNP-generated efficiency curves and VRF to deconvolute the 90 keV peak complex of uranium and obtain 238U and 235U activities. 226Ra activity was determined either from the radon daughters if the equilibrium status is known, or directly from the deconvoluted 186 keV line. 228Ra values were determined from the 228Ac daughter activity. The method was validated by analysis of radium, thorium and uranium soil standards and by inter-comparison with other methods for radium in soils. The method allows for a rapid determination of whether a sample has been impacted by a man-made activity by comparison of the uranium and radium concentrations to those that would be expected from a natural equilibrium state.

  15. Analysis of interfacial energy states in Au/pentacene/polyimide/indium-zinc-oxide diodes by electroluminescence spectroscopy and electric-field-induced optical second-harmonic generation measurement

    Science.gov (United States)

    Taguchi, Dai; Manaka, Takaaki; Iwamoto, Mitsumasa

    2016-03-01

    By using electroluminescence (EL) spectroscopy and electric-field-induced optical second-harmonic generation (EFISHG) measurement, we analyzed interfacial energy states in Au/pentacene/polyimide/indium-zinc-oxide (IZO) diodes, to characterize the pentacene/polyimide interface. Under positive voltage application to the Au electrode with reference to the IZO electrode, the EFISHG showed that holes are injected from Au electrode, and accumulate at the pentacene/polyimide interface with the surface charge density of Qs = 3.8 × 10-7 C/cm2. The EL spectra suggested that the accumulated holes are not merely located in the pentacene but they are transferred to the interface states of polyimide. These accumulated holes distribute with the interface state density greater than 1012 cm-2 eV-1 in the range E = 1.5-1.8 and 1.7-2.4 eV in pentacene and in polyimide, respectively, under assumption that accumulated holes govern recombination radiation. The EL-EFISHG measurement is helpful to characterize organic-organic layer interfaces in organic devices and provides a way to analyze interface energy states.

  16. Uranium, radium and thorium in soils with high-resolution gamma spectroscopy, MCNP-generated efficiencies, and VRF non-linear full-spectrum nuclide shape fitting

    Science.gov (United States)

    Metzger, Robert; Riper, Kenneth Van; Lasche, George

    2017-09-01

    A new method for analysis of uranium and radium in soils by gamma spectroscopy has been developed using VRF ("Visual RobFit") which, unlike traditional peak-search techniques, fits full-spectrum nuclide shapes with non-linear least-squares minimization of the chi-squared statistic. Gamma efficiency curves were developed for a 500 mL Marinelli beaker geometry as a function of soil density using MCNP. Collected spectra were then analyzed using the MCNP-generated efficiency curves and VRF to deconvolute the 90 keV peak complex of uranium and obtain 238U and 235U activities. 226Ra activity was determined either from the radon daughters if the equilibrium status is known, or directly from the deconvoluted 186 keV line. 228Ra values were determined from the 228Ac daughter activity. The method was validated by analysis of radium, thorium and uranium soil standards and by inter-comparison with other methods for radium in soils. The method allows for a rapid determination of whether a sample has been impacted by a man-made activity by comparison of the uranium and radium concentrations to those that would be expected from a natural equilibrium state.

  17. Gamma Spectroscopy

    NARCIS (Netherlands)

    Niemantsverdriet, J.W.; Butz, Tilman; Ertl, G.; Knözinger, H.; Schüth, F.

    2008-01-01

    No abstract. The sections in this article are 1 Introduction 2 Mössbauer Spectroscopy 3 Time-Differential Perturbed Angular Correlations (TDPAC) 4 Conclusions and Outlook Keywords: Mössbauer spectroscopy; gamma spectroscopy; perturbed angular correlation; TDPAC

  18. Fs–ns double-pulse Laser Induced Breakdown Spectroscopy of copper-based-alloys: Generation and elemental analysis of nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Guarnaccio, A.; Parisi, G.P.; Mollica, D. [CNR-ISM, U.O.S. Tito Scalo, Zona Industriale, 85050 Tito Scalo, PZ (Italy); De Bonis, A. [CNR-ISM, U.O.S. Tito Scalo, Zona Industriale, 85050 Tito Scalo, PZ (Italy); Dipartimento di Scienze, Università degli Studi della Basilicata, Via dell' Ateneo Lucano 10, 85100 Potenza (Italy); Teghil, R. [Dipartimento di Scienze, Università degli Studi della Basilicata, Via dell' Ateneo Lucano 10, 85100 Potenza (Italy); Santagata, A. [CNR-ISM, U.O.S. Tito Scalo, Zona Industriale, 85050 Tito Scalo, PZ (Italy)

    2014-11-01

    Evolution of nanoparticles ejected during ultra-short (250 fs) laser ablation of certified copper alloys and relative calibration plots of a fs–ns double-pulse Laser Induced Breakdown Spectroscopy orthogonal configuration is presented. All work was performed in air at atmospheric pressure using certified copper-based-alloy samples irradiated by a fs laser beam and followed by a delayed perpendicular ns laser pulse. In order to evaluate possible compositional changes of the fs induced nanoparticles, it was necessary to consider, for all samples used, comparable features of the detected species. With this purpose the induced nanoparticles black-body-like emission evolution and their relative temperature decay have been studied. These data were exploited for defining the distance between the target surface and the successive ns laser beam to be used. The consequent calibration plots of minor constituents (i.e. Sn, Pb and Zn) of the certified copper-based-alloy samples have been reported by taking into account self-absorption effects. The resulting linear regression coefficients suggest that the method used, for monitoring and ruling the fs laser induced nanoparticles, could provide a valuable approach for establishing the occurrence of potential compositional changes of the detected species. All experimental data reveal that the fs laser induced nanoparticles can be used for providing a coherent composition of the starting target. In the meantime, the fs–ns double-pulse Laser Induced Breakdown Spectroscopy orthogonal configuration here used can be considered as an efficient technique for compositional determination of the nanoparticles ejected during ultra-short laser ablation processes. - Highlights: • Laser induced NP continuum black-body-like emission was used for T determination. • Invariable composition of generated NPs was assumed in the range of 20 μs. • Fs-ns DP-LIBS was employed for the compositional characterization of NPs. • NPs obtained by fs

  19. PREFACE: Liquid-solid interfaces: structure and dynamics from spectroscopy and simulations Liquid-solid interfaces: structure and dynamics from spectroscopy and simulations

    Science.gov (United States)

    Gaigeot, Marie-Pierre; Sulpizi, Marialore

    2012-03-01

    /computational communities. On the experimental side, surface specific techniques, such as non-linear optical spectroscopy (sum frequency generation spectroscopy (SFG) and second harmonic generation (SHG)), surface sensitive x-ray scattering, in situ scanning tunneling microscopy (STM) and infrared reflection absorption spectroscopy provide information on layers of nanometric thickness at the interface. On the other hand, it is quite clear that the experiments require theoretical modelling in order to dissect the experimental results and to rationalize the different factors that contribute to the interfacial properties. In this respect molecular dynamics simulations are a major tool. While many successes have already been achieved with molecular dynamics simulations based on empirical force fields, first principles molecular dynamics simulations are now emerging as the other major approach where structure and reactivity are treated in a consistent way. Recent progress within the past 3-5 years on efficient treatments of basis sets and long range interactions in density functional theory (DFT) indeed extend such simulation capabilities to hundreds and thousands of atoms, thus allowing realistic models for interfaces to be tackled, maintaining first principles quality. Most of these simulations bring information on the structural organization of the solvent in the interfacial region between the solid and the liquid, but very few investigate the supplementary challenge of extracting vibrational spectroscopic fingerprints of the interface and, in particular, the direct modeling of the vibrational sum frequency generation (VSFG) non-linear spectra. The present special section reports an interesting contribution from the group of R Y Shen who pioneered VSFG optical experiments. They show how VSFG measurements can be used to unravel the behavior of interfacial water on alumina Al2O3 as a function of pH. The groups of A Hodgson and C Busse respectively provide complementary experiments based on low

  20. Nonlinear vibrational spectroscopy of surfactants at liquid interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Miranda, Paulo B. [Univ. of California, Berkeley, CA (United States)

    1998-12-14

    Surfactants are widely used to modify physical and chemical properties of interfaces. They play an important role in many technological problems. Surfactant monolayer are also of great scientific interest because they are two-dimensional systems that may exhibit a very rich phase transition behavior and can also be considered as a model system for biological interfaces. In this Thesis, we use a second-order nonlinear optical technique (Sum-Frequency Generation - SFG) to obtain vibrational spectra of surfactant monolayer at Iiquidhapor and solid/liquid interfaces. The technique has several advantages: it is intrinsically surface-specific, can be applied to buried interfaces, has submonolayer sensitivity and is remarkably sensitive to the confirmational order of surfactant monolayers.

  1. Supervised Mineral Classification with Semi-automatic Training and Validation Set Generation in Scanning Electron Microscope Energy Dispersive Spectroscopy Images of Thin Sections

    DEFF Research Database (Denmark)

    Flesche, Harald; Nielsen, Allan Aasbjerg; Larsen, Rasmus

    2000-01-01

    This paper addresses the problem of classifying minerals common in siliciclastic and carbonate rocks. Twelve chemical elements are mapped from thin sections by energy dispersive spectroscopy in a scanning electron microscope (SEM). Extensions to traditional multivariate statistical methods...

  2. Structure Sensitivity in Pt Nanoparticle Catalysts for Hydrogenation of 1,3-Butadiene: In Situ Study of Reaction Intermediates Using SFG Vibrational Spectroscopy

    KAUST Repository

    Michalak, William D.

    2013-01-31

    The product selectivity during 1,3-butadiene hydrogenation on monodisperse, colloidally synthesized, Pt nanoparticles was studied under reaction conditions with kinetic measurements and in situ sum frequency generation (SFG) vibrational spectroscopy. SFG was performed with the capping ligands intact in order to maintain nanoparticle size by reduced sintering. Four products are formed at 75 C: 1-butene, cis-2-butene, trans-2-butene, and n-butane. Ensembles of Pt nanoparticles with average diameters of 0.9 and 1.8 nm exhibit a ∼30% and ∼20% increase in the full hydrogenation products, respectively, as compared to Pt nanoparticles with average diameters of 4.6 and 6.7 nm. Methyl and methylene vibrational stretches of reaction intermediates observed under working conditions using SFG were used to correlate the stable reaction intermediates with the product distribution. Kinetic and SFG results correlate with previous DFT predictions for two parallel reaction pathways of 1,3-butadiene hydrogenation. Hydrogenation of 1,3-butadiene can initiate with H-addition at internal or terminal carbons leading to the formation of 1-buten-4-yl radical (metallocycle) and 2-buten-1-yl radical intermediates, respectively. Small (0.9 and 1.8 nm) nanoparticles exhibited vibrational resonances originating from both intermediates, while the large (4.6 and 6.7 nm) particles exhibited vibrational resonances originating predominately from the 2-buten-1-yl radical. This suggests each reaction pathway competes for partial and full hydrogenation and the nanoparticle size affects the kinetic preference for the two pathways. The reaction pathway through the metallocycle intermediate on the small nanoparticles is likely due to the presence of low-coordinated sites. © 2012 American Chemical Society.

  3. Multi-atom resonant photoemission and the development of next-generation software and high-speed detectors for electron spectroscopy

    International Nuclear Information System (INIS)

    Kay, Alexander William

    2000-01-01

    This dissertation has involved the exploration of a new effect in photoelectron emission, multi-atom resonant photoemission (MARPE), as well as the development of new software, data analysis techniques, and detectors of general use in such research. We present experimental and theoretical results related to MARPE, in which the photoelectron intensity from a core level on one atom is influenced by a core-level absorption resonance on another. We point out that some of our and others prior experimental data has been strongly influenced by detector non-linearity and that the effects seen in new corrected data are smaller and of different form. Corrected data for the MnO(001) system with resonance between the O 1s and Mn 2p energy levels are found to be well described by an extension of well-known intraatomic resonant photoemission theory to the interatomic case, provided that interactions beyond the usual second-order Kramers-Heisenberg treatment are included. This theory is also found to simplify under certain conditions so as to yield results equivalent to a classical x-ray optical approach, with the latter providing an accurate and alternative, although less detailed and general, physical picture of these effects. Possible future applications of MARPE as a new probe of near-neighbor identities and bonding and its relationship to other known effects are also discussed. We also consider in detail specially written data acquisition software that has been used for most of the measurements reported here. This software has been used with an existing experimental system to develop the method of detector characterization and then data correction required for the work described above. The development of a next generation one-dimensional, high-speed, electron detector is also discussed. Our goal has been to design, build and test a prototype high-performance, one-dimensional pulse-counting detector that represents a significant advancement in detector technology and is well

  4. [Time resolved plasma spectroscopy of imploded gas-filled microballoons: The next generation]. Final technical report, 17 April 1995--30 September 1997

    International Nuclear Information System (INIS)

    Hooper, C.F. Jr.

    1998-03-01

    This report is comprised of three documents which deal with plasma spectroscopy of laser-produced plasmas. In Appendix A the authors present a discussion of plasma line broadening with emphasis on the effects of accounting for ion-dynamic corrections. For two decades, high power lasers have been used to implode microballoons filled with gases such as neon, argon, deuterium, or mixtures of deuterium and argon. These implosions have generated high-temperature (∼ 1 keV) and high density (∼ 10 23 /cc--10 25 /cc) plasmas. As a result of these experiments, the authors are able to observe the radiative properties of highly charged ions in the presence of a variety of strongly coupled plasmas. Spectral radiation observed from these experiments is frequently in the x-ray region and the radiative properties are greatly influenced by plasma effects. In section 2 of this paper the authors discuss the theoretical techniques employed to interpret these spectra and describe two sets of implosion experiments. In section 3 they list some conclusions. Appendix B presents more research related to ion-dynamic corrections. The authors examine the combined effects of ion dynamics and opacity on line profiles used in the analysis of hot dense plasmas. Specifically, they have calculated Stark broadened line profiles for both resonance and satellite lines in highly stripped Ar ions, both in the quasi-static ion approximation, and including the effects of ion dynamics. Using the results of an NLTE kinetics code, combined with an escape factor formalism to account for the effects of radiative transfer, they have calculated the relative intensities of these lines, as well as the effects of opacity on their profiles. This model spectra is used in the analysis of experimental data. In a series of experiments performed at the Laboratory for Laser Energetics plastic microballoons filled with DD and doped with Ar were imploded using the Omega laser system. Here, the authors use time-resolved K

  5. Next Generation Virgo Survey Photometry and Keck/DEIMOS Spectroscopy of Globular Cluster Satellites of Dwarf Elliptical Galaxies in the Virgo Cluster

    Science.gov (United States)

    Guhathakurta, Puragra; Toloba, Elisa; Peng, Eric W.; Li, Biao; Gwyn, Stephen; Ferrarese, Laura; Cote, Patrick; Chu, Jason; Sparkman, Lea; Chen, Stephanie; Yagati, Samyukta; Muller, Meredith; Next Generation Virgo Survey Collaboration

    2015-01-01

    We present results from an ongoing study of globular cluster (GC) satellites of low-luminosity dwarf elliptical (dE) galaxies in the Virgo cluster. Our 21 dE targets and candidate GC satellites around them in the apparent magnitude range g ~ 20-24 were selected from the Next Generation Virgo Survey (NGVS) and followed up with medium-resolution Keck/DEIMOS spectroscopy (resolving power: R ~ 2000; wavelength coverage: 4800-9500 Angstrom). In addition, the remaining space available on the nine DEIMOS multi-slit masks were populated with "filler" targets in the form of distant Milky Way halo star candidates in a comparable apparent magnitude range. A combination of radial velocity information (measured from the Keck/DEIMOS spectra), color-color information (from four-band NGVS photometry), and sky position information was used to sort the sample into the following categories: (1) GC satellites of dEs, (2) other non-satellite GCs in the Virgo cluster (we dub them "orphan" GCs), (3) foreground Milky Way stars that are members of the Sagittarius stream, the Virgo overdensity, or the field halo population, and (4) distant background galaxies. We stack the GC satellite population across all 21 host dEs and carry out dynamical modeling of the stacked sample in order to constrain the average mass of dark matter halos that these dEs are embedded in. We study rotation in the system of GC satellites of dEs in the handful of more populated systems in our sample - i.e., those that contain 10 or more GC satellites per dE. A companion AAS poster presented at this meeting (Chu, J. et al. 2015) presents chemical composition and age constraints for these GC satellites relative to the nuclei of the host dEs based on absorption line strengths in co-added spectra. The orphan GCs are likely to be intergalactic GCs within the Virgo cluster (or, equivalently, GCs in the remote outer envelope of the cluster's central galaxy, the giant elliptical M87).This project is funded in part by the

  6. Multi-atom resonant photoemission and the development of next-generation software and high-speed detectors for electron spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Kay, Alexander William [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2000-09-01

    This dissertation has involved the exploration of a new effect in photoelectron emission, multi-atom resonant photoemission (MARPE), as well as the development of new software, data analysis techniques, and detectors of general use in such research. We present experimental and theoretical results related to MARPE, in which the photoelectron intensity from a core level on one atom is influenced by a core-level absorption resonance on another. We point out that some of our and others prior experimental data has been strongly influenced by detector non-linearity and that the effects seen in new corrected data are smaller and of different form. Corrected data for the MnO(001) system with resonance between the O 1s and Mn 2p energy levels are found to be well described by an extension of well-known intraatomic resonant photoemission theory to the interatomic case, provided that interactions beyond the usual second-order Kramers-Heisenberg treatment are included. This theory is also found to simplify under certain conditions so as to yield results equivalent to a classical x-ray optical approach, with the latter providing an accurate and alternative, although less detailed and general, physical picture of these effects. Possible future applications of MARPE as a new probe of near-neighbor identities and bonding and its relationship to other known effects are also discussed. We also consider in detail specially written data acquisition software that has been used for most of the measurements reported here. This software has been used with an existing experimental system to develop the method of detector characterization and then data correction required for the work described above. The development of a next generation one-dimensional, high-speed, electron detector is also discussed. Our goal has been to design, build and test a prototype high-performance, one-dimensional pulse-counting detector that represents a significant advancement in detector technology and is well

  7. Debris of potassium–magnesium silicate glass generated by femtosecond laser-induced ablation in air: An analysis by near edge X-ray absorption spectroscopy, micro Raman and energy dispersive X-ray spectroscopy

    International Nuclear Information System (INIS)

    Grehn, M.; Seuthe, T.; Reinhardt, F.; Höfner, M.; Griga, N.; Eberstein, M.; Bonse, J.

    2014-01-01

    The redeposited material (debris) resulting from ablation of a potassium–magnesium silicate glass upon scanning femtosecond laser pulse irradiation (130 fs, 800 nm) in air environment is investigated by means of three complementary surface analytical methods. Changes in the electronic band structure of the glass constituent Magnesium (Mg) were identified by X-ray Absorption Near Edge Structure spectroscopy (XANES) using synchrotron radiation. An up-shift of ≈0.8 eV of a specific Magnesium K-edge absorption peak in the spectrum of the redeposited material along with a significant change in its leading edge position was detected. In contrast, the surface left after laser ablation exhibits a downshift of the peak position by ≈0.9 eV. Both observations may be related to a change of the Mg coordinative state of the laser modified/redeposited glass material. The presence of carbon in the debris is revealed by micro Raman spectroscopy (μ-RS) and was confirmed by energy dispersive X-ray spectroscopy (EDX). These observations are attributed to structural changes and chemical reactions taking place during the ablation process.

  8. Molecular spectroscopy

    International Nuclear Information System (INIS)

    Kokh, Eh.; Zonntag, B.

    1981-01-01

    The latest investigation results on molecular spectroscopy with application of synchrotron radiation in the region of vacuum ultraviolet are generalized. Some results on investigation of excited, superexcited and ionized molecule states with the use of adsorption spectroscopy, photoelectron spectroscopy, by fluorescent and mass-spectrometric methods are considered [ru

  9. Atom spectroscopy

    International Nuclear Information System (INIS)

    Kodling, K.

    1981-01-01

    Experiments on atom photoabsorption spectroscopy using synchrotron radiation in the 10-1000 eV range are reviewed. Properties of the necessary synchrotron radiation and the experiment on absorption spectroscopy are briefly described. Comparison with other spectroscopy methods is conducted. Some data on measuring photoabsorption, photoelectron emission and atom mass spectra are presented [ru

  10. Vibrational spectroscopy

    Science.gov (United States)

    Umesh P. Agarwal; Rajai Atalla

    2010-01-01

    Vibrational spectroscopy is an important tool in modern chemistry. In the past two decades, thanks to significant improvements in instrumentation and the development of new interpretive tools, it has become increasingly important for studies of lignin. This chapter presents the three important instrumental methods-Raman spectroscopy, infrared (IR) spectroscopy, and...

  11. Terahertz spectroscopy

    DEFF Research Database (Denmark)

    Jepsen, Peter Uhd

    2009-01-01

    In this presentation I will review methods for spectroscopy in the THz range, with special emphasis on the practical implementation of the technique known ad THz time-domain spectroscopy (THz-TDS). THz-TDS has revived the old field of far-infrared spectroscopy, and enabled a wealth of new...... activities that promise commercial potential for spectroscopic applications in the THz range. This will be illustrated with examples of spectroscopy of liquids inside their bottles as well as sensitive, quantitative spectroscopy in waveguides....

  12. Polymer Adsorption on Graphite and CVD Graphene Surfaces Studied by Surface-Specific Vibrational Spectroscopy.

    Science.gov (United States)

    Su, Yudan; Han, Hui-Ling; Cai, Qun; Wu, Qiong; Xie, Mingxiu; Chen, Daoyong; Geng, Baisong; Zhang, Yuanbo; Wang, Feng; Shen, Y R; Tian, Chuanshan

    2015-10-14

    Sum-frequency vibrational spectroscopy was employed to probe polymer contaminants on chemical vapor deposition (CVD) graphene and to study alkane and polyethylene (PE) adsorption on graphite. In comparing the spectra from the two surfaces, it was found that the contaminants on CVD graphene must be long-chain alkane or PE-like molecules. PE adsorption from solution on the honeycomb surface results in a self-assembled ordered monolayer with the C-C skeleton plane perpendicular to the surface and an adsorption free energy of ∼42 kJ/mol for PE(H(CH2CH2)nH) with n ≈ 60. Such large adsorption energy is responsible for the easy contamination of CVD graphene by impurity in the polymer during standard transfer processes. Contamination can be minimized with the use of purified polymers free of PE-like impurities.

  13. Generation of three-mode continuous-variable entanglement by cascaded nonlinear interactions in a quasiperiodic superlattice

    International Nuclear Information System (INIS)

    Yu, Y. B.; Xie, Z. D.; Yu, X. Q.; Li, H. X.; Xu, P.; Yao, H. M.; Zhu, S. N.

    2006-01-01

    The generation of three-mode continuous-variable entanglement in a quasiperiodically optical superlattice is studied theoretically in this paper. This work is based on the previous experiment result in which three-color light generated from a quasiperiodically optical superlattice through a stimulated parametric down-conversion cascaded with a sum-frequency process. The degree of quadrature phase amplitude correlations, a nonclassical characteristic, among the three mode was discussed by a sufficient inseparability criterion for continuous-variable entanglement, which was proposed by van Loock and Furusawa

  14. Efficient generation of 3.9 W of diffraction-limited green light with spectrally combined tapered diode lasers

    DEFF Research Database (Denmark)

    Müller, André; Jensen, Ole Bjarlin; Andersen, Peter E.

    We propose an efficient concept increasing the power of diode laser systems in the visible spectral range. In comparison with second harmonic generation of single emitters, spectral beam combining with subsequent sum-frequency generation enhances the available power significantly. Combining two...... 1060 nm tapered diode lasers, we achieve a 2.5-3.2 fold increase of green light with a maximum power of 3.9 Watts in a diffraction-limited beam. At this level, diode lasers have a high application potential, for example, within the biomedical field. In order to enhance the power even further, our...

  15. Multidimensional high harmonic spectroscopy

    International Nuclear Information System (INIS)

    Bruner, Barry D; Soifer, Hadas; Shafir, Dror; Dudovich, Nirit; Serbinenko, Valeria; Smirnova, Olga

    2015-01-01

    High harmonic generation (HHG) has opened up a new frontier in ultrafast science where attosecond time resolution and Angstrom spatial resolution are accessible in a single measurement. However, reconstructing the dynamics under study is limited by the multiple degrees of freedom involved in strong field interactions. In this paper we describe a new class of measurement schemes for resolving attosecond dynamics, integrating perturbative nonlinear optics with strong-field physics. These approaches serve as a basis for multidimensional high harmonic spectroscopy. Specifically, we show that multidimensional high harmonic spectroscopy can measure tunnel ionization dynamics with high precision, and resolves the interference between multiple ionization channels. In addition, we show how multidimensional HHG can function as a type of lock-in amplifier measurement. Similar to multi-dimensional approaches in nonlinear optical spectroscopy that have resolved correlated femtosecond dynamics, multi-dimensional high harmonic spectroscopy reveals the underlying complex dynamics behind attosecond scale phenomena. (paper)

  16. Modern spectroscopy

    CERN Document Server

    Hollas, J Michael

    2013-01-01

    The latest edition of this highly acclaimed title introduces the reader to a wide range of spectroscopies, and includes both the background theory and applications to structure determination and chemical analysis.  It covers rotational, vibrational, electronic, photoelectron and Auger spectroscopy, as well as EXAFs and the theory of lasers and laser spectroscopy. A  revised and updated edition of a successful, clearly written book Includes the latest developments in modern laser techniques, such as cavity ring-down spectroscopy and femtosecond lasers Provides numerous worked examples, calculations and questions at the end of chapters.

  17. Outlook for baryon spectroscopy

    International Nuclear Information System (INIS)

    Tripp, R.D.

    1976-09-01

    The review of baryon spectroscopy includes a number of new generation experiments with greatly improved statistics which have emerged and are enhancing experimental knowledge of baryon resonances. The future research directions are pointed out, and some problems and deficiencies which can be resolved with contemporary techniques are mentioned

  18. Laser spectroscopy

    CERN Document Server

    Demtröder, Wolfgang

    Keeping abreast of the latest techniques and applications, this new edition of the standard reference and graduate text on laser spectroscopy has been completely revised and expanded. While the general concept is unchanged, the new edition features a broad array of new material, e.g., ultrafast lasers (atto- and femto-second lasers) and parametric oscillators, coherent matter waves, Doppler-free Fourier spectroscopy with optical frequency combs, interference spectroscopy, quantum optics, the interferometric detection of gravitational waves and still more applications in chemical analysis, medical diagnostics, and engineering.

  19. Laser spectroscopy

    International Nuclear Information System (INIS)

    Letokhov, V.S.

    1981-01-01

    This article describes recent progress in the application of laser atomic spectroscopy to study parameters of nuclei available in very small quantities; radioactive nuclei, rare isotopes, nuclear isomers, etc, for which study by conventional spectroscopic methods is difficult. (author)

  20. Fluorescence spectroscopy

    DEFF Research Database (Denmark)

    Bagatolli, Luis

    2016-01-01

    Fluorescence spectroscopy is a powerful experimental tool used by scientists from many disciplines. During the last decades there have been important developments on distinct fluorescence methods, particularly those related to the study of biological phenomena. This chapter discusses the foundati......Fluorescence spectroscopy is a powerful experimental tool used by scientists from many disciplines. During the last decades there have been important developments on distinct fluorescence methods, particularly those related to the study of biological phenomena. This chapter discusses...

  1. Analysis of functional organic molecules at noble metal surfaces by means of vibrational spectroscopies

    Energy Technology Data Exchange (ETDEWEB)

    Leyssner, Felix

    2011-10-24

    The goal of this work is to optimize the efficiency of photoinduced molecular switching processes on surfaces via controlled variations of the adsorption and electronic properties of the switch. We investigated the influence of external stimuli, i.e. photons and thermal activation, on surface bound molecular switches undergoing trans/cis-isomerizations and ring-opening/closing-reactions, respectively. High resolution electron energy loss spectroscopy (HREELS) and sum-frequency generation (SFG) spectroscopy have been used as the main tools to investigate the adsorption behavior and the molecular switching properties. Two basic concepts of coupling the molecular switch to the surface have been studied: (i) physisorbed or weakly chemisorbed systems deposited on noble metal surfaces under UHV conditions and (ii) molecular switches bound covalently via anchor groups. In the HREELS study following concept (i), we investigated the adsorption geometry and isomerization behavior of various molecular switches on metal substrates which are able to undergo a photoinduced trans/cis-isomerization in solution. We investigated three isoelectronic molecules on Au where we systematically changed the photochemically active group from the diazo-group in an azobenzene-derivative (on Cu(111)) to the imine-group, and the vinylene-group, respectively. Finding the photoisomerization quenched for all systems we observed considerable differences in their thermal isomerization behavior. Comparable we find the photoinduced ring-opening/closing-reaction of spiropyran quenched on Au(111) but a thermally induced ring-opening reaction resulting in the open form being strongly stabilized by the metal. SFG spectroscopy is employed to investigate the reversible, photoinduced trans/cis-isomerization of an azobenzene-functionalized self-assembled monolayer (SAM) on gold using a tripodal linker system. In consequence of the decoupling provided by the tripodal linker, the switching behavior of the

  2. Feasibility of generating a useful laser-induced breakdown spectroscopy plasma on rocks at high pressure: preliminary study for a Venus mission

    International Nuclear Information System (INIS)

    Arp, Zane A.; Cremers, David A.; Harris, Ronny D.; Oschwald, David M.; Parker, Gary R.; Wayne, David M.

    2004-01-01

    Laser-induced breakdown spectroscopy (LIBS) is being developed for future use on landers and rovers to Mars. The method also has potential for use on probes to other planets, the Moon, asteroids and comets. Like Mars, Venus is of strong interest because of its proximity to earth, but unlike Mars, conditions at the surface are far more hostile with temperatures in excess of 700 K and pressures on the order of 9.1 MPa (90 atm). These conditions present a significant challenge to spacecraft design and demand that rapid methods of chemical data gathering be implemented. The advantages of LIBS (e.g. stand-off and very rapid analysis) make the method particularly attractive for Venus exploration because of the expected short operational lifetimes (∼2 h) of surface instrumentation. Although the high temperature of Venus should pose no problem to the analytical capabilities of the LIBS spark, the demonstrated strong dependence of laser plasma characteristics on ambient gas pressures below earth atmospheric pressure requires that LIBS measurements be evaluated at the high Venus surface pressures. Here, we present a preliminary investigation of LIBS at 9.1 MPa for application to the analysis of a basalt rock sample. The results suggest the feasibility of the method for a Venus surface probe and that further study is justified

  3. Feasibility of generating a useful laser-induced breakdown spectroscopy plasma on rocks at high pressure: preliminary study for a Venus mission

    Energy Technology Data Exchange (ETDEWEB)

    Arp, Zane A.; Cremers, David A. E-mail: cremers_david@lanl.gov; Harris, Ronny D.; Oschwald, David M.; Parker, Gary R.; Wayne, David M

    2004-07-30

    Laser-induced breakdown spectroscopy (LIBS) is being developed for future use on landers and rovers to Mars. The method also has potential for use on probes to other planets, the Moon, asteroids and comets. Like Mars, Venus is of strong interest because of its proximity to earth, but unlike Mars, conditions at the surface are far more hostile with temperatures in excess of 700 K and pressures on the order of 9.1 MPa (90 atm). These conditions present a significant challenge to spacecraft design and demand that rapid methods of chemical data gathering be implemented. The advantages of LIBS (e.g. stand-off and very rapid analysis) make the method particularly attractive for Venus exploration because of the expected short operational lifetimes ({approx}2 h) of surface instrumentation. Although the high temperature of Venus should pose no problem to the analytical capabilities of the LIBS spark, the demonstrated strong dependence of laser plasma characteristics on ambient gas pressures below earth atmospheric pressure requires that LIBS measurements be evaluated at the high Venus surface pressures. Here, we present a preliminary investigation of LIBS at 9.1 MPa for application to the analysis of a basalt rock sample. The results suggest the feasibility of the method for a Venus surface probe and that further study is justified.

  4. A Flow System for Generation of Concentration Perturbation in Two-Dimensional Correlation Near-Infrared Spectroscopy: Application to Variable Selection in Multivariate Calibration

    OpenAIRE

    Pereira, CF; Pasquini, C

    2010-01-01

    A flow system is proposed to produce a concentration perturbation in liquid samples, aiming at the generation of two-dimensional correlation near-infrared spectra. The system presents advantages in relation to batch systems employed for the same purpose: the experiments are accomplished in a closed system; application of perturbation is rapid and easy; and the experiments can be carried out with micro-scale volumes. The perturbation system has been evaluated in the investigation and selection...

  5. Moessbauer spectroscopy

    International Nuclear Information System (INIS)

    Gonser, U.

    1975-01-01

    This book is addressed to persons interested in learning about what has been done and what can be done with Moessbauer spectroscopy. In an introductory chapter the basic principle is explained and the general parameters governing Moessbauer spectroscopy are tabulated. For the following chapters various disciplines are chosen and the wide applicability of this measuring technique is demonstrated. The second chapter discusses a few representative examples of chemical interesting information being reflected by isomer shifts and quadrupole splittings, particularly with respect to bonding and structural properties. The third chapter deals with some applications of Moessbauer spectroscopy for characterizing magnetic compounds and its use for magnetic structure investigations, particularly by making use of polarized radiation. The fourth chapter describes the use of the Moessbauer spectroscopy for studying iron in biological molecules. As an example of recent applications to mineralogy and geology the results of the studies of lunar samples are reviewed in the fifth chapter. Finally, in the last chapter, work is described on the use of Moessbauer spectroscopy in physical metallurgy, particularly quantitative analyses which have enabled metallurgists to solve many old problems. (orig./FW) [de

  6. Generation and reactivity of the phenyl cation in cryogenic argon matrices: monitoring the reactions with nitrogen and carbon monoxide directly by IR spectroscopy.

    Science.gov (United States)

    Winkler, Michael; Sander, Wolfram

    2006-08-18

    The phenyl cation 1 has been prepared by co-deposition of iodobenzene 6 or bromobenzene 7 with a microwave-induced argon plasma and characterized by IR spectroscopy in cryogenic argon matrices. The cation can clearly be identified by its strongest absorption at 3110 cm(-1) that is rapidly bleached upon visible light irradiation. This characteristic band is observed neither in the conventional photochemistry of 6 or 7 nor in discharge experiments with alkyl halides or chlorobenzene. The latter finding is in line with energetic considerations. According to density functional theory (DFT) computations, the strongest absorption of 1 is caused by a C-H stretching vibration that involves almost entirely the ortho-hydrogens. This is confirmed by isotopic labeling experiments. Co-deposition of halobenzene/N2 mixtures leads to a decrease of the 3110 cm(-1) absorption, whereas several new signals are detected in the 2200-2400 cm(-1) range of the IR spectrum. Annealing of a matrix that contains 1 and 1% N2 leads to an increase of a broad band at 2260 cm(-1) that is assigned to the benzenediazonium ion 2. A sharp signal at 2327 cm(-1) that had previously been assigned to the N-N stretching vibration of 2 is due to molecular nitrogen. The mechanism that triggers the IR activity of N2 is not yet understood. Annealing of a matrix that contains 1 and 0.5% CO leads to an increase of a broad band at 2217 cm(-1) that is considerably stronger than the 2260 cm(-1) absorption of 2. This signal is assigned to the C-O stretching vibration of the benzoyl cation 12, in excellent agreement with previous investigations of 12 in superacidic media. Some consequences of the measured frequencies with regard to bonding in 2 and 12 are discussed.

  7. Quick generation of Raman spectroscopy based in-process glucose control to influence biopharmaceutical protein product quality during mammalian cell culture.

    Science.gov (United States)

    Berry, Brandon N; Dobrowsky, Terrence M; Timson, Rebecca C; Kshirsagar, Rashmi; Ryll, Thomas; Wiltberger, Kelly

    2016-01-01

    Mitigating risks to biotherapeutic protein production processes and products has driven the development of targeted process analytical technology (PAT); however implementing PAT during development without significantly increasing program timelines can be difficult. The development of a monoclonal antibody expressed in a Chinese hamster ovary (CHO) cell line via fed-batch processing presented an opportunity to demonstrate capabilities of altering percent glycated protein product. Glycation is caused by pseudo-first order, non-enzymatic reaction of a reducing sugar with an amino group. Glucose is the highest concentration reducing sugar in the chemically defined media (CDM), thus a strategy controlling glucose in the production bioreactor was developed utilizing Raman spectroscopy for feedback control. Raman regions for glucose were determined by spiking studies in water and CDM. Calibration spectra were collected during 8 bench scale batches designed to capture a wide glucose concentration space. Finally, a PLS model capable of translating Raman spectra to glucose concentration was built using the calibration spectra and spiking study regions. Bolus feeding in mammalian cell culture results in wide glucose concentration ranges. Here we describe the development of process automation enabling glucose setpoint control. Glucose-free nutrient feed was fed daily, however glucose stock solution was fed as needed according to online Raman measurements. Two feedback control conditions were executed where glucose was controlled at constant low concentration or decreased stepwise throughout. Glycation was reduced from ∼9% to 4% using a low target concentration but was not reduced in the stepwise condition as compared to the historical bolus glucose feeding regimen. © 2015 American Institute of Chemical Engineers.

  8. Analysis of carrier transport and carrier trapping in organic diodes with polyimide-6,13-Bis(triisopropylsilylethynyl)pentacene double-layer by charge modulation spectroscopy and optical second harmonic generation measurement

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Eunju, E-mail: elim@dankook.ac.kr, E-mail: taguchi.d.aa@m.titech.ac.jp, E-mail: iwamoto@pe.titech.ac.jp [Department of Applied Physics, Institute of Nanosensor and Biotechnology, Dankook University, Jukjeon-dong, Gyeonggi-do 448-701 (Korea, Republic of); Taguchi, Dai, E-mail: elim@dankook.ac.kr, E-mail: taguchi.d.aa@m.titech.ac.jp, E-mail: iwamoto@pe.titech.ac.jp; Iwamoto, Mitsumasa, E-mail: elim@dankook.ac.kr, E-mail: taguchi.d.aa@m.titech.ac.jp, E-mail: iwamoto@pe.titech.ac.jp [Department of Physical Electronics, Tokyo Institute of Technology 2-12-1, O-okayama, Meguro-ku, Tokyo 152-8552 (Japan)

    2014-08-18

    We studied the carrier transport and carrier trapping in indium tin oxide/polyimide (PI)/6,13-Bis(triisopropylsilylethynyl)pentacene (TIPS-pentacene)/Au diodes by using charge modulation spectroscopy (CMS) and time-resolved electric field induced optical second harmonic generation (TR-EFISHG) measurements. TR-EFISHG directly probes the spatial carrier behaviors in the diodes, and CMS is useful in explaining the carrier motion with respect to energy. The results clearly indicate that the injected carriers move across TIPS-pentacene thorough the molecular energy states of TIPS-pentacene and accumulate at the PI/TIPS-pentacene interface. However, some carriers are trapped in the PI layers. These findings take into account the capacitance-voltage and current-voltage characteristics of the diodes.

  9. Optical Spectroscopy

    DEFF Research Database (Denmark)

    Thyrhaug, Erling

    The work presented in this thesis is broadly concerned with how complexation reactions and molecular motion can be characterized with the standard techniques in optical spectroscopy. The thesis aims to show a relatively broad range of methods for probing physico-chemical properties in fluorophore...... information about chemical equilibria, kinetics and molecular motion by monitoring changes in optical properties of the system. The five presented research projects are largely unrelated to each other both in aim and in what property is probed, however they are all connected in that they are fluorophore...... reactions by optical spectroscopy. In project 1 simple steady-state absorption and fluorescence spectroscopy is used to determine the stoichiometries and equilibrium constants in the inclusion complex formation between cyclodextrins and derivatives of the water-insoluble oligo(phenylene vinylene) in aqueous...

  10. A tunable dual-wavelength pump source based on simulated polariton scattering for terahertz-wave generation

    International Nuclear Information System (INIS)

    Sun, Bo; Liu, Jinsong; Yao, Jianquan; Li, Enbang

    2013-01-01

    We propose a dual-wavelength pump source by utilizing stimulated polariton scattering in a LiNbO 3 crystal. The residual pump and the generated tunable Stokes waves can be combined to generate THz-wave generation via difference frequency generation (DFG). With a pump energy of 49 mJ, Stokes waves with a tuning range from 1067.8 to 1074 nm have been generated, and an output energy of up to 14.9 mJ at 1070 nm has been achieved with a conversion efficiency of 21.7%. A sum frequency generation experiment was carried out to demonstrate the feasibility of the proposed scheme for THz-wave DFG. (paper)

  11. Optogalvanic spectroscopy

    International Nuclear Information System (INIS)

    Pianarosa, P.; Demers, Y.; Gagne, J.M.

    1983-01-01

    Laser induced optogalvanic spectroscopy in a hollow cathode-produced plasma has been used to resolve the isotopic structure of some absorption lines in uranium. We have shown that the optogalvanic signal associated with any isotope can be related to the concentration of that isotope in a multi-isotopic sample. From the results we have obtained, optogalvanic spectroscopy of sputtered samples appears to be an interesting approach to the isotopic analysis of both natural and enriched uranium and could easily be applied to the analysis of other fissile elements, such as the plutonium isotopes

  12. Photoelectron spectroscopy

    International Nuclear Information System (INIS)

    Price, W.C.

    1974-01-01

    A survey is given of the development of x-ray and ultraviolet photoelectron spectroscopy. Applications of photoelectron spectroscopy to studies of atomic electronic configurations are discussed, including photoelectron spectra of hydrides isoelectronic with the inert gases; photoelectron spectra of the halogen derivatives of methane; photoelectron spectra of multiple bonded diatomic molecules; spectra and structure of some multiple bonded polyatomic molecules; spectra and structure of triatomic molecules; and methods of orbital assignment of bands in photoelectron spectra. Physical aspects are considered, including intensities; selection rules; dependence of cross section on photoelectron energy; autoionization; angular distribution of photoelectrons; electron-molecule interactions; and transient species. (26 figures, 54 references) (U.S.)

  13. Perspectives of shaped pulses for EPR spectroscopy

    Science.gov (United States)

    Spindler, Philipp E.; Schöps, Philipp; Kallies, Wolfgang; Glaser, Steffen J.; Prisner, Thomas F.

    2017-07-01

    This article describes current uses of shaped pulses, generated by an arbitrary waveform generator, in the field of EPR spectroscopy. We show applications of sech/tanh and WURST pulses to dipolar spectroscopy, including new pulse schemes and procedures, and discuss the more general concept of optimum-control-based pulses for applications in EPR spectroscopy. The article also describes a procedure to correct for experimental imperfections, mostly introduced by the microwave resonator, and discusses further potential applications and limitations of such pulses.

  14. A flow system for generation of concentration perturbation in two-dimensional correlation near-infrared spectroscopy: application to variable selection in multivariate calibration.

    Science.gov (United States)

    Pereira, Claudete Fernandes; Pasquini, Celio

    2010-05-01

    A flow system is proposed to produce a concentration perturbation in liquid samples, aiming at the generation of two-dimensional correlation near-infrared spectra. The system presents advantages in relation to batch systems employed for the same purpose: the experiments are accomplished in a closed system; application of perturbation is rapid and easy; and the experiments can be carried out with micro-scale volumes. The perturbation system has been evaluated in the investigation and selection of relevant variables for multivariate calibration models for the determination of quality parameters of gasoline, including ethanol content, MON (motor octane number), and RON (research octane number). The main advantage of this variable selection approach is the direct association between spectral features and chemical composition, allowing easy interpretation of the regression models.

  15. Komet 650. Project: Emission spectroscopy and acoustic pyrometry for control of modern steam generators. Final report; Komet 650. Teilprojekt: Emissionsspektroskopie und Schallpyrometrie zur Regelung moderner Dampferzeuger. Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Moreno Rueda, R.; Frega Novales, L.; Ruiz, G.; Schulze-Kraasch, F.

    2002-01-31

    Two different techniques, i.e. acoustic pyrometry and emissionspectrometric tomography, were developed and combined into an online control system for optimization of gas and particle temperature and gas velocity both in flames and combustion chambers, in consideration of emissions and fuels, for a further improvement of the steam generator efficiency. [German] Das Ziel dieses Teilprojektes im BMBF-Verbundprogramm 'KOMET 650' war es, zwei unterschiedliche Messtechniken, die Schallpyrometrie und die emissionsspektroskopische Tomographie weiter zu entwickeln und zu einem onlinefaehigen Regelsystem zusammen zu fuehren. Letzteres soll sowohl die Einzelflammen als auch den gesamten Feuerraum bezueglich Gas-, Partikeltemperatur und Gasgeschwindigkeit unter Beachtung der Emissionen und unterschiedlicher Verbrennungseinsatzstoffe optimieren, und damit eine Verbesserung des Dampferzeugerwirkungsgrades zu bewirken. (orig.)

  16. Raman spectroscopy

    Science.gov (United States)

    Raman spectroscopy has gained increased use and importance in recent years for accurate and precise detection of physical and chemical properties of food materials, due to the greater specificity and sensitivity of Raman techniques over other analytical techniques. This book chapter presents Raman s...

  17. Bioimpedance Spectroscopy

    DEFF Research Database (Denmark)

    Klösgen, Beate; Rümenapp, Christine; Gleich, Bernhard

    2011-01-01

    causes relaxation processes with characteristic contributions to the frequency-dependent complex dielectric constant. These dipolar relaxations were initially described by Debye (Polare Molekeln 1929). They are the basis of impedance spectroscopy (K’Owino and Sadik Electroanalysis 17(23):2101–2113, 2005...

  18. Laser Spectroscopy and Frequency Combs

    International Nuclear Information System (INIS)

    Hänsch, Theodor W; Picqué, Nathalie

    2013-01-01

    The spectrum of a frequency comb, commonly generated by a mode-locked femtosecond laser consists of several hundred thousand precisely evenly spaced spectral lines. Such laser frequency combs have revolutionized the art measuring the frequency of light, and they provide the long-missing clockwork for optical atomic clocks. The invention of the frequency comb technique has been motivated by precision laser spectroscopy of the simple hydrogen atom. The availability of commercial instruments is facilitating the evolution of new applications far beyond the original purpose. Laser combs are becoming powerful instruments for broadband molecular spectroscopy by dramatically improving the resolution and recording speed of Fourier spectrometers and by creating new opportunities for highly multiplexed nonlinear spectroscopy, such as two-photon spectroscopy or coherent Raman spectroscopy. Other emerging applications of frequency combs range from fundamental research in astronomy, chemistry, or attosecond science to telecommunications and satellite navigation

  19. Broadband Rotational Spectroscopy

    Science.gov (United States)

    Pate, Brooks

    2014-06-01

    The past decade has seen several major technology advances in electronics operating at microwave frequencies making it possible to develop a new generation of spectrometers for molecular rotational spectroscopy. High-speed digital electronics, both arbitrary waveform generators and digitizers, continue on a Moore's Law-like development cycle that started around 1993 with device bandwidth doubling about every 36 months. These enabling technologies were the key to designing chirped-pulse Fourier transform microwave (CP-FTMW) spectrometers which offer significant sensitivity enhancements for broadband spectrum acquisition in molecular rotational spectroscopy. A special feature of the chirped-pulse spectrometer design is that it is easily implemented at low frequency (below 8 GHz) where Balle-Flygare type spectrometers with Fabry-Perot cavity designs become technologically challenging due to the mirror size requirements. The capabilities of CP-FTMW spectrometers for studies of molecular structure will be illustrated by the collaborative research effort we have been a part of to determine the structures of water clusters - a project which has identified clusters up to the pentadecamer. A second technology trend that impacts molecular rotational spectroscopy is the development of high power, solid state sources in the mm-wave/THz regions. Results from the field of mm-wave chirped-pulse Fourier transform spectroscopy will be described with an emphasis on new problems in chemical dynamics and analytical chemistry that these methods can tackle. The third (and potentially most important) technological trend is the reduction of microwave components to chip level using monolithic microwave integrated circuits (MMIC) - a technology driven by an enormous mass market in communications. Some recent advances in rotational spectrometer designs that incorporate low-cost components will be highlighted. The challenge to the high-resolution spectroscopy community - as posed by Frank De

  20. Development of novel and sensitive methods for the determination of sulfide in aqueous samples by hydrogen sulfide generation-inductively coupled plasma-atomic emission spectroscopy.

    Science.gov (United States)

    Colon, M; Todolí, J L; Hidalgo, M; Iglesias, M

    2008-02-25

    Two new, simple and accurate methods for the determination of sulfide (S(2-)) at low levels (microgL(-1)) in aqueous samples were developed. The generation of hydrogen sulfide (H(2)S) took place in a coil where sulfide reacted with hydrochloric acid. The resulting H(2)S was then introduced as a vapor into an inductively coupled plasma-atomic emission spectrometer (ICP-AES) and sulfur emission intensity was measured at 180.669nm. In comparison to when aqueous sulfide was introduced, the introduction of sulfur as H(2)S enhanced the sulfur signal emission. By setting a gas separator at the end of the reaction coil, reduced sulfur species in the form of H(2)S were removed from the water matrix, thus, interferences could be avoided. Alternatively, the gas separator was replaced by a nebulizer/spray chamber combination to introduce the sample matrix and reagents into the plasma. This methodology allowed the determination of both sulfide and sulfate in aqueous samples. For both methods the linear response was found to range from 5microgL(-1) to 25mgL(-1) of sulfide. Detection limits of 5microgL(-1) and 6microgL(-1) were obtained with and without the gas separator, respectively. These new methods were evaluated by comparison to the standard potentiometric method and were successfully applied to the analysis of reduced sulfur species in environmental waters.

  1. Doppler-free two-photon spectroscopy of Yb atoms and efficient generation of a cascade of two photons at 611.3 nm and 555.8 nm

    International Nuclear Information System (INIS)

    Song, Minsoo; Yoon, Duseong; Yoon, Taihyun

    2011-01-01

    We performed high-resolution Doppler-free two-photon spectroscopy of Yb atoms in an effusive atomic beam and generated a cascade of two photons at 611.3 nm (idler) and 555.8 nm (signal) with a narrow bandwidth of 37 MHz. Efficient population transfer from the ground state (6s 2 1 S 0 ) to the upper state (6s7s 1 S 0 ), where direct transition at 291.1 nm is dipole forbidden, was achieved through a resonant two-photon excitation enhanced by the electromagnetically-induced transparency mediated by the intermediate state (6s6p 1 P 1 ). From the upper state, a cascade of two photons in sequence was emitted via the spin triplet state (6s 2 3 P 1 ). Numerical calculations of the density matrix equations taking into account the residual Doppler effect and strong driving fields explain quantitatively the experimental results for the dependences of the idler and the signal beam intensities on the various parameters of the driving fields. We report on the generation of a cascade of two photons with fluxes at the level of a few times 10 6 photons/s detected at a solid angle of 0.01 sr.

  2. Doppler-free two-photon spectroscopy of Yb atoms and efficient generation of a cascade of two photons at 611.3 nm and 555.8 nm

    Energy Technology Data Exchange (ETDEWEB)

    Song, Minsoo; Yoon, Duseong; Yoon, Taihyun [Korea University, Seoul (Korea, Republic of)

    2011-10-15

    We performed high-resolution Doppler-free two-photon spectroscopy of Yb atoms in an effusive atomic beam and generated a cascade of two photons at 611.3 nm (idler) and 555.8 nm (signal) with a narrow bandwidth of 37 MHz. Efficient population transfer from the ground state (6s{sup 2} {sup 1}S{sub 0}) to the upper state (6s7s {sup 1}S{sub 0}), where direct transition at 291.1 nm is dipole forbidden, was achieved through a resonant two-photon excitation enhanced by the electromagnetically-induced transparency mediated by the intermediate state (6s6p {sup 1}P{sub 1}). From the upper state, a cascade of two photons in sequence was emitted via the spin triplet state (6s{sup 2} {sup 3}P{sub 1}). Numerical calculations of the density matrix equations taking into account the residual Doppler effect and strong driving fields explain quantitatively the experimental results for the dependences of the idler and the signal beam intensities on the various parameters of the driving fields. We report on the generation of a cascade of two photons with fluxes at the level of a few times 10{sup 6} photons/s detected at a solid angle of 0.01 sr.

  3. Development of novel and sensitive methods for the determination of sulfide in aqueous samples by hydrogen sulfide generation-inductively coupled plasma-atomic emission spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Colon, M. [Department of Chemistry, University of Girona, Campus Montilivi, 17071 Girona (Spain); Departamento de Quimica Analitica, Nutricion y Bromatologia, University of Alicante, 03080 Alicante (Spain); Todoli, J.L. [Departamento de Quimica Analitica, Nutricion y Bromatologia, University of Alicante, 03080 Alicante (Spain); Hidalgo, M. [Department of Chemistry, University of Girona, Campus Montilivi, 17071 Girona (Spain); Iglesias, M. [Department of Chemistry, University of Girona, Campus Montilivi, 17071 Girona (Spain)], E-mail: monica.iglesias@udg.es

    2008-02-25

    Two new, simple and accurate methods for the determination of sulfide (S{sup 2-}) at low levels ({mu}g L{sup -1}) in aqueous samples were developed. The generation of hydrogen sulfide (H{sub 2}S) took place in a coil where sulfide reacted with hydrochloric acid. The resulting H{sub 2}S was then introduced as a vapor into an inductively coupled plasma-atomic emission spectrometer (ICP-AES) and sulfur emission intensity was measured at 180.669 nm. In comparison to when aqueous sulfide was introduced, the introduction of sulfur as H{sub 2}S enhanced the sulfur signal emission. By setting a gas separator at the end of the reaction coil, reduced sulfur species in the form of H{sub 2}S were removed from the water matrix, thus, interferences could be avoided. Alternatively, the gas separator was replaced by a nebulizer/spray chamber combination to introduce the sample matrix and reagents into the plasma. This methodology allowed the determination of both sulfide and sulfate in aqueous samples. For both methods the linear response was found to range from 5 {mu}g L{sup -1} to 25 mg L{sup -1} of sulfide. Detection limits of 5 {mu}g L{sup -1} and 6 {mu}g L{sup -1} were obtained with and without the gas separator, respectively. These new methods were evaluated by comparison to the standard potentiometric method and were successfully applied to the analysis of reduced sulfur species in environmental waters.

  4. Ground based THz Spectroscopy of Obscured Starbursts in the Early Universe enabled by the 2nd generation Redshift (z) & Early Universe Spectrometer (ZEUS-2)

    Science.gov (United States)

    Vishwas, Amit; Stacey, Gordon; Nikola, Thomas; Ferkinhoff, Carl; Parshley, Stephen; Schoenwald, Justin; Lamarche, Cody James; Higdon, James; Higdon, Sarah; Brisbin, Drew; Güesten, Rolf; Weiss, Axel; Menten, Karl; Irwin, Kent; Cho, Hsiao-Mei; Niemack, Michael; Hilton, Gene; Hubmayr, Johannes; Amiri, Mandana; Halpern, Mark; Wiebe, Donald; Hasselfield, Matthew; Ade, Peter; Tucker, Carole

    2018-01-01

    Galaxies were surprisingly dusty in the early Universe, with more than half of the light emitted from stars being absorbed by dust within the system and re-radiated into far infrared (FIR, ~50-150μm) wavelengths. Dusty star forming galaxies (DSFGs) dominate the co-moving star formation rate density of the Universe that peaks around redshift, z~2, making it compelling to study them in rest frame FIR bands. From galaxies at z > 1, the FIR line emission from abundant ions like [O III], [C II] and [N II], are redshifted into the short sub-mm telluric windows. My thesis work is based on building and deploying the 2nd Generation Redshift (z) and Early Universe Spectrometer (ZEUS-2), a long-slit, echelle grating spectrometer optimized to study broad (Δv = 300km/s) spectral lines from galaxies in the 200-650µm telluric windows using TES bolometers. These far-IR lines being extinction free and major coolants of the gas heated by (young) massive stars, are powerful probes of the physical conditions of the gas and the stellar radiation field. I present results from our survey of the [O III] 88µm line in galaxies at redshift, z ~ 2.8 to 4.6, with ZEUS-2 at the Atacama Pathfinder Experiment (APEX) Telescope. To interpret our observations along with ancillary data from optical to radio facilities, we apply photoionization models for HII regions and Photo Dissociation Region (PDR) models and confirm that the galaxies host substantial ongoing obscured star formation. The presence of doubly ionized oxygen suggests hard radiation fields and hence, elevated ionization parameters that can only be accounted for by a large population of massive stars formed during the ongoing starburst, that contribute a large fraction of the infrared luminosity. This study highlights the use of FIR line emission to trace the assembly of current day massive galaxies, conditions of star formation and details of their stellar populations. The construction and operation of ZEUS-2 were funded by NSF ATI

  5. Photoelectron spectroscopy

    International Nuclear Information System (INIS)

    Bosch, A.

    1982-01-01

    In this work examples of the various aspects of photoelectron spectroscopy are given. The investigation was started with the development of an angle-resolved spectrometer so that the first chapters deal with angle-resolved ultra-violet photoelectron spectroscopy. To indicate the possibilities and pitfalls of the technique, in chapter II the theory is briefly reviewed. In chapter III the instrument is described. The system is based on the cylindrical mirror deflection analyzer, which is modified and improved for angle-resolved photoelectron spectroscopy. In combination with a position sensitive detector, a spectrometer is developed with which simultaneously several angle-resolved spectra can be recorded. In chapter IV, the results are reported of angle-integrated UPS experiments on dilute alloys. Using the improved energy resolution of the instrument the author was able to study the impurity states more accurately and shows that the photoemission technique has become an important tool in the study of impurities and the interactions involved. XPS and Auger results obtained from dilute alloys are presented in chapter V. It is shown that these systems are especially suited for the study of correlation effects and can provide interesting problems related to the satellite structure and the interaction of the impurity with the host. In chapter VI, the valence bands of ternary alloys are studied with UPS and compared to recent band structure calculation. The core level shifts are analyzed in a simple, thermodynamic scheme. (Auth.)

  6. Fusion spectroscopy

    International Nuclear Information System (INIS)

    Peacock, N.J.

    1995-09-01

    This article traces developments in the spectroscopy of high temperature laboratory plasma used in controlled fusion research from the early 1960's until the present. These three and a half decades have witnessed many orders of magnitude increase in accessible plasma parameters such as density and temperature as well as particle and energy confinement timescales. Driven by the need to interpret the radiation in terms of the local plasma parameters, the thrust of fusion spectroscopy has been to develop our understanding of (i) the atomic structure of highly ionised atoms, usually of impurities in the hydrogen isotope fuel; (ii) the atomic collision rates and their incorporation into ionization structure and emissivity models that take into account plasma phenomena like plasma-wall interactions, particle transport and radiation patterns; (iii) the diagnostic applications of spectroscopy aided by increasingly sophisticated characterisation of the electron fluid. These topics are discussed in relation to toroidal magnetically confined plasmas, particularly the Tokamak which appears to be the most promising approach to controlled fusion to date. (author)

  7. Magnetic resonance spectroscopy

    International Nuclear Information System (INIS)

    Meyerhoff, D.J.; Weiner, M.W.

    1989-01-01

    A major function of the liver is regulation of carbohydrate, lipid, and nitrogen metabolism. Food is absorbed by the intestines and transported to the liver by the portal circulation. Substrates are metabolized and stored in the liver to maintain optimal blood concentrations of glucose and lipids. Ammonia generated in the gastrointestinal tract is converted to urea in the liver by the urea cycle. Various forms of liver disease are associated with disorders of carbohydrate, fat, and nitrogen metabolism. Therefore the ability to characterize liver metabolism noninvasively is of potential diagnostic value. Magnetic resonance spectroscopy (MRS) provides information about tissue metabolism by measuring concentrations of metabolites. However, to determine the anatomic location from which spectroscopic signals are derived, MRS could be performed in conjunction with MRI. This paper summarizes the current experience with spectroscopy ion animal models of human disease and reviews the clinical experience with hepatic MRS to date

  8. Laser spectroscopy

    CERN Document Server

    Demtröder, Wolfgang

    2008-01-01

    Keeping abreast of the latest techniques and applications, this new edition of the standard reference and graduate text on laser spectroscopy has been completely revised and expanded. While the general concept is unchanged, the new edition features a broad array of new material, e.g., frequency doubling in external cavities, reliable cw-parametric oscillators, tunable narrow-band UV sources, more sensitive detection techniques, tunable femtosecond and sub-femtosecond lasers (X-ray region and the attosecond range), control of atomic and molecular excitations, frequency combs able to synchronize independent femtosecond lasers, coherent matter waves, and still more applications in chemical analysis, medical diagnostics, and engineering.

  9. Photo release of nitrous oxide from the hyponitrite ion studied by infrared spectroscopy. Evidence for the generation of a cobalt-N2O complex. Experimental and DFT calculations.

    Science.gov (United States)

    Chacón Villalba, M Elizabeth; Franca, Carlos A; Güida, Jorge A

    2017-04-05

    The solid state photolysis of sodium, silver and thallium hyponitrite (M 2 N 2 O 2 , M=Na, Ag, Tl) salts and a binuclear complex of cobalt bridged by hyponitrite ([Co(NH 3 ) 5 -N(O)-NO-Co(NH 3 ) 5 ] 4+ ) were studied by irradiation with visible and UV light in the electronic absorption region. The UV-visible spectra for free hyponitrite ion and binuclear complex of cobalt were interpreted in terms of Density Functional Theory calculations in order to explain photolysis behavior. The photolysis of each compound depends selectively on the irradiation wavelength. Irradiation with 340-460nm light and with the 488nm laser line generates photolysis only in silver and thallium hyponitrite salts, while 253.7nm light photolyzed all the studied compounds. Infrared spectroscopy was used to follow the photolysis process and to identify the generated products. Remarkably, gaseous N 2 O was detected after photolysis in the infrared spectra of sodium, silver, and thallium hyponitrite KBr pellets. The spectra for [Co(NH 3 ) 5 -N(O)-NO-Co(NH 3 ) 5 ] 4+ suggest that one cobalt ion remains bonded to N 2 O from which the generation of a [(NH 3 ) 5 CoNNO] +3 complex is inferred. Density Functional Theory (DFT) based calculations confirm the stability of this last complex and provide the theoretical data which are used in the interpretation of the electronic spectra of the hyponitrite ion and the cobalt binuclear complex and thus in the elucidation of their photolysis behavior. Carbonate ion is also detected after photolysis in all studied compounds, presumably due to the reaction of atmospheric CO 2 with the microcrystal surface reaction products. Kinetic measurements for the photolysis of the binuclear complex suggest a first order law for the intensity decay of the hyponitrite IR bands and for the intensity increase in the N 2 O generation. Predicted and experimental data are in very good agreement. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. NMR spectroscopy

    International Nuclear Information System (INIS)

    Gruenert, J.

    1989-01-01

    The book reviews the applications of NMR-spectroscopy in medicine and biology. The first chapter of about 40 pages summarizes the history of development and explains the chemical and physical fundamentals of this new and non-invasive method in an easily comprehensible manner. The other chapters summarize diagnostic results obtained with this method in organs and tissues, so that the reader will find a systematic overview of the available findings obtained in the various organ systems. It must be noted, however, that ongoing research work and new insight quite naturally will necessitate corrections to be done, as is the case here with some biochemical interpretations which would need adjustment to latest research results. NMR-spectroscopy is able to measure very fine energy differences on the molecular level, and thus offers insight into metabolic processes, with the advantage that there is no need of applying ionizing radiation in order to qualitatively or quantitatively analyse the metabolic processes in the various organ systems. (orig./DG) With 40 figs., 4 tabs [de

  11. Hadron spectroscopy

    International Nuclear Information System (INIS)

    Igi, K.

    1979-01-01

    This paper is related to mini-rapporteur talk on baryonium spectroscopy. First of all, the models of baryonium, namely the diquark model, the string picture, the linear baryonium and the bag model, are described. All of these models so far discussed are highly suggestive. In this paper, discussions are confined to the spectroscopy of the string and the bag models. Because of the color degree of freedom, the bag model has mock diquonium and mock mesonium besides true baryonium. It might be possible that the string model takes into account only a part of them. The constraints among baryonium, baryon and boson trajectories using duality and unitarity were proposed as a guide for classifying various spectra. Inequalities were derived as the modest and reliable constraints on baryonium intercepts from baryon and boson intercepts by imposing unitarity and Regge behaviors on scattering amplitudes. As a consequence of residue factorization and duality, the baryonium slopes were derived. The spin of S (1936) was also obtained. The baryonium containing s or c quarks can also be studied. Topics such as the EXD patterns of baryons, linear baryons, linear Regge trajectories for all Q-anti Q families, and the Al and two Q mesons, are presented in this paper. Comments on di-baryon are described. (Kato, T.)

  12. Hadron spectroscopy

    International Nuclear Information System (INIS)

    Oka, Makoto

    2012-01-01

    Spectra of hadrons show various and complex structures due to the strong coupling constants of the quantum chromodynamics (QCD) constituting its fundamental theory. For their understandings, two parameters, i.e., (1) the quark mass and (2) their excitation energies are playing important roles. In low energies, for example, rather simple structures similar to the positronium appear in the heavy quarks such as charms and bottoms. It has been, however, strongly suggested by the recent experiments that the molecular resonant state shows up when the threshold to decay to mesons is exceeded. On the other hand, chiral symmetry and its breaking play important roles in the dynamics of light quarks. Strange quarks are in between and show special behaviors. In the present lecture, the fundamental concept of the hadron spectroscopy based on the QCD is expounded to illustrate the present understandings and problems of the hadron spectroscopy. Sections are composed of 1. Introduction, 2. Fundamental Concepts (hadrons, quarks and QCD), 3. Quark models and exotic hadrons, 4. Lattice QCD and QCD sum rules. For sections 1 to 3, only outline of the concepts is described because of the limited space. Exotic hadrons, many quark pictures of light hadrons and number of quarks in hadrons are described briefly. (S. Funahashi)

  13. Laser Materials and Laser Spectroscopy - A Satellite Meeting of IQEC '88

    Science.gov (United States)

    Wang, Zhijiang; Zhang, Zhiming

    1989-03-01

    Ionization-fragmentation Patterns of Ethylamine and Dimethylamine Isomers * Cars Measurements of SF6 Pumped by a CO2 Laser Pulse * Angular Dependence of Phase Conjugation of CO2 Laser on SF6 Gas * Resolution of Stretching-vibrational and Translational Raman Bands of Liquid Water by Means of Polarization Four-photon Spectroscopy * Laser-produced Plasma as an Effective Source for X-Ray Spectroscopy * Rotational Structure of the Low Lying Electronic States of Samarium Monoxide * Effects of Poling and Stretching on Second-harmonic Generation in Amorphous Vinylidene Cyanide/Vinyl Acetate Copolymer * Laser-induced Spectroscopy of Cardiovascular Tissues * Laser-excited Malignancy Autofluorescence for Tumour Malignancy Investigation and its Origin * A Study on Several Hematoporphyrin Derivatives by Time-resolved Spectroscopy * Research on Strong Field Processes with a Subpicosecond 400 GW Ultraviolet Source * Growth, Decay and Quenching of Stimulated Raman Scattering in Transparent Liquid Droplets * Layer Condensed Ammonia Studied by Photoacoustic Spectroscopy * High Efficiency Raman Conversion of XeCl Laser Radiation in Lead Vapor * Combined Effect of Stimulated Scattering and Phase Modulation on Generation of Supercontinum * Resonant Multiwave Mixing in Sodium Vapor * High Pressure Brillouin Scattering in Liquid Toluene * Optical Nonlinearities and Bistability in Gold Colloid * Sum-frequency Generation for Surface Vibrational Spectroscopy * Optical Studies of Molecule/Surface Interactions * Optical Second Harmonic Generation with Coupled Surface Plasmons from a Multi-layer Silver/Quartz Grating * Evidence of Silver Cluster and its Role in Surface Enhanced Raman Scattering (SERS) * Study on Cold-evaporated Silver Surfaces with Second-harmonic-generation * Study of Optical Second-harmonic-generation at Metal Surface with Polarization States * Spectroscopic Studies of J-Aggregates of Pseudoisocyanine in Molecular Monolayers in the Range 300 to 20 K * Study of Polymerization of

  14. Statistical nuclear spectroscopy

    International Nuclear Information System (INIS)

    Parikh, J.C.

    1985-01-01

    The aim of nuclear spectroscopy is to study properties of nuclear energy levels and transitions (electromagnetic, particle transfer, etc.) between these levels. Traditionally, the properties that involve a single level or a few levels have theoretically been investigated using models e.g. shell model, self-consistent field approximation, collective model (RPA, Generator Coordinate) and so on. Basically from these models, one obtains eigenvalues and eigenfunctions (or expectation values and transfer strengths) which can be compared with data. The choice of the model depends upon the properties that one wants to examine and the usefulness of the model depends upon its ability to explain observations and make predictions

  15. Moessbauer spectroscopy

    International Nuclear Information System (INIS)

    Zemcik, T.

    1984-01-01

    The emission and absorption of photons taking place without changes in the frequency spectrum of the crystal lattice are known as the Moessbauer effect. It takes place in the low energy levels of heavy nuclei in solid lattices at low temperatures. On the basis of the hyperfine structure of Moessbauer spectra the notions are explained of isomer shift, quadrupole splitting and magnetic splitting. The principle and function are explained of Moessbauer spectrometers and the methods of graphical processing of spectra, also the use of the least square fit. Moessbauer spectroscopy is nondestructive, highly sensitive and selective and makes structural resolution possible. It is used for quantitative and qualitative analysis of compounds. Examples are given of the use of this method for mineralogical and crystallo-chemical analysis of lunar minerals and rocks, for analysis of corrosion products of iron and for phase analysis of alloys. (M.D.)

  16. Photoelectron spectroscopy

    International Nuclear Information System (INIS)

    Shirley, D.A.

    1976-01-01

    Research activities in photoelectron spectroscopy at Lawrence Radiation Laboratory during 1976 are described. Topics covered include: the orientation of CO on Pt(III) and Ni(III) surfaces from angle-resolved photoemission; photoemission from CO on Pt(III) in the range 40 eV less than or equal to dirac constant ω less than or equal to 150 eV; photoemission studies of electron states at clean surfaces using synchrotron radiation; angle and energy dependent photoemission studies of plasmon loss structure in Al and In; d-orbital directed photoemission from copper; interpretation of angle-resolved x-ray photoemission from valence bands; atomic cross-section effects in soft x-ray photoemission from Ag, Au, and Pt valence bands; x-ray photoelectron spectroscopic studies of the electronic structure of transition metal difluorides; x-ray photoemission investigation of the density of states of B'-NiAl; the electronic structure of SrTiO 3 and some simple related oxides; fluorescence lifetime measurements of np 5 (n+1)S' states in krypton and xenon; Zeeman beats in the resonance fluorescence of the 3P 1 , states in krypton and xenon; lifetime measurements of rare-gas dimers; configuration interaction effects in the atomic photoelectron spectra of Ba, Sm, Eu, and Yb; glow discharge lamps as electron sources for electron impact excitation; electron impact excitation of electron correlation states in Ca, Sr, and Ba; photoelectron spectroscopy of atomic and molecular bismuth; relativistic effects in the uv photoelectron spectra of group VI diatomic molecules; and relative gas-phase acidities and basicities from a proton potential model

  17. High-Power, Solid-State, Deep Ultraviolet Laser Generation

    Directory of Open Access Journals (Sweden)

    Hongwen Xuan

    2018-02-01

    Full Text Available At present, deep ultraviolet (DUV lasers at the wavelength of fourth harmonics of 1 μm (266 nm/258 nm and at the wavelength of 193 nm are widely utilized in science and industry. We review the generation of these DUV lasers by nonlinear frequency conversion processes using solid-state/fiber lasers as the fundamental frequency. A DUV laser at 258 nm by fourth harmonics generation (FHG could achieve an average power of 10 W with a beam quality of M2 < 1.5. Moreover, 1 W of average power at 193 nm was obtained by sum-frequency generation (SFG. A new concept of 193-nm DUV laser generation by use of the diamond Raman laser is also introduced. A proof-of-principle experiment of the diamond Raman laser is reported with the conversion efficiency of 23% from the pump to the second Stokes wavelength, which implies the potential to generate a higher power 193 nm DUV laser in the future.

  18. SIMP spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Hochberg, Yonit [Ernest Orlando Lawrence Berkeley National Laboratory, University of California,Berkeley, CA 94720 (United States); Department of Physics, University of California,Berkeley, CA 94720 (United States); Kuflik, Eric [Department of Physics, LEPP, Cornell University,Ithaca NY 14853 (United States); Murayama, Hitoshi [Ernest Orlando Lawrence Berkeley National Laboratory, University of California,Berkeley, CA 94720 (United States); Department of Physics, University of California,Berkeley, CA 94720 (United States); Kavli Institute for the Physics and Mathematics of the Universe (WPI),University of Tokyo Institutes for Advanced Study, University of Tokyo,Kashiwa 277-8583 (Japan); Center for Japanese Studies, University of California,Berkeley, CA 94720 (United States)

    2016-05-16

    We study the interactions between strongly interacting massive particle dark matter and the Standard Model via a massive vector boson that is kinetically mixed with the hypercharge gauge boson. The relic abundance is set by 3→2 self-interactions of the dark matter, while the interactions with the vector mediator enable kinetic equilibrium between the dark and visible sectors. We show that a wide range of parameters is phenomenologically viable and can be probed in various ways. Astrophysical and cosmological constraints are evaded due to the p-wave nature of dark matter annihilation into visible particles, while direct detection methods using electron recoils can be sensitive to parts of the parameter space. In addition, we propose performing spectroscopy of the strongly coupled dark sector at e{sup +}e{sup −} colliders, where the energy of a mono-photon can track the resonance structure of the dark sector. Alternatively, some resonances may decay back into Standard Model leptons or jets, realizing ‘hidden valley’ phenomenology at the LHC and ILC in a concrete fashion.

  19. SIMP spectroscopy

    International Nuclear Information System (INIS)

    Hochberg, Yonit; Kuflik, Eric; Murayama, Hitoshi

    2016-01-01

    We study the interactions between strongly interacting massive particle dark matter and the Standard Model via a massive vector boson that is kinetically mixed with the hypercharge gauge boson. The relic abundance is set by 3→2 self-interactions of the dark matter, while the interactions with the vector mediator enable kinetic equilibrium between the dark and visible sectors. We show that a wide range of parameters is phenomenologically viable and can be probed in various ways. Astrophysical and cosmological constraints are evaded due to the p-wave nature of dark matter annihilation into visible particles, while direct detection methods using electron recoils can be sensitive to parts of the parameter space. In addition, we propose performing spectroscopy of the strongly coupled dark sector at e + e − colliders, where the energy of a mono-photon can track the resonance structure of the dark sector. Alternatively, some resonances may decay back into Standard Model leptons or jets, realizing ‘hidden valley’ phenomenology at the LHC and ILC in a concrete fashion.

  20. Planetary spectroscopy

    International Nuclear Information System (INIS)

    Fink, U.

    1988-01-01

    The main goal of the research is charge coupled device (CCD) spectroscopic and imaging studies of the solar system in support of spacecraft investigations. Studies include the physical behavior of comets, the atmosphere of the gaseous planets, and the solid surfaces of satellites and asteroids. The major observing program consisted of approximately 50 nights of photometry of Comet Halley in order to resolve the controversy over this comet's rotation period. This data is presently being analyzed. Additional observing projects included the spectroscopic occultation of Charon by Pluto, reflection spectroscopy of Mercury, and a spectrum of the satellite Oberon. Mercury data does not corroborate the Fe(++) absorption feature reported by McCord and Clark at 8800 A but instead potentially shows a weaker feature at longer wavelengths. This position is in much closer accord with expectations for Mercury since a band center near 8800 A implies too little Fe(++) on Mercury, especially if band shifts with temperature are considered. The Pluto project proved that the deep methane absorptions visible in their combined specta are due soley to Pluto with Charon showing a flat and featureless spectrum. It appears that if Charon ever contained a substantial methane component, the satellite's low surface gravity could not hold it and the methane evaporated and escaped

  1. Intermolecular spectroscopy

    International Nuclear Information System (INIS)

    Gelbart, W.M.

    1980-01-01

    In this article some of the theoretical background is presented for the following papers on 'Intermolecular Spectroscopy and Dynamical Properties of Dense Systems'. In Section 1 we outline a simple semi-classical description of the interaction between optical radiation and matter. The motion of a many-body polarizability is introduced; limiting forms of this complicated quantity lead to the familiar cases of light scattering spectra. In Section 2 we consider the linear response approximation, and the equation of motion for the many-body density matrix is solved to first order in the matter-radiation interaction. The often quoted fluctuation-dissipation theorem and the time-dependent, equilibrium correlation functions are discussed. Section 3 treats the problem of the local field. In Section 4 we consider the special case of collision-induced light scattering by atomic fluids in the low-density limit. This allows us to focus on determining the interaction polarizability for simple gases. Finally, in Section 5 we distinguish between collision-induced and multiple light scattering, and discuss the double-light-scattering analyses which provide new information about critical and thermodynamically unstable fluids. (KBE)

  2. Multi-pollutants sensors based on near-IR telecom lasers and mid-IR difference frequency generation: development and applications; Instruments de mesure multi-polluants par spectroscopie infrarouge bases sur des lasers fibres et par generation de difference de frequences: developpement et applications

    Energy Technology Data Exchange (ETDEWEB)

    Cousin, J

    2006-12-15

    At present the detection of VOC and other anthropic trace pollutants is an important challenge in the measurement of air quality. Infrared spectroscopy, allowing spectral regions rich in molecular absorption to be probed, is a suitable technique for in-situ monitoring of the air pollution. Thus the aim of this work was to develop instruments capable of detecting multiple pollutants for in-situ monitoring by IR spectroscopy. A first project benefited from the availability of the telecommunications lasers emitting in near-IR. This instrument was based on an external cavity diode laser (1500 - 1640 nm) in conjunction with a multipass cell (100 m). The detection sensitivity was optimised by employing a balanced detection and a sweep integration procedure. The instrument developed is deployable for in-situ measurements with a sensitivity of < 10{sup -8} cm{sup -1} Hz{sup -1/2} and allowed the quantification of chemical species such as CO{sub 2}, CO, C{sub 2}H{sub 2}, CH{sub 4} and the determination of the isotopic ratio {sup 13}CO{sub 2}/{sup 12}CO{sub 2} in combustion environment The second project consisted in mixing two near-IR fiber lasers in a non-linear crystal (PPLN) in order to produce a laser radiation by difference frequency generation in the middle-IR (3.15 - 3.43 {mu}m), where the absorption bands of the molecules are the most intense. The first studies with this source were carried out on detection of ethylene (C{sub 2}H{sub 4}) and benzene (C{sub 6}H{sub 6}). Developments, characterizations and applications of these instruments in the near and middle IR are detailed and the advantages of the 2 spectral ranges is highlighted. (author)

  3. SFG study of methanol dissociative adsorption at Pt(1 0 0), Pt(1 1 0) and Pt(1 1 1) electrodes surfaces

    Science.gov (United States)

    Vidal, F.; Busson, B.; Six, C.; Pluchery, O.; Tadjeddine, A.

    2002-04-01

    The Pt( hkl)/methanol in acidic solution interface which constitutes a model of the anodic part of a fuel cell is studied by infrared-visible sum frequency generation vibrational spectroscopy. Methanol dissociative adsorption leads to CO poisoning of the Pt electrode surfaces. The structure of the CO/Pt( hkl) interface depends strongly on the orientation of the surface electrode.

  4. Laser-heating-induced displacement of surfactants on the water surface

    NARCIS (Netherlands)

    Backus, E.H.G.; Bonn, D.; Cantin, S.; Roke, S.; Bonn, M.

    2012-01-01

    We report a combined vibrational sum-frequency generation (SFG) spectroscopy, Brewster angle microscopy (BAM), and ellipsometry study of different surfactants on water as a function of surfactant density. Vibrational SFG spectra of surfactants on the water surface in a Langmuir trough have been

  5. Experimental and theoretical evidence for bilayer-by-bilayer surface melting of crystalline ice

    DEFF Research Database (Denmark)

    Sánchez, M. Alejandra; Kling, Tanja; Ishiyama, Tatsuya

    2017-01-01

    , and its nature, we investigate the surface melting of hexagonal ice by combining noncontact, surfacespecific vibrational sum frequency generation (SFG) spectroscopy and spectra calculated from molecular dynamics simulations. Using SFG, we probe the outermost water layers of distinct single crystalline ice...

  6. Optoacoustic Spectroscopy.

    Science.gov (United States)

    1984-06-15

    cosmic ray muons or neutrinos) in deep oceans. To cause acoustic generation, the incident beam can be pulsed, or modulated at close to 50% duty...the case in most OA studies) or in other spectral regions from RF to X- rays ; it can also be a particle beam of electron, proton, muon , neutrino, 0. etc...discovered by A. G. Bell in 1880, who observed that audible sound is produced when chopped sunlight is absorbed at a surface . Although the OA effect

  7. Auger electron spectroscopy, ionization loss spectroscopy, appearance potential spectroscopy

    International Nuclear Information System (INIS)

    Riwan, R.

    1973-01-01

    The spectroscopy of surfaces using an incident electron beam is studied. The fundamental mechanisms are discussed together with the parameters involved in Auger emission: excitation of the atom, de-excitation by electron emission, and the migration of electrons towards the surface and their ejection. Some examples of applications are given (surface structures, metallurgy, chemical information). Two new techniques for analyzing surfaces are studied: ionization spectroscopy, and appearance potential spectroscopy [fr

  8. Photoemission spectroscopy using synchrotron radiation

    International Nuclear Information System (INIS)

    Kobayashi, K.L.I.

    1980-01-01

    It is an epoch making event for photoemission spectroscopy that the light sources of continuous wavelength from vacuum ultra-violet to X-ray region have become available by the advent of synchrotron radiation. Specifically the progress after stable intense light has become obtainable from storage rings is very significant. One of the features of these synchrotron radiation is its extreme polarization of radiating pattern. Though the elementary processes of photoemission out of solids are the basic themes, phenomenalistic 3-stage model is usually applied to the analysis of experiments. In this model, the process of photoemission is considered by dividing into three stages, namely the generation of photoelectrons due to optical transition between electron status -- the transportation of photoelectrons to solid surfaces -- breaking away from the surfaces. The spectrometers, the energy analyzers of photoelectrons, and sample-preparing room used for photoemission spectroscopy are described. Next, energy distribution curves are explained. At the end, photoelectron yield spectroscopy, CFS (constant final energy spectroscopy) and CIS (constant initial energy spectroscopy), Auger yield and interatomic Auger yield, the determination of surface structure by normal emission CIS, and surface EXAFS (extended X-ray absorption fine structure) are described. As seen above, the application specifically to surface physics is promising in the future. (Wakatsuki, Y.)

  9. High resolution photoelectron spectroscopy

    International Nuclear Information System (INIS)

    Arko, A.J.

    1988-01-01

    Photoelectron Spectroscopy (PES) covers a very broad range of measurements, disciplines, and interests. As the next generation light source, the FEL will result in improvements over the undulator that are larger than the undulater improvements over bending magnets. The combination of high flux and high inherent resolution will result in several orders of magnitude gain in signal to noise over measurements using synchrotron-based undulators. The latter still require monochromators. Their resolution is invariably strongly energy-dependent so that in the regions of interest for many experiments (h upsilon > 100 eV) they will not have a resolving power much over 1000. In order to study some of the interesting phenomena in actinides (heavy fermions e.g.) one would need resolving powers of 10 4 to 10 5 . These values are only reachable with the FEL

  10. Analytical applications of spectroscopy

    International Nuclear Information System (INIS)

    Creaser, C.S.

    1988-01-01

    This book provides an up to date overview of recent developments in analytical spectroscopy, with a particular emphasis on the common themes of chromatography - spectroscopy combinations, Fourier transform methods, and data handling techniques, which have played an increasingly important part in the development of all spectroscopic techniques. The book contains papers originally presented at a conference entitled 'Spectroscopy Across The Spectrum' held jointly with the first 'International Near Infrared Spectroscopy Conference' at the University of East Anglia, Norwich, UK, in July 1987, which have been edited and rearranged with some additional material. Each section includes reviews of key areas of current research as well as short reports of new developments. The fields covered are: Near Infrared Spectroscopy; Infrared Spectroscopy; Mass Spectroscopy; NMR Spectroscopy; Atomic and UV/Visible Spectroscopy; Chemometrics and Data Analysis. (author)

  11. Synchrotron radiation spectroscopy including X-ray absorption spectroscopy and industrial applications

    International Nuclear Information System (INIS)

    Oshima, Masaharu

    2016-01-01

    Recent trends of synchrotron radiation spectroscopy, especially X-ray absorption spectroscopy for industrial applications are introduced based on our latest results for energy efficient devices such as magnetic RAM, LSI and organic FET, power generation devices such as fuel cells, and energy storage devices such as Li ion batteries. Furthermore, future prospects of spectroscopy with higher energy resolution, higher spatial resolution, higher temporal resolution and operando spectroscopy taking advantage of much brighter synchrotron radiation beam at low emittance SR rings are discussed from the view point of practical applications. (author)

  12. Introductory Raman spectroscopy

    CERN Document Server

    Ferraro, John R

    2012-01-01

    Praise for Introductory Raman Spectroscopy Highlights basic theory, which is treated in an introductory fashion Presents state-of-the-art instrumentation Discusses new applications of Raman spectroscopy in industry and research.

  13. Sub-Doppler spectroscopy

    International Nuclear Information System (INIS)

    Hansch, T.W.

    1983-01-01

    This chapter examines Doppler-free saturation spectroscopy, tunable cw sources, and Doppler-free two-photon spectroscopy. Discusses saturation spectroscopy; continuous wave saturation spectroscopy in the ultraviolet; and two-photon spectroscopy of atomic hydrogen 1S-2S. Focuses on Doppler-free laser spectroscopy of gaseous samples. Explains that in saturation spectroscopy, a monochromatic laser beam ''labels'' a group of atoms within a narrow range of axial velocities through excitation or optical pumping, and a Doppler-free spectrum of these selected atoms is observed with a second, counterpropagating beam. Notes that in two-photon spectroscopy it is possible to record Doppler-free spectra without any need for velocity selection by excitation with two counterpropagating laser beams whose first order Doppler shifts cancel

  14. Stable, high power, high efficiency picosecond ultraviolet generation at 355 nm in K3B6O10 Br crystal

    Science.gov (United States)

    Hou, Z. Y.; Wang, L. R.; Xia, M. J.; Yan, D. X.; Zhang, Q. L.; Zhang, L.; Liu, L. J.; Xu, D. G.; Zhang, D. X.; Wang, X. Y.; Li, R. K.; Chen, C. T.

    2018-06-01

    We demonstrate a high efficiency and high power picosecond ultraviolet source at 355 nm with stable output by sum frequency generation from a Nd:YAG laser using a type-I critically phase matched K3B6O10 Br crystal as nonlinear optical material. Conversion efficiency as high as 30.8% was achieved using a 25 ps laser at 1064 nm operated at 10 Hz. Similar work is done by using a 35 W 10 ps laser at 1064 nm as the pump source with a repetition rate of 80 MHz, and the highest average output power obtained was up to 5.3 W. In addition, the power stability of the 355 nm output power measurement shows that the standard deviation fluctuations of the average power are ±0.69% and ±0.91% at 3.0 W and 3.5 W, respectively.

  15. Advances in atomic spectroscopy

    CERN Document Server

    Sneddon, J

    1997-01-01

    This series describes selected advances in the area of atomic spectroscopy. It is primarily intended for the reader who has a background in atmoic spectroscopy; suitable to the novice and expert. Although a widely used and accepted method for metal and non-metal analysis in a variety of complex samples, Advances in Atomic Spectroscopy covers a wide range of materials. Each Chapter will completely cover an area of atomic spectroscopy where rapid development has occurred.

  16. Basic molecular spectroscopy

    CERN Document Server

    Gorry, PA

    1985-01-01

    BASIC Molecular Spectroscopy discusses the utilization of the Beginner's All-purpose Symbolic Instruction Code (BASIC) programming language in molecular spectroscopy. The book is comprised of five chapters that provide an introduction to molecular spectroscopy through programs written in BASIC. The coverage of the text includes rotational spectra, vibrational spectra, and Raman and electronic spectra. The book will be of great use to students who are currently taking a course in molecular spectroscopy.

  17. Symposium on atomic spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    1979-01-01

    Topics covered by the conference include: fast beam spectroscopy; astrophysical and other spectra; highly ionized spectroscopy; complex spectra; rydberg levels; fine structure, hyperfine structure and isotope shift; lineshapes; lifetimes, oscillator strengths and Einstein coefficients; and spectroscopy with lasers. Abstracts of the conference papers are presented. (GHT)

  18. Symposium on atomic spectroscopy

    International Nuclear Information System (INIS)

    1979-01-01

    Topics covered by the conference include: fast beam spectroscopy; astrophysical and other spectra; highly ionized spectroscopy; complex spectra; rydberg levels; fine structure, hyperfine structure and isotope shift; lineshapes; lifetimes, oscillator strengths and Einstein coefficients; and spectroscopy with lasers. Abstracts of the conference papers are presented

  19. Spectroscopy in catalysis : an introduction

    NARCIS (Netherlands)

    Niemantsverdriet, J.W.

    2000-01-01

    Spectroscopy in Catalysis describes the most important modern analytical techniques used to investigate catalytic surfaces. These include electron spectroscopy (XPS, UPS, AES, EELS), ion spectroscopy (SIMS, SNMS, RBS, LEIS), vibrational spectroscopy (infrared, Raman, EELS), temperature-programmed

  20. Advances in atomic spectroscopy

    CERN Document Server

    Sneddon, J

    2000-01-01

    This fifth volume of the successful series Advances in Atomic Spectroscopy continues to discuss and investigate the area of atomic spectroscopy.It begins with a description of the use of various atomic spectroscopic methods and applications of speciation studies in atomic spectroscopy. The emphasis is on combining atomic spectroscopy with gas and liquid chromatography. In chapter two the authors describe new developments in tunable lasers and the impact they will have on atomic spectroscopy. The traditional methods of detection, such as photography and the photomultiplier, and how they are being replaced by new detectors is discussed in chapter three. The very active area of glow discharge atomic spectrometry is presented in chapter four where, after a brief introduction and historical review, the use of glow discharge lamps for atomic spectroscopy and mass spectrometry are discussed. Included in this discussion is geometry and radiofrequency power. The future of this source in atomic spectroscopy is also dis...

  1. Nuclear spectroscopy with lithium ions

    International Nuclear Information System (INIS)

    Heiser, C.

    1977-02-01

    A survey of the state of nuclear spectroscopy with lithium ions is given. Proceeding from the physical and nuclear properties the specific topics arising by the acceleration of these ions are discussed. The results obtained from measurements of excitation functions of different lithium reactions, particularly of compound reactions, with several target nuclei are summarized. Besides compound reactions direct reactions are important, especially transfer reactions, elastic and inelastic scattering and exchange reactions. The results on high spin states obtained by in-beam gamma-spectroscopy are discussed in detail. Finally the possibilities are considered for accelerating lithium ions in the cyclotron U-120 and in the tandem generator EGP-10 of the ZfK. (author)

  2. Chemische Reaktionen auf Oberflächen - eine SFG Studie

    OpenAIRE

    Kirsch, Harald

    2014-01-01

    This thesis focused on the investigation of chemical reactions on surfaces by usage of Sum Frequency Generation (SFG) spectroscopy and Thermal Desorption Spectroscopy (TDS). Understanding of chemical reactions on surfaces is of critical importance for modification and optimization of a variety of environmental and industrial processes, but the complexity of the ongoing reactions under "realistic" conditions often hinders an understanding on a molecular level. The aim of this work was to get i...

  3. Femtosecond time-resolved vibrational SFG spectroscopy of CO/Ru( 0 0 1 )

    Science.gov (United States)

    Hess, Ch.; Wolf, M.; Roke, S.; Bonn, M.

    2002-04-01

    Vibrational sum-frequency generation (SFG) employing femtosecond infrared (IR) laser pulses is used to study the dynamics of the C-O stretch vibration on Ru(0 0 1). Time-resolved measurements of the free induction decay (FID) of the IR-polarization for 0.33 ML CO/Ru(0 0 1) exhibit single exponential decays over three decades corresponding to dephasing times of T2=1.94 ps at 95 K and T2=1.16 ps at 340 K. This is consistent with pure homogeneous broadening due to anharmonic coupling with the thermally activated low-frequency dephasing mode together with a contribution from saturation of the IR transition. In pump-probe SFG experiments using a strong visible (VIS) pump pulse the perturbation of the FID leads to transient line shifts even at negative delay times, i.e. when the IR-VIS SFG probe pair precedes the pump pulse. Based on an analysis of the time-dependent polarization we discuss the influence of the perturbed FID on time-resolved SFG spectra. We investigate how coherent effects affect the SFG spectra and we examine the time resolution in these experiments, in particular in dependence of the dephasing time.

  4. Progress in atomic spectroscopy

    International Nuclear Information System (INIS)

    Beyer, H.J.; Kleinpoppen, H.

    1984-01-01

    This book presents reviews by leading experts in the field covering areas of research at the forefront of atomic spectroscopy. Topics considered include the k ordering of atomic structure, multiconfiguration Hartree-Fock calculations for complex atoms, new methods in high-resolution laser spectroscopy, resonance ionization spectroscopy (inert atom detection), trapped ion spectroscopy, high-magnetic-field atomic physics, the effects of magnetic and electric fields on highly excited atoms, x rays from superheavy collision systems, recoil ion spectroscopy with heavy ions, investigations of superheavy quasi-atoms via spectroscopy of electron rays and positrons, impact ionization by fast projectiles, and amplitudes and state parameters from ion- and atom-atom excitation processes

  5. Ultrafast Laser-Based Spectroscopy and Sensing: Applications in LIBS, CARS, and THz Spectroscopy

    Science.gov (United States)

    Leahy-Hoppa, Megan R.; Miragliotta, Joseph; Osiander, Robert; Burnett, Jennifer; Dikmelik, Yamac; McEnnis, Caroline; Spicer, James B.

    2010-01-01

    Ultrafast pulsed lasers find application in a range of spectroscopy and sensing techniques including laser induced breakdown spectroscopy (LIBS), coherent Raman spectroscopy, and terahertz (THz) spectroscopy. Whether based on absorption or emission processes, the characteristics of these techniques are heavily influenced by the use of ultrafast pulses in the signal generation process. Depending on the energy of the pulses used, the essential laser interaction process can primarily involve lattice vibrations, molecular rotations, or a combination of excited states produced by laser heating. While some of these techniques are currently confined to sensing at close ranges, others can be implemented for remote spectroscopic sensing owing principally to the laser pulse duration. We present a review of ultrafast laser-based spectroscopy techniques and discuss the use of these techniques to current and potential chemical and environmental sensing applications. PMID:22399883

  6. Ultrafast Laser-Based Spectroscopy and Sensing: Applications in LIBS, CARS, and THz Spectroscopy

    Directory of Open Access Journals (Sweden)

    Megan R. Leahy-Hoppa

    2010-04-01

    Full Text Available Ultrafast pulsed lasers find application in a range of spectroscopy and sensing techniques including laser induced breakdown spectroscopy (LIBS, coherent Raman spectroscopy, and terahertz (THz spectroscopy. Whether based on absorption or emission processes, the characteristics of these techniques are heavily influenced by the use of ultrafast pulses in the signal generation process. Depending on the energy of the pulses used, the essential laser interaction process can primarily involve lattice vibrations, molecular rotations, or a combination of excited states produced by laser heating. While some of these techniques are currently confined to sensing at close ranges, others can be implemented for remote spectroscopic sensing owing principally to the laser pulse duration. We present a review of ultrafast laser-based spectroscopy techniques and discuss the use of these techniques to current and potential chemical and environmental sensing applications.

  7. New Hadronic Spectroscopy

    International Nuclear Information System (INIS)

    Faccini, R.

    2010-01-01

    In the past few years the field of hadron spectroscopy has seen renewed interest due to the publication, initially mostly from B-Factories, of evidences of states that do not match regular spectroscopy, but are rather candidates for bound states with additional quarks or gluons (four quarks for tetraquarks and molecules and two quarks and gluons for hybrids). A huge effort in understanding the nature of this new states and in building a new spectroscopy is ongoing. This paper reviews the experimental and theoretical state of the art on heavy quarkonium exotic spectroscopy, with particular attention on the steps towards a global picture.

  8. Advances in DUV spectroscopy

    DEFF Research Database (Denmark)

    Buchhave, Preben; Tidemand-Lichtenberg, Peter; Mogensen, Claus Tilsted

    The would-be advantages of deep UV (DUV) spectroscopy are well known, but the potential applications have so far not been fully realized due to technological limitations and, perhaps, lack of bright ideas. However, new components and new knowledge about DUV spectra and spectroscopic methods...... combined with increasing needs for solutions to practical problems in environmental protection, medicine and pollution monitoring promise a new era in DUV spectroscopy. Here we shall review the basis for DUV spectroscopy, both DUV fluorescence and DUV Raman spectroscopy, and describe recent advances...

  9. Spectroscopy for Dummies

    DEFF Research Database (Denmark)

    Lindvold, Lars René

    This presentation will give short introduction to the most pertinent topics of optical spectroscopy. The following topics will be discussed: • The origin of spectra in UV, VIS and IR spectral range • Spectroscopic methods like absorption, luminescence and Raman • Wavelength dispersive optical...... components • Materials for use optical spectroscopy • Spectrometer geometries • Detectors for use in spectrometer • Practical examples of optical spectroscopy The objective of this presentation is to give the audience a good feel for the range of possibilities that optical spectroscopy can provide....

  10. Narrow-line, cw orange light generation in a diode-pumped Nd:YVO4 laser using volume Bragg gratings.

    Science.gov (United States)

    Chen, Y L; Chen, W W; Du, C E; Chang, W K; Wang, J L; Chung, T Y; Chen, Y H

    2009-12-07

    We report on the demonstration of a narrow-line, cw orange 593-nm laser achieved via intracavity sum-frequency generation (SFG) of a diode-pumped dual-wavelength (1064 and 1342 nm) Nd:YVO(4) laser using two volume Bragg grating (VBG) reflectors. At diode pump power of up to 3.6 W, the 593-nm intracavity SFG laser radiates at the single longitudinal mode of spectral linewidth as narrow as approximately 15 MHz. More than 23-mW single-longitudinal-mode or 40-mW, diode pump power) 593-nm orange lights can be obtained from this compact laser system. Spectral tuning of the orange light was performed via the temperature tuning of the two VBGs in this system, achieving an effective tuning rate of ~5 pm/degrees C.

  11. Infrared diode laser spectroscopy

    Czech Academy of Sciences Publication Activity Database

    Civiš, Svatopluk; Cihelka, Jaroslav; Matulková, Irena

    2010-01-01

    Roč. 18, č. 4 (2010), s. 408-420 ISSN 1230-3402 R&D Projects: GA AV ČR IAA400400705 Institutional research plan: CEZ:AV0Z40400503 Keywords : FTIR spectroscopy * absorption spectroscopy * laser diodes Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.027, year: 2010

  12. Acoustic force spectroscopy

    NARCIS (Netherlands)

    Sitters, G.; Kamsma, D.; Thalhammer, G.; Ritsch-Marte, M.; Peterman, E.J.G.; Wuite, G.J.L.

    2015-01-01

    Force spectroscopy has become an indispensable tool to unravel the structural and mechanochemical properties of biomolecules. Here we extend the force spectroscopy toolbox with an acoustic manipulation device that can exert forces from subpiconewtons to hundreds of piconewtons on thousands of

  13. Coherent atomic spectroscopy

    International Nuclear Information System (INIS)

    Garton, W.R.S.

    1988-01-01

    The Argonne Spectroscopy Laboratory, initiated and advanced over several decades by F.S. Tomkins and M. Fred, has been a major international facility. A range of collaborative work in atomic spectroscopy is selected to illustrate advances in experimental physics which have been made possible by combination of the talents of Tomkins and Fred with the unique facilities of the Argonne Laboratory. (orig.)

  14. Laser induced breakdown spectroscopy in water | Boudjemai ...

    African Journals Online (AJOL)

    Sparks were generated in water by the focused beam of a Q-switched Nd:YAG laser Na and Cu aqueous solutions exhibited fluorescence signal on the decaying edge of plasma emission at their respective characteristic resonance lines. Potential of the laser plasma spectroscopy for in-situ pollution monitoring in natural ...

  15. Surface Fluctuation Scattering using Grating Heterodyne Spectroscopy

    DEFF Research Database (Denmark)

    Edwards, R. V.; Sirohi, R. S.; Mann, J. A.

    1982-01-01

    Heterodyne photon spectroscopy is used for the study of the viscoelastic properties of the liquid interface by studying light scattered from thermally generated surface fluctuations. A theory of a heterodyne apparatus based on a grating is presented, and the heterodyne condition is given in terms...

  16. Nanoscale Infrared Spectroscopy of Biopolymeric Materials

    Science.gov (United States)

    Curtis Marcott; Michael Lo; Kevin Kjoller; Craig Prater; Roshan Shetty; Joseph Jakes; Isao Noda

    2012-01-01

    Atomic Force Microscopy (AFM) and infrared (IR) spectroscopy have been combined in a single instrument capable of producing 100 nm spatial resolution IR spectra and images. This new capability enables the spectroscopic characterization of biomaterial domains at levels not previously possible. A tunable IR laser source generating pulses on the order of 10 ns was used...

  17. A Simple LIBS (Laser-Induced Breakdown Spectroscopy) Laboratory Experiment to Introduce Undergraduates to Calibration Functions and Atomic Spectroscopy

    Science.gov (United States)

    Chinni, Rosemarie C.

    2012-01-01

    This laboratory experiment introduces students to a different type of atomic spectroscopy: laser-induced breakdown spectroscopy (LIBS). LIBS uses a laser-generated spark to excite the sample; once excited, the elemental emission is spectrally resolved and detected. The students use LIBS to analyze a series of standard synthetic silicate samples…

  18. Gamma-ray spectroscopy with relativistic exotic heavy-ions

    Indian Academy of Sciences (India)

    Abstract. Feasibility of gamma-ray spectroscopy at relativistic energies with exotic heavy-ions and new generation of germanium detectors (segmented Clover) is discussed. An experiment with such detector array and radioactive is discussed.

  19. Quantum cascade laser infrared spectroscopy of single cancer cells

    KAUST Repository

    Patel, Imran

    2017-03-27

    Quantum cascade laser infrared spectroscopy is a next generation novel imaging technique allowing high resolution spectral imaging of cells. We show after spectral pre-processing, identification of different cancer cell populations within minutes.

  20. Quantum cascade laser infrared spectroscopy of single cancer cells

    KAUST Repository

    Patel, Imran; Rajamanickam, Vijayakumar Palanisamy; Bertoncini, Andrea; Pagliari, Francesca; Tirinato, Luca; Laptenok, Sergey P.; Liberale, Carlo

    2017-01-01

    Quantum cascade laser infrared spectroscopy is a next generation novel imaging technique allowing high resolution spectral imaging of cells. We show after spectral pre-processing, identification of different cancer cell populations within minutes.

  1. Cavity-enhanced spectroscopies

    CERN Document Server

    van Zee, Roger

    2003-01-01

    ""Cavity-Enhanced Spectroscopy"" discusses the use of optical resonators and lasers to make sensitive spectroscopic measurements. This volume is written by the researcchers who pioneered these methods. The book reviews both the theory and practice behind these spectroscopic tools and discusses the scientific discoveries uncovered by these techniques. It begins with a chapter on the use of optical resonators for frequency stabilization of lasers, which is followed by in-depth chapters discussing cavity ring-down spectroscopy, frequency-modulated, cavity-enhanced spectroscopy, intracavity spectr

  2. Homogeneity spoil spectroscopy

    International Nuclear Information System (INIS)

    Hennig, J.; Boesch, C.; Martin, E.; Grutter, R.

    1987-01-01

    One of the problems of in vivo MR spectroscopy of P-31 is spectra localization. Surface coil spectroscopy, which is the method of choice for clinical applications, suffers from the high-intensity signal from subcutaneous muscle tissue, which masks the spectrum of interest from deeper structures. In order to suppress this signal while maintaining the simplicity of surface coil spectroscopy, the authors introduced a small sheet of ferromagnetically dotted plastic between the surface coil and the body. This sheet destroys locally the field homogeneity and therefore all signal from structures around the coil. The very high reproducibility of the simple experimental procedure allows long-term studies important for monitoring tumor therapy

  3. Baryon spectroscopy at KAON

    Energy Technology Data Exchange (ETDEWEB)

    Comyn, Martin

    1992-07-01

    The unique opportunities for the study of baryon spectroscopy at the TRIUMF KAON Factory are outlined. Related issues in other areas of hadron spectroscopy are discussed. The complex of accelerators that comprise the TRIUMF KAON Factory, and the properties of the separated beams that will be available to experimenters, are described. Initial design considerations for detectors to be used in the study of hadron spectroscopy are presented, along with a proposed detector configuration. The progress towards realization of the TRIUMF KAON Factory is examined, and the timetable for the determination of the initial experimental programme and facilities is explained. 23 refs., 4 figs., 5 tabs.

  4. Hypernuclear Spectroscopy at JLab Hall C

    International Nuclear Information System (INIS)

    Hashimoto, Osamu; Chiba, Atsushi; Doi, Daisuke; Fujii, Yu; Toshiyuki, Gogami; Kanda, Hiroki; Kaneta, M.; Kawama, Daisuke; Maeda, Kazushige; Maruta, Tomofumi; Matsumura, Akihiko; Nagao, Sho; Nakamura, Satoshi; Shichijo, Ayako; Tamura, Hirokazu; Taniya, Naotaka; Yamamoto, Taku; Yokota, Kosuke; Kato, S.; Sato, Yoshinori; Takahashi, Toshiyuki; Noumi, Hiroyuki; Motoba, T.; Hiyama, E.; Albayrak, Ibrahim; Ates, Ozgur; Chen, Chunhua; Christy, Michael; Keppel, Cynthia; Kohl, Karl; Li, Ya; Liyanage, Anusha Habarakada; Tang, Liguang; Walton, T.; Ye, Zhihong; Yuan, Lulin; Zhu, Lingyan; Baturin, Pavlo; Boeglin, Werner; Dhamija, Seema; Markowitz, Pete; Raue, Brian; Reinhold, Joerg; Hungerford, Ed; Ent, Rolf; Fenker, Howard; Gaskell, David; Horn, Tanja; Jones, Mark; Smith, Gregory; Vulcan, William; Wood, Stephen; Johnston, C.; Simicevic, Neven; Wells, Stephen; Samanta, Chhanda; Hu, Bitao; Shen, Ji; Wang, W.; Zhang, Xiaozhuo; Zhang, Yi; Feng, Jing; Fu, Y.; Zhou, Jian; Zhou, S.; Jiang, Yi; Lu, H.; Yan, Xinhu; Ye, Yunxiu; Gan, Liping; Ahmidouch, Abdellah; Danagoulian, Samuel; Gasparian, Ashot; Elaasar, Mostafa; Wesselmann, Frank; Asaturyan, Arshak; Margaryan, Amur; Mkrtchyan, Arthur; Mkrtchyan, Hamlet; Tadevosyan, Vardan; Androic, Darko; Furic, Miroslav; Petkovic, Tomislav; Seva, Tomislav; Niculescu, Gabriel; Niculescu, Maria-Ioana; Rodriguez, Victor; Cisbani, Evaristo; Cusanno, Francesco; Garibaldi, Franco; Urciuoli, Guido; De Leo, Raffaele; Maronne, S.; Achenbach, Carsten; Pochodzalla, J.

    2010-01-01

    Since the 1st generation experiment, E89-009, which was successfully carried out as a pilot experiment of (e,e(prime)K + ) hypernuclear spectroscopy at JLab Hall C in 2000, precision hypernuclear spectroscopy by the (e,e(prime)K + ) reactions made considerable progress. It has evolved to the 2nd generation experiment, E01-011, in which a newly constructed high resolution kaon spectrometer (HKS) was installed and the 'Tilt method' was adopted in order to suppress large electromagnetic background and to run with high luminosity. Preliminary high-resolution spectra of 7 ΛHe and 28 ΛAl together with that of 12 ΛB that achieved resolution better than 500 keV(FWHM) were obtained. The third generation experiment, E05-115, has completed data taking with an experimental setup combining a new splitter magnet, high resolution electron spectrometer (HES) and the HKS used in the 2nd generation experiment. The data were accumulated with targets of 7 Li, 9 Be, 10 B, 12 C and 52 Cr as well as with those of CH 2 and H 2 O for calibration. The analysis is under way with particular emphasis of determining precision absolute hypernuclear masses. In this article, hypernuclear spectroscopy program in the wide mass range at JLab Hall C that has undergone three generation is described.

  5. IR Spectroscopy. An introduction

    International Nuclear Information System (INIS)

    Guenzler, H.; Gremlich, H.U.

    2002-01-01

    The following topics are dealt with: absorption and molecular design, spectrometers, sample preparation, qualitative spectral interpretation and assertions, near-infrared and far-infrared spectroscopy, reference spectra and expert systems

  6. Charmonium spectroscopy, 1987

    International Nuclear Information System (INIS)

    Cahn, R.N.

    1987-01-01

    The state of charmonium spectroscopy is reviewed. All analyses proceed from a spin-dependent, non-relativistic Schroedinger equation. Many of the possible branching ratios for charm like states are investigated. 17 refs

  7. Dual THz comb spectroscopy

    Science.gov (United States)

    Yasui, Takeshi

    2017-08-01

    Optical frequency combs are innovative tools for broadband spectroscopy because a series of comb modes can serve as frequency markers that are traceable to a microwave frequency standard. However, a mode distribution that is too discrete limits the spectral sampling interval to the mode frequency spacing even though individual mode linewidth is sufficiently narrow. Here, using a combination of a spectral interleaving and dual-comb spectroscopy in the terahertz (THz) region, we achieved a spectral sampling interval equal to the mode linewidth rather than the mode spacing. The spectrally interleaved THz comb was realized by sweeping the laser repetition frequency and interleaving additional frequency marks. In low-pressure gas spectroscopy, we achieved an improved spectral sampling density of 2.5 MHz and enhanced spectral accuracy of 8.39 × 10-7 in the THz region. The proposed method is a powerful tool for simultaneously achieving high resolution, high accuracy, and broad spectral coverage in THz spectroscopy.

  8. Foundations of laser spectroscopy

    CERN Document Server

    Stenholm, Stig

    2005-01-01

    A simple presentation of the theoretical foundations of steady-state laser spectroscopy, this text helps students to apply theory to calculations with a systematic series of examples and exercises. 1984 edition.

  9. Surface vibrational spectroscopy (EELS)

    International Nuclear Information System (INIS)

    Okuyama, Hiroshi

    2006-01-01

    Adsorbed states of hydrogen on metal surfaces have been studied by means of electron energy loss spectroscopy (EELS). In this article, typical spectra and analysis as well as recent development are introduced. (author)

  10. EDITORIAL: Nano Meets Spectroscopy Nano Meets Spectroscopy

    Science.gov (United States)

    Birch, David J. S.

    2012-08-01

    The multidisciplinary two-day Nano Meets Spectroscopy (NMS) event was held at the National Physical Laboratory (NPL), Teddington, UK, in September 2011. The event was planned from the outset to be at the interface of several areas—in particular, spectroscopy and nanoscience, and to bring together topics and people with different approaches to achieving common goals in biomolecular science. Hence the meeting cut across traditional boundaries and brought together researchers using diverse techniques, particularly fluorescence and Raman spectroscopy. Despite engaging common problems, these techniques are frequently seen as mutually exclusive with the two communities rarely interacting at conferences. The meeting was widely seen to have lived up to its billing in good measure. It attracted the maximum capacity of ~120 participants, including 22 distinguished speakers (9 from outside the UK), over 50 posters and a vibrant corporate exhibition comprising 10 leading instrument companies and IOP Publishing. The organizers were Professor David Birch (Chair), Dr Karen Faulds and Professor Duncan Graham of the University of Strathclyde, Professor Cait MacPhee of the University of Edinburgh and Dr Alex Knight of NPL. The event was sponsored by the European Science Foundation, the Institute of Physics, the Royal Society of Chemistry, NPL and the Scottish Universities Physics Alliance. The full programme and abstracts are available at http://sensor.phys.strath.ac.uk/nms/program.php. The programme was quite ambitious in terms of the breadth and depth of scope. The interdisciplinary and synergistic concept of 'X meets Y' played well, cross-fertilization between different fields often being a source of inspiration and progress. Fluorescence and Raman spectroscopy provided the core, but the meeting had little repetition and also attracted contributions on more specialist techniques such as CARS, super-resolution, single molecule and chiral methods. In terms of application the

  11. Positron annihilation spectroscopy

    International Nuclear Information System (INIS)

    Sundar, C.S.; Viswanathan, B.

    1996-01-01

    An overview of positron annihilation spectroscopy, the experimental techniques and its application to studies on defects and electronic structure of materials is presented. The scope of this paper is to present the requisite introductory material, that will enable a better appreciation of the subsequent specialized articles on the applications of positron annihilation spectroscopy to investigate various problems in materials science. (author). 31 refs., 3 figs

  12. Ultrafast infrared vibrational spectroscopy

    CERN Document Server

    Fayer, Michael D

    2013-01-01

    The past ten years or so have seen the introduction of multidimensional methods into infrared and optical spectroscopy. The technology of multidimensional spectroscopy is developing rapidly and its applications are spreading to biology and materials science. Edited by a recognized leader in the field and with contributions from top researchers, including experimentalists and theoreticians, this book presents the latest research methods and results and will serve as an excellent resource for other researchers.

  13. Spectroscopy stepping stones

    International Nuclear Information System (INIS)

    Hammer, M.R.; Sturman, B.T.

    2003-01-01

    Determining the elemental composition of samples has long been a basic task of analytical science. Some very powerful and convenient approaches are based on the wavelength-specific absorption or emission of light by gas-phase atoms. Techniques briefly described as examples of analytical atomic spectrometry include atomic emission and absorption spectroscopy, inductively coupled plasma emission and mass spectroscopy and laser induced breakdown spectrometry

  14. Fast antihydrogen beam spectroscopy

    International Nuclear Information System (INIS)

    Neumann, R.

    1989-01-01

    The motivation for production and precision spectroscopy of antihydrogen atoms is outlined. An experimental configuration is considered, concerning laser-microwave spectroscopy of a fast hydrogen beam with characteristics similar to those of an antihydrogen beam emanating from an antiproton-positron overlap region in an antiproton storage ring. In particular, a possible experiment for the measurement of the ground state hyperfine structure splitting is described. (orig.)

  15. Generation of carotenoid radical cation in the vicinity of a chlorophyll derivative bound to titanium oxide, upon excitation of the chlorophyll derivative to the Q y state, as identified by time-resolved absorption spectroscopy

    Science.gov (United States)

    Wang, Xiao-Feng; Kakitani, Yoshinori; Xiang, Junfeng; Koyama, Yasushi; Rondonuwu, Ferdy S.; Nagae, Hiroyoshi; Sasaki, Shin-ichi; Tamiaki, Hitoshi

    2005-12-01

    Electron injection from a chlorophyll derivative (methyl 3-carboxy-3-devinylpyropheophorobide a, abbreviated as PPB a) to TiO 2 nanoparticle took place in ≈30 fs following the decay of an excimer that was generated immediately after excitation to the Q y state (681 nm). Then, electron transfer from carotenoids (Cars) to PPB arad + took place in ≈200-240 ps. The latter observation supports the electron-transfer mechanism proposed in a previous investigation, in which Cars were added as redox spacers to the PPB a-sensitized TiO 2 solar cells to enhance their performance (X.-F. Wang, J. Xiang, P. Wang, Y. Koyama, S. Yanagida, Y. Wada, K. Hamada, S. Sasaki, H. Tamiaki, Chem. Phys. Lett. 408 (2005) 409).

  16. High-power continuous-wave mid-infrared radiation generated by difference frequency mixing of diode-laser-seeded fiber amplifiers and its application to dual-beam spectroscopy

    Science.gov (United States)

    Lancaster, D. G.; Richter, D.; Curl, R. F.; Tittel, F. K.; Goldberg, L.; Koplow, J.

    1999-01-01

    We report the generation of up to 0.7 mW of narrow-linewidth (radiation at 3.3 micrometers by difference frequency mixing of a Nd:YAG-seeded 1.6-W Yb fiber amplifier and a 1.5-micrometers diode-laser-seeded 0.6-W Er/Yb fiber amplifier in periodically poled LiNbO3. A conversion efficiency of 0.09%/W (0.47 mWW-2 cm-1) was achieved. A room-air CH4 spectrum acquired with a compact 80-m multipass cell and a dual-beam spectroscopic configuration indicates an absorption sensitivity of +/-2.8 x 10(-5) (+/-1 sigma), corresponding to a sub-parts-in-10(9) (ppb) CH4 sensitivity (0.8 ppb).

  17. Photoacoustic Spectroscopy Analysis of Traditional Chinese Medicine

    Science.gov (United States)

    Chen, Lu; Zhao, Bin-xing; Xiao, Hong-tao; Tong, Rong-sheng; Gao, Chun-ming

    2013-09-01

    Chinese medicine is a historic cultural legacy of China. It has made a significant contribution to medicine and healthcare for generations. The development of Chinese herbal medicine analysis is emphasized by the Chinese pharmaceutical industry. This study has carried out the experimental analysis of ten kinds of Chinese herbal powder including Fritillaria powder, etc., based on the photoacoustic spectroscopy (PAS) method. First, a photoacoustic spectroscopy system was designed and constructed, especially a highly sensitive solid photoacoustic cell was established. Second, the experimental setup was verified through the characteristic emission spectrum of the light source, obtained by using carbon as a sample in the photoacoustic cell. Finally, as the photoacoustic spectroscopy analysis of Fritillaria, etc., was completed, the specificity of the Chinese herb medicine analysis was verified. This study shows that the PAS can provide a valid, highly sensitive analytical method for the specificity of Chinese herb medicine without preparing and damaging samples.

  18. Microresonator soliton dual-comb spectroscopy

    Science.gov (United States)

    Suh, Myoung-Gyun; Yang, Qi-Fan; Yang, Ki Youl; Yi, Xu; Vahala, Kerry J.

    2016-11-01

    Measurement of optical and vibrational spectra with high resolution provides a way to identify chemical species in cluttered environments and is of general importance in many fields. Dual-comb spectroscopy has emerged as a powerful approach for acquiring nearly instantaneous Raman and optical spectra with unprecedented resolution. Spectra are generated directly in the electrical domain, without the need for bulky mechanical spectrometers. We demonstrate a miniature soliton-based dual-comb system that can potentially transfer the approach to a chip platform. These devices achieve high-coherence pulsed mode locking. They also feature broad, reproducible spectral envelopes, an essential feature for dual-comb spectroscopy. Our work shows the potential for integrated spectroscopy with high signal-to-noise ratios and fast acquisition rates.

  19. Unquenched lattice upsilon spectroscopy

    International Nuclear Information System (INIS)

    Marcantonio, L.M.

    2001-03-01

    A non-relativistic effective theory of QCD (NRQCD) is used in calculations of the upsilon spectrum. Simultaneous multi-correlation fitting routines are used to yield lattice channel energies and amplitudes. The lattice configurations used were both dynamical, with two flavours of sea quarks included in the action; and quenched, with no sea quarks. These configurations were generated by the UKQCD collaboration. The dynamical configurations used were ''matched'', having the same lattice spacing, but differing in the sea quark mass. Thus, it was possible to analyse trends of observables with sea quark mass, in the certainty that the trend isn't partially due to varying lattice spacing. The lattice spacing used for spectroscopy was derived from the lattice 1 1 P 1 - 1 3 S 1 splitting. On each set of configurations two lattice bare b quark masses were used, giving kinetic masses bracketing the physical Υ mass. The only quantity showing a strong dependence on these masses was the hyperfine splitting, so it was interpolated to the real Υ mass. The radial and orbital splittings gave good agreement with experiment. The hyperfine splitting results showed a clear signal for unquenching and the dynamical hyperfine splitting results were extrapolated to a physical sea quark mass. This result, combined with the quenched result yielded a value for the hyperfine splitting at n f = 3, predicting an η b mass of 9.517(4) GeV. The NRQCD technique for obtaining a value of the strong coupling constant in the M-barS-bar scheme was followed. Using quenched and dynamical results a value was extrapolated to n f = 3. Employing a three loop beta function to run the coupling, with suitable matching conditions at heavy quark thresholds, the final result was obtained for n f = 5 at a scale equal to the Z boson mass. This result was α(5)/MS(Mz)=0.110(4). Two methods for finding the mass of the b quark in the MS scheme were employed. The results of both methods agree within error but the

  20. Transcutaneous Raman Spectroscopy of Bone

    Science.gov (United States)

    Maher, Jason R.

    Clinical diagnoses of bone health and fracture risk typically rely upon measurements of bone density or structure, but the strength of a bone is also dependent upon its chemical composition. One technology that has been used extensively in ex vivo, exposed-bone studies to measure the chemical composition of bone is Raman spectroscopy. This spectroscopic technique provides chemical information about a sample by probing its molecular vibrations. In the case of bone tissue, Raman spectra provide chemical information about both the inorganic mineral and organic matrix components, which each contribute to bone strength. To explore the relationship between bone strength and chemical composition, our laboratory has contributed to ex vivo, exposed-bone animal studies of rheumatoid arthritis, glucocorticoid-induced osteoporosis, and prolonged lead exposure. All of these studies suggest that Raman-based predictions of biomechanical strength may be more accurate than those produced by the clinically-used parameter of bone mineral density. The utility of Raman spectroscopy in ex vivo, exposed-bone studies has inspired attempts to perform bone spectroscopy transcutaneously. Although the results are promising, further advancements are necessary to make non-invasive, in vivo measurements of bone that are of sufficient quality to generate accurate predictions of fracture risk. In order to separate the signals from bone and soft tissue that contribute to a transcutaneous measurement, we developed an overconstrained extraction algorithm that is based upon fitting with spectral libraries derived from separately-acquired measurements of the underlying tissue components. This approach allows for accurate spectral unmixing despite the fact that similar chemical components (e.g., type I collagen) are present in both soft tissue and bone and was applied to experimental data in order to transcutaneously detect, to our knowledge for the first time, age- and disease-related spectral

  1. Generating Units

    Data.gov (United States)

    Department of Homeland Security — Generating Units are any combination of physically connected generators, reactors, boilers, combustion turbines, and other prime movers operated together to produce...

  2. In vivo spectroscopy

    International Nuclear Information System (INIS)

    Williams, S.R.; Cady, E.B.

    1987-01-01

    The technique which the authors describe in this chapter provides alternative information to imaging, although based upon the same physical principles. The experiments are carried out differently and have instrumental requirements which are not met by a standard imaging system. Furthermore, although the clinical efficacy of NMR imaging has been proven, clinical spectroscopy is very much in its infancy. With the exception of some specific /sup 31/P applications not is not even clear how spectroscopic investigations will be performed. This is particularly true with regard to localization techniques for investigating other than superficial organs and and in the use of /sup 1/H spectroscopy. They attempt to show what information spectroscopy can provide in principle and point out some of the problems associated with such investigations. NMR has come to the notice of the clinical community mainly through its use as an imaging technique, and many may consider spectroscopy as a secondary discipline. NMR spectroscopy, however, has a longer history than imaging and has been a standard technique in chemistry laboratories for more than two decades. It is a technique without peer for structural analysis of molecules and no new chemical compound is discovered or synthesized without an NMR spectrum being taken. The influence of molecular structure on resonant frequency has been termed the chemical shift

  3. Moessbauer spectroscopy. Tutorial book

    International Nuclear Information System (INIS)

    Yoshida, Yutaka; Langouche, Guido

    2013-01-01

    First textbook on Moessbauer Spectroscopy covering the complete field. Offers a concise introduction to all aspects of Moessbauer spectroscopy by the leading experts in the field. Tutorials on Moessbauer Spectroscopy. Since the discovery of the Moessbauer Effect many excellent books have been published for researchers and for doctoral and master level students. However, there appears to be no textbook available for final year bachelor students, nor for people working in industry who have received only basic courses in classical mechanics, electromagnetism, quantum mechanics, chemistry and materials science. The challenge of this book is to give an introduction to Moessbauer Spectroscopy for this level. The ultimate goal of this book is to give this audience not only a scientific introduction to the technique, but also to demonstrate in an attractive way the power of Moessbauer Spectroscopy in many fields of science, in order to create interest among the readers in joining the community of Moessbauer spectroscopists. This is particularly important at times where in many Moessbauer laboratories succession is at stake.

  4. Plasma polarization spectroscopy. Time resolved spectroscopy in soft x-ray region on recombining plasma

    International Nuclear Information System (INIS)

    Iwamae, Atsushi; Hasuo, Masahiro; Atake, Makoto; Hasegawa, Noboru; Kawachi, Tetsuya

    2007-01-01

    We present an experimental study of polarization of emission radiations from recombining plasmas generated by the interaction of 60 fs ultra-short laser pulses with a gas jet. Time-resolved spectroscopy with a temporal resolution of 5 ps with repetitive accumulation is used to follow the recombination time histories. (author)

  5. Generational diversity.

    Science.gov (United States)

    Kramer, Linda W

    2010-01-01

    Generational diversity has proven challenges for nurse leaders, and generational values may influence ideas about work and career planning. This article discusses generational gaps, influencing factors and support, and the various generational groups present in today's workplace as well as the consequences of need addressing these issues. The article ends with a discussion of possible solutions.

  6. Autobalanced Ramsey Spectroscopy

    Science.gov (United States)

    Sanner, Christian; Huntemann, Nils; Lange, Richard; Tamm, Christian; Peik, Ekkehard

    2018-01-01

    We devise a perturbation-immune version of Ramsey's method of separated oscillatory fields. Spectroscopy of an atomic clock transition without compromising the clock's accuracy is accomplished by actively balancing the spectroscopic responses from phase-congruent Ramsey probe cycles of unequal durations. Our simple and universal approach eliminates a wide variety of interrogation-induced line shifts often encountered in high precision spectroscopy, among them, in particular, light shifts, phase chirps, and transient Zeeman shifts. We experimentally demonstrate autobalanced Ramsey spectroscopy on the light shift prone Yb+ 171 electric octupole optical clock transition and show that interrogation defects are not turned into clock errors. This opens up frequency accuracy perspectives below the 10-18 level for the Yb+ system and for other types of optical clocks.

  7. Terahertz Spectroscopy and Imaging

    CERN Document Server

    Zeitler, Axel; Kuwata-Gonokami, Makoto

    2013-01-01

    "This book presents the current state of knowledge in the field of terahertz spectroscopy, providing a comprehensive source of information for beginners and experienced researchers alike whose interests lie in this area. The book aims to explain the fundamental physics that underpins terahertz  technology and to describe its key applications. Highlights of scientific research in the field of terahertz science are also outlined in some chapters, providing an overview as well as giving an insight into future directions for research.  Over the past decade terahertz spectroscopy has developed into one of the most rapidly growing areas of its kind, gaining an important impact across a wide range of scientific disciplines. Due to substantial advances in femtosecond laser technology, terahertz time-domain spectroscopy (THz-TDS) has established itself as the dominant spectroscopic technique for experimental scientists interested in measurements at this frequency range. In solids and liquids THz radiation is in reso...

  8. Role of Confined Water in Underwater Adhesion

    Science.gov (United States)

    Dhinojwala, Ali

    Surface bound water is a strong deterrent for forming strong bonds between two surfaces underwater and expelling that bound water is important for strong adhesion. I will discuss examples of different strategies used by geckos, spiders, and mussels to handle this last layer of bound water. Recent results using infrared-visible sum frequency generation spectroscopy to probe the structure of this bound water will be discussed. National Science Foundation.

  9. Frequency-agile dual-comb spectroscopy

    OpenAIRE

    Millot, Guy; Pitois, Stéphane; Yan, Ming; Hovannysyan, Tatevik; Bendahmane, Abdelkrim; Hänsch, Theodor W.; Picqué, Nathalie

    2015-01-01

    We propose a new approach to near-infrared molecular spectroscopy, harnessing advanced concepts of optical telecommunications and supercontinuum photonics. We generate, without mode-locked lasers, two frequency combs of slightly different repetition frequencies and moderate, but rapidly tunable, spectral span. The output of a frequency-agile continuous wave laser is split and sent into two electro-optic intensity modulators. Flat-top low-noise frequency combs are produced by wave-breaking in ...

  10. Standoff spectroscopy using a conditioned target

    Science.gov (United States)

    Van Neste, Charles W [Kingston, TN; Morales-Rodriguez, Marissa E [Knoxville, TN; Senesac, Lawrence R [Knoxville, TN; Thundat, Thomas G [Knoxville, TN

    2011-12-20

    A system and method are disclosed for standoff spectroscopy of molecules (e.g. from a residue) on a surface from a distance. A source emits radiation that modifies or conditions the residue, such as through photodecomposition. A spectral generating source measures a spectrum of the residue before and after the residue is exposed to the radiation from that source. The two spectra are compared to produce a distinct identification of the residues on the surface or identify certain properties of the residue.

  11. Dye lasers in atomic spectroscopy

    International Nuclear Information System (INIS)

    Lange, W.; Luther, J.; Steudel, A.

    1974-01-01

    The properties of dye lasers which are relevant to atomic spectroscopy are discussed. Several experiments made possible by tunable dye lasers are discussed. Applications of high spectral density dye lasers are covered in areas such as absorption spectroscopy, fluorescence spectroscopy, photoionization and photodetachment, and two- and multi-photon processes. Applications which take advantage of the narrow bandwidth of tunable dye lasers are discussed, including saturation spectroscopy, fluorescence line narrowing, classic absorption and fluorescence spectroscopy, nonoptical detection of optical resonances, heterodyne spectroscopy, and nonlinear coherent resonant phenomena. (26 figures, 180 references) (U.S.)

  12. Electron Paramagnetic Resonance Spectroscopy

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 20; Issue 11. Electron Paramagnetic Resonance Spectroscopy: Biological Applications. B G Hegde. General Article Volume 20 Issue 11 November 2015 pp 1017-1032. Fulltext. Click here to view fulltext PDF. Permanent link:

  13. Photoacoustic and photothermal spectroscopies

    International Nuclear Information System (INIS)

    Sawada, Tsuguo; Kitamori, Takehiko; Nakamura, Masato

    1995-01-01

    Photoacoustic and photothermal spectroscopy methods can be effectively applied to the analysis of microparticles in condensed matter. A more violent photothermal conversion phenomenon of a particle, laser breakdown and accompanying plasma and acoustic emission, was applied to individual detection and analysis of ultrafine particles in ultrapure water. Laser-like nonlinear emission from the plasma was observed. (author)

  14. Nuclear magnetic resonance spectroscopy

    International Nuclear Information System (INIS)

    Rueterjans, H.

    1987-01-01

    Contributions by various authors who are working in the field of NMR imaging present the current status and the perspectives of in-vivo nuclear magnetic resonance spectroscopy, explaining not only the scientific and medical aspects, but also technical and physical principles as well as questions concerning practical organisation and training, and points of main interest for further research activities. (orig./TRV) [de

  15. Single-Molecule Spectroscopy

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 20; Issue 2. Single-Molecule Spectroscopy: Every Molecule is Different! Kankan Bhattacharyya. General Article Volume 20 Issue 2 February 2015 pp 151-164. Fulltext. Click here to view fulltext PDF. Permanent link:

  16. Perspectives in hadron spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Richard, J.M. [Universite Joseph Fourier-IN2P3-CNRS, Lab. de Physique Subatomique et Cosmologie, 38 - Grenoble (France)

    2005-07-01

    A brief survey is presented of selected recent results on hadron spectroscopy and related theoretical studies. Among the new hadron states, some of them are good candidates for exotic structures: chiral partners of ground-states, hybrid mesons (quark, antiquark and constituent gluon), four-quark states, or meson-meson molecules.

  17. Laser magnetic resonance spectroscopy

    International Nuclear Information System (INIS)

    Ferrari, C.A.

    1985-01-01

    The technique of laser resonance magnetic resonance allows one to study the high-resolution spectroscopy of transient paramagnetic species, viz, atoms, radicals, and molecular ions. This article is a brief exposition of the method, describing the principles, instrumentation and applicability of the IR and FIR-LMR and shows results of HF + . (Author) [pt

  18. Astronomical Spectroscopy -24 ...

    Indian Academy of Sciences (India)

    growth of spectroscopy and its application to the study of .... Cesium was discovered ten years earlier, in 1859; it is the ... Kirchhoff and Bunsen's discovery; he was spared the pain of seeing ... We will have to go back about twenty years.

  19. Zeeman atomic absorption spectroscopy

    International Nuclear Information System (INIS)

    Loos-Vollebregt, M.T.C. de.

    1980-01-01

    A new method of background correction in atomic absorption spectroscopy has recently been introduced, based on the Zeeman splitting of spectral lines in a magnetic field. A theoretical analysis of the background correction capability observed in such instruments is presented. A Zeeman atomic absorption spectrometer utilizing a 50 Hz sine wave modulated magnetic field is described. (Auth.)

  20. Surface vibrational spectroscopy

    International Nuclear Information System (INIS)

    Erskine, J.L.

    1984-01-01

    A brief review of recent studies which combine measurements of surface vibrational energies with lattice dynamical calculations is presented. These results suggest that surface vibrational spectroscopy offers interesting prospects for use as a molecular-level probe of surface geometry, adsorbate bond distances and molecular orientations

  1. Spectroscopy of new particles

    International Nuclear Information System (INIS)

    Goldhaber, G.

    1977-08-01

    A review of the spectroscopy of the ''psions'' with hidden charm or charm quantum number ch = o is followed by a discussion of charmed mesons and baryons. The anomalous C-μ events and the heavy lepton hypothesis are briefly considered

  2. Nuclear Magnetic Resonance Spectroscopy

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 9; Issue 1. Nuclear Magnetic Resonance Spectroscopy. Susanta Das. General Article Volume 9 Issue 1 January 2004 pp 34-49. Fulltext. Click here to view fulltext PDF. Permanent link: https://www.ias.ac.in/article/fulltext/reso/009/01/0034-0049. Keywords.

  3. FTIR spectroscopy applications in forensic science

    International Nuclear Information System (INIS)

    Roux, C.; Maynard, P.; Dawson, M.

    1999-01-01

    Infrared spectroscopy, and especially Fourier transform infrared spectroscopy, is a well-established technique in analytical chemistry and finds widespread application in qualitative and quantitative analyses. Infrared spectra depend on the nature of the functional groups present in the analyte, and are generally complex with numerous maxima and minima. These features are useful for comparison purposes and, in most cases, the infrared spectrum of an organic compound is considered as a unique functional print of this compound (i e the infrared spectrum constitutes the chemical signature or fingerprint of an organic compound). Many inorganic substances may also be uniquely identified using infrared spectroscopy. Until recently, infrared spectroscopy was of only limited utility in forensic science, despite its high selectivity. This is because infrared spectroscopy suffered from a lack of sensitivity in its early forms. However, with the advance of modern technology this is no longer the case. The widespread use of microscope attachments, along with numerous new sampling accessories, has overcome most of the previous limitations. For example, with an infrared microscope, it is possible to focus the infrared beam, and therefore select relevant areas of the sample as small as 10 x 10 μm and achieve a measurement in situ. Such a configuration enables the rapid generation of high-resolution spectra from samples of 10 ng. Typical forensic applications include the analysis of single textile fibres, minute paint chips or smears, drugs, laser printer and photocopy toners, polymers and miscellaneous unknown substances. Here we will broadly review the most common applications of infrared spectroscopy in forensic science

  4. Isotope generator

    International Nuclear Information System (INIS)

    1979-01-01

    The patent describes an isotope generator incorporating the possibility of stopping elution before the elution vessel is completely full. Sterile ventilation of the whole system can then occur, including of both generator reservoir and elution vessel. A sterile, and therefore pharmaceutically acceptable, elution fluid is thus obtained and the interior of the generator is not polluted with non-sterile air. (T.P.)

  5. Instant Generation

    Science.gov (United States)

    Loveland, Elaina

    2017-01-01

    Generation Z students (born between 1995-2010) have replaced millennials on college campuses. Generation Z students are entrepreneurial, desire practical skills with their education, and are concerned about the cost of college. This article presents what need to be known about this new generation of students.

  6. Optimising generators

    Energy Technology Data Exchange (ETDEWEB)

    Guerra, E.J.; Garcia, A.O.; Graffigna, F.M.; Verdu, C.A. (IMPSA (Argentina). Generators Div.)

    1994-11-01

    A new computer tool, the ARGEN program, has been developed for dimensioning large hydroelectric generators. This results in better designs, and reduces calculation time for engineers. ARGEN performs dimensional tailoring of salient pole synchronous machines in generators, synchronous condensers, and generator-motors. The operation and uses of ARGEN are explained and its advantages are listed in this article. (UK)

  7. International symposium on NMR spectroscopy

    International Nuclear Information System (INIS)

    The publication consists of 32 papers and presentations from the field of NMR spectroscopy applications submitted to the International Symposium on NMR Spectroscopy held at Smolenice between 29 Sep and 3 Oct, 1980. (B.S.)

  8. Surface-Enhanced Raman Spectroscopy

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 15; Issue 2. Surface-Enhanced Raman Spectroscopy - Recent Advancement of Raman Spectroscopy. Ujjal Kumar Sur. General Article Volume 15 Issue 2 February 2010 pp 154-164 ...

  9. Ultrabroadband spectroscopy for security applications

    DEFF Research Database (Denmark)

    Engelbrecht, Sunniva; Berge, Luc; Skupin, Stefan

    2015-01-01

    Ultrabroadband spectroscopy is a promising novel approach to overcome two major hurdles which have so far limited the application of THz spectroscopy for security applications: the increased bandwidth enables to record several characteristic spectroscopic features and the technique allows...

  10. New positron annihilation spectroscopy techniques for thick materials

    International Nuclear Information System (INIS)

    Selim, F.A.; Wells, D.P.; Harmon, J.F.; Kwofie, J.; Erikson, G.; Roney, T.

    2003-01-01

    The Idaho Accelerator Center (IAC) has developed new techniques for positron annihilation spectroscopy (PAS) by using highly penetrating γ-rays to create positrons inside the material via pair production. Two sources of γ-rays have been employed. Bremsstrahlung beams from small-electron linacs (6 MeV) were used to generate positrons inside the material to perform Doppler-broadening spectroscopy. A 2 MeV proton beam was used to obtain coincident γ-rays from 27 Al target and enable lifetime and Doppler-broadening spectroscopy. This technique successfully measured stress/strain in thick samples, and showed promise to extend PAS into a variety of applications

  11. Gamma-ray spectroscopy on irradiated fuel rods

    International Nuclear Information System (INIS)

    Terremoto, Luis Antonio Albiac

    2009-01-01

    The recording of gamma-ray spectra along an irradiated fuel rod allows the fission products to be qualitatively and quantitatively examined. Among all nondestructive examinations performed on irradiated fuel rods by gamma-ray spectroscopy, the most comprehensive one is the average burnup measurement, which is quantitative. Moreover, burnup measurements by means of gamma-ray spectroscopy are less time-consuming and waste-generating than burnup measurements by radiochemical, destructive methods. This work presents the theoretical foundations and experimental techniques necessary to measure, using nondestructive gamma-ray spectroscopy, the average burnup of irradiated fuel rods in a laboratory equipped with hot cells. (author)

  12. [Current views on surface enhanced Raman spectroscopy in microbiology].

    Science.gov (United States)

    Jia, Xiaoxiao; Li, Jing; Qin, Tian; Deng, Aihua; Liu, Wenjun

    2015-05-01

    Raman spectroscopy has generated many branches during the development for more than 90 years. Surface enhanced Raman spectroscopy (SERS) improves SNR by using the interaction between tested materials and the surface of rough metal, as to quickly get higher sensitivity and precision spectroscopy without sample pretreatment. This article describes the characteristic and classification of SERS, and updates the theory and clinical application of SERS. It also summarizes the present status and progress of SERS in various disciplines and illustrates the necessity and urgency of its research, which provides rationale for the application for SERS in microbiology.

  13. Mid-infrared upconversion spectroscopy

    DEFF Research Database (Denmark)

    Tidemand-Lichtenberg, Peter; Dam, Jeppe Seidelin; Andersen, H. V.

    2016-01-01

    Mid-infrared (MIR) spectroscopy is emerging as an attractive alternative to near-infrared or visible spectroscopy. MIR spectroscopy offers a unique possibility to probe the fundamental absorption bands of a large number of gases as well as the vibrational spectra of complex molecules. In this paper...

  14. Antihydrogen Experiment Gravity Interferometry Spectroscopy

    CERN Multimedia

    Trezzi, D; Dassa, L; Rienacker, B; Khalidova, O; Ferrari, G; Krasnicky, D; Perini, D; Cerchiari, G; Belov, A; Boscolo, I; Sacerdoti, M G; Ferragut, R O; Nedelec, P; Hinterberger, A; Al-qaradawi, I; Malbrunot, C L S; Brusa, R S; Prelz, F; Manuzio, G; Riccardi, C; Fontana, A; Genova, P; Haider, S; Haug, F; Turbabin, A; Castelli, F; Testera, G; Lagomarsino, V E; Doser, M; Penasa, L; Gninenko, S; Cataneo, F; Zenoni, A; Cabaret, L; Comparat, D P; Zmeskal, J; Scampoli, P; Nesteruk, K P; Dudarev, A; Kellerbauer, A G; Mariazzi, S; Carraro, C; Zavatarelli, S M

    The AEGIS experiment (Antihydrogen Experiment: Gravity, Interferometry, Spectroscopy) has the aim of carrying out the first measurement of the gravitational interaction of antimatter to a precision of 1%, by applying techniques from atomic physics, laser spectroscopy and interferometry to a beam of antihydrogen atoms. A further goal of the experiment is to carry out spectroscopy of the antihydrogen atoms in flight.

  15. Femtosecond laser spectroscopy

    CERN Document Server

    Hannaford, Peter

    2005-01-01

    As concepts and methodologies have evolved over the past two decades, the realm of ultrafast science has become vast and exciting and has impacted many areas of chemistry, biology and physics, and other fields such as materials science, electrical engineering, and optical communication. The field has recently exploded with the announcement of a series of remarkable new developments and advances. This volume surveys this recent growth in eleven chapters written by leading international researchers in the field. It includes sections on femtosecond optical frequency combs, soft x-ray femtosecond laser sources, and attosecond laser sources. In addition, the contributors address real-time spectroscopy of molecular vibrations with sub-5-fs pulses and multidimensional femtosecond coherent spectroscopies for studying molecular and electron dynamics. Novel methods for measuring and characterizing ultrashort laser pulses and ultrashort pulses of light are also described. The topics covered are revolutionizing the field...

  16. Visible spectroscopy on ASDEX

    International Nuclear Information System (INIS)

    Hofmann, J.V.

    1991-12-01

    In this report visible spectroscopy and impurity investigations on ASDEX are reviewed and several sets of visible spectra are presented. As a basis for identification of metallic impurity lines during plasma discharges spectra from a stainless steel - Cu arc have been recorded. In a next step a spectrum overview of ASDEX discharges is shown which reveals the dominating role of lines from light impurities like carbon and oxygen throughout the UV and visible range (2000 A ≤ λ ≤ 8000 A). Metallic impurity lines of neutrals or single ionized atoms are observed near localized surfaces. The dramatic effect of impurity reduction by boronization of the vessel walls is demonstrated in a few examples. In extension to some ivesti-gations already published, further diagnostic applications of visible spectroscopy are presented. Finally, the hardware and software system used on ASDEX are described in detail. (orig.)

  17. Hadron spectroscopy in LHCb

    CERN Document Server

    Palano, Antimo

    2018-01-01

    The LHCb experiment is designed to study the properties and decays of heavy flavored hadrons produced in pp collisions at the LHC. The data collected in the LHC Run I enables precision spectroscopy studies of beauty and charm hadrons. The latest results on spectroscopy of conventional and exotic hadrons are reviewed. In particular the discovery of the first charmonium pentaquark states in the $J/\\psi p$ system, the possible existence of four-quark states decaying to $J/\\psi \\phi$ and the confirmation of resonant nature of the $Z_c(4430)^−$ mesonic state are discussed. In the sector of charmed baryons, the observation of five new $\\Omega_c$ states, the observation of the $\\Xi^+_{cc}$ and the study of charmed baryons decaying to $D^0 p$ are presented.

  18. Fluorescence fluctuation spectroscopy (FFS)

    CERN Document Server

    Tetin, Sergey

    2012-01-01

    This new volume of Methods in Enzymology continues the legacy of this premier serial with quality chapters authored by leaders in the field. This volume covers fluorescence fluctuation spectroscopy and includes chapters on such topics as Förster resonance energy transfer (fret) with fluctuation algorithms, protein corona on nanoparticles by FCS, and FFS approaches to the study of receptors in live cells. Continues the legacy of this premier serial with quality chapters authored by leaders in the field Covers fluorescence fluctuation spectroscopy Contains chapters on such topics as Förster resonance energy transfer (fret) with fluctuation algorithms, protein corona on nanoparticles by FCS, and FFS approaches to the study of receptors in live cells.

  19. Precision muonium spectroscopy

    International Nuclear Information System (INIS)

    Jungmann, Klaus P.

    2016-01-01

    The muonium atom is the purely leptonic bound state of a positive muon and an electron. It has a lifetime of 2.2 µs. The absence of any known internal structure provides for precision experiments to test fundamental physics theories and to determine accurate values of fundamental constants. In particular ground state hyperfine structure transitions can be measured by microwave spectroscopy to deliver the muon magnetic moment. The frequency of the 1s–2s transition in the hydrogen-like atom can be determined with laser spectroscopy to obtain the muon mass. With such measurements fundamental physical interactions, in particular quantum electrodynamics, can also be tested at highest precision. The results are important input parameters for experiments on the muon magnetic anomaly. The simplicity of the atom enables further precise experiments, such as a search for muonium–antimuonium conversion for testing charged lepton number conservation and searches for possible antigravity of muons and dark matter. (author)

  20. Basic Principles of Spectroscopy

    Science.gov (United States)

    Penner, Michael H.

    Spectroscopy deals with the production, measurement, and interpretation of spectra arising from the interaction of electromagnetic radiation with matter. There are many different spectroscopic methods available for solving a wide range of analytical problems. The methods differ with respect to the species to be analyzed (such as molecular or atomic spectroscopy), the type of radiation-matter interaction to be monitored (such as absorption, emission, or diffraction), and the region of the electromagnetic spectrum used in the analysis. Spectroscopic methods are very informative and widely used for both quantitative and qualitative analyses. Spectroscopic methods based on the absorption or emission of radiation in the ultraviolet (UV), visible (Vis), infrared (IR), and radio (nuclear magnetic resonance, NMR) frequency ranges are most commonly encountered in traditional food analysis laboratories. Each of these methods is distinct in that it monitors different types of molecular or atomic transitions. The basis of these transitions is explained in the following sections.

  1. Mössbauer spectroscopy.

    Science.gov (United States)

    Huynh, Boi Hanh

    2011-01-01

    Mössbauer spectroscopy has contributed significantly to the studies of Fe-containing proteins. Early applications yielded detailed electronic characterizations of hemeproteins, and thus enhanced our understanding of the chemical properties of this important class of proteins. The next stage of the applications was marked by major discoveries of several novel Fe clusters of complex structures, including the 8Fe7S P cluster and the mixed metal 1Mo7Fe M center in nitrogenase. Since early 1990 s, rapid kinetic techniques have been used to arrest enzymatic reactions for Mössbauer studies. A number of reaction intermediates were discovered and characterized, both spectroscopically and kinetically, providing unprecedented detailed molecular-level mechanistic information. This chapter gives a brief summary of the historical accounts and a concise description of some experimental and theoretical elements in Mössbauer spectroscopy that are essential for understanding Mössbauer spectra. Major biological applications are summarized at the end.

  2. Spectroscopy of neutral radium

    Energy Technology Data Exchange (ETDEWEB)

    Mol, Aran; De, Subhadeep; Jungmann, Klaus; Wilschut, Hans; Willmann, Lorenz [KVI, University of Groningen, Groningen (Netherlands)

    2008-07-01

    The heavy alkaline earth atoms radium is uniquely sensitive towards parity and time reversal symmetry violations due to a large enhancement of an intrinsic permanent electric dipole moment of the nucleous or the electron. Furthermore, radium is sensitive to atomic parity violation and the nuclear anapole moment. To prepare such experiments spectroscopy of relevant atomic states need to be done. At a later stage we will build a neutral atom trap for radium. We have built an atomic beam of the short lived isotope {sup 225}Ra with a flux of several 10{sup 4} atoms/sec. We are preparing the laser spectroscopy using this beam setup. In the preparation for efficient laser cooling and trapping we have successfully trapped barium, which is similar in it's requirements for laser cooling. The techniques which we have developed with barium can be used to trap rare radium isotopes. We report on the progress of the experiments.

  3. Wavelength tunable CW red laser generated based on an intracavity-SFG composite cavity

    Science.gov (United States)

    Zhang, Z. N.; Bai, Y.; Lei, G. Z.; Bai, B.; Sun, Y. X.; Hu, M. X.; Wang, C.; Bai, J. T.

    2016-12-01

    We report a wavelength-tunable watt-level continuous wave (CW) red laser that uses a composite cavity based on an intracavity sum-frequency generation (SFG). The composite cavity is composed of a LD side-pumped Nd: GdVO4 p-polarized 1062.9 nm resonant cavity and a resonant optical parametric oscillator (SRO) of s-polarized signal light using a periodically poled crystal MgO: PPLN. Based on the temperature tuning from 30 °C to 200 °C, the CW red laser beams are obtained in a tunable waveband from 634.4 nm to 649.1 nm, corresponding to a tunable output waveband from 3278.0 nm to 2940.2 nm of the mid-infrared idler lights. The maximum CW output power of the red laser at 634.4 nm and the idler light at 3278.0 nm reach 3.03 W and 4.13 W under 30 °C, respectively.

  4. Theory and spectroscopy

    Science.gov (United States)

    Stanton, John F.

    2015-05-01

    The interaction between quantum-mechanical theory and spectroscopy is one of the most fertile interfaces in all of science, and has a richly storied history. Of course it was spectroscopy that provided essentially all of the evidence that not all was well (or, perhaps more correctly put, complete) with the world of 19th century classical physics. From the discoveries of the dark lines in the solar spectrum by Fraunhöfer in 1814 to the curiously simple geometric formula discovered seventy years later that described the hydrogen atom spectrum, spectroscopy and spectroscopists have consistently identified the areas of atomic and molecular science that are most in need of hard thinking by theoreticians. The rest of the story, of course, is well-known: spectroscopic results were used to understand and motivate the theory of radioactivity and ultimately the quantum theory, first in its immature form that was roughly contemporaneous with the first World War, and then the Heisenberg-Schrödinger-Dirac version that has withstood the test of time. Since the basic principles of quantum mechanics ware first understood, the subject has been successfully used to understand the patterns found in spectra, and how these relate to molecular structure, symmetry, energy levels, and dynamics. But further understanding required to attain these intellectual achievements has often come only as a result of vital and productive interactions between theoreticians and spectroscopists (of course, many people have strengths in both areas). And indeed, a field that might be termed "theoretical spectroscopy" was cultivated and is now an important part of modern molecular science.

  5. NEUROFEEDBACK USING FUNCTIONAL SPECTROSCOPY

    OpenAIRE

    Hinds, Oliver; Wighton, Paul; Tisdall, M. Dylan; Hess, Aaron; Breiter, Hans; van der Kouwe, André

    2014-01-01

    Neurofeedback based on real-time measurement of the blood oxygenation level-dependent (BOLD) signal has potential for treatment of neurological disorders and behavioral enhancement. Commonly employed methods are based on functional magnetic resonance imaging (fMRI) sequences that sacrifice speed and accuracy for whole-brain coverage, which is unnecessary in most applications. We present multi-voxel functional spectroscopy (MVFS): a system for computing the BOLD signal from multiple volumes of...

  6. Total Absorption Spectroscopy

    International Nuclear Information System (INIS)

    Rubio, B.; Gelletly, W.

    2007-01-01

    The problem of determining the distribution of beta decay strength (B(GT)) as a function of excitation energy in the daughter nucleus is discussed. Total Absorption Spectroscopy is shown to provide a way of determining the B(GT) precisely. A brief history of such measurements and a discussion of the advantages and disadvantages of this technique, is followed by examples of two recent studies using the technique. (authors)

  7. 2008 Vibrational Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Philip J. Reid

    2009-09-21

    The conference focuses on using vibrational spectroscopy to probe structure and dynamics of molecules in gases, liquids, and interfaces. The goal is to bring together a collection of researchers who share common interests and who will gain from discussing work at the forefront of several connected areas. The intent is to emphasize the insights and understanding that studies of vibrations provide about a variety of systems.

  8. Optical imaging and spectroscopy

    CERN Document Server

    Brady, David J

    2009-01-01

    An essential reference for optical sensor system design This is the first text to present an integrated view of the optical and mathematical analysis tools necessary to understand computational optical system design. It presents the foundations of computational optical sensor design with a focus entirely on digital imaging and spectroscopy. It systematically covers: Coded aperture and tomographic imaging Sampling and transformations in optical systems, including wavelets and generalized sampling techniques essential to digital system analysis Geometric, wave, and statis

  9. Spectroscopy with trapped highly charged ions

    International Nuclear Information System (INIS)

    Beiersdorfer, Peter

    2009-01-01

    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.

  10. Layman friendly spectroscopy

    Science.gov (United States)

    Sentic, Stipo; Sessions, Sharon

    Affordable consumer grade spectroscopes (e.g. SCiO, Qualcomm Tricorder XPRIZE) are becoming more available to the general public. We introduce the concepts of spectroscopy to the public and K12 students and motivate them to delve deeper into spectroscopy in a dramatic participatory presentation and play. We use diffraction gratings, lasers, and light sources of different spectral properties to provide a direct experience of spectroscopy techniques. Finally, we invite the audience to build their own spectroscope--utilizing the APS SpectraSnapp cell phone application--and study light sources surrounding them in everyday life. We recontextualize the stigma that science is hard (e.g. ``Math, Science Popular Until Students Realize They're Hard,'' The Wall Street Journal) by presenting the material in such a way that it demonstrates the scientific method, and aiming to make failure an impersonal scientific tool--rather than a measure of one's ability, which is often a reason for shying away from science. We will present lessons we have learned in doing our outreach to audiences of different ages. This work is funded by the APS Outreach Grant ``Captain, we have matter matters!'' We thank New Mexico Tech Physics Department and Physics Club for help and technical equipment.

  11. Biomolecular EPR spectroscopy

    CERN Document Server

    Hagen, Wilfred Raymond

    2008-01-01

    Comprehensive, Up-to-Date Coverage of Spectroscopy Theory and its Applications to Biological SystemsAlthough a multitude of books have been published about spectroscopy, most of them only occasionally refer to biological systems and the specific problems of biomolecular EPR (bioEPR). Biomolecular EPR Spectroscopy provides a practical introduction to bioEPR and demonstrates how this remarkable tool allows researchers to delve into the structural, functional, and analytical analysis of paramagnetic molecules found in the biochemistry of all species on the planet. A Must-Have Reference in an Intrinsically Multidisciplinary FieldThis authoritative reference seamlessly covers all important bioEPR applications, including low-spin and high-spin metalloproteins, spin traps and spin lables, interaction between active sites, and redox systems. It is loaded with practical tricks as well as do's and don'ts that are based on the author's 30 years of experience in the field. The book also comes with an unprecedented set of...

  12. Vibrational Spectroscopy and Astrobiology

    Science.gov (United States)

    Chaban, Galina M.; Kwak, D. (Technical Monitor)

    2001-01-01

    Role of vibrational spectroscopy in solving problems related to astrobiology will be discussed. Vibrational (infrared) spectroscopy is a very sensitive tool for identifying molecules. Theoretical approach used in this work is based on direct computation of anharmonic vibrational frequencies and intensities from electronic structure codes. One of the applications of this computational technique is possible identification of biological building blocks (amino acids, small peptides, DNA bases) in the interstellar medium (ISM). Identifying small biological molecules in the ISM is very important from the point of view of origin of life. Hybrid (quantum mechanics/molecular mechanics) theoretical techniques will be discussed that may allow to obtain accurate vibrational spectra of biomolecular building blocks and to create a database of spectroscopic signatures that can assist observations of these molecules in space. Another application of the direct computational spectroscopy technique is to help to design and analyze experimental observations of ice surfaces of one of the Jupiter's moons, Europa, that possibly contains hydrated salts. The presence of hydrated salts on the surface can be an indication of a subsurface ocean and the possible existence of life forms inhabiting such an ocean.

  13. Generation of green frequency comb from chirped χ{sup (2)} nonlinear photonic crystals

    Energy Technology Data Exchange (ETDEWEB)

    Lai, C.-M. [Department of Electronic Engineering, Ming Chuan University, Taoyuan, Taiwan (China); Chang, K.-H.; Yang, Z.-Y.; Fu, S.-H.; Tsai, S.-T.; Hsu, C.-W.; Peng, L.-H. [Department of Electrical Engineering and Graduate Institute of Photonics and Optoelectronics, National Taiwan University, Taipei, Taiwan (China); Yu, N. E. [Advanced Photonics Research Institute, Gwangju Institute of Science and Technology, Gwangju (Korea, Republic of); Boudrioua, A. [LPL, CNRS - UMR 7538, Université Paris 13, Sorbone Paris Cité (France); Kung, A. H. [Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei, Taiwan (China); Institute of Photonics Technologies, National Tsing Hua University, Hsinchu, Taiwan (China)

    2014-12-01

    Spectrally broad frequency comb generation over 510–555 nm range was reported on chirped quasi-phase-matching (QPM) χ{sup (2)} nonlinear photonic crystals of 12 mm length with periodicity stepwise increased from 5.9 μm to 7.1 μm. When pumped with nanosecond infrared (IR) frequency comb derived from a QPM optical parametric oscillator (OPO) and spanned over 1040 nm to 1090 nm wavelength range, the 520 nm to 545 nm up-converted green spectra were shown to consist of contributions from (a) second-harmonic generation among the signal or the idler modes, and (b) sum-frequency generation (SFG) from the neighboring pairs of the signal or the idler modes. These mechanisms led the up-converted green frequency comb to have the same mode spacing of 450 GHz as that in the IR-OPO pump comb. As the pump was further detuned from the aforementioned near-degeneracy point and moved toward the signal (1020–1040 nm) and the idler (1090–1110 nm) spectral range, the above QPM parametric processes were preserved in the chirped QPM devices to support up-converted green generation in the 510–520 nm and the 545–555 nm spectral regime. Additional 530–535 nm green spectral generation was also observed due to concurrence of multi-wavelength SFG processes between the (signal, idler) mode pairs. These mechanisms facilitate the chirped QPM device to support a single-pass up-conversion efficiency ∼10% when subject to an IR-OPO pump comb with 200 mW average power operated near- or off- the degeneracy point.

  14. Vacuum ultraviolet light generation applications to resonance ionization spectroscopy

    International Nuclear Information System (INIS)

    Payne, M.G.

    1986-08-01

    A theoretical discussion is given for sum mixing with unfocused Gaussian beams. The four-wave sum and difference mixing are carried out in two ''active'' gases: xenon and krypton. In the negatively dispersive regions buffer gases are added to achieve phase matching. 6 refs., 2 figs

  15. High resolution X-ray spectroscopy of laser generated plasmas

    International Nuclear Information System (INIS)

    Faenov, A.Ya.; Skobelev, I.Yu.; Rosmej, F.B.

    1999-01-01

    The application of recently developed spectroscopic instruments in laser produced plasmas with simultaneous high spectral and spatial resolution combined with high luminosity discovered new types of X-ray spectra. These new types are characterised by the disappearance of the resonance lines and the strong emission of dielectronic satellite spectra. Several types of transitions of highly charged ions are discovered which are unknown from usual sources employed in atomic physics. New theoretical models are developed and successfully applied for the interpretation and for plasma diagnostics. (orig.)

  16. High resolution X-ray spectroscopy of laser generated plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Faenov, A.Ya.; Skobelev, I.Yu. [Multicharged Ions Spectra Data Center of VNIIFTRI, Mendeleevo (Russian Federation); Rosmej, F.B. [Technische Hochschule Darmstadt (Germany). Inst. fuer Kernphysik

    1999-11-01

    The application of recently developed spectroscopic instruments in laser produced plasmas with simultaneous high spectral and spatial resolution combined with high luminosity discovered new types of X-ray spectra. These new types are characterised by the disappearance of the resonance lines and the strong emission of dielectronic satellite spectra. Several types of transitions of highly charged ions are discovered which are unknown from usual sources employed in atomic physics. New theoretical models are developed and successfully applied for the interpretation and for plasma diagnostics. (orig.) 28 refs.

  17. Wind Generators

    Science.gov (United States)

    1989-01-01

    When Enerpro, Inc. president, Frank J. Bourbeau, attempted to file a patent on a system for synchronizing a wind generator to the electric utility grid, he discovered Marshall Space Flight Center's Frank Nola's power factor controller. Bourbeau advanced the technology and received a NASA license and a patent for his Auto Synchronous Controller (ASC). The ASC reduces generator "inrush current," which occurs when large generators are abruptly brought on line. It controls voltage so the generator is smoothly connected to the utility grid when it reaches its synchronous speed, protecting the components from inrush current damage. Generator efficiency is also increased in light winds by applying lower than rated voltage. Wind energy is utilized to drive turbines to generate electricity for utility companies.

  18. Two-dimensional nuclear magnetic resonance spectroscopy

    International Nuclear Information System (INIS)

    Bax, A.; Lerner, L.

    1986-01-01

    Great spectral simplification can be obtained by spreading the conventional one-dimensional nuclear magnetic resonance (NMR) spectrum in two independent frequency dimensions. This so-called two-dimensional NMR spectroscopy removes spectral overlap, facilitates spectral assignment, and provides a wealth of additional information. For example, conformational information related to interproton distances is available from resonance intensities in certain types of two-dimensional experiments. Another method generates 1 H NMR spectra of a preselected fragment of the molecule, suppressing resonances from other regions and greatly simplifying spectral appearance. Two-dimensional NMR spectroscopy can also be applied to the study of 13 C and 15 N, not only providing valuable connectivity information but also improving sensitivity of 13 C and 15 N detection by up to two orders of magnitude. 45 references, 10 figures

  19. Generative Semantics.

    Science.gov (United States)

    King, Margaret

    The first section of this paper deals with the attempts within the framework of transformational grammar to make semantics a systematic part of linguistic description, and outlines the characteristics of the generative semantics position. The second section takes a critical look at generative semantics in its later manifestations, and makes a case…

  20. Generative Semantics

    Science.gov (United States)

    Bagha, Karim Nazari

    2011-01-01

    Generative semantics is (or perhaps was) a research program within linguistics, initiated by the work of George Lakoff, John R. Ross, Paul Postal and later McCawley. The approach developed out of transformational generative grammar in the mid 1960s, but stood largely in opposition to work by Noam Chomsky and his students. The nature and genesis of…

  1. Sound generator

    NARCIS (Netherlands)

    Berkhoff, Arthur P.

    2008-01-01

    A sound generator, particularly a loudspeaker, configured to emit sound, comprising a rigid element (2) enclosing a plurality of air compartments (3), wherein the rigid element (2) has a back side (B) comprising apertures (4), and a front side (F) that is closed, wherein the generator is provided

  2. Sound generator

    NARCIS (Netherlands)

    Berkhoff, Arthur P.

    2010-01-01

    A sound generator, particularly a loudspeaker, configured to emit sound, comprising a rigid element (2) enclosing a plurality of air compartments (3), wherein the rigid element (2) has a back side (B) comprising apertures (4), and a front side (F) that is closed, wherein the generator is provided

  3. Pulse Generator

    Science.gov (United States)

    Greer, Lawrence (Inventor)

    2017-01-01

    An apparatus and a computer-implemented method for generating pulses synchronized to a rising edge of a tachometer signal from rotating machinery are disclosed. For example, in one embodiment, a pulse state machine may be configured to generate a plurality of pulses, and a period state machine may be configured to determine a period for each of the plurality of pulses.

  4. Sound generator

    NARCIS (Netherlands)

    Berkhoff, Arthur P.

    2007-01-01

    A sound generator, particularly a loudspeaker, configured to emit sound, comprising a rigid element (2) enclosing a plurality of air compartments (3), wherein the rigid element (2) has a back side (B) comprising apertures (4), and a front side (F) that is closed, wherein the generator is provided

  5. Steam generator

    International Nuclear Information System (INIS)

    Fenet, J.-C.

    1980-01-01

    Steam generator particularly intended for use in the coolant system of a pressurized water reactor for vaporizing a secondary liquid, generally water, by the primary cooling liquid of the reactor and comprising special arrangements for drying the steam before it leaves the generator [fr

  6. Nanosecond fluorescence spectroscopy

    International Nuclear Information System (INIS)

    Leskovar, B.

    1985-03-01

    This article is a summary of a short course lecture given in conjunction with the 1984 Nuclear Science Symposium. Measuring systems for nanosecond fluorescence spectroscopy using single-photon counting techniques are presented. These involve systems based on relaxation-type spark gap light pulser and synchronously pumped mode-locked dye lasers. Furthermore, typical characteristics and optimization of operating conditions of the critical components responsible for the system time resolution are discussed. A short comparison of the most important deconvolution methods for numerical analysis of experimental data is given particularly with respect to the signal-to-noise ratio of the fluorescence signal. 22 refs., 8 figs

  7. Theory overview on spectroscopy

    International Nuclear Information System (INIS)

    Ali, Ahmed

    2011-08-01

    A theoretical overview of the exotic spectroscopy in the charm and beauty quark sector is presented. These states are unexpected harvest from the e + e - and hadron colliders and a permanent abode for the majority of them has yet to be found. We argue that some of these states, in particular the Y b (10890) and the recently discovered states Z b (10610) and Z b (10650), discovered by the Belle collaboration are excellent candidates for tetraquark states [bq][ anti b anti q], with q=u,d light quarks. Theoretical analyses of the Belle data carried out in the tetraquark context is reviewed. (orig.)

  8. Hadron spectroscopy 1987

    International Nuclear Information System (INIS)

    Anon.

    1987-01-01

    With much particle physics research using particle beams to probe the behaviour of the quark constituents deep inside nucleons and other strongly interacting particles (hadrons), it is easy to overlook the progress being made through hadron spectroscopy – the search for and classification of rare particles – and the way it has increased our understanding of quark physics. One way of remedying this was to attend the stimulating and encouraging Hadron 87 meeting held earlier this year at the Japanese KEK Laboratory, where Jonathan Rosner from Chicago's Enrico Fermi Institute gave the concluding talk

  9. Hadron spectroscopy 1987

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1987-09-15

    With much particle physics research using particle beams to probe the behaviour of the quark constituents deep inside nucleons and other strongly interacting particles (hadrons), it is easy to overlook the progress being made through hadron spectroscopy – the search for and classification of rare particles – and the way it has increased our understanding of quark physics. One way of remedying this was to attend the stimulating and encouraging Hadron 87 meeting held earlier this year at the Japanese KEK Laboratory, where Jonathan Rosner from Chicago's Enrico Fermi Institute gave the concluding talk.

  10. Auger electron spectroscopy

    International Nuclear Information System (INIS)

    Gopalaraman, C.P.

    1975-01-01

    General features of electron excited Auger electron spectroscopy (AES) which is a nondestructive technique for the analysis of surfaces upto about 15 Adeg depth with a detection limit of about 0.1% of a monolayer. Methods of measuring the Auger electron energies and recent improvements in the instrumentation are reviewed. Typical energy resolution is found to be about 0.5% which is specially suited for the detection of light elements. It is widely used in metallurgy, surface chemistry and thin film studies. (K.B.)

  11. Spectroscopy of 212Rn

    International Nuclear Information System (INIS)

    Stuchbery, A.E.; Dracoulis, G.D.; Byrne, A.P.; Poletti, A.R.

    1988-01-01

    Excited states of 212 Rn have been studied using γ-ray and electron spectroscopy following the reactions 208 Pb( 9 Be, 5n) and 204 Hg( 13 C,5n). With the exception of the energy of the yrast 8 + → 6 + transition, the previously proposed level scheme has been verified. New transitions have been placed in the level scheme and new lifetime and g-factor results obtained. The level scheme and electromagnetic properties of selected isomeric states are compared with the results of shell model and semi-empirical shell-model calculations, including coupling to octupole vibrations. (orig.)

  12. Spectroscopy of 212Rn

    International Nuclear Information System (INIS)

    Stuchbery, A.E.; Dracoulis, G.D.; Byrne, A.P.; Poletti, A.R.

    1988-06-01

    Excited states of 212 Rn have been studied using γ-ray and electron spectroscopy following the reactions 208 Pb ( 9 Be,5n) and 204 Hg( 13 C,5n). With the exception of the energy of the yrast 8 + → 6 + transition, the previously proposed level scheme has been verified. New transitions have been placed in the level scheme and new lifetime and g-factor results obtained. The level scheme and electromagnetic properties of selected isomeric states are compared with the results of shell model and semi-empirical shell-model calculations, including coupling to octupole vibrations

  13. MR spectroscopy in dementia

    International Nuclear Information System (INIS)

    Hauser, T.; Gerigk, L.; Giesel, F.; Schuster, L.; Essig, M.

    2010-01-01

    With an increasingly aging population we are faced with the problem of an increasing number of dementia patients. In addition to clinical, neuropsychological and laboratory procedures, MRI plays an important role in the early diagnosis of dementia. In addition to various morphological changes functional changes can also help in the diagnosis and differential diagnosis of dementia. Overall the diagnosis of dementia can be improved by using parameters from MR spectroscopy. This article focuses on MR spectroscopic changes in the physiological aging process as well as on changes in mild cognitive impairment a precursor of Alzheimer's dementia, in Alzheimer's dementia, frontotemporal dementia, vascular dementia and Lewy body dementia. (orig.) [de

  14. Fourier transforms in spectroscopy

    CERN Document Server

    Kauppinen, Jyrki

    2000-01-01

    This modern approach to the subject is clearly and logically structured, and gives readers an understanding of the essence of Fourier transforms and their applications. All important aspects are included with respect to their use with optical spectroscopic data. Based on popular lectures, the authors provide the mathematical fundamentals and numerical applications which are essential in practical use. The main part of the book is dedicated to applications of FT in signal processing and spectroscopy, with IR and NIR, NMR and mass spectrometry dealt with both from a theoretical and practical poi

  15. Picosecond spectroscopy: The first 20 years

    International Nuclear Information System (INIS)

    Rentzepis, P.M.

    1987-01-01

    Lasers were at first operating in the pulsed mode. That was the ruby, Cr/sup 3+/, emitting at 694.3 nm with a few kilowatts power, several microseconds time width, and a rather broad non-smooth-spiky-intensity profile. Even with such a primitive laser source, several noteworthy, novel experiments were performed such as two photon processes and second harmonic generation. The advent of Q-switch lasers by means of dyes, Kerr cells and electro-optic crystals introduced the era of high power lasers and laser spectroscopy. The high intensity and rather smooth intensity versus time profile pulses emitted by ruby and Nd/sup 3+//glass lasers provided excellent means for non-linear spectroscopy studies and nanosecond Raman spectroscopy, a field which flourished ten years later. In the mid-sixties, the He/Ne laser was mode locked, and shortly thereafter, the Nd/sup 3+//glass laser was also mode locked and shown to emit picosecond duration pulses. This paper presents what one observes on the screen of an oscilloscope once a laser is set up so as to generate picosecond pulses by use of either a saturable absorbing dye or solid state modulator. What is seen is, of course, a train of pulses. It is characteristic of these pulses that their intensity is extremely high, in the gigawatt region. In this particular case, the band width is approximately twenty to thirty wavenumbers. The method utilized to measure the picosecond pulses, initially, was the two photon method. This paper also gives a more graphic illustration how this technique operates. This same procedure provides an extremely simple technique which the author believes made possible the initial development of the picosecond spectroscopy field

  16. Communication: Probing the absolute configuration of chiral molecules at aqueous interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Lotze, Stephan, E-mail: lotze@amolf.nl; Versluis, Jan [FOM Institute for Atomic and Molecular Physics, Science Park 104, 1098 XG Amsterdam (Netherlands); Olijve, Luuk L. C.; Schijndel, Luuk van; Milroy, Lech G.; Voets, Ilja K. [Laboratory of Macromolecular and Organic Chemistry, Department of Chemical Engineering and Chemistry, and Institute for Complex Molecular Systems, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven (Netherlands); Bakker, Huib J., E-mail: bakker@amolf.nl [FOM Institute AMOLF, Science Park 104, 1098 XG Amsterdam (Netherlands)

    2015-11-28

    We demonstrate that the enantiomers of chiral macromolecules at an aqueous interface can be distinguished with monolayer sensitivity using heterodyne-detected vibrational sum-frequency generation (VSFG). We perform VSFG spectroscopy with a polarization combination that selectively probes chiral molecular structures. By using frequencies far detuned from electronic resonances, we probe the chiral macromolecular structures with high surface specificity. The phase of the sum-frequency light generated by the chiral molecules is determined using heterodyne detection. With this approach, we can distinguish right-handed and left-handed helical peptides at a water-air interface. We thus show that heterodyne-detected VSFG is sensitive to the absolute configuration of complex, interfacial macromolecules and has the potential to determine the absolute configuration of enantiomers at interfaces.

  17. Resonance ionization spectroscopy 1990

    International Nuclear Information System (INIS)

    Parks, J.E.; Omenetto, N.

    1991-01-01

    The Fifth International Symposium on Resonance Ionization Spectroscopy (RIS) and its Applications was held in Varese, Italy, 16-21 September 1990. Interest in RIS and its applications continues to grow, and RIS is expanding into a more diverse and mature field of study. This maturity was evident in this meeting both in the basic science and understanding of RIS processes and in the number of new and improved applications and techniques. The application of RIS techniques to molecular detection problems made remarkable progress since the last meeting two years ago. Subtle effects pertaining to isotopic discrimination received more theoretical attention, and there now seems to be good understanding of these effects, which can lead to correction procedures and/or methods to avoid isotopic effects. RIS applications were presented in which significant, real world problems were addressed, demonstrating its capability to solve problems that previously could not be accurately solved by other more traditional techniques. The contributions to the conference are grouped under the following major topic headings: physics applications of rare atoms; laser ionization mechanisms - spectroscopy; atomic, molecular and ion sources; molecular RIS; atomic RIS - Rydberg states; environmental trace analysis; biological and medical applications; state selected chemistry; new laser sources and techniques; ultra-high resolution and isotopic selectivity; surface and bulk analysis. (Author)

  18. Charmonium(like) spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Zhiqing [Johannes Gutenberg University Mainz, Mainz (Germany)

    2016-07-01

    Since its discovery in 1974, charmonium spectroscopy has always been an important probe to study strong interactions and the structure of hadronic matter. Below open-charm threshold, the charmonium spectrum is well established now. Also our understanding of charmonium states above the open-charm threshold has seen a big progress during recent years. However, the most surprising was the discovery of charmonium-like states, which have a similar mass scale as charmonium states but can not be classified as conventional states easily. Indeed, charmonium-like states are good candidates for the so-called exotic hadron states, i.e. particles with a quark content different from normal mesons and baryons, such as multi-quark states, hybrid states or molecule states. Although neutral charmonium-like states are more difficult to be identified, the observation of charged states provide us a convincing evidence. In this talk, I review the recent progress on charmonium and charmonium-like spectroscopy from BESIII, Belle, BABAR, CLEO-c and LHCb and the prospect for future experiments at Belle II and PANDA.

  19. Neutron resonance spectroscopy

    International Nuclear Information System (INIS)

    Gunsing, F.

    2005-06-01

    The present document has been written in order to obtain the diploma 'Habilitation a Diriger des Recherches'. Since this diploma is indispensable to supervise thesis students, I had the intention to write a document that can be useful for someone starting in the field of neutron resonance spectroscopy. Although the here described topics are already described elsewhere, and often in more detail, it seemed useful to have most of the relevant information in a single document. A general introduction places the topic of neutron-nucleus interaction in a nuclear physics context. The large variations of several orders of magnitude in neutron-induced reaction cross sections are explained in terms of nuclear level excitations. The random character of the resonances make nuclear model calculation predictions impossible. Then several fields in physics where neutron-induced reactions are important and to which I have contributed in some way or another, are mentioned in a first synthetic chapter. They concern topics like parity nonconservation in certain neutron resonances, stellar nucleosynthesis by neutron capture, and data for nuclear energy applications. The latter item is especially important for the transmutation of nuclear waste and for alternative fuel cycles. Nuclear data libraries are also briefly mentioned. A second chapter details the R-matrix theory. This formalism is the foundation of the description of the neutron-nucleus interaction and is present in all fields of neutron resonance spectroscopy. (author)

  20. Neutron resonance spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Gunsing, F

    2005-06-15

    The present document has been written in order to obtain the diploma 'Habilitation a Diriger des Recherches'. Since this diploma is indispensable to supervise thesis students, I had the intention to write a document that can be useful for someone starting in the field of neutron resonance spectroscopy. Although the here described topics are already described elsewhere, and often in more detail, it seemed useful to have most of the relevant information in a single document. A general introduction places the topic of neutron-nucleus interaction in a nuclear physics context. The large variations of several orders of magnitude in neutron-induced reaction cross sections are explained in terms of nuclear level excitations. The random character of the resonances make nuclear model calculation predictions impossible. Then several fields in physics where neutron-induced reactions are important and to which I have contributed in some way or another, are mentioned in a first synthetic chapter. They concern topics like parity nonconservation in certain neutron resonances, stellar nucleosynthesis by neutron capture, and data for nuclear energy applications. The latter item is especially important for the transmutation of nuclear waste and for alternative fuel cycles. Nuclear data libraries are also briefly mentioned. A second chapter details the R-matrix theory. This formalism is the foundation of the description of the neutron-nucleus interaction and is present in all fields of neutron resonance spectroscopy. (author)

  1. Photothermal spectroscopy of aerosols

    International Nuclear Information System (INIS)

    Campillo, A.J.; Lin, H.B.

    1981-04-01

    In situ aerosol absorption spectroscopy was performed using two novel photothermal detection schemes. The first, based on a photorefractive effect and coherent detection, called phase fluctuation optical heterodyne (PFLOH) spectroscopy, could, depending on the geometry employed, yield particle specific or particle and gas absorption data. Single particles of graphite as small as 1 μm were detected in the particle specific mode. In another geometrical configuration, the total absorption (both gas and particle) of submicron sized aerosols of ammonium sulfate particles in equilibrium with gaseous ammonia and water vapor were measured at varying CO 2 laser frequencies. The specific absorption coefficient for the sulfate ion was measured to be 0.5 m 2 /g at 1087 cm -1 . The absorption coefficient sensitivity of this scheme was less than or equal to 10 -8 cm -1 . The second scheme is a hybrid visible Mie scattering scheme incorporating photothermal modulation. Particle specific data on ammonium sulfate droplets were obtained. For chemically identical species, the relative absorption spectrum versus laser frequency can be obtained for polydisperse aerosol distributions directly from the data without the need for complex inverse scattering calculations

  2. Raman spectroscopy in graphene

    International Nuclear Information System (INIS)

    Malard, L.M.; Pimenta, M.A.; Dresselhaus, G.; Dresselhaus, M.S.

    2009-01-01

    Recent Raman scattering studies in different types of graphene samples are reviewed here. We first discuss the first-order and the double resonance Raman scattering mechanisms in graphene, which give rise to the most prominent Raman features. The determination of the number of layers in few-layer graphene is discussed, giving special emphasis to the possibility of using Raman spectroscopy to distinguish a monolayer from few-layer graphene stacked in the Bernal (AB) configuration. Different types of graphene samples produced both by exfoliation and using epitaxial methods are described and their Raman spectra are compared with those of 3D crystalline graphite and turbostratic graphite, in which the layers are stacked with rotational disorder. We show that Resonance Raman studies, where the energy of the excitation laser line can be tuned continuously, can be used to probe electrons and phonons near the Dirac point of graphene and, in particular allowing a determination to be made of the tight-binding parameters for bilayer graphene. The special process of electron-phonon interaction that renormalizes the phonon energy giving rise to the Kohn anomaly is discussed, and is illustrated by gated experiments where the position of the Fermi level can be changed experimentally. Finally, we discuss the ability of distinguishing armchair and zig-zag edges by Raman spectroscopy and studies in graphene nanoribbons in which the Raman signal is enhanced due to resonance with singularities in the density of electronic states.

  3. Wave mixing spectroscopy

    International Nuclear Information System (INIS)

    Smith, R.W.

    1980-08-01

    Several new aspects of nonlinear or wave mixing spectroscopy were investigated utilizing the polarization properties of the nonlinear output field and the dependence of this field upon the occurrence of multiple resonances in the nonlinear susceptibility. First, it is shown theoretically that polarization-sensitive detection may be used to either eliminate or controllably reduce the nonresonant background in coherent anti-Stokes Raman spectroscopy, allowing weaker Raman resonances to be studied. The features of multi-resonant four-wave mixing are examined in the case of an inhomogeneously broadened medium. It is found that the linewidth of the nonlinear output narrows considerably (approaching the homogeneous width) when the quantum mechanical expressions for the doubly- and triply-resonant susceptibilities are averaged over a Doppler or strain broadened profile. Experimental studies of nonlinear processes in Pr +3 :LaF 3 verify this linewidth narrowing, but indicate that this strain broadened system cannot be treated with a single broadening parameter as in the case of Doppler broadening in a gas. Several susceptibilities are measured from which are deduced dipole matrix elements and Raman polarizabilities related to the 3 H 4 , 3 H 6 , and 3 P 0 levels of the praseodymium ions

  4. Future Directions in Ultraviolet Spectroscopy

    Science.gov (United States)

    Sonneborn, George (Editor); Moos, Warren; VanSteenberg, Michael

    2009-01-01

    The 'Future Directions in Ultraviolet Spectroscopy' conference was inspired by the accomplishments of the Far Ultraviolet Spectroscopic Explorer (FUSE) Mission. The FUSE mission was launched in June 1999 and spent over eight years exploring the far-ultraviolet universe, gathering over 64 million seconds of high-resolution spectral data on nearly 3000 astronomical targets. The goal of this conference was not only to celebrate the accomplishments of FUSE, but to look toward the future and understand the major scientific drivers for the ultraviolet capabilities of the next generation fo space observatories. Invited speakers presented discussions based on measurements made by FUSE and other ultraviolet instruments, assessed their connection with measurements made with other techniques and, where appropriate, discussed the implications of low-z measurements for high-z phenomena. In addition to the oral presentations, many participants presented poster papers. The breadth of these presentation made it clear that much good science is still in progress with FUSE data and that these result will continue to have relevance in many scientific areas.

  5. Nonlinear vibrational spectroscopy of surfactants at liquid interfaces

    Science.gov (United States)

    Miranda, Paulo Barbeitas

    Surfactants are widely used to modify physical and chemical properties of interfaces. They play an important role in many technological problems. Surfactant monolayers are also of great scientific interest because they are two-dimensional systems that may exhibit a very rich phase transition behavior and can also be considered as a model system for biological interfaces. In this Thesis, we use a second-order nonlinear optical technique (Sum-Frequency Generation - SFG) to obtain vibrational spectra of surfactant monolayers at liquid/vapor and solid/liquid interfaces. The technique has several advantages: it is intrinsically surface-specific, can be applied to buried interfaces, has submonolayer sensitivity and is remarkably sensitive to the conformational order of surfactant monolayers. The first part of the Thesis is concerned with surfactant monolayers at the air/water interface (Langmuir films). Surface crystallization of an alcohol Langmuir film and of liquid alkanes are studied and their phase transition behaviors are found to be of different nature, although driven by similar intermolecular interactions. The effect of crystalline order of Langmuir monolayers on the interfacial water structure is also investigated. It is shown that water forms a well-ordered hydrogen-bonded network underneath an alcohol monolayer, in contrast to a fatty acid monolayer which induces a more disordered structure. In the latter case, ionization of the monolayer becomes more significant with increase of the water pH value, leading to an electric-field-induced ordering of interfacial water molecules. We also show that the orientation and conformation of fairly complicated molecules in a Langmuir monolayer can be completely mapped out using a combination of SFG and second harmonic generation (SHG). For a quantitative analysis of molecular orientation at an interface, local-field corrections must be included. The second part is a study of self-assembled surfactant monolayers at the

  6. Energy generation

    CSIR Research Space (South Africa)

    Osburn, L

    2009-02-01

    Full Text Available Current perceptions conjure images of photovoltaic panels and wind turbines when green building or sustainable development is discussed. How energy is used and how it is generated are core components of both green building and sustainable...

  7. Radionuclide generators

    International Nuclear Information System (INIS)

    Lambrecht, R.M.; Wollongong Univ.; Tomiyoshi, K.; Sekine, T.

    1997-01-01

    The present status and future directions of research and development on radionuclide generator technology are reported. The recent interest to develop double-neutron capture reactions for production of in vivo generators; neutron rich nuclides for radio-immunotherapeutic pharmaceuticals: and advances with ultra-short lived generators is highlighted. Emphasis is focused on: production of the parent radionuclide; the selection and the evaluation of support materials and eluents with respect to the resultant radiochemical yield of the daughter, and the breakthrough of the radionuclide parent: and, the uses of radionuclide generators in radiopharmaceutical chemistry, biomedical and industrial applications. The 62 Zn → 62 Cu, 66 Ni → 66 Cu, 103m Rh → 103 Rh, 188 W → 188 Re and the 225 Ac → 221 Fr → 213 Bi generators are predicted to be emphasized for future development. Coverage of the 99 Mo → 99m Tc generator was excluded, as it the subject of another review. The literature search ended June, 1996. (orig.)

  8. Photoelectron photoion molecular beam spectroscopy

    International Nuclear Information System (INIS)

    Trevor, D.J.

    1980-12-01

    The use of supersonic molecular beams in photoionization mass spectroscopy and photoelectron spectroscopy to assist in the understanding of photoexcitation in the vacuum ultraviolet is described. Rotational relaxation and condensation due to supersonic expansion were shown to offer new possibilities for molecular photoionization studies. Molecular beam photoionization mass spectroscopy has been extended above 21 eV photon energy by the use of Stanford Synchrotron Radiation Laboratory (SSRL) facilities. Design considerations are discussed that have advanced the state-of-the-art in high resolution vuv photoelectron spectroscopy. To extend gas-phase studies to 160 eV photon energy, a windowless vuv-xuv beam line design is proposed

  9. Molecular studies by electron spectroscopy

    International Nuclear Information System (INIS)

    Hansteen, J.M.

    1977-01-01

    Experience gained in experimental nuclear physics has played a large role in the development of electron spectroscopy as a powerful tool for studying chemical systems. The use of ESCA (Electron Spectroscopy for Chemical Analysis) for the mapping of molecular properties connected with inner as well as outer electron shells is reviewed, mainly from a phenomological point of view. Molecular Auger electron spectroscopy is described as a means of gaining information on details in molecular structure, simultaneously being extensively applied for surface studies. Future highly promising research areas for molecular electron spectroscopy are suggested to be (e,2e) processes as well as continued exploitation of synchrotron radiation from high energy nuclear devices. (Auth.)

  10. Fourier transform infrared spectroscopy of peptides.

    Science.gov (United States)

    Bakshi, Kunal; Liyanage, Mangala R; Volkin, David B; Middaugh, C Russell

    2014-01-01

    Fourier transform infrared (FTIR) spectroscopy provides data that are widely used for secondary structure characterization of peptides. A wide array of available sampling methods permits structural analysis of peptides in diverse environments such as aqueous solution (including optically turbid media), powders, detergent micelles, and lipid bilayers. In some cases, side chain vibrations can also be resolved and used for tertiary structure and chemical analysis. Data from several low-resolution spectroscopic techniques, including FTIR, can be combined to generate an empirical phase diagram, an overall picture of peptide structure as a function of environmental conditions that can aid in the global interpretation of large amounts of spectroscopic data.

  11. Multichannel euv spectroscopy of high temperature plasmas

    International Nuclear Information System (INIS)

    Fonck, R.J.

    1983-11-01

    Spectroscopy of magnetically confined high temperature plasmas in the visible through x-ray spectral ranges deals primarily with the study of impurity line radiation or continuum radiation. Detailed knowledge of absolute intensities, temporal behavior, and spatial distributions of the emitted radiation is desired. As tokamak facilities become more complex, larger, and less accessible, there has been an increased emphasis on developing new instrumentation to provide such information in a minimum number of discharges. The availability of spatially-imaging detectors for use in the vacuum ultraviolet region (especially the intensified photodiode array) has generated the development of a variety of multichannel spectrometers for applications on tokamak facilities

  12. Method for conducting nonlinear electrochemical impedance spectroscopy

    Science.gov (United States)

    Adler, Stuart B.; Wilson, Jamie R.; Huff, Shawn L.; Schwartz, Daniel T.

    2015-06-02

    A method for conducting nonlinear electrochemical impedance spectroscopy. The method includes quantifying the nonlinear response of an electrochemical system by measuring higher-order current or voltage harmonics generated by moderate-amplitude sinusoidal current or voltage perturbations. The method involves acquisition of the response signal followed by time apodization and fast Fourier transformation of the data into the frequency domain, where the magnitude and phase of each harmonic signal can be readily quantified. The method can be implemented on a computer as a software program.

  13. Near-infrared spectroscopy

    Directory of Open Access Journals (Sweden)

    Virendra Jain

    2015-01-01

    Full Text Available Tissue ischaemia can be a significant contributor to increased morbidity and mortality. Conventional oxygenation monitoring modalities measure systemic oxygenation, but regional tissue oxygenation is not monitored. Near-infrared spectroscopy (NIRS is a non-invasive monitor for measuring regional oxygen saturation which provides real-time information. There has been increased interest in the clinical application of NIRS following numerous studies that show improved outcome in various clinical situations especially cardiac surgery. Its use has shown improved neurological outcome and decreased postoperative stay in cardiac surgery. Its usefulness has been investigated in various high risk surgeries such as carotid endarterectomy, thoracic surgeries, paediatric population and has shown promising results. There is however, limited data supporting its role in neurosurgical population. We strongly feel, it might play a key role in future. It has significant advantages over other neuromonitoring modalities, but more technological advances are needed before it can be used more widely into clinical practice.

  14. Transit spectroscopy with GTC

    Directory of Open Access Journals (Sweden)

    Osorio M.R. Zapatero

    2013-04-01

    Full Text Available Thanks to different ground-based surveys and space missions, nowadays we have a fairly large sample of discovered extra-solar planets to study and, without a doubt, this number will increase in the future. One of the most succesful techniques that allows us to prove the physical properties and atmospheric composition of these exoplanets is transmission spectroscopy. The level of precision that is require to measure these effects provides a technical challenge that is solved by using big telescopes and stable instruments to reach low noise levels. In this article, we will discuss the use of the 10m class telescope GTC to observed planetary transits in spectroscopic mode and some of the results that we are currently obtaining.

  15. Advances in atomic spectroscopy

    CERN Document Server

    Sneddon, J

    1998-01-01

    This volume continues the series'' cutting-edge reviews on developments in this field. Since its invention in the 1920s, electrostatic precipitation has been extensively used in industrial hygiene to remove dust and particulate matter from gases before entering the atmosphere. This combination of electrostatic precipitation is reported upon in the first chapter. Following this, chapter two reviews recent advances in the area of chemical modification in electrothermal atomization. Chapter three consists of a review which deal with advances and uses of electrothermal atomization atomic absorption spectrometry. Flow injection atomic spectroscopy has developed rapidly in recent years and after a general introduction, various aspects of this technique are looked at in chapter four. Finally, in chapter five the use of various spectrometric techniques for the determination of mercury are described.

  16. Astronomical Spectroscopy for Amateurs

    CERN Document Server

    Harrison, Ken M

    2011-01-01

    Astronomical Spectroscopy for Amateurs is a complete guide for amateur astronomers who are looking for a new challenge beyond astrophotography. The book provides a brief overview of the history and development of the spectroscope, then a short introduction to the theory of stellar spectra, including details on the necessary reference spectra required for instrument testing and spectral comparison. The various types of spectroscopes available to the amateur are then described. Later sections cover all aspects of setting up and using various types of commercially available and home-built spectroscopes, starting with basic transmission gratings and going through more complex models, all the way to the sophisticated Littrow design. The final part of the text is about practical spectroscope design and construction. This book uniquely brings together a collection of observing, analyzing, and processing hints and tips that will allow the amateur to build skills in preparing scientifically acceptable spectra data. It...

  17. Introduction to NSE spectroscopy

    International Nuclear Information System (INIS)

    Pappas, C.

    2001-01-01

    Neutron Spin Echo (NSE) spectroscopy allows for reaching the highest energy resolution in inelastic neutron scattering while keeping the high intensity advantage of a beam which is only 10-20% monochromatic. Most spectroscopic methods determine separately the energies of the incident (ω 0 ) and scattered beams (ω) in order to deduce the energy transfer (Δω = ω-ω 0 ), which is the relevant parameter in inelastic neutron scattering. The accuracy in the determination of ω 0 and ω also determines the lowest limit for Δω, which can reach 10 -3 , but with the cost of a high incident beam monocromatisation. In NSE the precession of neutron spins in a magnetic field is used as a stop-watch, which is carried by each neutron individually and measures directly, with an accuracy of 10 -5 to 10 -3 , the difference in energy before and after the scattering process at the sample. (R.P.)

  18. Fast beam radiofrequency spectroscopy

    International Nuclear Information System (INIS)

    Pipkin, F.M.

    1983-01-01

    The combination of a fast atom or ion beam derived from a small accelerator with radiofrequency spectroscopy methods provides a powerful method for measuring the fine structure of atomic and molecular systems. The fast beam makes possible measurements in which two separated oscillatory fields are used to obtain resonance lines whose widths are less than the natural line width due to the lifetimes of the states. The separated oscillatory field lines have, in addition, a number of features which make possible measurements with greater precision and less sensitivity to systematic errors. The fast beam also makes accessible multiple photon radiofrequency transitions whose line width is intrinsically narrower than that of the single photon transitions and which offer great potential for high precision measurements. This report focuses on the techniques and their promise. Recent measurements of the fine structure of H and He + are used as illustrations

  19. Baryon spectroscopy in COMPASS

    Energy Technology Data Exchange (ETDEWEB)

    Austregesilo, Alexander; Chung, Suh-Urk; Ketzer, Bernhard; Neubert, Sebastian; Paul, Stephan [Technische Universitaet Muenchen, Physik Department E18, D-85748 Garching (Germany)

    2010-07-01

    COMPASS is a fixed-target experiment at CERN SPS which investigates the structure and spectroscopy of hadrons. During in total 9 weeks in 2008 and 2009, a 190 GeV/c proton beam impinging on a liquid hydrogen target has been used primarily to study the production of exotic mesons and glueball candidates at central rapidities. As no bias on the rapidity was introduced by the trigger system, the data also yield the unique possibility to study diffractive dissociation of the beam proton while an inert target is assumed. To this end exclusive events with three charged particles including one proton in the final state have been extracted. We report on the status of the event selection studies and discuss the prospect of using partial wave analysis techniques, which have been successfully applied for diffractive dissociation reactions of pions in COMPASS.

  20. Bragg Curve Spectroscopy

    International Nuclear Information System (INIS)

    Gruhn, C.R.

    1981-05-01

    An alternative utilization is presented for the gaseous ionization chamber in the detection of energetic heavy ions, which is called Bragg Curve Spectroscopy (BCS). Conceptually, BCS involves using the maximum data available from the Bragg curve of the stopping heavy ion (HI) for purposes of identifying the particle and measuring its energy. A detector has been designed that measures the Bragg curve with high precision. From the Bragg curve the range from the length of the track, the total energy from the integral of the specific ionization over the track, the dE/dx from the specific ionization at the beginning of the track, and the Bragg peak from the maximum of the specific ionization of the HI are determined. This last signal measures the atomic number, Z, of the HI unambiguously

  1. Laboratory molecular spectroscopy

    International Nuclear Information System (INIS)

    Margolis, J.

    1982-04-01

    The precision required in making spectroscopic measurements is discussed. Remarks are directed specifically to vibration-rotation spectra rather than continuum absorptions. The ultimate precision that is required for line positions is related to the width of the lines which may be no narrower than the Doppler width. The spectroscopic methods considered are those which are of the most general value to the astronomers, those which acquire and can handle large volumes of spectra in digital form, or in a form which is compatible with computer analysis, and in a form which is at least internally consistent. The use of dye laser, grating instruments, and the most versatile instrument for laboratory spectroscopy, the Fourier transform spectrometer is discussed

  2. EXAFS spectroscopy of quasicrystals

    International Nuclear Information System (INIS)

    Menushenkov, A. P.; Rakshun, Ya. V.

    2007-01-01

    The results of the investigation of the features of the local structure of quasicrystalline materials by extended X-ray absorption fine structure (EXAFS) spectroscopy with the use of synchrotron radiation are analyzed. The advantages of this method from the point of view of deriving information about the local shifts of the atoms forming an icosahedral structure are demonstrated. The rearrangement of the local environment of copper and iron in Al-Fe-Cu ternary alloys at a transition from the crystalline to the quasicrystalline phase has been investigated. It is established that the nearest copper coordination retains the symmetry characteristic of the crystal; however, rotation and small displacements of copper matrix atoms lead to significant rearrangement of aluminum atoms around iron atoms. As a result, icosahedral clusters with pentagonal symmetry are formed around iron atoms and violation of the translational symmetry is accompanied by the transition of Al-Fe-Cu to the quasicrystalline state

  3. Intermediate valence spectroscopy

    International Nuclear Information System (INIS)

    Gunnarsson, O.; Schoenhammer, K.

    1987-01-01

    Spectroscopic properties of intermediate valence compounds are studied using the Anderson model. Due to the large orbital and spin degeneracy N/sub f/ of the 4f-level, 1/N/sub f/ can be treated as a small parameter. This approach provides exact T = 0 results for the Anderson impurity model in the limit N/sub f/ → ∞, and by adding 1/N/sub f/ corrections some properties can be calculated accurately even for N/sub f/ = 1 or 2. In particular valence photoemission and resonance photoemission spectroscopies are studied. A comparison of theoretical and experimental spectra provides an estimate of the parameters in the model. Core level photoemission spectra provide estimates of the coupling between the f-level and the conduction states and of the f-level occupancy. With these parameters the model gives a fair description of other electron spectroscopies. For typical parameters the model predicts two structures in the f-spectrum, namely one structure at the f-level and one at the Fermi energy. The resonance photoemission calculation gives a photon energy dependence for these two peaks in fair agreement with experiment. The peak at the Fermi energy is partly due to a narrow Kondo resonance, resulting from many-body effects and the presence of a continuous, partly filled conduction band. This resonance is related to a large density of low-lying excitations, which explains the large susceptibility and specific heat observed for these systems at low temperatures. 38 references, 11 figures, 2 tables

  4. Vibrational spectroscopy of proteins

    International Nuclear Information System (INIS)

    Schwaighofer, A.

    2013-01-01

    Two important steps for the development of a biosensor are the immobilization of the biological component (e.g. protein) on a surface and the enhancement of the signal to improve the sensitivity of detection. To address these subjects, the present work describes Fourier transform infrared (FTIR) investigations of several proteins bound to the surface of an attenuated total reflection (ATR) crystal. Furthermore, new nanostructured surfaces for signal enhancement were developed for use in FTIR microscopy. The mitochondrial redox-protein cytochrome c oxidase (CcO) was incorporated into a protein-tethered bilayer lipid membrane (ptBLM) on an ATR crystal featuring a roughened two-layer gold surface for signal enhancement. Electrochemical excitation by periodic potential pulses at different modulation frequencies was followed by time-resolved FTIR spectroscopy. Phase sensitive detection was used for deconvolution of the IR spectra into vibrational components. A model based on protonation-dependent chemical reaction kinetics could be fitted to the time evolution of IR bands attributed to several different redox centers of the CcO. Further investigations involved the odorant binding protein 14 (OBP14) of the honey bee (Apis mellifera), which was studied using ATR-FTIR spectroscopy and circular dichroism. OBP14 was found to be thermally stable up to 45 °C, thus permitting the potential application of this protein for the fabrication of biosensors. Thermal denaturation measurements showed that odorant binding increases the thermal stability of the OBP-odorant complex. In another project, plasmonic nanostructures were fabricated that enhance the absorbance in FTIR microscopy measurements. The nanostructures are composed of an array of round-shaped insulator and gold discs on top of a continuous gold layer. Enhancement factors of up to ⁓125 could be observed with self-assembled monolayers of dodecanethiol molecules immobilized on the gold surface (author) [de

  5. Hard X-ray photoemission spectroscopy

    International Nuclear Information System (INIS)

    Kobayashi, Keisuke

    2009-01-01

    Except in the very early stage of the development of X-ray photoemission spectroscopy (XPS) by Kai Siegbahn and his coworkers, the excitation sources for XPS studies have predominantly been the Al Kα and Mg Kα emission lines. The advent of synchrotron radiation sources opened up the possibility of tuning the excitation photon energy with much higher throughputs for photoemission spectroscopy, however the excitation energy range was limited to the vacuum ultra violet and soft X-ray regions. Over the past 5-6 years, bulk-sensitive hard X-ray photoemission spectroscopy using high-brilliance high-flux X-rays from third generation synchrotron radiation facilities has been developed. This article reviews the history of HXPES covering the period from Kai Siegbahn and his coworkers' pioneering works to the present, and describes the fundamental aspects, instrumentation, applications to solid state physics, applied physics, materials science, and industrial applications of HXPES. Finally, several challenging new developments which have been conducted at SPring-8 by collaborations among several groups are introduced.

  6. Radionuclide generators

    International Nuclear Information System (INIS)

    Lambrecht, R.M.

    1983-01-01

    The status of radionuclide generators for chemical research and applications related to the life sciences and biomedical research are reviewed. Emphasis is placed upon convenient, efficient and rapid separation of short-lived daughter radionuclides in a chemical form suitable for use without further chemical manipulation. The focus is on the production of the parent, the radiochemistry associated with processing the parent and daughter, the selection and the characteristic separation methods, and yields. Quality control considerations are briefly noted. The scope of this review includes selected references to applications of radionuclide generators in radiopharmaceutical chemistry, and the life sciences, particularly in diagnostic and therapeutic medicine. The 99 Mo-sup(99m)Tc generator was excluded. 202 references are cited. (orig.)

  7. X-ray photoelectron spectroscopy

    International Nuclear Information System (INIS)

    Attekum, P.M.T.M. van.

    1979-01-01

    The methods and results of X-ray photoelectron spectroscopy in the study of plasmons, alloys and gold compounds are discussed. After a comprehensive introduction, seven papers by the author, previously published elsewhere, are reprinted and these cover a wide range of the uses of X-ray photoelectron spectroscopy. (W.D.L.)

  8. Diffusion measurements by Raman spectroscopy

    DEFF Research Database (Denmark)

    Hansen, Susanne Brunsgaard; Shapiro, Alexander; Berg, Rolf W.

    Poster "Diffusion measurements by Raman spectroscopy", See poster at http://www.kemi.dtu.dk/~ajo/rolf/petroday2004.ppt......Poster "Diffusion measurements by Raman spectroscopy", See poster at http://www.kemi.dtu.dk/~ajo/rolf/petroday2004.ppt...

  9. Spectroscopy, Understanding the Atom Series.

    Science.gov (United States)

    Hellman, Hal

    This booklet is one of the "Understanding the Atom" Series. The science of spectroscopy is presented by a number of topics dealing with (1) the uses of spectroscopy, (2) its origin and background, (3) the basic optical systems of spectroscopes, spectrometers, and spectrophotometers, (4) the characteristics of wave motion, (5) the…

  10. Future perspective of meson spectroscopy studies at KEK-PS

    International Nuclear Information System (INIS)

    Tsuru, T.

    1992-01-01

    Physics of light-quark meson spectroscopy at present is simply reviewed and a direction of next generation experiment is investigated. A new charge and gamma spectrometer is proposed to push forward next generation physics at KEK-PS. It should have almost 4π acceptance for both charged particles and gamma's and have options of π/K separation and good π 0 /γ separation. (author)

  11. High-field EPR spectroscopy of thermal donors in silicon

    DEFF Research Database (Denmark)

    Dirksen, R.; Rasmussen, F.B.; Gregorkiewicz, T.

    1997-01-01

    Thermal donors generated in p-type boron-doped Czochralski-grown silicon by a 450 degrees C heat treatment have been studied by high-field magnetic resonance spectroscopy. In the experiments conducted at a microwave frequency of 140 GHz and in a magnetic field of approximately 5 T four individual...

  12. International conference on matrix isolation spectroscopy. Extended Abstracts

    Energy Technology Data Exchange (ETDEWEB)

    1977-07-01

    Seventy-five extended abstracts are arranged under the following headings: generation of reactive species and their isolation in matrices, spectra of metal atoms and cluster formation, stable molecules in matrices, Raman- and IR-spectroscopy, high-temperature molecules, reactive matrices, relaxation phenomena studied in matrices, and physical properties of matrices. (DLC)

  13. Trace gas absorption spectroscopy using laser difference-frequency spectrometer for environmental application

    Science.gov (United States)

    Chen, W.; Cazier, F.; Boucher, D.; Tittel, F. K.; Davies, P. B.

    2001-01-01

    A widely tunable infrared spectrometer based on difference frequency generation (DFG) has been developed for organic trace gas detection by laser absorption spectroscopy. On-line measurements of concentration of various hydrocarbons, such as acetylene, benzene, and ethylene, were investigated using high-resolution DFG trace gas spectroscopy for highly sensitive detection.

  14. Raman spectroscopy of triolein under high pressures

    Science.gov (United States)

    Tefelski, D. B.; Jastrzębski, C.; Wierzbicki, M.; Siegoczyński, R. M.; Rostocki, A. J.; Wieja, K.; Kościesza, R.

    2010-03-01

    This article presents results of the high pressure Raman spectroscopy of triolein. Triolein, a triacylglyceride (TAG) of oleic acid, is an unsaturated fat, present in natural oils such as olive oil. As a basic food component and an energy storage molecule, it has considerable importance for food and fuel industries. To generate pressure in the experiment, we used a high-pressure cylindrical chamber with sapphire windows, presented in (R.M. Siegoczyński, R. Kościesza, D.B. Tefelski, and A. Kos, Molecular collapse - modification of the liquid structure induced by pressure in oleic acid, High Press. Res. 29 (2009), pp. 61-66). Pressure up to 750 MPa was applied. A Raman spectrometer in "macro"-configuration was employed. Raman spectroscopy provides information on changes of vibrational modes related to structural changes of triolein under pressure. Interesting changes in the triglyceride C‒H stretching region at 2650-3100 cm-1 were observed under high-pressures. Changes were also observed in the ester carbonyl (C˭ O) stretching region 1700-1780 cm-1 and the C‒C stretching region at 1050-1150 cm-1. The overall luminescence of the sample decreased under pressure, making it possible to set longer spectrum acquisition time and obtain more details of the spectrum. The registered changes suggest that the high-pressure solid phase of triolein is organized as β-polymorphic, as was reported in (C. Akita, T. Kawaguchi, and F. Kaneko, Structural study on polymorphism of cis-unsaturated triacylglycerol: Triolein, J. Phys. Chem. B 110 (2006), pp. 4346-4353; E. Da Silva and D. Rousseau, Molecular order and thermodynamics of the solid-liquid transition in triglycerides via Raman spectroscopy, Phys. Chem. Chem. Phys. 10 (2008), pp. 4606-4613) (with temperature-induced phase transitions). The research has shown that Raman spectroscopy in TAGs under pressure reveals useful information about its structural changes.

  15. Photoacoustic spectroscopy of β-hematin

    International Nuclear Information System (INIS)

    Samson, Edward B; Goldschmidt, Benjamin S; Whiteside, Paul J D; Sudduth, Amanda S M; Custer, John R; Viator, John A; Beerntsen, Brenda

    2012-01-01

    Malaria affects over 200 million individuals annually, resulting in 800 000 fatalities. Current tests use blood smears and can only detect the disease when 0.1–1% of blood cells are infected. We are investigating the use of photoacoustic flowmetry to sense as few as one infected cell among 10 million or more normal blood cells, thus diagnosing infection before patients become symptomatic. Photoacoustic flowmetry is similar to conventional flow cytometry, except that rare cells are targeted by nanosecond laser pulses to induce ultrasonic responses. This system has been used to detect single melanoma cells in 10 ml of blood. Our objective is to apply photoacoustic flowmetry to detection of the malaria pigment hemozoin, which is a byproduct of parasite-digested hemoglobin in the blood. However, hemozoin is difficult to purify in quantities greater than a milligram, so a synthetic analog, known as β-hematin was derived from porcine hemin. The specific purpose of this study is to establish the efficacy of using β-hematin, rather than hemozoin, for photoacoustic measurements. We characterized β-hematin using UV–vis spectroscopy, TEM, and FTIR, then tested the effects of laser irradiation on the synthetic product. We finally determined its absorption spectrum using photoacoustic excitation. UV–vis spectroscopy verified that β-hematin was distinctly different from its precursor. TEM analysis confirmed its previously established nanorod shape, and comparison of the FTIR results with published spectroscopy data showed that our product had the distinctive absorbance peaks at 1661 and 1206 cm −1 . Also, our research indicated that prolonged irradiation dramatically alters the physical and optical properties of the β-hematin, resulting in increased absorption at shorter wavelengths. Nevertheless, the photoacoustic absorption spectrum mimicked that generated by UV–vis spectroscopy, which confirms the accuracy of the photoacoustic method and strongly suggests

  16. Generation Next

    Science.gov (United States)

    Hawkins, B. Denise

    2010-01-01

    There is a shortage of accounting professors with Ph.D.s who can prepare the next generation. To help reverse the faculty deficit, the American Institute of Certified Public Accountants (CPAs) has created the new Accounting Doctoral Scholars program by pooling more than $17 million and soliciting commitments from more than 70 of the nation's…

  17. Generative Contexts

    Science.gov (United States)

    Lyles, Dan Allen

    Educational research has identified how science, technology, engineering, and mathematics (STEM) practice and education have underperforming metrics in racial and gender diversity, despite decades of intervention. These disparities are part of the construction of a culture of science that is alienating to these populations. Recent studies in a social science framework described as "Generative Justice" have suggested that the context of social and scientific practice might be modified to bring about more just and equitable relations among the disenfranchised by circulating the value they and their non-human allies create back to them in unalienated forms. What is not known are the underlying principles of social and material space that makes a system more or less generative. I employ an autoethnographic method at four sites: a high school science class; a farm committed to "Black and Brown liberation"; a summer program geared towards youth environmental mapping; and a summer workshop for Harlem middle school students. My findings suggest that by identifying instances where material affinity, participatory voice, and creative solidarity are mutually reinforcing, it is possible to create educational contexts that generate unalienated value, and circulate it back to the producers themselves. This cycle of generation may help explain how to create systems of justice that strengthen and grow themselves through successive iterations. The problem of lack of diversity in STEM may be addressed not merely by recruiting the best and the brightest from underrepresented populations, but by changing the context of STEM education to provide tools for its own systematic restructuring.

  18. Steam generators

    International Nuclear Information System (INIS)

    Hayden, R.L.J.

    1979-01-01

    Steam generators for nuclear reactors are designed so that deposition of solids on the surface of the inlet side of the tubesheet or the inlet header with the consequent danger of corrosion and eventual tube failure is obviated or substantially reduced. (U.K.)

  19. Quasienergy Spectroscopy of Excitons

    DEFF Research Database (Denmark)

    Johnsen, Kristinn; Jauho, Antti-Pekka

    1999-01-01

    We theoretically study nonlinear optics of excitons under intense THz irradiation. In particular, the linear near-infrared absorption and resonantly enhanced nonlinear sideband generation are described. We predict a rich structure in the spectra which an be interpreted in terms of the quasienergy...

  20. Transient Infrared Emission Spectroscopy

    Science.gov (United States)

    Jones, Roger W.; McClelland, John F.

    1989-12-01

    Transient Infrared Emission Spectroscopy (TIRES) is a new technique that reduces the occurrence of self-absorption in optically thick solid samples so that analytically useful emission spectra may be observed. Conventional emission spectroscopy, in which the sample is held at an elevated, uniform temperature, is practical only for optically thin samples. In thick samples the emission from deep layers of the material is partially absorbed by overlying layers.1 This self-absorption results in emission spectra from most optically thick samples that closely resemble black-body spectra. The characteristic discrete emission bands are severely truncated and altered in shape. TIRES bypasses this difficulty by using a laser to heat only an optically thin surface layer. The increased temperature of the layer is transient since the layer will rapidly cool and thicken by thermal diffusion; hence the emission collection must be correlated with the laser heating. TIRES may be done with both pulsed and cw lasers.2,3 When a pulsed laser is used, the spectrometer sampling must be synchronized with the laser pulsing so that only emission during and immediately after each laser pulse is observed.3 If a cw laser is used, the sample must move rapidly through the beam. The hot, transient layer is then in the beam track on the sample at and immediately behind the beam position, so the spectrometer field of view must be limited to this region near the beam position.2 How much self-absorption the observed emission suffers depends on how thick the heated layer has grown by thermal diffusion when the spectrometer samples the emission. Use of a pulsed laser synchronized with the spectrometer sampling readily permits reduction of the time available for heat diffusion to about 100 acs .3 When a cw laser is used, the heat-diffusion time is controlled by how small the spectrometer field of view is and by how rapidly the sample moves past within this field. Both a very small field of view and a