WorldWideScience

Sample records for atomic collision physics

  1. Theoretical atomic collision physics

    Energy Technology Data Exchange (ETDEWEB)

    Lane, N.F. (Rice Univ., Houston, TX (USA) Rice Univ., Houston, TX (USA). Quantum Inst.)

    1990-01-01

    The theoretical atomic physics at Rice University focuses on obtaining a better understanding of the mechanisms that control inelastic collisions between excited atoms and atoms, molecules and ions. Particular attention is given to systems and processes that are of potential importance to advanced energy technologies. In the current year, significant progress has been made in quantitative studies of: quenching of low-Rydberg Na atoms in thermal energy collisions with He, Ne and Ar atoms; selective excitation resulting from charge transfer in collisions of highly stripped ions of He, Li, C, and with Li, Na and He atoms and H{sub 2} molecules at keV energies; differential elastic and single, and double electron transfer in He{sup ++} collisions with He at keV energies; inelastic electron-transfer in ultra-low-energy-energy (T=8 to 80K) collisions between {sup 3}He{sup +} and {sup 4}He and {sup 4}He{sup +} and {sup 3}He; a formalism for ionization by electron impact of ions in dense, high temperature plasmas.

  2. Plasmas applied atomic collision physics, v.2

    CERN Document Server

    Barnett, C F

    1984-01-01

    Applied Atomic Collision Physics, Volume 2: Plasmas covers topics on magnetically confined plasmas. The book starts by providing the history of fusion research and describing the various approaches in both magnetically and inertially confined plasmas. The text then gives a general discussion of the basic concepts and properties in confinement and heating of a plasma. The theory of atomic collisions that result in excited quantum states, particularly highly ionized impurity atoms; and diverse diagnostic topics such as emission spectra, laser scattering, electron cyclotron emission, particle bea

  3. Case studies in atomic collision physics

    CERN Document Server

    McDaniel, E W

    2013-01-01

    Case Studies in Atomic Collision Physics II focuses on studies on the role of atomic collision processes in astrophysical plasmas, including ionic recombination, electron transport, and position scattering. The book first discusses three-body recombination of positive and negative ions, as well as introduction to ionic recombination, calculation of the recombination coefficient, ions recombining in their parent gas, and three-body recombination at moderate and high gas-densities. The manuscript also takes a look at precision measurements of electron transport coefficients and differential cr

  4. Applied atomic and collision physics special topics

    CERN Document Server

    Massey, H S W; Bederson, Benjamin

    1982-01-01

    Applied Atomic Collision Physics, Volume 5: Special Topics deals with topics on applications of atomic collisions that were not covered in the first four volumes of the treatise. The book opens with a chapter on ultrasensitive chemical detectors. This is followed by separate chapters on lighting, magnetohydrodynamic electrical power generation, gas breakdown and high voltage insulating gases, thermionic energy converters, and charged particle detectors. Subsequent chapters deal with the operation of multiwire drift and proportional chambers and streamer chambers and their use in high energy p

  5. On the utility and ubiquity of atomic collision physics

    International Nuclear Information System (INIS)

    This paper is divided into three parts. In the introduction, we discuss the history and makeup of ICPEAC. In the second part, we discuss the extent of applicability of atomic collision physics. In the third part, we chose one subject (dielectronic excitation) to show the interrelationship of various sub-branches of atomic collision physics. 28 refs., 14 figs

  6. Condensed matter applied atomic collision physics, v.4

    CERN Document Server

    Datz, Sheldon

    1983-01-01

    Applied Atomic Collision Physics, Volume 4: Condensed Matter deals with the fundamental knowledge of collision processes in condensed media.The book focuses on the range of applications of atomic collisions in condensed matter, extending from effects on biological systems to the characterization and modification of solids. This volume begins with the description of some aspects of the physics involved in the production of ion beams. The radiation effects in biological and chemical systems, ion scattering and atomic diffraction, x-ray fluorescence analysis, and photoelectron and Auger spectrosc

  7. Gas lasers applied atomic collision physics, v.3

    CERN Document Server

    McDaniel, E W

    1982-01-01

    Applied Atomic Collision Physics, Volume 3: Gas Lasers describes the applications of atomic collision physics in the development of many types of gas lasers. Topics covered range from negative ion formation in gas lasers to high-pressure ion kinetics and relaxation of molecules exchanging vibrational energy. Ion-ion recombination in high-pressure plasmas is also discussed, along with electron-ion recombination in gas lasers and collision processes in chemical lasers.Comprised of 14 chapters, this volume begins with a historical summary of gas laser developments and an overview of the basic ope

  8. Sixteenth International Conference on the physics of electronic and atomic collisions

    International Nuclear Information System (INIS)

    This report contains abstracts of papers on the following topics: photons, electron-atom collisions; electron-molecule collisions; electron-ion collisions; collisions involving exotic species; ion- atom collisions, ion-molecule or atom-molecule collisions; atom-atom collisions; ion-ion collisions; collisions involving rydberg atoms; field assisted collisions; collisions involving clusters and collisions involving condensed matter

  9. Sixteenth International Conference on the physics of electronic and atomic collisions

    Energy Technology Data Exchange (ETDEWEB)

    Dalgarno, A.; Freund, R.S.; Lubell, M.S.; Lucatorto, T.B. (eds.)

    1989-01-01

    This report contains abstracts of papers on the following topics: photons, electron-atom collisions; electron-molecule collisions; electron-ion collisions; collisions involving exotic species; ion- atom collisions, ion-molecule or atom-molecule collisions; atom-atom collisions; ion-ion collisions; collisions involving rydberg atoms; field assisted collisions; collisions involving clusters and collisions involving condensed matter.

  10. Topics in atomic collision theory

    CERN Document Server

    Geltman, Sydney; Brueckner, Keith A

    1969-01-01

    Topics in Atomic Collision Theory originated in a course of graduate lectures given at the University of Colorado and at University College in London. It is recommended for students in physics and related fields who are interested in the application of quantum scattering theory to low-energy atomic collision phenomena. No attention is given to the electromagnetic, nuclear, or elementary particle domains. The book is organized into three parts: static field scattering, electron-atom collisions, and atom-atom collisions. These are in the order of increasing physical complexity and hence necessar

  11. Atomic collisions involving pulsed positrons

    DEFF Research Database (Denmark)

    Merrison, J. P.; Bluhme, H.; Field, D.;

    2000-01-01

    Conventional slow positron beams have been widely and profitably used to study atomic collisions and have been instrumental in understanding the dynamics of ionization. The next generation of positron atomic collision studies are possible with the use of charged particle traps. Not only can large...... instantaneous intensities be achieved with in-beam accumulation, but more importantly many orders of magnitude improvement in energy and spatial resolution can be achieved using positron cooling. Atomic collisions can be studied on a new energy scale with unprecedented precion and control. The use of...... accelerators for producing intense positron pulses will be discussed in the context of atomic physics experiments....

  12. Atoms, molecules and optical physics 2. Molecules and photons - Spectroscopy and collisions

    Energy Technology Data Exchange (ETDEWEB)

    Hertel, Ingolf V.; Schulz, Claus-Peter [Max-Born-Institut fuer Nichtlineare Optik und Kurzzeitspektroskopie im Forschungsverbund Berlin e.V. (Germany)

    2015-09-01

    This is the second volume of textbooks on atomic, molecular and optical physics, aiming at a comprehensive presentation of this highly productive branch of modern physics as an indispensable basis for many areas in physics and chemistry as well as in state of the art bio- and material-sciences. It primarily addresses advanced students (including PhD students), but in a number of selected subject areas the reader is lead up to the frontiers of present research. Thus even the active scientist is addressed. This volume 2 introduces lasers and quantum optics, while the main focus is on the structure of molecules and their spectroscopy, as well as on collision physics as the continuum counterpart to bound molecular states. The emphasis is always on the experiment and its interpretation, while the necessary theory is introduced from this perspective in a compact and occasionally somewhat heuristic manner, easy to follow even for beginners.

  13. Collision-produced atomic states

    International Nuclear Information System (INIS)

    The last 10-15 years have witnessed the development of a new, powerful class of experimental techniques for atomic collision studies, allowing partial or complete determination of the state of the atoms after a collision event, i.e. the full set of quantum-mechanical scattering amplitudes or - more generally - the density matrix describing the system. Evidently, such studies, involving determination of alignment and orientation parameters, provide much more severe tests of state-of-the-art scattering theories than do total or differential cross section measurements which depend on diagonal elements of the density matrix. The off-diagonal elements give us detailed information about the shape and dynamics of the atomic states. Therefore, close studies of collision-produced atomic states are currently leading to deeper insights into the fundamental physical mechanisms governing the dynamics of atomic collision events. The first part of the lectures deals with the language used to describe atomic states, while the second part presents a selection of recent results for model systems which display fundamental aspects of the collision physics in particularly instructive ways. I shall here restrict myself to atom-atom collisions. The discussion will be focused on states decaying by photon emission though most of the ideas can be easily modified to include electron emission as well. (orig./AH)

  14. Atomic Physics

    CERN Document Server

    Foot, Christopher J

    2007-01-01

    This text will thoroughly update the existing literature on atomic physics. Intended to accompany an advanced undergraduate course in atomic physics, the book will lead the students up to the latest advances and the applications to Bose-Einstein Condensation of atoms, matter-wave inter-ferometry and quantum computing with trapped ions. The elementary atomic physics covered in the early chapters should be accessible to undergraduates when they are first introduced to the subject. To complement. the usual quantum mechanical treatment of atomic structure the book strongly emphasizes the experimen

  15. Atomic physics

    CERN Document Server

    Born, Max

    1989-01-01

    The Nobel Laureate's brilliant exposition of the kinetic theory of gases, elementary particles, the nuclear atom, wave-corpuscles, atomic structure and spectral lines, electron spin and Pauli's principle, quantum statistics, molecular structure and nuclear physics. Over 40 appendices, a bibliography, numerous figures and graphs.

  16. Atomic physics

    International Nuclear Information System (INIS)

    Research activities in atomic physics at Lawrence Berkeley Laboratory during 1976 are described. Topics covered include: experiments on stored ions; test for parity violation in neutral weak currents; energy conservation and astrophysics; atomic absorption spectroscopy, atomic and molecular detectors; theoretical studies of quantum electrodynamics and high-z ions; atomic beam magnetic resonance; radiative decay from the 23Po,2 levels of helium-like argon; quenching of the metastable 2S/sub 1/2/ state of hydrogen-like argon in an external electric field; and lifetime of the 23Po level of helium-like krypton

  17. Atomic and molecular collision processes

    International Nuclear Information System (INIS)

    530Accomplishments during the course of a 44-month program of code development and high precision calculations for electron collisions with atoms, atomic ions, and molecules are summarized. In electron-atom and -ion collisions, we were primarily concerned with the fundamental physics of the process that controls excitation in high temperature plasmas. In the molecular work, we pursued the development of techniques for accurate calculations of ro-vibrational excitation of polyatomic molecules, to the modeling of gas-phase laser systems. Highlights from the seven technical paper published as a result of this contract include: The resolution of a long history of unexplained anomalies and experimental/theoretical discrepancies by a demonstration that the Coulomb phase must be included in scattering amplitudes for electron-ion collisions. Definitive close-coupling calculations of cross sections for electron impact excitation of Be+, using a very elaborate expansion for the collision system and inclusion of both one- and two-body terms for the effect of core polarization. Detailed state-of-the-art calculations for electron-impact excitation of the sodium-like ion A ell 2+ that included core-polarization interactions, and which also produced new data on bound-state energy levels for the magnesium-like ion A ell + and oscillator strengths for A ell 2+. Partial cross sections for excitation of the 3p level of sodium at energies just above threshold calculated using a four-state close-coupling approach, including both total cross sections and those for excitation as a function of the change in the spin and orbital angular momentum projection quantum numbers of the target electron. Generalization of our electron-molecule scattering code to carry out full vibrational close-coupling calculations with an exact treatment of exchange and with a parameter-free representation of correlation and polarization interactions, and application to HF and H2

  18. Electron-Atom Collisions in Gases

    Science.gov (United States)

    Kraftmakher, Yaakov

    2013-01-01

    Electron-atom collisions in gases are an aspect of atomic physics. Three experiments in this field employing a thyratron are described: (i) the Ramsauer-Townsend effect, (ii) the excitation and ionization potentials of xenon and (iii) the ion-electron recombination after interrupting the electric discharge.

  19. Atomic physics

    Energy Technology Data Exchange (ETDEWEB)

    Livingston, A.E.; Kukla, K.; Cheng, S. [Univ. of Toledo, OH (United States)] [and others

    1995-08-01

    In a collaboration with the Atomic Physics group at Argonne and the University of Toledo, the Atomic Physics group at the University of Notre Dame is measuring the fine structure transition energies in highly-charged lithium-like and helium-like ions using beam-foil spectroscopy. Precise measurements of 2s-2p transition energies in simple (few-electron) atomic systems provide stringent tests of several classes of current atomic- structure calculations. Analyses of measurements in helium-like Ar{sup 16+} have been completed, and the results submitted for publication. A current goal is to measure the 1s2s{sup 3}S{sub 1} - 1s2p{sup 3}P{sub 0} transition wavelength in helium-like Ni{sup 26+}. Measurements of the 1s2s{sup 2}S{sub 1/2} - 1s2p{sup 2}P{sub 1/2,3/2} transition wavelengths in lithium-like Kr{sup 33+} is planned. Wavelength and lifetime measurements in copper-like U{sup 63+} are also expected to be initiated. The group is also participating in measurements of forbidden transitions in helium-like ions. A measurement of the lifetime of the 1s2s{sup 3}S{sub 1} state in Kr{sup 34+} was published recently. In a collaboration including P. Mokler of GSI, Darmstadt, measurements have been made of the spectral distribution of the 2E1 decay continuum in helium-like Kr{sup 34+}. Initial results have been reported and further measurements are planned.

  20. The collision between two hydrogen atoms

    CERN Document Server

    Ray, Hasi

    2013-01-01

    The electron-electron correlation term in two-atomic collision is the most important, most difficult term to obtain the effective interatomic potential. Generally the H and H collision is a four center problem. It is extremely difficult to compute the electron-electron correlation term to include the effect of exchange or antisymmetry between two system electrons exactly. All the two-atomic collision related theoretical data differ from each other due to its difference in approximating the electron-electron correlation term. I invent a trick to evaluate the term exactly. Earlier the positronium (Ps) and H system was easily approximated as a three center problem due to the light mass of Ps. My new code for H-H collision using the ab-initio and exact static-exchange model (SEM) can reproduce exactly the same data of Ps and H system just by using the appropriate atomic parameters. The success of the present trick makes the foundation of a big monument in cold and low energy atomic collision physics. The Feshbach...

  1. Photonic, Electronic and Atomic Collisions

    Science.gov (United States)

    Fainstein, Pablo D.; Lima, Marco Aurelio P.; Miraglia, Jorge E.; Montenegro, Eduardo C.; Rivarola, Roberto D.

    2006-11-01

    Plenary. Electron collisions - past, present and future / J. W. McConkey. Collisions of slow highly charged ions with surfaces / J. Burgdörfer ... [et al.]. Atomic collisions studied with "reaction-microscopes" / R. Moshammer ... [et al.]. Rydberg atoms: a microscale laboratory for studying electron-molecule tnteractions / F. B. Dunning -- Collisions involvintg photons. Quantum control of photochemical reaction dynamics and molecular functions / M. Yamaki ... [et al.]. Manipulating and viewing Rydberg wavepackets / R. R. Jones. Angle-resolved photoelectrons as a probe of strong-field interactions / M. Vrakking. Ultracold Rydberg atoms in a structured environment / I. C. H. Liu and J. M. Rost. Synchrotron-radiation-based recoil ion momentum spectroscopy of laser cooled and trapped cesium atoms / L. H. Coutinho. Reconstruction of attosecond pulse trains / Y. Mairesse ... [et al.]. Selective excitation of metastable atomic states by Femto- and attosecond laser pulses / A. D. Kondorskiy. Accurate calculations of triple differential cross sections for double photoionization of the hygrogen molecule / W. Vanroose ... [et al.]. Double and triple photoionization of Li and Be / J. Colgan, M. S. Pindzola and F. Robicheaux. Few/many body dynamics in strong laser fields / J. Zanghellini and T. Brabec. Rescattering-induced effects in electron-atom scattering in the presence of a circularly polarized laser field / A. V. Flegel ... [et al.]. Multidimensional photoelectron spectroscopy / P. Lablanquie ... [et al.]. Few photon and strongly driven transitions in the XUV and beyond / P. Lambropoulos, L. A. A. Nikolopoulos and S. I. Themelis. Ionization dynamics of atomic clusters in intense laser pulses / U. Saalmann and J. M. Rost. On the second order autocorrelation of an XUV attosecond pulse train / E. P. Benis ... [et al.]. Evidence for rescattering in molecular dissociation / I. D. Williams ... [et al.]. Photoionizing ions using synchrotron radiation / R. Phaneuf. Photo double

  2. Multiple Electron Capture Processes in Slow Collisions of Ar9+ Ions with Na Atoms

    Institute of Scientific and Technical Information of China (English)

    ZhuXiaolong; ShaShan; LiuHuiping; WeiBaoren; MaXinwen; WangZhengling; CaoShiping; QianDongbing; YangZhihu

    2003-01-01

    Slow collisions of highly charged ions with neutral atoms and molecules are of great importance in basic atomic collision physics, Recently, we built a new research facility for atomic physics at the Institute of Modern Physics. We report here the multiple electron transfer processes in collisions of Ar9+ with Na gas target at energy of 180 keV.

  3. The Kansas State atomic collision physics facility dedicated to the studies of atomic interactions of highly charged, low and medium energy ions

    International Nuclear Information System (INIS)

    We discuss our facility at Kansas State University, which is perfectly suited for studies of atomic collisions involving highly charged, low and medium energy ions. It should be fully operational by next year and will be operated as a user facility. We encourage collaborations with in-house researchers, because it facilitates communications and experiments. 13 refs., 3 figs

  4. Atomic collisions under extreme conditions in space

    International Nuclear Information System (INIS)

    In space, atoms and molecules are often placed under the extreme conditions which are very difficult to be realized on Earth. For instance, extremely hot and dense plasmas are found in and around various stellar objects (e.g., neutron stars) on one hand and extremely cold and diffuse gases prevail in interstellar space on the other. There is so strong a magnetic field that electron clouds in atoms and molecules are distorted. The study of atomic collisions under the extreme conditions is not only helpful in understanding the astrophysical environment but also reveals new aspects of the physics of atoms and molecules. This paper is an invitation to the study. (References are not exhaustive but only provide a clue with which more details can be found.) (author)

  5. Observation of atomic collisions in crystalline solids

    CERN Document Server

    Nelson, R S; Gevers, R

    2013-01-01

    The Observation of Atomic Collisions in Crystalline Solids presents a critical account of the more important experiments which have provided the basis for a better understanding of atomic collision phenomena in crystalline solids. Collisions have been divided into two artificial regimes; primary collisions which deal with the interaction of the incident particles with the solid, and secondary collisions which deal with those events which occur as a result of lattice atoms recoiling from primary encounters. Although the book is intended principally for the experimentalist some simple theoretica

  6. The Atomic Physics Center of Toulouse

    International Nuclear Information System (INIS)

    The research program was concerned with the aerosol and atmospheric exchange physics and, in atomic physics essentially with: atomic collisions, postluminescence in gases, discharges in gases at medium and high pressure, the electric arc, dielectric physics, and radiation transport in matter

  7. Rydberg atom ionization by slow collisions with alkali element atoms

    International Nuclear Information System (INIS)

    A new mechanism for ionization of highexcited atoms due to the electron capture into the autoionization state of a negative ion is suggested. Calculations of cross-sections and the ionization rate for sodium and lithium atoms collisions are performed

  8. Cold heteronuclear atom-ion collisions

    CERN Document Server

    Zipkes, Christoph; Ratschbacher, Lothar; Sias, Carlo; Köhl, Michael

    2010-01-01

    We study cold heteronuclear atom ion collisions by immersing a trapped single ion into an ultracold atomic cloud. Using ultracold atoms as reaction targets, our measurement is sensitive to elastic collisions with extremely small energy transfer. The observed energy-dependent elastic atom-ion scattering rate deviates significantly from the prediction of Langevin but is in full agreement with the quantum mechanical cross section. Additionally, we characterize inelastic collisions leading to chemical reactions at the single particle level and measure the energy-dependent reaction rate constants. The reaction products are identified by in-trap mass spectrometry, revealing the branching ratio between radiative and non-radiative charge exchange processes.

  9. Atomic collision dynamics in optical lattices

    CERN Document Server

    Piilo, J; Berg-Sørensen, K

    2001-01-01

    We simulate collisions between two atoms, which move in an optical lattice under the dipole-dipole interaction. The model describes simultaneously the two basic dynamical processes, namely the Sisyphus cooling of single atoms, and the light-induced inelastic collisions between them. We consider the J=1/2 -> J=3/2 laser cooling transition for Cs, Rb and Na. We find that the hotter atoms in a thermal sample are selectively lost or heated by the collisions, which modifies the steady state distribution of atomic velocities, reminiscent of the evaporative cooling process.

  10. Withdrawal of Chinese Physics Letters 28 (2011) 043401 “Measurement of Absolute Atomic Collision Cross Section with Helium Using 87Rb Atoms Confined in Magneto-Optic and Magnetic Traps” by WANG Ji-Cheng et al.

    Institute of Scientific and Technical Information of China (English)

    WANG Ji-Cheng; ZHOU Ke-Ya; WANG Yue-Yuan; LIAO Qing-Hong; LIU Shu-Tian

    2011-01-01

    We announce the withdrawal of the article entitled “Measurement of Absolute Atomic Collision Cross Section with Helium Using 87Rb Atoms Confined in Magneto-Optic and Magnetic Traps”,which was published in Chinese Physics Letters [28(4)(2011)043401].The first author,Jicheng Wang,had participated in related research with Professor Kirk Madison's group at the Department of Physics & Astronomy at the University of British Columbia,Canada from September 2008 to February 2010.Even though consent had been granted for some of the experimental data to be used by Jicheng Wang in his own thesis,its publication had not been authorized.We apologize to Professor K.Madison for the misunderstanding,and to Chinese Physics Letters and the readers of Chinese Physics Letters for any inconvenience this mistake may have caused.%We announce the withdrawal of the article entitled "Measurement of Absolute Atomic Collision Cross Section with Helium Using 87Rb Atoms Confined in Magneto-Optic and Magnetic Traps", which was published in Chinese Physics Letters [28(4) (2011)043401]. The first author, Jicheng Wang, had participated in related research with Professor Kirk Madison's group at the Department of Physics & Astronomy at the University of British Columbia, Canada from September 2008 to February 2010. Even though consent had been granted for some of the experimental data to be used by Jicheng Wang in his own thesis, its publication had not been authorized. We apologize to Professor K. Madison for the misunderstanding, and to Chinese Physics Letters ad the readers of Chinese Physics Letters for any inconvenience this mistake may have caused.

  11. Experimental atomic physics

    International Nuclear Information System (INIS)

    The atomic structure and collision phenomena of highly stripped ions in the range Z = 6 to 35 were studied. Charge-transfer and multiple-electron-loss cross sections were determined. Absolute x-ray-production cross sections for incident heavy ions were measured. 10 figures, 1 table

  12. Advances in atomic physics

    Directory of Open Access Journals (Sweden)

    Tharwat M. El-Sherbini

    2015-09-01

    Full Text Available In this review article, important developments in the field of atomic physics are highlighted and linked to research works the author was involved in himself as a leader of the Cairo University – Atomic Physics Group. Starting from the late 1960s – when the author first engaged in research – an overview is provided of the milestones in the fascinating landscape of atomic physics.

  13. Advances in atomic physics

    OpenAIRE

    Tharwat M. El-Sherbini

    2015-01-01

    Graphical abstract In this review article, important developments in the field of atomic physics are highlighted and linked to research works the author was involved in himself as a leader of the Cairo University – Atomic Physics Group. Starting from the late 1960s – when the author first engaged in research - an overview is provided of the milestones in the fascinating landscape of atomic physics.

  14. Transition rates in proton - Rydberg atom collisions

    Science.gov (United States)

    Vrinceanu, Daniel

    2016-05-01

    Monte Carlo simulations for energy and angular momentum transfer processes in proton - Ryderg atom collisions were performed and the corresponding rates are reported.The relevance of these rates in the context of cosmological recombination is discussed. The rates are contrasted with the similar rates in electron - Rydberg atom collisions. This work has been supported by National Science Foundation through grants for the Center for Research on Complex Networks (HRD-1137732) and Research Infrastructure for Science and Engineering (RISE) (HRD-1345173).

  15. Division of atomic physics

    International Nuclear Information System (INIS)

    The Division of Atomic Physics, Lund Institute of Technology (LTH), is responsible for the basic physics teaching in all subjects at LTH and for specialized teaching in Optics, Atomic Physics, Atomic and Molecular Spectroscopy and Laser Physics. The Division has research activities in basic and applied optical spectroscopy, to a large extent based on lasers. It is also part of the Physics Department, Lund University, where it forms one of eight divisions. Since the beginning of 1980 the research activities of our division have been centred around the use of lasers. The activities during the period 1991-1992 is described in this progress reports

  16. Cross section data for electron collisions in plasma physics

    Energy Technology Data Exchange (ETDEWEB)

    Marinkovic, B P [Institute of Physics, Belgrade, P. O. Box 68, Pregrevica 118, 11080 Belgrade (Serbia); Pejcev, V [Institute of Physics, Belgrade, P. O. Box 68, Pregrevica 118, 11080 Belgrade (Serbia); Filipovic, D M [Institute of Physics, Belgrade, P. O. Box 68, Pregrevica 118, 11080 Belgrade (Serbia); Sevic, D [Institute of Physics, Belgrade, P. O. Box 68, Pregrevica 118, 11080 Belgrade (Serbia); Milosavljevic, A R [Institute of Physics, Belgrade, P. O. Box 68, Pregrevica 118, 11080 Belgrade (Serbia); Milisavljevic, S [Institute of Physics, Belgrade, P. O. Box 68, Pregrevica 118, 11080 Belgrade (Serbia); Rabasovic, M S [Institute of Physics, Belgrade, P. O. Box 68, Pregrevica 118, 11080 Belgrade (Serbia); Pavlovic, D [Institute of Physics, Belgrade, P. O. Box 68, Pregrevica 118, 11080 Belgrade (Serbia); Maljkovic, J B [Institute of Physics, Belgrade, P. O. Box 68, Pregrevica 118, 11080 Belgrade (Serbia)

    2007-10-15

    We present a survey of cross section data for electron collisions used in plasma physics. Needs for cross section data have been identified in different fields of plasma physics and a brief review of existing data on electron/radical data has been presented. Experimental capabilities and recent results obtained in the Belgrade Laboratory for Atomic Collision Processes have been discussed.

  17. Experimental atomic and molecular physics research

    International Nuclear Information System (INIS)

    The Atomic Physics research in the Physics Division consists of five ongoing experimental programs: dissociation and other interactions of energetic molecular ions in solid and gaseous targets; beam-foil research and collision dynamics of heavy ions; photoionization-photoelectron research; spectroscopy of free atoms and molecules, high precision laser-rf double-resonance spectroscopy with atomic and molecular beams; and Moessbauer effect research

  18. Collision rates and new physics

    International Nuclear Information System (INIS)

    This talk provides an introduction to event rates in a variety of collisions available for high energy physics experiments. Comparison is made between different beams as sources for the same physics. Specific examples are Higgs and supersymmetry searches. Attention is paid to initial states with e+e, eγ, eq, qq, gg, W+W-, bb and t anti t. 27 references

  19. Atomic and Molecular Physics

    OpenAIRE

    Cohen-Tannoudji, Claude

    2015-01-01

    When physicists began to explore the world of atoms more precisely, as they endeavoured to understand its structure and the laws governing its behaviour, they soon encountered serious difficulties. Our intuitive concepts, based on our daily experience of the macroscopic world around us, proved to be completely erroneous on the atomic scale; the atom was incomprehensible within the framework of classical physics. In order to uncover these new mysteries, after a great deal of trial and error, e...

  20. Topics in atomic physics

    CERN Document Server

    Burkhardt, Charles E

    2006-01-01

    The study of atomic physics propelled us into the quantum age in the early twentieth century and carried us into the twenty-first century with a wealth of new and, in some cases, unexplained phenomena. Topics in Atomic Physics provides a foundation for students to begin research in modern atomic physics. It can also serve as a reference because it contains material that is not easily located in other sources. A distinguishing feature is the thorough exposition of the quantum mechanical hydrogen atom using both the traditional formulation and an alternative treatment not usually found in textbooks. The alternative treatment exploits the preeminent nature of the pure Coulomb potential and places the Lenz vector operator on an equal footing with other operators corresponding to classically conserved quantities. A number of difficult to find proofs and derivations are included as is development of operator formalism that permits facile solution of the Stark effect in hydrogen. Discussion of the classical hydrogen...

  1. Role of atomic collisions in fusion

    International Nuclear Information System (INIS)

    Atomic physics issues have played a large role in controlled fusion research. A general discussion of the present role of atomic processes in both magnetic and inertial controlled fusion work is presented

  2. Atomic collisions in fusion plasmas involving multiply charged ions

    International Nuclear Information System (INIS)

    A short survey is given on atomic collisions involving multiply charged ions. The basic features of charge transfer processes in ion-ion and ion-atom collisions relevant to fusion plasmas are discussed. (author)

  3. Positronium collisions with rare-gas atoms

    CERN Document Server

    Gribakin, G F; Wilde, R S; Fabrikant, I I

    2015-01-01

    We calculate elastic scattering of positronium (Ps) by the Xe atom using the recently developed pseudopotential method [Fabrikant I I and Gribakin G F 2014 Phys. Rev. A 90 052717] and review general features of Ps scattering from heavier rare-gas atoms: Ar, Kr and Xe. The total scattering cross section is dominated by two contributions: elastic scattering and Ps ionization (break-up). To calculate the Ps ionization cross sections we use the binary-encounter method for Ps collisions with an atomic target. Our results for the ionization cross section agree well with previous calculations carried out in the impulse approximation. Our total Ps-Xe cross section, when plotted as a function of the projectile velocity, exhibits similarity with the electron-Xe cross section for the collision velocities higher than 0.8 a.u., and agrees very well with the measurements at Ps velocities above 0.5 a.u.

  4. Collisions of Rydberg Atoms with Charged Particles

    Science.gov (United States)

    MacAdam, Keith B.

    2000-10-01

    The long range of Coulomb interactions, together with the large size, long radiative lifetimes and high state densities of highly excited Rydberg atoms, results in inelastic collision cross sections of prodigious size -- often large enough to outweigh small number densities in astrophysica and cool laboratory plasmas -- and in other unusual features. This talk will provide: (a) a brief survey of the significant features of collisions between electron or positive ions and state-selected Rydberg atoms and of recent experiments( O. Makarov and K.B. MacAdam, Phys. Rev. A 60), 2131-8 (1999); and K.B. MacAdam, J.C. Day and D.M. Homan, Comm. At. Mol. Phys./Comm. Mod. Phys. 1(2), Part D, 57-73 (1999). to investigate them; (b) an introduction to some of the special techniques that have been developed(J.L. Horn, D.M. Homan, C.S. Hwang, W.L. Fuqua III and K.B. MacAdam, Rev. Sci. Instrum. 69), 4086-93 (1998). for preparation, manipulation and detection of Rydberg atoms; and (c) a glimpse at new directions in Rydberg atom collision research.

  5. Electron collisions with coherently prepared atomic targets

    Energy Technology Data Exchange (ETDEWEB)

    Trajmar, S.; Kanik, I.; LeClair, L.R.; Khakoo, M.S. [California Inst. of Tech., Pasadena, CA (United States). Jet Propulsion Lab.; Bray, I.; Fursa, D. [Flinders Univ. of South Australia, Adelaide (Australia). Electronics Structure of Materials Centre; Csanak, G. [Los Alamos National Lab., NM (United States)

    1998-02-01

    The subject of electron scattering by laser-excited atoms is briefly reviewed. To demonstrate some aspects of these electron collision processes, the authors describe the procedures and the results of a joint experimental and theoretical study concerning elastic scattering by coherently excited {sup 138}Ba (...6s6p {sup 1}P{sub 1}) atoms. Examples of experimental and theoretical collision parameters and magnetic sublevel differential cross sections for elastic scattering are given and compared. The convergent close coupling calculations (with the neglect of spin-orbit interaction) are in good agreement with experiment at 20 eV impact energy and 10, 15 and 20{degree} scattering angles and can be expected to yield reliable integral magnetic sublevel and alignment creation cross sections. The role of these quantities in plasma polarization spectroscopy is pointed out.

  6. Atomic collision databases and data services -- A survey

    International Nuclear Information System (INIS)

    Atomic collision databases and data services constitute an important resource for scientific and engineering applications such as astrophysics, lighting, materials processing, and fusion energy, as well as an important knowledge base for current developments in atomic collision physics. Data centers and research groups provide these resources through a chain of efforts that include producing and collecting primary data, performing evaluation of the existing data, deducing scaling laws and semiempirical formulas to compactly describe and extend the data, producing the recommended sets of data, and providing convenient means of maintaining, updating, and disseminating the results of this process. The latest efforts have utilized modern database, storage, and distribution technologies including the Internet and World Wide Web. Given here is an informal survey of how these resources have developed, how they are currently characterized, and what their likely evolution will lead them to become in the future

  7. Investigations in atomic physics by heavy ion projectiles

    International Nuclear Information System (INIS)

    Investigations in atomic physics by high-energy heavy ions are discussed. The main attention is paid to collision mechanisms (direct Coulomb interaction, quasi-molecular collision mechanism and other models) and the structure of highly ionized and excited atoms. Some problems of fundamental issues (Lamb shift of H-like heavy ions, the superheavy quasi-atoms and the position production in supercritical fields) are conside-- red in detail

  8. Spin Dependent Collision of Ultracold Metastable Atoms

    CERN Document Server

    Uetake, Satoshi; Doyle, John M; Takahashi, Yoshiro

    2015-01-01

    Spin-polarized metastable atoms of ultracold ytterbium are trapped at high density and their inelastic collisional properties are measured. We reveal that in collisions of Yb(3P2) with Yb(1S0) there is relatively weak inelastic loss, but with a significant spin-dependence consistent with Zeeman sublevel changes as being the dominant decay process. This is in strong contrast to our observations of Yb(3P2)-Yb(3P2) collisional loss, which are, at low field, much more rapid and have essentially no spin dependence. Our results give a guideline to use the 3P2 states in many possible applications.

  9. Phase dynamics in a binary-collisions atom laser scheme

    OpenAIRE

    Zobay, O.; Meystre, P.

    1997-01-01

    Various aspects of the phase dynamics of an atom laser scheme based on binary collisions are investigated. Analytical estimates of the influence of elastic atom-atom collisions on the laser linewidth are given, and linewidths achievable in a recently proposed atom laser scheme [Phys. Rev. A 56, 2989 (1997)] are evaluated explicitly. The extent to which a relative phase can be established between two interfering atom lasers, as well as the properties of that phase, are also investigated.

  10. Proceedings of the 2. Latin American Meeting on Atomic, Molecular and Electronic Collisions

    International Nuclear Information System (INIS)

    Annals of the II Latin American Meeting on Atomic, Molecular and Electronic Collisions. Over than 50 people from Latin America participated on this meeting giving talks on different subjects (theoretical and experimental), related to atomic and molecular physics, as well as, nuclear physics. (A.C.A.S.)

  11. Collision physics with highly stripped slow ions

    International Nuclear Information System (INIS)

    A review about recent studies with highly stripped heavy ions is given. Its scope is limited to mainly inner shell processes and slow collisions compared to the Bohr velocity of electrons in these shells. The processes discussed are: population of excited states by electron capture in asymmetric collision systems; electron capture and excitation in symmetric collisions with an emphasis on the impact parameter dependence of K- to L-shell and K- to K-shell vacancy transfer; the interference structure in the quasimolecular X-rays from slow hydrogen-like ion-atom collisions which is used for direct spectroscopy of quasimolecular energies. (Auth.)

  12. Heavy particle atomic collisions in astrophysics: Beyond H and He targets

    Energy Technology Data Exchange (ETDEWEB)

    Stancil, P.C.; Krstic, P.S.; Schultz, D.R.

    1998-06-01

    The physical conditions relating to the emission of x-rays from Jovian and cometary atmospheres and to supernova ejecta are briefly described. Emphasis is placed on elucidating the relevance and importance of atomic collision processes, the availability of data, and the outstanding data needs for modeling these environments. Some preliminary theoretical studies of electron capture for important collisions systems, involving molecular and atomic metal targets, are presented.

  13. [Electron transfer, ionization, and excitation in atomic collisions]: Progress report

    International Nuclear Information System (INIS)

    The fundamental processes of electron transfer, ionization, and excitation in ion-atom collisions are being studied. These collision processes are treated in the context of simple one- or two-electron systems in order to provide unambiguous results and reveal more clearly the collisional mechanisms. As outlined in the original proposal, three coupled-state calculations are being carried out over the present three-year period: a Sturmian-pseudostate study of ionization in collisions between protons and the hydrogenic ions He+, Li2+, Be3+, ...; a triple-center, atomic-state study of ionization in collisions between α particles and H(ls) atoms and between protons and He+(ls) ions; and an atomic-state study of electron transfer and excitation in collisions between protons and neutral He atoms. 12 refs

  14. Production of ultra slow antiprotons, its application to atomic collisions and atomic spectroscopy - ASACUSA project

    International Nuclear Information System (INIS)

    The Atomic Spectroscopy And Collisions Using Slow Antiprotons (ASACUSA) project aims at studying collision dynamics with slow antiprotons and high precision spectroscopy of antiprotonic atoms. To realize these purposes, the production of high quality ultra slow antiproton beams is essential, which is achieved by the combination of antiproton decelerator (AD) from 3 GeV to 5 MeV, a radio frequency quadrupole (RFQ) decelerator from 5 MeV to 50 keV, and finally an electromagnetic trap from 50 keV to 10 eV. From the atomic physics point of view, an antiproton is an extremely heavy electron and/or a negatively charged proton, i.e., the antiproton is a unique tool to shed light on collision dynamics from the other side of the world. In addition to this fundamentally important feature, the antiproton has also a big practical advantage, i.e., it annihilates with the target nuclei emitting several energetic pions, which provides high detection efficiency with very good time resolution. Many-body effects which are of great importance to several branches of science will be studied through ionization and antiprotonic atom formation processes under single collision conditions. Various antiprotonic atoms including protonium (p anti-p) are expected to be meta-stable in vacuum, which is never true for those in dense media except for antiprotonic helium. High precision spectroscopy of protonium will for the first time become feasible benefited by this meta-stability. The present review reports briefly the production scheme of ultra slow antiproton beams and several topics proposed in the ASACUSA project

  15. New trends in atomic and molecular physics advanced technological applications

    CERN Document Server

    2013-01-01

    The field of Atomic and Molecular Physics (AMP) has reached significant advances in high–precision experimental measurement techniques. The area covers a wide spectrum ranging from conventional to new emerging multi-disciplinary areas like physics of highly charged ions (HCI), molecular physics, optical science, ultrafast laser technology etc. This book includes the important topics of atomic structure, physics of atomic collision, photoexcitation, photoionization processes, Laser cooling and trapping, Bose Einstein condensation and advanced technology applications of AMP in the fields of astronomy , astrophysics , fusion, biology and nanotechnology. This book is useful for researchers, professors, graduate, post graduate and PhD students dealing with atomic and molecular physics. The book has a wide scope with applications in neighbouring fields like plasma physics, astrophysics, cold collisions, nanotechnology and future fusion energy sources like ITER (international Thermonuclear Experimental Reactor) To...

  16. Theory of ion-atom collisions at high energy, I

    International Nuclear Information System (INIS)

    Electron capture process by an ion from a neutral atom is one of the fundamental problems in the theory of atomic collision physics. Here a brief review is given mainly on the processes of non-radiative and radiative electron capture (charge transfer and REC). The main mechanism which govern the charge transfer process is introduced and the characteristic feature which is predicted by the theory is explained. As for the radiative electron capture process, after introducting the present theories, the full-quantum mechanical theoretical treatment is introduced. The theory leads a result which includes some inconsistency with formulae obtained by guage transformation. The relativistic quantum mechanical treatment is being tried in order to remove this inconsistency. The some results including mass and velocity dependence are reported and discussed. (author)

  17. The state of Atomic Physics

    International Nuclear Information System (INIS)

    This chapter presents the final lecture given at the Eighth International Conference on Atomic Physics held in Sweden in 1982. Discusses (in general terms) new tools, positron investigations, quantum electrodynamics, physical metaphors, Bell's inequalities, quantum mechanics, precision measurements, sensitivity, high-resolution laser spectroscopy, and the theoretical papers given at the conference. Concludes that there are gaps in atomic physics which need to be filled

  18. Innershell ionisation at small impactparameters in proton-atom collisions

    International Nuclear Information System (INIS)

    This thesis concentrates on innershell ionisation in proton-atom collisions. An experiment on K-shell ionisation of argon is described, performed in a gasfilled collision chamber under single collision conditions. Further experiments with carbon and aluminium were performed, the K-shell vacancy production in the collision of protons with these atoms being detected through the measurement of Auger-electrons. A spectrometer with a large solid angle was specially constructed for this and its performance is described. K-shell ionisation accompanying nuclear (p,γ) reactions has also been measured using 26Mg and 27Al. (Auth./C.F.)

  19. Landau quantization effects in ultracold atom-ion collisions

    Science.gov (United States)

    Simoni, Andrea; Launay, Jean-Michel

    2011-12-01

    We study ultracold atom-ion collisions in the presence of an external magnetic field. At low collision energy the field can drastically modify the translational motion of the ion, which follows quantized cyclotron orbits. We present a rigorous theoretical approach for the calculation of quantum scattering amplitudes in these conditions. Collisions in different magnetic field regimes, identified by the size of the cyclotron radius with respect to the range of the interaction potential, are investigated. Our results are important in cases where use of a magnetic field to control the atom-ion collision dynamics is envisioned.

  20. Landau quantization effects in ultracold atom-ion collisions

    International Nuclear Information System (INIS)

    We study ultracold atom-ion collisions in the presence of an external magnetic field. At low collision energy the field can drastically modify the translational motion of the ion, which follows quantized cyclotron orbits. We present a rigorous theoretical approach for the calculation of quantum scattering amplitudes in these conditions. Collisions in different magnetic field regimes, identified by the size of the cyclotron radius with respect to the range of the interaction potential, are investigated. Our results are important in cases where use of a magnetic field to control the atom-ion collision dynamics is envisioned.

  1. Overview on collision processes of highly charged ions with atoms present status and problems

    International Nuclear Information System (INIS)

    This paper provides a brief discussion on the present status of the collision physics of highly charged ions with atoms. The emphasis is on the main achievements in understanding and describing the most important collision processes, and as charge transfer, ionization and Auger-type processes, and even more on those open problems which, due either to their scientific or practical importance, represent challenges to current research in this field. The paper concentrates on general ideas and problems whose development and solutions have advanced or will advance our basic understanding of the collision dynamics of multiply charged ions with atoms

  2. Atom-molecule collisions in an optically trapped gas

    OpenAIRE

    Zahzam, Nassim; Vogt, Thibault; Mudrich, Marcel; Comparat, Daniel; Pillet, Pierre

    2005-01-01

    Cold inelastic collisions between confined cesium (Cs) atoms and Cs$\\_2$ molecules are investigated inside a CO$\\_2$ laser dipole trap. Inelastic atom-molecule collisions can be observed and measured with a rate coefficient of $\\sim 2.5 \\times 10^{-11} $cm$^3$ s$^{-1}$, mainly independent of the molecular ro-vibrational state populated. Lifetimes of purely atomic and molecular samples are essentially limited by rest gas collisions. The pure molecular trap lifetime ranges 0,3-1 s, four times s...

  3. Classical approach in atomic physics

    Energy Technology Data Exchange (ETDEWEB)

    Solov' ev, E.A. [Bogoliubov Laboratory of Theoretical Physics, Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation)

    2011-12-15

    The application of a classical approach to various quantum problems - the secular perturbation approach to quantization of a hydrogen atom in external fields and a helium atom, the adiabatic switching method for calculation of a semiclassical spectrum of a hydrogen atom in crossed electric and magnetic fields, a spontaneous decay of excited states of a hydrogen atom, Gutzwiller's approach to Stark problem, long-lived excited states of a helium atom discovered with the help of Poincare section, inelastic transitions in slow and fast electron-atom and ion-atom collisions - is reviewed. Further, a classical representation in quantum theory is discussed. In this representation the quantum states are treated as an ensemble of classical states. This approach opens the way to an accurate description of the initial and final states in classical trajectory Monte Carlo (CTMC) method and a purely classical explanation of tunneling phenomenon. The general aspects of the structure of the semiclassical series such as renormalization group symmetry, criterion of accuracy and so on are reviewed as well. (author)

  4. Atomic physics and reality

    CERN Multimedia

    1985-01-01

    An account of the long standing debate between Niels Bohr and Albert Einstein regarding the validity of the quantum mechanical description of atomic phenomena.With physicts, John Wheeler (Texas), John Bell (CERN), David Rohm (London), Abner Shimony (Boston), Alain Aspect (Paris)

  5. Landau quantization effects in ultracold atom-ion collisions

    OpenAIRE

    Simoni, Andrea; Launay, Jean-Michel

    2011-01-01

    We study ultracold atom-ion collisions in the presence of an external magnetic field. At low collision energy the field can drastically modify the translational motion of the ion, which follows quantized cyclotron orbits. We present a rigorous theoretical approach for the calculation of quantum scattering amplitudes in these conditions. Collisions in different magnetic field regimes, identified by the size of the cyclotron radius with respect to the range of the interaction potential, are inv...

  6. Energetic ion-atom collisions: early beginnings and recent advances

    International Nuclear Information System (INIS)

    From the discovery of canal rays and radioactivity to the invention of accelerators and the first applications of the Born approximation, some developments which were seminal for the development of ion-atom collisions are described. Collision theory is shown to have played a key role in the evolution of the early quantum theory and of quantum mechanics and its probability interpretation

  7. Scattering processes in atomic physics, nuclear physics, and cosmology

    Science.gov (United States)

    Shchedrin, Gavriil

    The universal way to probe a physical system is to scatter a particle or radiation off the system. The results of the scattering are governed by the interaction Hamiltonian of the physical system and scattered probe. An object of the investigation can be a hydrogen atom immersed in a laser field, heavy nucleus exposed to a flux of neutrons, or space-time metric perturbed by the stress-energy tensor of neutrino flux in the early Universe. This universality of scattering process designates the Scattering Matrix, defined as the unitary matrix of the overlapping in and out collision states, as the central tool in theoretical physics. In this Thesis we present our results in atomic physics, nuclear physics, and cosmology. In these branches of theoretical physics the key element that unifies all of them is the scattering matrix. Additionally, within the scope of Thesis we present underlying ideas responsible for the unification of various physical systems. Within atomic physics problems, namely the axial anomaly contribution to parity nonconservation in atoms, and two-photon resonant transition in a hydrogen atom, it was the scattering matrix which led to the Landau-Yang theorem, playing the central role in these problems. In scattering problems of cosmology and quantum optics we developed and implemented mathematical tools that allowed us to get a new point of view on the subject. Finally, in nuclear physics we were able to take advantage of the target complexity in the process of neutron scattering which led to the formulation of a new resonance width distribution for an open quantum system.

  8. Correlated charge-changing ion-atom collisions

    International Nuclear Information System (INIS)

    This report summarizes the progress and accomplishments in accelerator atomic physics research supported by DOE grant DE-FG02-87ER13778 from February 16, 1990 through February 15, 1993. This work involves the experimental investigation of atomic interactions in collisions of charged projectiles with neutral targets or electrons, with particular emphasis on two-electron interactions and electron-correlation effects. The processes studied are of interest both from fundamental and applied points of view. In the latter case, results are obtained which are relevant to the understanding of laboratory and astrophysical plasmas, highly-excited (Rydberg) and continuum states of atoms and ions, atomic structure effects, the interaction of ions with surfaces, and the development of heavy-ion storage-rings. The results obtained have provided the basis for several M.A. thesis projects at Western Michigan and several Ph.D. dissertation projects are currently underway. Summaries of work completed and work in progress are given below in Section II. This research has resulted in 26 papers (in print and in press), 12 invited presentations at national and international meetings, and 28 contributed presentations as detailed in Section III

  9. Physics of atomic nuclei

    CERN Document Server

    Zelevinsky, Vladimir

    2016-01-01

    This advanced textbook presents an extensive and diverse study of low-energy nuclear physics considering the nucleus as a quantum system of strongly interacting constituents. The contents guide students from the basic facts and ideas to more modern topics including important developments over the last 20 years, resulting in a comprehensive collection of major modern-day nuclear models otherwise unavailable in the current literature. The book emphasizes the common features of the nucleus and other many-body mesoscopic systems currently in the center of interest in physics. The authors have also included full problem sets that can be selected by lecturers and adjusted to specific interests for more advanced students, with many chapters containing links to freely available computer code. As a result, readers are equipped for scientific work in mesoscopic physics.

  10. Ion-atom collisions for materials study

    International Nuclear Information System (INIS)

    The diffusion process of silver in aluminium was studied in thin films as a function of temperature, the most important characteristics of dispersor atoms that technique permits us to study are the atomic mass and depth into the solid. This is possible because when a sample is bombarded with ions of a given energy, the ions are dispersed with different energies for different masses and depths, hence this technique is a useful instrument for research into the physical processes which ocurr in thin films up to depths of several microns, one of the results obtained after the bombardment of the target with protons having an energy of 650 KeV was that when the target reached a temperature of approximately 400C, 800C, 1100C and 1600C during 15 minutes and the spectra of heated and unheated targets were compared it was found that the aluminium peak, the valley, the silver peak and the peak over the silver peak change with the increase of temperature and tend to get mixed, that is to say that silver and the aluminium are diffusing themselves. The analysis is essentially qualitative with this technique we ca also measure the thickness of thin films, the silver thickness was measured (3320A). (author)

  11. MULTIPLY CHARGED IONS COLLISIONS WITH ATOMS INTO EXCITED STATES

    Institute of Scientific and Technical Information of China (English)

    PanGuangyan

    1990-01-01

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

  12. Multichannel eikonal treatment of electron--atom collisions

    International Nuclear Information System (INIS)

    A multichannel treatment of atomic collisions is presented and applied to the excitation of atomic hydrogen and helium by electrons with incident energy above the ionization threshold. The calculated cross sections compare very favorably with other refined theoretical procedures and with various experiments

  13. Measurements of Scattering Processes in Negative Ion- Atom Collisions

    Energy Technology Data Exchange (ETDEWEB)

    Kvale, T. J.

    2000-12-22

    The main research activity is to study various scattering processes which occur in H{sup -} collisions with atomic (specifically, noble gas and atomic hydrogen) targets in the intermediate energy region. These processes include: elastic scattering, single- and double-electron detachment, and target excitation/ionization.

  14. Theoretical atomic and molecular physics: Progress report, July 1, 1988 through June 30, 1989

    International Nuclear Information System (INIS)

    The theoretical atomic and molecular physics program at Rice University emphasizes fundamental questions regarding the structure and collision dynamics of various atomic and molecular systems with some attention given to atomic processes at surfaces. Our activities have been centered on continuing the projects initiated last year as well as beginning some new studies. These include: differential elastic and charge-transfer scattering and alignment and orientation of the excited electron cloud in ion-atom, atom-atom and ion-molecule collisions, using a molecular-orbital representation and both semiclassical and quantal methods; quenching of low-lying Rydberg states of a sodium atom in a collision with a rare-gas atom, using a semiclassical representation; so far, target atoms He, Ne and Ar have been studied; chemiionization and ion-pair formation in a collision of a Li atom with a metastable He atom at intermediate collision energies, using a combination of quantal and semi-classical methods; Penning ionization of alkali atoms Na and K, using advanced Cl and Stieltjes imaging methods; radiative and nonradiative charge-transfer in He+ + H collisions at ultra-low collision energies, using quantal methods; elastic and inelastic processes in electron-molecule collisions, using the continuum-multiple-scattering method; and inelastic collision processes in dense, high-temperature plasmas. Selected highlights of our research progress are briefly summarized in this paper

  15. Time-dependent, lattice approach to atomic collisions

    Energy Technology Data Exchange (ETDEWEB)

    Schultz, D.R. [Oak Ridge National Lab., TN (United States). Physics Div.

    1995-12-31

    Recent progress in developing and applying methods of direct numerical solution of atomic collision problems is described. Various forms of the three-body problem are used to illustrate these techniques. Specifically, the process of ionization in proton-, antiproton-, and electron-impact of atomic hydrogen is considered in applications ranging in computational intensity from collisions simulated in two spatial dimensions to treatment of the three-dimensional, fully correlated two-electron Schroedinger equation. These examples demonstrate the utility and feasibility of treating strongly interacting atomic systems through time-dependent, lattice approaches.

  16. The Underlying Physics in Wetted Particle Collisions

    Science.gov (United States)

    Donahue, Carly; Hrenya, Christine; Davis, Robert

    2008-11-01

    Wetted granular particles are relevant in many industries including the pharmaceutical and chemical industries and has applications to granulation, filtration, coagulation, spray coating, drying and pneumatic transport. In our current focus, we investigate the dynamics of a three-body normal wetted particle collision. In order to conduct collisions we use an apparatus called a ``Stokes Cradle,'' similar to the Newton's Cradle (desktop toy) except that the target particles are covered with oil. Here, we are able to vary the oil thickness, oil viscosity, and material properties. With a three particle collision there are four possible outcomes: fully agglomerated (FA); Newton's Cradle (NC), the striker and the first target ball are agglomerated and the last target ball is separated; Reverse Newton's Cradle (RNC), the striker is separated and the two targets are agglomerated; and fully separated (FS). Varying the properties of the collisions, we have observed all four outcomes. We use elastohydrodynamics as a theoretical basis for modeling the system. We also have considered the glass transition of the oil as the pressure increases upon impact and the cavitation of the oil as the pressure drops below the vapor pressure upon rebound. A toy model has been developed where the collision is modeled as a series of two-body collisions. A qualitative agreement between the toy model and experiments gives insight into the underlying physics.

  17. THE PHYSICAL MECHANISM OF COLLISION BETWEEN SOLITONS

    Institute of Scientific and Technical Information of China (English)

    张卓; 唐翌; 颜晓红

    2001-01-01

    An easy and general way to access more complex soliton phenomena is introduced in this paper. The collisionprocess between two solitons of the KdV equation is investigated in great detail with this novel approach, which is different from the sophisticated method of inverse scattering transformation. A more physical and transparent picture describing the collision of solitons is presented.

  18. Fast ion-atom and ion-molecule collisions

    CERN Document Server

    2013-01-01

    The principal goal of this book is to provide state-of-the art coverage of the non-relativistic three- and four-body theories at intermediate and high energy ion-atom and ion-molecule collisions. The focus is on the most frequently studied processes: electron capture, ionization, transfer excitation and transfer ionization. The content is suitable both for graduate students and experienced researchers. For these collisions, the literature has seen enormous renewal of activity in the development and applications of quantum-mechanical theories. This subject is of relevance in several branches of science and technology, like accelerator-based physics, the search for new sources of energy and high temperature fusion of light ions. Other important applications are in life sciences via medicine, where high-energy ion beams are used in radiotherapy for which a number of storage ring accelerators are in full operation, under construction or planned to be built worldwide. Therefore, it is necessary to review this fiel...

  19. Excitation of atoms and molecules in collisions with fast, highly charged ions

    International Nuclear Information System (INIS)

    This paper discusses the following topics: charge distributions for Ar recoil-ions produced in one- and two-electron capture collisions by Oq+ projectiles; charge distributions of He, Ne, and Ar recoil-ions produced in collisions with 10 to 30 MeV/u N7+ ions; studies of recoil ions produced in collisions of 40 MeV Ar13+ with atomic and molecular targets; two-fragment coincidence studies of molecular dissociation induced by heavy ion collisions; resonant electron transfer to double K-vacancy states in oxygen compounds; quenching of metastable states in fast Mg projectiles; and design and construction of an atomic physics beamline for the ECR ion source

  20. Physics of Atoms and Molecules

    CERN Document Server

    Bransden, B H

    2003-01-01

    New edition of a well-established second and third year textbook for Physics degree students, covering the physical structure and behaviour of atoms and molecules. The aim of this new edition is to provide a unified account of the subject within an undergraduate framework, taking the opportunity to make improvements based on the teaching experience of users of the first edition, and cover important new developments in the subject.

  1. High-energy atomic physics

    CERN Document Server

    Drukarev, Evgeny G

    2016-01-01

    This self-contained text introduces readers to the field of high-energy atomic physics - a new regime of photon-atom interactions in which the photon energies significantly exceed the atomic or molecular binding energies, and which opened up with the recent advent of new synchrotron sources. From a theoretical point of view, a small-parameter characteristic of the bound system emerged, making it possible to perform analytic perturbative calculations that can in turn serve as benchmarks for more powerful numerical computations. The first part of the book introduces readers to the foundations of this new regime and its theoretical treatment. In particular, the validity of the small-parameter perturbation expansion and of the lowest-order approximation is critically reviewed. The following chapters then apply these insights to various atomic processes, such as photoionization as a many-body problem, dominant mechanisms for the production of ions at higher energies, Compton scattering and ionization accompanied b...

  2. K-shell ionization in relativistic ion-atom collisions

    Energy Technology Data Exchange (ETDEWEB)

    Mehler, G.; Soff, G.; Rumrich, K.; Greiner, W.

    1989-08-01

    We present calculations of K-shell ionization probabilities in asymmetric ion-atom collisions at relativistic velocities of the projectile. The time-dependent Dirac equation is represented as a system of coupled differential equations. The transition probabilities are determined using the coordinate space method. This necessitates an extension of the angular momentum coupling compared with nonrelativistic collision systems. Effects of the relativistic projectile motion on the coupling matrix elements and their consequences on K-shell ionization are discussed. (orig.).

  3. K-shell ionization in relativistic ion-atom collisions

    Energy Technology Data Exchange (ETDEWEB)

    Mehler, G.; Rumrich, K.; Greiner, W.; Soff, G.

    1989-02-01

    We present calculations of K-shell ionization probabilities in asymmetric ion-atom collisions at relativistic velocities of the projectile. The time-dependent Dirac equation is represented as a system of coupled differential equations. The transition probabilities are determined using the coordinate space method. This necessitates an extension of the angular momentum coupling compared with nonrelativistic collision systems. Effects of the relativistic projectile motion on the coupling matrix elements and their consequences on K-shell ionization are discussed.

  4. PAMOP: Petascale Atomic, Molecular and Optical Collision Calculations

    OpenAIRE

    McLaughlin, Brendan M.; Ballance, Connor P.; Pindzola, Michael S.; Müller, Alfred

    2015-01-01

    Petaflop architectures are currently being utilized efficiently to perform large scale computations in Atomic, Molecular and Optical Collisions. We solve the Schr\\"odinger or Dirac equation for the appropriate collision problem using the R-matrix or R-matrix with pseudo-states approach. We briefly outline the parallel methodology used and implemented for the current suite of Breit-Pauli and DARC codes. In this report, various examples are shown from our theoretical results compared with exper...

  5. Petascale computations for Large-scale Atomic and Molecular collisions

    OpenAIRE

    McLaughlin, Brendan M.; Ballance, Connor P.

    2014-01-01

    Petaflop architectures are currently being utilized efficiently to perform large scale computations in Atomic, Molecular and Optical Collisions. We solve the Schroedinger or Dirac equation for the appropriate collision problem using the R-matrix or R-matrix with pseudo-states approach. We briefly outline the parallel methodology used and implemented for the current suite of Breit-Pauli and DARC codes. Various examples are shown of our theoretical results compared with those obtained from Sync...

  6. Physics of Ultra-Peripheral Nuclear Collisions

    Energy Technology Data Exchange (ETDEWEB)

    Bertulani, Carlos A.; Klein, Spencer R.; Nystrand, Joakim

    2005-02-02

    Moving highly-charged ions carry strong electromagnetic fields which act as a field of photons. In collisions at large impact parameters, hadronic interactions are not possible, and the ions interact through photon-ion and photon-photon collisions known as ultra-peripheral collisions (UPC). Hadron colliders like the Relativistic Heavy Ion Collider (RHIC), the Tevatron and the Large Hadron Collider (LHC) produce photonuclear and two-photon interactions at luminosities and energies beyond that accessible elsewhere; the LHC will reach a {gamma}p energy ten times that of the Hadron-Electron Ring Accelerator (HERA). Reactions as diverse as the production of anti-hydrogen, photoproduction of the {rho}{sup 0}, transmutation of lead into bismuth and excitation of collective nuclear resonances have already been studied. At the LHC, UPCs can study many types of ''new physics''.

  7. Collision and collusion in physics

    CERN Document Server

    Fraser, Gordon Murray

    1997-01-01

    This end-of-term seminar looks at science behind the scenes. While physicists study the forces at work in Nature, physical force - the exercise of power - drives history. As well as diligent investigation, the focus and progress of science are also strongly influenced by contemporary issues. The search for new applications, the availability of new technology, the cult of personality, political upheaval and war, large-scale investment, and communications barriers have all played major roles.

  8. Spin Effects in Collisions of Electrons with Atoms and Molecules

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Some recent experimental and theoretical work on spin-dependent electron-atom and electron-molecule collisions is reviewed. The spin is involved in such collisions by explicit spin-dependent interactions such as the spin-orbit interaction of the continuum electron (Mott scattering) but also by exchange, which, in conjunction with the Pauli principle, gives rise to observable spin exchange effects. We present results for Mn and Na atoms and experiments in which electron dichroism with chiral molecules has been studied.

  9. Hydrogen negative ions and collisions of atomic particles

    International Nuclear Information System (INIS)

    This paper will be an overview presenting some of the basic atomic collisions processes (gas phase) which are fundamental to production and destruction of H-(D-). More detailed discussions of the most important processes will be left to other papers at this Symposium, and primarily new results since the 1977 Symposium will be discussed. Recent results provide insight into mechanisms responsible for the high H-(D-) ion fractions in hydrogen gas discharges, and the ion-atom collision processes important for double capture negative ion sources are better understood than in 1977

  10. Atoms, molecules and optical physics

    CERN Document Server

    Hertel, Ingolf V

    2015-01-01

    This is the first volume of textbooks on atomic, molecular and optical physics, aiming at a comprehensive presentation of this highly productive branch of modern physics as an indispensable basis for many areas in physics and chemistry as well as in state of the art bio- and material-sciences. It primarily addresses advanced students (including PhD students), but in a number of selected subject areas the reader is lead up to the frontiers of present research. Thus even the active scientist is addressed. This volume 1 provides the canonical knowledge in atomic physics together with basics of modern spectroscopy. Starting from the fundamentals of quantum physics, the reader is familiarized in well structured chapters step by step with the most important phenomena, models and measuring techniques. The emphasis is always on the experiment and its interpretation, while the necessary theory is introduced from this perspective in a compact and occasionally somewhat heuristic manner, easy to follow even for beginner...

  11. Light assisted collisions in ultra cold Tm atom

    Science.gov (United States)

    Akimov, Alexey; Cojocaru, Ivan; Pyatchenkov, Sergey; Snigirev, Stepan; Luchnokov, Ilia; Sukachev, Denis; Kalganova, Elena; Sorokin, Vadim

    2016-05-01

    Recently laser cooled rare earth elements attracted considerable attention due to the high orbital and magnetic moments. Such a systems allow low-field Feshabach resonances enabling tunable in wide range interactions. In particular, thulium atom has one hole in 4f shell therefore having orbital moment of 3 in the ground state, magnetic moment of 4 Bohr magnetons in ground state. While magnetic moment of the thulium atom is less than that of Erbium or Dysprosium simpler level structure, possibility to capture thulium atoms and the dipole trap at 532 nm make thulium atom an extremely attractive subject for quantum simulations. Nevertheless collisional properties of thulium atom are not yet explored in details, in particular light assisted collision of thulium atom were not yet investigated. In this contribution, we performed studies of light assisted collisions near in Magneto optical trap operating on narrow 530.7 nm transition. We found, that light assisted inelastic binary collisions losses rate is around β ~10-9cm3cm3s s . Possible mechanism of losses from the trap are discussed

  12. Atomic Parity Violation, Muon Pair Production in e+e - Collisions and Detection of CDM WIMP-Physics Related to Neutral Vector Boson D1

    Science.gov (United States)

    Senju, H.

    1999-11-01

    In our preon model there exists a neutral vector boson D1 which is an isoscalar partner of W(Z) in the vector boson octet. It is shown that the exchange of a D1 of about 1 TeV mass naturally explains a positive excess of the weak charge of atomic cesium recently observed. Other processes occurring through the D1 exchange are discussed, including the detection of CDM WIMP.

  13. Atom capture and loss in ion molecule collisions

    International Nuclear Information System (INIS)

    Progress is reported in measuring the energy and angular distribution of protons emerging with velocity close to the beam velocity from the target region when Ar+ beams collide with a CH4 target and ArH+ beams collide with a He target at asymptotically high speeds. The protons result from the transfer of a target constituent to the projectile (atom capture) or from the dissociation of the projectile molecule in the collision (atom loss). For atom capture processes the Thomas peak is clearly observed. 10 refs., 3 figs

  14. Physics through the 1990s: Atomic, molecular, and optical physics

    International Nuclear Information System (INIS)

    This report was prepared by the Panel on Atomic, Molecular, and Optical Physics of the Physics Survey Committee in response to its charge to describe the field, to characterize the recent advances, and to identify the current frontiers of research. Some of the areas discussed are: atomic structure, atomic dynamics, accelerator-based atomic physics, molecular photoionization and electron-molecule scattering, astrophysics, laser spectroscopy, atmospheric physics, plasma physics, and applications

  15. PAMOP: Petascale Atomic, Molecular and Optical Collision Calculations

    CERN Document Server

    McLaughlin, Brendan M; Pindzola, Michael S; Müller, Alfred

    2015-01-01

    Petaflop architectures are currently being utilized efficiently to perform large scale computations in Atomic, Molecular and Optical Collisions. We solve the Schr\\"odinger or Dirac equation for the appropriate collision problem using the R-matrix or R-matrix with pseudo-states approach. We briefly outline the parallel methodology used and implemented for the current suite of Breit-Pauli and DARC codes. In this report, various examples are shown from our theoretical results compared with experimental results obtained from Synchrotron Radiation facilities where the Cray architecture at HLRS is playing an integral part in our computational projects.

  16. Petascale computations for Large-scale Atomic and Molecular collisions

    CERN Document Server

    McLaughlin, Brendan M

    2014-01-01

    Petaflop architectures are currently being utilized efficiently to perform large scale computations in Atomic, Molecular and Optical Collisions. We solve the Schroedinger or Dirac equation for the appropriate collision problem using the R-matrix or R-matrix with pseudo-states approach. We briefly outline the parallel methodology used and implemented for the current suite of Breit-Pauli and DARC codes. Various examples are shown of our theoretical results compared with those obtained from Synchrotron Radiation facilities and from Satellite observations. We also indicate future directions and implementation of the R-matrix codes on emerging GPU architectures.

  17. Coherent coupling of alkali atoms by random collisions

    CERN Document Server

    Katz, Or; Firstenberg, Ofer

    2015-01-01

    Random spin-exchange collisions in warm alkali vapor cause rapid decoherence and act to equilibriate the spin state of the atoms. In contrast, here we demonstrate experimentally and theoretically a coherent coupling of one alkali specie to another specie, mediated by these random collisions. We show that, the minor specie (potassium) inherits the magnetic properties of the dominant specie (rubidium), including its lifetime (T1), coherence time (T2), gyromagnetic ratio, and SERF magnetic-field threshold. We further show that this coupling can be completely controlled by varying the strength of the magnetic field. Finally, we explain these phenomena analytically by modes-mixing of the two species via spin-exchange collisions.

  18. Physics of Nuclear Collisions at High Energy

    Energy Technology Data Exchange (ETDEWEB)

    Hwa, Rudolph C. [Univ. of Oregon, Eugene, OR (United States)

    2012-05-01

    A wide range of problems has been investigated in the research program during the period of this grant. Although the major effort has been in the subject of heavy-ion collisions, we have also studied problems in biological and other physical systems. The method of analysis used in reducing complex data in multiparticle production to simple descriptions can also be applied to the study of complex systems of very different nature. Phase transition is an important phenomenon in many areas of physics, and for heavy-ion collisions we study the fluctuations of multiplicities at the critical point. Human brain activities as revealed in EEG also involve fluctuations in time series, and we have found that our experience enables us to find the appropriate quantification of the fluctuations in ways that can differentiate stroke and normal subjects. The main topic that characterizes the research at Oregon in heavy-ion collisions is the recombination model for the treatment of the hadronization process. We have avoided the hydrodynamical model partly because there is already a large community engaged in it, but more significantly we have found the assumption of rapid thermalization unconvincing. Recent results in studying LHC physics lead us to provide more evidence that shower partons are very important even at low p_T, but are ignored by hydro. It is not easy to work in an environment where the conventional wisdom regards our approach as being incorrect because it does not adhere to the standard paradigm. But that is just what a vibrant research community needs: unconventional approach may find evidences that can challenge the orthodoxy. An example is the usual belief that elliptic flow in fluid dynamics gives rise to azimuthal anisotropy. We claim that it is only sufficient but not necessary. With more data from LHC and more independent thinkers working on the subject what is sufficient as a theory may turn out to be incorrect in reality. Another area of investigation that

  19. Energy distributions for ionization in ion-atom collisions

    CERN Document Server

    Amaya-Tapia, A

    2016-01-01

    In this paper we discuss how through the process of applying the Fourier transform to solutions of the Schr\\"odinger equation in the Close Coupling approach, good results for the ionization differential cross section in energy for electrons ejected in ion-atom collisions are obtained. The differential distributions are time dependent and through their time average, the comparison with experimental and theoretical data reported in the literature can be made. The procedure is illustrated with reasonable success in two systems, $p+H$ and $p+He$, and is expected to be extended without inherent difficulties to more complex systems. This allows advancing in the understanding of the calculation of ionization processes in ion-atom collisions.

  20. 24. International Conference on Atomic Collisions in Solids ICACS-24

    International Nuclear Information System (INIS)

    This Book contains the abstracts of invited and contributed talks submitted for presentation at the 24th International Conference on Atomic Collisions in Solids - ICACS-24. Out of nearly 200 submitted abstracts the International Programme Committee selected 46 oral and 89 poster contributions. Furthermore, 15 plenary invited lectures and the honorary Lindhard lecture are included in the scientific program. An additional tutorial day with 4 tutorial lectures is organised on Sunday prior to the Conference.

  1. Low-energy collisions of antiprotons with atoms and molecules

    International Nuclear Information System (INIS)

    Time-dependent close-coupling calculations were performed using the impact parameter method for antiproton and proton collisions with alkali-metal atoms and hydrogen molecules. The targets are described as effective one-electron systems using appropriate model potentials. The proton data verify the employed method while the results for antiprotons improve the literature on these systems considerably. Cross sections for ionization and excitation as well as electron-energy spectra and stopping power will be presented.

  2. Dynamical processes in atomic and molecular physics

    CERN Document Server

    Ogurtsov, Gennadi

    2012-01-01

    Atomic and molecular physics underlie a basis for our knowledge of fundamental processes in nature and technology and in such applications as solid state physics, chemistry and biology. In recent years, atomic and molecular physics has undergone a revolutionary change due to great achievements in computing and experimental techniques. As a result, it has become possible to obtain information both on atomic and molecular characteristics and on dynamics of atomic and molecular processes. This e-book highlights the present state of investigations in the field of atomic and molecular physics. Rece

  3. 2nd International Symposium "Atomic Cluster Collisions : Structure and Dynamics from the Nuclear to the Biological Scale"

    CERN Document Server

    Solov'yov, Andrey; ISACC 2007; Latest advances in atomic cluster collisions

    2008-01-01

    This book presents a 'snapshot' of the most recent and significant advances in the field of cluster physics. It is a comprehensive review based on contributions by the participants of the 2nd International Symposium on Atomic Cluster Collisions (ISACC 2007) held in July 19-23, 2007 at GSI, Darmstadt, Germany. The purpose of the Symposium is to promote the growth and exchange of scientific information on the structure and properties of nuclear, atomic, molecular, biological and complex cluster systems studied by means of photonic, electronic, heavy particle and atomic collisions. Particular attention is devoted to dynamic phenomena, many-body effects taking place in cluster systems of a different nature - these include problems of fusion and fission, fragmentation, collective electron excitations, phase transitions, etc.Both the experimental and theoretical aspects of cluster physics, uniquely placed between nuclear physics on the one hand and atomic, molecular and solid state physics on the other, are discuss...

  4. Experimental methods of ultracold atomic physics

    OpenAIRE

    Stamper-Kurn, D.M.; Thywissen, J. H.

    2011-01-01

    Experiments on solid-state materials and atomic quantum gases are increasingly investigating similar concepts in many-body quantum physics. Yet, the flavor of experiments on the gaseous atomic materials is different from that of conventional materials research. Here, we summarize some aspects of atomic physics and some of the common technical elements of cold-atom experiments which underlie the investigations described in the remaining chapters of this volume.

  5. Advances in atomic, molecular, and optical physics

    CERN Document Server

    Bederson, Benjamin

    1993-01-01

    Advances in Atomic, Molecular, and Optical Physics, established in 1965, continues its tradition of excellence with Volume 32, published in honor of Founding Editor Sir David Bates upon his retirement as editorof the series. This volume presents reviews of topics related to the applications of atomic and molecular physics to atmospheric physics and astrophysics.

  6. Atomic physics with highly charged ions

    International Nuclear Information System (INIS)

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

  7. Atomic physics with highly charged ions

    Energy Technology Data Exchange (ETDEWEB)

    Richard, P.

    1991-08-01

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

  8. Symmetric eikonal model for projectile-electron excitation and loss in relativistic ion-atom collisions

    OpenAIRE

    Voitkiv, A. B.; Najjari, B.; Shevelko, S. P.

    2010-01-01

    At impact energies $ \\stackrel{>}{\\sim}1$ GeV/u the projectile-electron excitation and loss occurring in collisions between highly charged ions and neutral atoms is already strongly influenced by the presence of atomic electrons. In order to treat these processes in collisions with heavy atoms we generalize the symmetric eikonal model, used earlier for considerations of electron transitions in ion-atom collisions within the scope of a three-body Coulomb problem. We show that at asymptotically...

  9. Physics through the 1990s: Atomic, molecular and optical physics

    Science.gov (United States)

    1986-01-01

    The volume presents a program of research initiatives in atomic, molecular, and optical physics. The current state of atomic, molecular, and optical physics in the US is examined with respect to demographics, education patterns, applications, and the US economy. Recommendations are made for each field, with discussions of their histories and the relevance of the research to government agencies. The section on atomic physics includes atomic theory, structure, and dynamics; accelerator-based atomic physics; and large facilities. The section on molecular physics includes spectroscopy, scattering theory and experiment, and the dynamics of chemical reactions. The section on optical physics discusses lasers, laser spectroscopy, and quantum optics and coherence. A section elucidates interfaces between the three fields and astrophysics, condensed matter physics, surface science, plasma physics, atmospheric physics, and nuclear physics. Another section shows applications of the three fields in ultra-precise measurements, fusion, national security, materials, medicine, and other topics.

  10. Relaxation of diatomic molecules by isotropic collisions: application to depolarizing collisions of CS by He atoms

    Science.gov (United States)

    Lique, F.; Spielfiedel, A.; Feautrier, N.

    2007-02-01

    An irreducible tensor formalism is applied to isotropic collisions of diatomic molecules with 1S atoms. Explicit expressions of the generalized spectroscopic relaxation cross sections are given, including pressure broadening cross sections as well as collisional transfer and destruction cross sections of the k-component of the target density matrix. For applications in the high temperature limit, formulae within the infinite order sudden approximation (IOS) are given for 1Σ electronic state molecules and 2S+1Σ electronic state molecules in the Hund's case (b) limit. Application to collisions of CS by He atoms shows that a good agreement is found between close coupling and IOS results at moderate energies and that multipolar depolarizing rates within a j-level are of the same order of magnitude whatever the considered multipole order k whereas multipolar transfer rates are lower by an order of magnitude. Propensity rules in relation to the CS-He potential energy surface are given.

  11. Atomic physics in strong fields

    International Nuclear Information System (INIS)

    This report discusses: Microwave Driven Multiphoton Excitation Dynamics in Rydberg Atoms; Nonadiabatic Geometric Phases of Multiphoton Transitions in Dissipative Systems and Spin-j Systems; and Nonperturbative Treatments of Atomic and Molecular Processes in Intense Laser Fields

  12. Computer simulation of electronic excitation in atomic collision cascades

    Energy Technology Data Exchange (ETDEWEB)

    Duvenbeck, A.

    2007-04-05

    The impact of an keV atomic particle onto a solid surface initiates a complex sequence of collisions among target atoms in a near-surface region. The temporal and spatial evolution of this atomic collision cascade leads to the emission of particles from the surface - a process usually called sputtering. In modern surface analysis the so called SIMS technology uses the flux of sputtered particles as a source of information on the microscopical stoichiometric structure in the proximity of the bombarded surface spots. By laterally varying the bombarding spot on the surface, the entire target can be scanned and chemically analyzed. However, the particle detection, which bases upon deflection in electric fields, is limited to those species that leave the surface in an ionized state. Due to the fact that the ionized fraction of the total flux of sputtered atoms often only amounts to a few percent or even less, the detection is often hampered by rather low signals. Moreover, it is well known, that the ionization probability of emitted particles does not only depend on the elementary species, but also on the local environment from which a particle leaves the surface. Therefore, the measured signals for different sputtered species do not necessarily represent the stoichiometric composition of the sample. In the literature, this phenomenon is known as the Matrix Effect in SIMS. In order to circumvent this principal shortcoming of SIMS, the present thesis develops an alternative computer simulation concept, which treats the electronic energy losses of all moving atoms as excitation sources feeding energy into the electronic sub-system of the solid. The particle kinetics determining the excitation sources are delivered by classical molecular dynamics. The excitation energy calculations are combined with a diffusive transport model to describe the spread of excitation energy from the initial point of generation. Calculation results yield a space- and time-resolved excitation

  13. Atomic excitations in heavy ion collisions with nuclear contact

    International Nuclear Information System (INIS)

    The dynamical semiclassical theory of atomic excitations, especially of positron creation, in heavy ion scattering is presented and extended to collisions with nuclear contact. The characteristic dependence of inner shell vacancy formation on nuclear reaction times as well as the emergence of interference patterns in the energy spectra of emitted delta-electrons and positrons in delayed collisions is discussed in terms of a simplified, schematic model for the nuclear reaction dynamics. In addition, the spontaneous decay mechanism in giant nuclear systems with Z> or approx.173 leads, for sufficiently long reaction times, to a characteristic line in the positron spectra at the position of the 1ssigma-resonance. The position and width of the positron line is calculated in dependence on the nuclear configuration taking into account the influence of the electron-electron interaction. Furthermore, a quantum mechanical extension of our semiclassical treatment of the atomic scattering process and its effect on atomic positron spectra are discussed. In addition, the influence of E0-transitions in the giant nuclear system on positron emission is treated qualitatively in a semiclassical approximation, indicating that nuclear collective modes can be revealed by the measurement of Stokes and anti-Stokes lines in the positron spectra. (orig./HSI)

  14. Measurements of scattering processes in negative ion-atom collisions

    Energy Technology Data Exchange (ETDEWEB)

    Kvale, T.J.

    1992-01-01

    This Technical Progress Report describes the progress made on the research objectives during the past twelve months. This research project is designed to provide measurements of various scattering processes which occur in H{sup {minus}} collisions with atomic (specifically, noble gas and atomic hydrogen) targets at intermediate energies. These processes include: elastic scattering,single- and double-electron detachment, and target excitation/ionization. For the elastic and target inelastic processes where H{sup {minus}} is scattered intact, the experimental technique of Ion Energy-Loss Spectroscopy (IELS) will be employed to identify the final target state(s). In most of the above processes, cross sections are unknown both experimentally and theoretically. The measurements in progress will provide either experimentally-determined cross sections or set upper limits to those cross sections. In either case, these measurements will be stringent tests of our understanding in energetic negative ion-atom collisions. This series of experiments required the construction of a new facility and the initial ion beam was accelerated through the apparatus in April 1991.

  15. Theoretical atomic physics code development I: CATS: Cowan Atomic Structure Code

    International Nuclear Information System (INIS)

    An adaptation of R.D. Cowan's Atomic Structure program, CATS, has been developed as part of the Theoretical Atomic Physics (TAPS) code development effort at Los Alamos. CATS has been designed to be easy to run and to produce data files that can interface with other programs easily. The CATS produced data files currently include wave functions, energy levels, oscillator strengths, plane-wave-Born electron-ion collision strengths, photoionization cross sections, and a variety of other quantities. This paper describes the use of CATS. 10 refs

  16. Ion-atom cold collision: Formation of cold molecular ion by radiative processes

    OpenAIRE

    Rakshit, Arpita; Deb, Bimalendu

    2010-01-01

    We discuss theoretically ion-atom collisions at low energy and predict the possibility of formation of cold molecular ion by photoassociation. We present results on radiative homo- and hetero-nuclear atom-ion cold collisions that reveal threshold behaviour of atom-ion systems.

  17. Theoretical atomic physics for fusion

    International Nuclear Information System (INIS)

    The understanding of electron-ion collision processes in plasmas remains a key factor in the ultimate development of nuclear fusion as a viable energy source for the nation. Our 1993--1995 research proposal delineated several areas of research in electron-ion scattering theory. In this paper we summarize our efforts in 1993

  18. Two-potential eikonal approximation for electron-atom collisions

    International Nuclear Information System (INIS)

    The Glauber approximation is known to be in appreciable error at all angles when applied to the elastic electron-atom scattering at medium and lower energies. It is shown that this is not due to the frozen-target approximation but mainly a result of the inadequate semiclassical treatment of close-encounter collisions in the Glauber approximation. A simple method is proposed to correct this inadequacy and is applied to e-H elastic scattering at energies from 20 to 100 eV. A remarkable improvement over the Glauber approximation is obtained, and the results agree with experiments very well at all angles where measurements are available

  19. Atomic physics at high brilliance synchrotron sources: Proceedings

    International Nuclear Information System (INIS)

    This report contains papers on the following topics: present status of SPring-8 and the atomic physics undulator beamline; recent photoabsorption measurements in the rare gases and alkalis in the 3 to 15 keV proton energy region; atomic and molecular physics at LURE; experiments on atoms, ions and small molecules using the new generation of synchrotron radiation sources; soft x-ray fluorescence spectroscopy using tunable synchrotron radiation; soft x-ray fluorescence spectroscopy excited by synchrotron radiation: Inelastic and resonant scattering near threshold; outer-shell photoionization of ions; overview of the APS BESSRC beamline development; the advanced light source: Research opportunities in atomic and molecular physics; Photoionization of the Ba+ ion by 4d shell excitation; decay dynamics of inner-shell excited atoms and molecules; absorption of atomic Ca, Cr, Mn and Cu; High-resolution photoelectron studies of resonant molecular photoionization; radiative and radiationless resonant raman scattering by synchrotron radiation; auger spectrometry of atoms and molecules; some thoughts of future experiments with the new generation of storage rings; Electron spectroscopy studies of argon K-shell excitation and vacancy cascades; ionization of atoms by high energy photons; ion coincidence spectroscopy on rare gas atoms and small molecules after photoexcitation at energies of several keV; an EBIS for use with synchrotron radiation photoionization of multiply charged ions and PHOBIS; gamma-2e coincidence measurements the wave of the future in inner-shell electron spectroscopy; recoil momentum spectroscopy in ion-atom and photon-atom collisions; a study of compton ionization of helium; future perspectives of photoionization studies at high photon energies; and status report on the advanced photon source. These papers have been cataloged separately elsewhere

  20. Physics of Ultra-Peripheral Nuclear Collisions

    OpenAIRE

    Bertulani, Carlos A.; Klein, Spencer R.; Nystrand, Joakim

    2005-01-01

    Moving highly-charged ions carry strong electromagnetic fields that act as a field of photons. In collisions at large impact parameters, hadronic interactions are not possible, and the ions interact through photon-ion and photon-photon collisions known as {\\it ultra-peripheral collisions} (UPC). Hadron colliders like the Relativistic Heavy Ion Collider (RHIC), the Tevatron and the Large Hadron Collider (LHC) produce photonuclear and two-photon interactions at luminosities and energies beyond ...

  1. Formation of positron-atom bound states in collisions between Rydberg Ps and neutral atoms

    CERN Document Server

    Swann, A R; Deller, A; Gribakin, G F

    2016-01-01

    Predicted twenty years ago, positron binding to neutral atoms has not yet been observed experimentally. A new scheme is proposed to detect positron-atom bound states by colliding Rydberg positronium (Ps) with neutral atoms. Estimates of the charge-transfer-reaction cross section are obtained using the first Born approximation for a selection of neutral atom targets and a wide range of incident Ps energies and principal quantum numbers. We also estimate the corresponding Ps ionization cross section. The accuracy of the calculations is tested by comparison with earlier predictions for Ps charge transfer in collisions with hydrogen and antihydrogen. We describe an existing Rydberg Ps beam suitable for producing positron-atom bound states and estimate signal rates based on the calculated cross sections and realistic experimental parameters. We conclude that the proposed methodology is capable of producing such states and of testing theoretical predictions of their binding energies.

  2. Electron capture in collisions of S4+ with atomic hydrogen

    International Nuclear Information System (INIS)

    Charge transfer processes due to collisions of ground state S4+(3s21S) ions with atomic hydrogen are investigated for energies between 1 meV u-1 and 10 MeV u-1 using the quantum mechanical molecular-orbital close-coupling (MOCC), atomic-orbital close-coupling, classical trajectory Monte Carlo (CTMC) and continuum distorted wave methods. The MOCC calculations utilize ab initio adiabatic potentials and nonadiabatic radial coupling matrix elements obtained with the spin-coupled valence-bond approach. A number of variants of the CTMC approach were explored, including different momentum and radial distributions for the initial state, as well as effective charge and quantum-defect models to determine the corresponding quantum state after capture into final partially stripped S3+ excited classical states. Hydrogen target isotope effects are explored and rate coefficients for temperatures between 100 and 106 K are also presented. (author)

  3. Single electron capture in fast ion-atom collisions

    Science.gov (United States)

    Milojević, Nenad

    2014-12-01

    Single-electron capture cross sections in collisions between fast bare projectiles and heliumlike atomic systems are investigated by means of the four-body boundary-corrected first Born (CB1-4B) approximation. The prior and post transition amplitudes for single charge exchange encompassing symmetric and asymmetric collisions are derived in terms of twodimensional real integrals in the case of the prior form and five-dimensional quadratures for the post form. The dielectronic interaction V12 = 1/r12 = 1/|r1 - r2| explicitly appears in the complete perturbation potential Vf of the post transition probability amplitude T+if. An illustrative computation is performed involving state-selective and total single capture cross sections for the p - He (prior and post form) and He2+, Li3+Be4+B5+C6+ - He (prior form) collisions at intermediate and high impact energies. We have also studied differential cross sections in prior and post form for single electron transfer from helium by protons. The role of dynamic correlations is examined as a function of increased projectile energy. Detailed comparisons with the measurements are carried out and the obtained theoretical cross sections are in reasonable agreement with the available experimental data.

  4. Dynamics of two atoms undergoing light-assisted collisions in an optical microtrap

    CERN Document Server

    Sompet, P; Fung, Y H; McGovern, M; Andersen, M F

    2013-01-01

    We study the dynamics of atoms in optical traps when exposed to laser cooling light that induces light-assisted collisions. We experimentally prepare individual atom pairs and observe their evolution. Due to the simplicity of the system (just two atoms in a microtrap) we can directly simulate the pair's dynamics, thereby revealing detailed insight into it. We find that often only one of the collision partners gets expelled, similar to when using blue detuned light for inducing the collisions. This enhances schemes for using light-assisted collisions to prepare individual atoms and affects other applications as well.

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

    CERN Document Server

    Haze, Shinsuke; Saito, Ryoichi; Mukaiyama, Takashi

    2014-01-01

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

  6. Convergent Close-Coupling Approach to Electron-Atom Collisions

    Science.gov (United States)

    Bray, Igor; Stelbovics, Andris

    2007-01-01

    It was with great pleasure and honour to accept the invitation to make a presentation at the symposium celebrating the life-long work of Aaron Temkin and Richard Drachman. The work of Aaron Temkin was particularly influential on our own during the development of the CCC method for electron-atom collisions. There are a number of key problems that need to be dealt with when developing a general computational approach to such collisions. Traditionally, the electron energy range was subdivided into the low, intermediate, and high energies. At the low energies only a finite number of channels are open and variational or close-coupling techniques could be used to obtain accurate results. At high energies an infinite number of discrete channels and the target continuum are open, but perturbative techniques are able to yield accurate results. However, at the intermediate energies perturbative techniques fail and computational approaches need to be found for treating the infinite number of open channels. In addition, there are also problems associated with the identical nature of electrons and the difficulty of implementing the boundary conditions for ionization processes. The beauty of the Temkin-Poet model of electron-hydrogen scattering is that it simplifies the full computational problem by neglecting any non-zero orbital angular momenta in the partial-wave expansion, without loosing the complexity associated with the above-mentioned problems. The unique nature of the problem allowed for accurate solution leading to benchmark results which could then be used to test the much more general approaches to electron-atom collision problems. The immense value of the Temkin-Poet model is readily summarised by the fact that the initial papers of Temkin and Poet have been collectively cited around 250 times to date and are still being cited in present times. Many of the citations came from our own work during the course of the development of the CCC method, which we now describe.

  7. Investigation of ion-atom collision dynamics through imaging techniques

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The principle and technique details of recoil ion momentum imaging are discussed and summarized. The recoil ion momentum spectroscopy built at the Institute of Modern Physics (Lanzhou) is presented. The first results obtained at the setup are analyzed. For 30 keV He2+ on He collision, it is found that the capture of single electron occurs dominantly into the first excited states, and the related scattering angle results show that the ground state capture occurs at large impact parameters, while the capture into excited states occurs at small impact parameters. The results manifest the collision dynamics for the sub-femto-second process can be studied through the techniques uniquely. Finally, the future possibilities of applications of the recoil ion momentum spectroscopy in other fields are outlined.

  8. Physics Opportunities in Ultraperipheral Heavy Ion Collisions at LHC

    OpenAIRE

    Baur, G.

    2001-01-01

    Due to coherence, there are strong electromagnetic fields of short duration in very peripheral heavy ion collisions. They give rise to photon-photon and photon-nucleus collisions with high flux. Photon-photon and photon-hadron physics at various invariant mass scales are discussed.

  9. Making More-Complex Molecules Using Superthermal Atom/Molecule Collisions

    Science.gov (United States)

    Shortt, Brian; Chutjian, Ara; Orient, Otto

    2008-01-01

    A method of making more-complex molecules from simpler ones has emerged as a by-product of an experimental study in outer-space atom/surface collision physics. The subject of the study was the formation of CO2 molecules as a result of impingement of O atoms at controlled kinetic energies upon cold surfaces onto which CO molecules had been adsorbed. In this study, the O/CO system served as a laboratory model, not only for the formation of CO2 but also for the formation of other compounds through impingement of rapidly moving atoms upon molecules adsorbed on such cold interstellar surfaces as those of dust grains or comets. By contributing to the formation of increasingly complex molecules, including organic ones, this study and related other studies may eventually contribute to understanding of the origins of life.

  10. Nearside-farside analysis of differential cross sections: Diffraction and rainbow scattering in atom-atom and atom-molecule rotationally inelastic sudden collisions

    Science.gov (United States)

    McCabe, P.; Connor, J. N. L.

    1996-02-01

    Nearside-farside (NF) theory, as used to understand nuclear heavy-ion differential cross sections, is applied for the first time to the angular scattering of atom-atom and atom-diatom collisions. A NF decomposition of the partial wave series (PWS) for the scattering amplitude has the following advantages: (a) it is exact, (b) it uses PW scattering matrix elements (quantum or semiclassical) as calculated by standard computer programs, (c) it is easily incorporated into existing computer programs which calculate angular distributions, (d) semiclassical techniques, such as stationary phase or saddle point integration, are not invoked for the PWS, although the semiclassical picture is still evident. A disadvantage of a NF decomposition is that it is not unique. The Fuller and Hatchell NF decompositions are used to analyze the angular scattering of four collision systems whose PWS involve Legendre polynomials: (a) atom-atom He+Ne elastic diffraction scattering, (b) atom-atom H++Ar elastic rainbow scattering, (c) atom rigid-rotator Ne+D2(j=0) →Ne+D2(j) diffraction scattering under sudden conditions so that the infinite-order-sudden (IOS) approximation is valid, (d) atom rigid-rotator He+N2(j=0)→He+N2(j) rotational rainbow IOS scattering. The utility of these two NF decompositions is assessed by comparison with results from the semiclassical complex angular momentum (CAM) representation of the scattering amplitude. This is chosen because it allows an unambiguous separation of the scattering amplitude into nearside and farside subamplitudes under semiclassical conditions. The Fuller NF decomposition, unlike the Hatchell NF decomposition, provides a physically clear explanation of the angular scattering, which always agrees with the semiclassical CAM interpretation (except for scattering angles ≊180°). The Fuller NF decomposition is therefore recommended for applications to atomic and molecular collisions. The NF theory for the decomposition of Legendre polynomials

  11. Atoms, molecules and optical physics 1. Atoms and spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Hertel, Ingolf V.; Schulz, Claus-Peter

    2015-09-01

    This is the first volume of textbooks on atomic, molecular and optical physics, aiming at a comprehensive presentation of this highly productive branch of modern physics as an indispensable basis for many areas in physics and chemistry as well as in state of the art bio- and material-sciences. It primarily addresses advanced students (including PhD students), but in a number of selected subject areas the reader is lead up to the frontiers of present research. Thus even the active scientist is addressed. This volume 1 provides the canonical knowledge in atomic physics together with basics of modern spectroscopy. Starting from the fundamentals of quantum physics, the reader is familiarized in well structured chapters step by step with the most important phenomena, models and measuring techniques. The emphasis is always on the experiment and its interpretation, while the necessary theory is introduced from this perspective in a compact and occasionally somewhat heuristic manner, easy to follow even for beginners.

  12. Treatment of Ion-Atom Collisions Using a Partial-Wave Expansion of the Projectile Wavefunction

    Science.gov (United States)

    Wong, T. G.; Foster, M.; Colgan, J.; Madison, D. H.

    2009-01-01

    We present calculations of ion-atom collisions using a partial-wave expansion of the projectile wavefunction. Most calculations of ion-atom collisions have typically used classical or plane-wave approximations for the projectile wavefunction, since partial-wave expansions are expected to require prohibitively large numbers of terms to converge…

  13. Cold atomic and molecular collisions: approaching the universal loss regime

    CERN Document Server

    Frye, Matthew D; Hutson, Jeremy M

    2014-01-01

    We investigate the behaviour of single-channel theoretical models of cold and ultracold collisions that take account of inelastic and reactive processes using a single parameter to represent short-range loss. We present plots of the resulting energy-dependence of elastic and inelastic cross sections over the full parameter space of loss parameters and short-range phase shifts. We then test the single-channel model by comparing it with the results of coupled-channel calculations of rotationally inelastic collisions between LiH molecules and Li atoms. We find that the single-channel model becomes increasingly accurate as the initial LiH rotational quantum number increases, with a corresponding increase in the number of open loss channels. The results suggest that coupled-channel calculations at very low energy (in the s-wave regime) could in some cases be used to estimate a loss parameter and then to predict the range of possible loss rates at higher energy, without the need for an explicit partial-wave sum.

  14. Progress in numerical calculations of ion-atom collisions

    Energy Technology Data Exchange (ETDEWEB)

    Reading, J.F.; Ford, A.L.; Becker, R.L.

    1983-01-01

    An ion-atom collision produces a time dependent perturbation of a many fermion system. In this collision, excitation, ionization and charge transfer can occur. The driving mechanism for these processes may be thought of as the potentials seen by individual electrons at any given separation of the projectile and target nuclei. If we think of these potentials as belonging to the target (a nucleus and electrons) and the projectile (another nucleus and electrons) then as detected by an electron the potentials change because: (a) the target and projectile change position, and (b) electrons on the target and projectile change states. Most work in the past fifty years has concentrated on solving the independent particle model (IPM). Cracks are beginning to appear in this model which only allows for type (a) changes in the potential. But in a short review we shall have quite enough to do in understanding the progress made in the last decade on the IPM. This paper is divided into three parts. The first deals with how to reduce the IPM to the single electron model (SEM). The second is on a new method where charge transfer is important. The third confronts some standard models with modern calculations.

  15. Progress in numerical calculations of ion-atom collisions

    International Nuclear Information System (INIS)

    An ion-atom collision produces a time dependent perturbation of a many fermion system. In this collision, excitation, ionization and charge transfer can occur. The driving mechanism for these processes may be thought of as the potentials seen by individual electrons at any given separation of the projectile and target nuclei. If we think of these potentials as belonging to the target (a nucleus and electrons) and the projectile (another nucleus and electrons) then as detected by an electron the potentials change because: (a) the target and projectile change position, and (b) electrons on the target and projectile change states. Most work in the past fifty years has concentrated on solving the independent particle model (IPM). Cracks are beginning to appear in this model which only allows for type (a) changes in the potential. But in a short review we shall have quite enough to do in understanding the progress made in the last decade on the IPM. This paper is divided into three parts. The first deals with how to reduce the IPM to the single electron model (SEM). The second is on a new method where charge transfer is important. The third confronts some standard models with modern calculations

  16. Atomic physics in strong fields

    International Nuclear Information System (INIS)

    This report discusses the following topics: nonadiabatic geometric phases of multiphoton transitions; nonperturbative treatments of level shifts of excited states in strong fields; multiple high-order harmonic generation in intense laser fields; quantum fractal character of quasi-energy states in multi-color fields; complex- scaling Fourier-grid Hamiltonian method for intense-field multiphoton resonances; and microwave driven multiphoton excitation dynamics in Rydberg atoms: Fast Fourier transformation propagation method

  17. Advances in atomic, molecular, and optical physics

    CERN Document Server

    Berman, Paul R; Arimondo, Ennio

    2006-01-01

    Volume 54 of the Advances Series contains ten contributions, covering a diversity of subject areas in atomic, molecular and optical physics. The article by Regal and Jin reviews the properties of a Fermi degenerate gas of cold potassium atoms in the crossover regime between the Bose-Einstein condensation of molecules and the condensation of fermionic atom pairs. The transition between the two regions can be probed by varying an external magnetic field. Sherson, Julsgaard and Polzik explore the manner in which light and atoms can be entangled, with applications to quantum information processing

  18. Artificial Atoms: from Quantum Physics to Applications

    International Nuclear Information System (INIS)

    The primary objective of this workshop is to survey the most recent advances of technologies enabling single atom- and artificial atom-based devices. These include the assembly of artificial molecular structures with magnetic dipole and optical interactions between engineered atoms embedded in solid-state lattices. The ability to control single atoms in diamond or similar solids under ambient operating conditions opens new perspectives for technologies based on nanoelectronics and nanophotonics. The scope of the workshop is extended towards the physics of strong coupling between atoms and radiation field modes. Beyond the traditional atom-cavity systems, artificial dipoles coupled to microwave radiation in circuit quantum electrodynamics is considered. All these technologies mutually influence each other in developing novel devices for sensing at the quantum level and for quantum information processing.

  19. Atomic jet with ionization detection for laser spectroscopy of Rydberg atoms under collisions and fields

    Science.gov (United States)

    Philip, G.

    2008-03-01

    An efficient atomic jet setup offering many unprecedented advantages over a conventional heat pipe setup used in multi-photon spectroscopy, mainly of alkaline-earth metals, has been constructed by a scheme in which the sample material is encapsulated in a disposable cartridge oven located inside a thermally stabilised heat-pipe and is made to effuse in to a row of atomic beams merging to form a jet target. This novel scheme combines the advantages of both high density atomic beam with convenient geometry for orthogonal excitation and high sensitive ionisation detection capabilities of thermionic diodes, besides eliminating several problems inherent in the usual heat-pipe operation. Out of various designs, typical results are presented for a linear heat-pipe with vertical atomic jet used in two-photon spectroscopy of highly excited states of Sr I. Controlled excitations of both Rydberg and non-Rydberg states, which cannot otherwise be accessed from the ground state due to parity and spectroscopic selection rules, have been achieved by employing a weak electric field complimented by collisions. The atomic jet setup is also found very useful for the study of collisional broadening and shift of excited states and time evolution of Rydberg atoms.

  20. Advances in atomic physics an overview

    CERN Document Server

    Cohen-Tannoudji, Claude

    2011-01-01

    This book presents a comprehensive overview of the spectacular advances seen in atomic physics during the last 50 years. The authors explain how such progress was possible by highlighting connections between developments that occurred at different times. They discuss the new perspectives and the new research fields that look promising. The emphasis is placed, not on detailed calculations, but rather on physical ideas. Combining both theoretical and experimental considerations, the book will be of interest to a wide range of students, teachers and researchers in quantum and atomic physics.

  1. Atomic physics precise measurements and ultracold matter

    CERN Document Server

    Inguscio, Massimo

    2013-01-01

    Atomic Physics provides an expert guide to two spectacular new landscapes in physics: precision measurements, which have been revolutionized by the advent of the optical frequency comb, and atomic physics, which has been revolutionized by laser cooling. These advances are not incremental but transformative: they have generated a consilience between atomic and many-body physics, precipitated an explosion of scientific and technological applications, opened new areas of research, and attracted a brilliant generation of younger scientists. The research is advancing so rapidly, the barrage of applications is so dazzling, that students can be bewildered. For both students and experienced scientists, this book provides an invaluable description of basic principles, experimental methods, and scientific applications.

  2. Theoretical Atomic Physics code development II: ACE: Another collisional excitation code

    International Nuclear Information System (INIS)

    A new computer code for calculating collisional excitation data (collision strengths or cross sections) using a variety of models is described. The code uses data generated by the Cowan Atomic Structure code or CATS for the atomic structure. Collisional data are placed on a random access file and can be displayed in a variety of formats using the Theoretical Atomic Physics Code or TAPS. All of these codes are part of the Theoretical Atomic Physics code development effort at Los Alamos. 15 refs., 10 figs., 1 tab

  3. A unified numerical model of collisional depolarization and broadening rates due to hydrogen atom collisions

    CERN Document Server

    Derouich, M; Barklem, P S

    2015-01-01

    Interpretation of solar polarization spectra accounting for partial or complete frequency redistribution requires data on various collisional processes. Data for depolarization and polarization transfer are needed but often missing, while data for collisional broadening are usually more readily available. Recent work by Sahal-Br\\'echot and Bommier concluded that despite underlying similarities in the physics of collisional broadening and depolarization processes, relationships between them are not possible to derive purely analytically. We aim to derive accurate numerical relationships between the collisional broadening rates and the collisional depolarization and polarization transfer rates due to hydrogen atom collisions. Such relationships would enable accurate and efficient estimation of collisional data for solar applications. Using earlier results for broadening and depolarization processes based on general (i.e. not specific to a given atom), semi-classical calculations employing interaction potentials...

  4. Applications of Hubble Volume in Atomic Physics, Nuclear Physics, Particle Physics, Quantum Physics and Cosmic Physics

    Directory of Open Access Journals (Sweden)

    U. V. S. Seshavatharam

    2013-08-01

    Full Text Available In this paper an attempt is made to emphasize the major shortcomings of standard cosmology. It can be suggested that, the current cosmological changes can be understood by studying the atom and the atomic nucleus through ground based experiments. If light is coming from the atoms of the gigantic galaxy, then redshift can be interpreted as an index of the galactic atomic ‘light emission mechanism’. In no way it seems to be connected with ‘galaxy receding’. With ‘cosmological increasing (emitted photon energy’, observed cosmic redshift can be considered as a measure of the age difference between our galaxy and any observed galaxy. If it is possible to show that, (from the observer older galaxy’s distance increases with its ‘age’, then ‘galaxy receding’ and ‘accelerating universe’ concepts can be put for a revision at fundamental level. At any given cosmic time, the product of ‘critical density’ and ‘Hubble volume’ gives a characteristic cosmic mass and it can be called as the ‘Hubble mass’. Interesting thing is that, Schwarzschild radius of the ‘Hubble mass’ again matches with the ‘Hubble length’. Most of the cosmologists believe that this is merely a coincidence. At any given cosmic time,’Hubble length’ can be considered as the gravitational or electromagnetic interaction range. If one is willing to think in this direction, by increasing the number of applications of Hubble mass and Hubble volume in other areas of fundamental physics like quantum physics, nuclear physics, atomic physics and particle physics - slowly and gradually - in a progressive way, concepts of ‘Black hole Cosmology’ can be strengthened and can also be confirmed.

  5. PREFACE: XXVII International Conference on Photonic, Electronic and Atomic Collisions (ICPEAC 2011)

    Science.gov (United States)

    Williams, I. D.; van der Hart, H. W.; McCann, J. F.; Crothers, D. S. F.

    2012-11-01

    The XXVII International Conference on Photonic, Electronic and Atomic Collisions was held at Queen's University Belfast, Northern Ireland, 27 July - 2 August 2011. Members of the Local Organising Committee were drawn from the School of Mathematics and Physics of Queen's University Belfast, the School of Physical Sciences at Dublin City University, the School of Physics at University College Dublin and the Department of Experimental Physics at the National University of Ireland, Maynooth. The Conference was attended by 566 participants with contributions from 54 countries. The meeting attracted 786 contributed papers for presentation in the poster sessions. The conference included 20 Special Reports selected from the contributed papers, and these are included in part 1 of this volume. During the meeting a total of 65 Progress Reports were also presented, and the authors invited to submit written versions of their talks (see Part 1). Of the total number of contributed papers, 663 are included as refereed abstracts in parts 2 to 15 of this volume of Journal of Physics: Conference Series. Part 1 of this volume includes detailed write-ups of the majority of plenary lectures, progress reports and special reports, constituting a comprehensive tangible record of the meeting, and is additionally published in hard-copy as the Conference Proceedings. There were 5 plenary lectures given by Margaret Murnane on Ultrafast processes in atomic dynamics; Chris Greene on Few-body highly-correlated dynamics; Michael Allan on Electron-molecule collisions; Yasunori Yamazaki on Antiproton and positron collisions and Thomas Stöhlker on Relativistic ion collisions. Ian Spielman, winner of the IUPAP Young Scientist Prize for 2011, gave a special lecture entitled Modifying interatomic interactions using Raman coupling: a tale of slowly colliding Bose-Einstein condensates. In addition an evening public lecture by Mike Baillie on How precise tree-ring dating raises issues concerning the

  6. Low energy heavy particle collisions relevant to gas divertor physics

    Energy Technology Data Exchange (ETDEWEB)

    Onda, Kunizo [Science Univ. of Tokyo (Japan)

    1997-01-01

    Cross sections for rotational and vibrational excitations of H{sub 2} molecules caused by impact of electron, proton, H atom, H{sub 2}, H{sub 2}{sup +}, or H{sup -} are compared with one another and reviewed for rotational excitations by examining an interaction potential between collision partners. It is pointed out what are difficulties in theoretical approaches to collision of atoms with H{sub 2} molecules initially in vibrationally and rotationally excited states. A theoretical approach developed by our group, which aims quantum mechanically to investigate vibrationally inelastic scattering, exchange reaction, or dissociation of molecule in vibrationally excited states collided with an atom or its ion, is presented. Newly obtained dissociation cross sections of H{sub 2} in vibrationally excited states by He impact are presented and compared in magnitude with those of H{sub 2} caused by electron impact. (author)

  7. Theory of phonon inelastic atom--surface scattering. I. Quantum mechanical treatment of collision dynamics

    International Nuclear Information System (INIS)

    We present a systematic formulation of the atom--surface scattering dynamics which includes the vibrational states of the atoms in the solid (phonons). The properties of the total scattering wave function of the system, a representation of the interaction potential matrix, and the characteristics of the independent physical solutions are all derived from the translational invariance of the full Hamiltonian. The scattering equations in the integral forms as well as the related Green functions were also obtained. The configurational representations of the Green functions, in particular, are quite different from those of the conventional scattering theory where the collision partners are spatially localized. Various versions of the integral expression of scattering, transition, and reactance matrices were also obtained. They are useful for introducing approximation schemes. From the present formulation, some specific theoretical schemes which are more realistic compared to those that have been employed so far and at the same time capable of yielding effective ab initio computation are derived in the following paper. The time reversal invariance and the microscopic reversibility of the atom--surface scattering were discussed. The relations between the in and outgoing scattering wave functions which are satisfied in the atom--surface system and important in the transition matrix methods were presented. The phonon annihilation and creation, and the adsorption and desorption of the atom are related through the time reversal invariance, and thus the microscopic reversibility can be tested by the experiment

  8. Interatomic collisions

    International Nuclear Information System (INIS)

    The relevance of the study and understanding of atomic collision processes to nuclear power developments and the impact of the particular contributions made by members of the Theoretical Physics Division, Harwell to this work are considered. These contributions fall into two main parts; up to 1970 when interest concentrated on the lighter collision systems involving protons, α-particles and the helium and hydrogen atoms at collision energies in the range 1 keV - 1 MeV, and after 1970 when interest broadened to include the collisions of heavy atoms, such as the O+-Ne collision system which was used as a prototype for the development of scaling laws for inner-shell excitation in any heavy-ion collision. Particular aspects of the work discussed include the Born expansion and beyond, close-coupling expansions, and continuum x-ray emission. (UK)

  9. Accelerator based atomic physics experiments: an overview

    International Nuclear Information System (INIS)

    Atomic Physics research with beams from accelerators has continued to expand and the number of papers and articles at meetings and in journals reflects a steadily increasing interest and an increasing support from various funding agencies. An attempt will be made to point out where interdisciplinary benefits have occurred, and where applications of the new results to engineering problems are expected. Drawing from material which will be discussed in the conference, a list of the most active areas of research is presented. Accelerator based atomic physics brings together techniques from many areas, including chemistry, astronomy and astrophysics, nuclear physics, solid state physics and engineering. An example is the use of crystal channeling to sort some of the phenomena of ordinary heavy ion stopping powers. This tool has helped us to reach a better understanding of stopping mechanisms with the result that now we have established a better base for predicting energy losses of heavy ions in various materials

  10. Quantum-mechanical calculations of cross sections for electron collisions with atoms and molecules

    CERN Document Server

    Bartschat, Klaus; Zatsarinny, Oleg

    2016-01-01

    An overview of quantum-mechanical methods to generate cross-section data for electron collisions with atoms and molecules is presented. Particular emphasis is placed on the time-independent close-coupling approach, since it is particularly suitable for low-energy collisions and also allows for systematic improvements as well as uncertainty estimates. The basic ideas are illustrated with examples for electron collisions with argon atoms and methane. For many atomic systems, such as e-Ar collisions, highly reliable cross sections can now be computed with quantified uncertainties. On the other hand, while electron collision calculations with molecules do provide key input data for plasma models, the methods and computer codes presently used require further development to make these inputs robust.

  11. Simulation of Collisions of Ions with Atoms by the PIC-MC Method. Comparative Estimates

    Science.gov (United States)

    Sysun, V. I.; Sysun, A. V.; Ignakhin, V. S.; Titov, V. O.

    2015-11-01

    Monte Carlo models which simulate ion-atom collisions are considered. Efficient models for calculating the time between collisions are proposed which take into account the velocity dependence of the cross sections and also the probability distribution of the velocities of the ions and the probability distribution of the angles after a collision. The simulation results are compared with theoretical values of the drift velocity of the ions.

  12. The fundamentals of atomic and molecular physics

    CERN Document Server

    Brooks, Robert L

    2013-01-01

    The Fundamentals of Atomic and Molecular Physics is intended as an introduction to the field for advanced undergraduates who have taken quantum mechanics. Each chapter builds upon the previous, using the same tools and methods throughout. As the students progress through the book, their ability to use these tools will steadily increase, along with their confidence in their efficacy. The book treats the two-electron atom as the simplest example of the many-electron atom—as opposed to using techniques that are not applicable to many-electron atoms—so that it is unnecessary to develop additional equations when turning to multielectron atoms, such as carbon. External fields are treated using both perturbation theory and direct diagonalization and spontaneous emission is developed from first principles. Only diatomic molecules are considered with the hydrogen molecular ion and neutral molecule treated in some detail. This comprehensive coverage of the quantum mechanics of complex atoms and simple diatomic mole...

  13. Atomic physics research with synchrotron radiation

    International Nuclear Information System (INIS)

    Applications of synchrotron radiation to research in high-energy atomic physics are summarized. These lie in the areas of photoelectron spectrometry, photon scattering, x-ray absorption spectroscopy, time-resolved measurements, resonance spectroscopy and threshold excitation, and future, yet undefined studies

  14. Guide to Laboratory Practicum in Atomic Physics

    Science.gov (United States)

    Burbulea, N. F.; Golban, G. N.; Scurtul, V. V.; Oleynik, V. A.

    1980-12-01

    The broshure represents a collection of 11 Laboratory works in Quantum Optics, Semiconductor, Atomic and Nuclear Physics for students of 2-nd years from Technical High Schools. A minimum of theoretical knowledges is given as well as a description of experimental installation (setup),a number of control questions and a task to be carried out is presented for every of the Laboratory work.

  15. SSPALS for atomic physics with positronium

    CERN Document Server

    Deller, Adam

    2016-01-01

    Single-shot positron annihilation lifetime spectroscopy (SSPALS) has proven an extremely useful tool for atomic physics experiments with positronium (Ps). Using a Monte-Carlo simulation, I examine methods employed to analyze lifetime spectra and explore the advantages and limitations these have in laser spectroscopy experiments, such as resonance-enhance multiphoton ionization (REMPI) or the production of Rydberg Ps.

  16. The physics of Hanbury Brown-Twiss intensity interferometry from stars to nuclear collisions

    International Nuclear Information System (INIS)

    In the 1950's Hanbury Brown and Twiss showed that one could measure the angular sizes of astronomical radio sources and stars from correlations of signal intensities, rather than amplitudes, in independent detectors. Their subsequent correlation experiments demonstrating quantum bunching of photons in incoherent light beams were seminal in the development of quantum optics. Since that time the technique of intensity interferometry has become a valuable probe of high energy nuclear and particle collisions, providing information on the space-time geometry of the collision. The effect is one of the few measurements in elementary particle detection that depends on the wave mechanics of the produced particles. Here we discuss the basic physics of intensity interferometry, and its current applications in high energy nuclear physics, as well as recent applications in condensed matter and atomic physics. (author)

  17. Bibliography on electron transfer processes in ion-ion/atom/molecule collisions (updated 1993)

    International Nuclear Information System (INIS)

    Following our previous compilations [IPPJ-AM-45 (1986), NIFS-DATA-7 (1990)], bibliographic information on experimental and theoretical studies on electron transfer processes in ion-ion/atom/molecule collisions is up-dated. The references published through 1980-1992 are included. For easy finding references for particular combination of collision partners, a simple list is also provided. (author) 1542 refs

  18. Atomic, molecular, and optical physics charged particles

    CERN Document Server

    Dunning, F B

    1995-01-01

    With this volume, Methods of Experimental Physics becomes Experimental Methods in the Physical Sciences, a name change which reflects the evolution of todays science. This volume is the first of three which will provide a comprehensive treatment of the key experimental methods of atomic, molecular, and optical physics; the three volumes as a set will form an excellent experimental handbook for the field. The wide availability of tunable lasers in the pastseveral years has revolutionized the field and lead to the introduction of many new experimental methods that are covered in these volumes. Traditional methods are also included to ensure that the volumes will be a complete reference source for the field.

  19. NATO Advanced Study Institute on Topics in Atomic and Nuclear Collisions

    CERN Document Server

    Rémaud, B; Zoran, V

    1994-01-01

    The ASI 'Topics in Atomic and Nuclear Collisions' was organized in Predeal from August 31 to September 11. It brought together people with a broad interest in Atomic and Nuclear Physics from several research institutes and universities in Ro­ mania and 16 other countries. The school continues a tradition that started on a small scale back in 1968, fo­ cussing mainly on current problems in nuclear physics. Though the organizing of this edition started very late and in very uncertain economic and financial conditions, it turned out to be the largest meeting of this type ever organized in Romania, both in topics and participation. There were many applicants for participation and grants, considerably more than could be handled. The selection made by the local organizing committee was based on the following criteria: a proper balance of atomic and nuclear physicists, a broad representation of people from Research Institutes and Universities, a balanced par­ ticipat!on with respect to age, sex, nationali...

  20. Learning about three particle continuum states from fast ion-atom collisions

    International Nuclear Information System (INIS)

    Preliminary results for two fast ion-atom collision experiments were presented. The double detachment of H- leads to some low energy three-particle states which offer interesting possibilities for further investigations into the three-particle Coulomb problem. Secondary electrons from fast ion-atom collisions moving in the region between the two resulting ions appear to express some special features that merit further experimental and theoretical work. 8 refs.; 2 figs

  1. High efficiency preparation of single trapped atoms using blue detuned light assisted collisions

    CERN Document Server

    Carpentier, A V; Sompet, P; Hilliard, A J; Walker, T G; Andersen, M F

    2012-01-01

    We report on a procedure by which we obtain a 91% loading efficiency of single 85Rb atoms in an optical microtrap. This can be achieved within a total preparation time of 542 ms. We employ blue detuned light assisted collisions to realize a process in which only one of the collision partners is lost. We explain the mechanism for efficiently loading a single atom and discuss the factors that limit the final efficiency.

  2. X-ray emission from heavy atomic collisions : couplings of inner shells in superheavy quasimolecules

    OpenAIRE

    Verma, Punita

    2010-01-01

    Overcritical electromagnetic fields with a coupling strength of ZUA greater than or equal to 1/alpha (=137, with alpha being the fine structure constant) can be experienced in superheavy quasimolecules (atomic number ZUA = Z1+Z2) formed transiently in close collisions of two very heavy atomic partners (Z1, Z2) at velocities (vion) smaller compared to the orbital velocity of the innermost electrons of concern (ve-). The inner shell processes in these collisions are governed approximately by th...

  3. Atomic physics processes in radial transport calculations

    International Nuclear Information System (INIS)

    These lectures were intended as preparation for detailed discussions of the role of atomic and molecular physics in confinement research at the 1982 NATO Advanced Study Institute. They begin with a description of the major approaches to magnetic confinement: tandem (ambipolar) mirrors with their associated auxiliary barriers, tokamaks, and stellarators. The leading alternatives, the ELMO Bumpy Torus and the reversed field pinch, are also treated. The evolution equations for particle, energy, and (where relevant) field diffusion are presented and discussed. This is the context for atomic and molecular processes relevant to confinement

  4. Airborne Collision Avoidance System as a Cyber-Physical System

    Directory of Open Access Journals (Sweden)

    Andrei C. NAE

    2015-12-01

    Full Text Available In this paper the key concepts of ITS - Intelligent Transport Systems, CPS - Cyber-Physical Systems and SM - Smart Mobility are defined and correlated with the need for ACAS – Airborne Collision Avoidance System, as the last resort safety net and indispensable ingredient in civil aviation. Smart Mobility is addressed from a Cyber Physical-Systems perspective, detailing some of the elements that this entails. Here we consider the Air Transportations System of the future as a Cyber-Physical System and analyze the implications of doing so from different perspectives. The objective is to introduce a 4D collision avoidance shield technology which forms a last resort safety net technology for the next generation air transport (2050 and beyond. The new system will represent a step change over the performance of current technology. As conclusions, the benefits of implementing Transport Cyber-Physical Systems are discussed, as well as what this would require for future deployment.

  5. The physics of proton antiproton collisions

    Energy Technology Data Exchange (ETDEWEB)

    Shochet, M. (Chicago Univ., IL (United States))

    1991-12-03

    This paper contains information information on: accelerator and detector; QCD studies; studies of the electroweak force; The search for the top quark; {beta} physics at hadron colliders; and the search for exotic objects and prospects for the future.

  6. Some themes from physics in collision

    International Nuclear Information System (INIS)

    The inadequacy of the Standard Model is illustrated for a specific way, and its unfinished business, knowledge of the top quark parameters and the Higgs boson, is discussed. At present supersymmetry is the only hint, uncertain, of where to look for the new physics needed; it predicts a stable bino of large mass. The highest energies of cosmic ray particles are beyond present accelerator energies but appear unavailable for high energy particle physics. (author)

  7. General model of depolarization and transfer of polarization of singly ionized atoms by collisions with hydrogen atoms

    CERN Document Server

    Derouich, Moncef

    2016-01-01

    Simulations of the generation of the atomic polarization is necessary for interpreting the second solar spectrum. For this purpose, it is important to rigorously determine the effects of the isotropic collisions with neutral hydrogen on the atomic polarization of the neutral atoms, ionized atoms and molecules. Our aim is to treat in generality the problem of depolarizing isotropic collisions between singly ionized atoms and neutral hydrogen in its ground state. Using our numerical code, we computed the collisional depolarization rates of the $p$-levels of ions for large number of values of the effective principal quantum number $n^{*}$ and the Uns\\"old energy $E_p$. Then, genetic programming has been utilized to fit the available depolarization rates. As a result, strongly non-linear relationships between the collisional depolarization rates, $n^{*}$ and $E_p$ are obtained, and are shown to reproduce the original data with accuracy clearly better than 10\\%. These relationships allow quick calculations of the ...

  8. Positronium formation and ionization in slow positron-hydrogen atom collisions

    International Nuclear Information System (INIS)

    The electron capture and ionization processes in slow collisions of positrons with hydrogen atoms are considered within the advanced adiabatic approach to atomic collisions. The mass asymmetry of the (p,e-,e+) collision system is properly taken into account. The calculated positronium formation and ionization cross sections compare favourably with the available experimental data in the adiabatic energy region. It is shown that the potential energy curve of the 2p σ molecular state supports a quasi-bound level of the three-particle (p,e+,e-) system with an energy of -0.3 eV and decay width of 0.15 eV, approximately. (author)

  9. Fast low-rank approximations of multidimensional integrals in ion-atomic collisions modelling

    CERN Document Server

    Litsarev, M S

    2015-01-01

    An efficient technique based on low-rank separated approximations is proposed for computation of three-dimensional integrals arising in the energy deposition model that describes ion-atomic collisions. Direct tensor-product quadrature requires grids of size $4000^3$ which is unacceptable. Moreover, several of such integrals have to be computed simultaneously for different values of parameters. To reduce the complexity, we use the structure of the integrand and apply numerical linear algebra techniques for the construction of low-rank approximation. The resulting algorithm is $10^3$ faster than spectral quadratures in spherical coordinates used in the original DEPOSIT code. The approach can be generalized to other multidimensional problems in physics.

  10. Application of Ion and Electron Momentum Imaging to Atomic Collisions

    Science.gov (United States)

    Cocke, C. L.

    2000-06-01

    COLTRIMS (COLd Target Recoil Ion Momentum Spectroscopy) combines fast imaging detectors with a supersonically cooled gas target to allow the charged particles from any ionizing collision, including both recoil ions and electrons, to be collected with extremely high efficiency and with fully measured vector momenta. Since all particles are measured in event mode, the full multi-dimensional momentum space is mapped. We will review several examples of the use of this technique to study two- , three- and four-body final states created in ionizing interactions of photons and charged particles with He and D2 . The momentum spectra of electrons ejected from these targets by slow projectiles reveal the stucture of the molecular orbitals which are promoted into the continuum. Double photoionization of the same targets reveals patterns which can be interpreted in terms of collective coordinates. Two-electron removal from D2 by Xe ^26+ reveals the influence of the projectile field on the dissociation process. A recent application of the technique to ionization by high intensity laser fields will be discussed. Work performed in collaboration with M.A.Abdallah^1, I.Ali^1, Matthias Achler^2, H.Braeuning^2,3, Angela Braeuning-Deminian^2, Achim Czasch^2,3, R.Doerner^2,3, R.DuBois^6, A. Landers^1,5, V.Mergel^2, R.E.Olson^6, T.Osipov^1, M.Prior^3, H.Schmidt-Boecking^2, M.Singh^1, A.Staudte^2,3, T.Weber^2, W.Wolff^4, and H.E.Wolf^4 ^1J.R.Macdonald Laboratory, Physics Department, Kansas State University, Manhattan, KS 66506; ^2 Institut fuer Kernphysik, Univ. Frankfurt, August-Euler-Str.6,D-60486 Frankfurt, Germany ; ^3Lawrence Berkeley National Laboratory, Berkeley, CA 94720; ^4Instituto de Fisica, Universidade Federal do Rio de Janeiro Caixa Postal 68.528, 21945-970, Rio de Janeiro, Brazil; ^5Physics Dept., Western Michigan University, Kalamazoo, MI 49008; ^6Physics Dept., Univ. Missouri Rolla, Rolla, MO 65409 Work supported by the Division of Chemical Sciences, Office of Basic

  11. Magneto optical trap recoil ion momentum spectroscopy: application to ion-atom collisions

    International Nuclear Information System (INIS)

    87Rb atoms have been cooled, trapped and prepared as targets for collision studies with 2 and 5 keV Na+ projectiles. The physics studied deals with charge exchange processes. The active electron, which is generally the most peripheral electron of the atomic target, is transferred from the target onto the ionic projectile. The ionized target is called recoil ion. The technique used to study this physics is the MOTRIMS (Magneto Optical Trap Recoil Ion Momentum Spectroscopy) technique, which combines a magneto optical trap and a recoil ion momentum spectrometer. The spectrometer is used for the measurement of the recoil ions momentum, which gives access to all the information of the collision: the Q-value (which is the potential energy difference of the active electron on each particle) and the scattering angle of the projectile. The trap provides extremely cold targets to optimize the measurement of the momentum, and to release the latter from thermal motion. Through cinematically complete experiments, the MOTRIMS technique gives access to better resolutions on momentum measurements. Measurements of differential cross sections in initial and final capture states and in scattering angle have been done. Results obtained for differential cross sections in initial and final states show globally a good agreement with theory and an other experiment. Nevertheless, discrepancies with theory and this other experiment are shown for the measurements of doubly differential cross sections. These discrepancies are not understood yet. The particularity of the experimental setup designed and tested in this work, namely a low background noise, allows a great sensitivity to weak capture channels, and brings a technical and scientific gain compared with previous works. (author)

  12. Database for inelastic collisions of lithium atoms with electrons, protons, and multiply charged ions

    NARCIS (Netherlands)

    Schweinzer, J; Brandenburg, R; Bray, [No Value; Hoekstra, R; Aumayr, F; Janev, RK; Winter, HP

    1999-01-01

    New experimental and theoretical cross-section data for inelastic collision processes of Li atoms in the ground state and excited states (up to n = 4) with electrons, protons, and multiply charged ions have been reported since the database assembled by Wutte et al. [ATOMIC DATA AND NUCLEAR DATA TABL

  13. Multiple electron capture in close ion-atom collisions

    International Nuclear Information System (INIS)

    Multiple electron capture is reported for Ca17+ in Ar. Close collisions are defined by the observation of a coincident Ca K or Ar K x-ray. A large number of electrons is transferred to the projectile in a single close collision when the Ca ion projectile is of the order of the Ar L-shell electron velocity. The cross section for electron capture is reported

  14. Boundary Collisions of Slow Atoms with Two-dimensional Hexagonal Structure

    Directory of Open Access Journals (Sweden)

    A.S. Dolgov

    2014-11-01

    Full Text Available It is shown that location of target atoms, specified by the structure geometry, define the distribution of impact parameters and energy transfer which strongly differs from the distribution of random location of targets. Considering model of solid spheres, energy spectrum of reflected atoms and probability of single or multiple collisions with the structure are found. Increase in the energy efficiency with respect to the disordered structure is established. Possibility and conditions of realizations of collisions with the second layer atoms omitting first ones are demonstrated.

  15. Suppression of Zeeman Relaxation in Cold Collisions of \\(^2P_{1/2}\\) Atoms

    OpenAIRE

    Tscherbul, T.V.; Buchachenko, A. A.; Dalgarno, Alexander; Lu, M.-J.; Weinstein, J. D.

    2009-01-01

    We present a combined experimental and theoretical study of angular momentum depolarization in cold collisions of \\(^2P\\) atoms in the presence of an external magnetic field. We show that collision-induced Zeeman relaxation of Ga\\(^2P_{1/2}\\) and In \\(^2P_{1/2}\\) atoms in cold \\(^4\\)He gas is dramatically suppressed compared to atoms in \\(^2P_{3/2}\\) states. Using rigorous quantum-scattering calculations based on ab initio interaction potentials, we demonstrate that Zeeman transitions in coll...

  16. Atomic Physics 15: Proceedings of the Fifteenth International Conference on Atomic Physics.

    Science.gov (United States)

    van Linden van den Heuvell, H. B.; Walraven, J. T. M.; Reynolds, M. W.

    1997-07-01

    The Table of Contents for the full book PDF is as follows: * Preface * Generation of a "Schrödinger cat" of radiation and observation of its decoherence * Synthesis of entangled states and quantum computing * Entangled states of atomic ions for quantum metrology and computation * Entanglement and indistinguishability: Coherence experiments with photon pairs and triplets * Atom optics as a testing ground for quantum chaos * Coherent ultra-bright XUV lasers and harmonics * Hollow atoms * Interdisciplinary experiments with polarized noble gases * The creation and study of Bose-Einstein condensation in a cold alkali vapor * oscopic quantum phenomena in trapped Bose-condensed gases * Doppler-free spectroscopy of trapped atomic hydrogen * QED and the ground state of helium * Towards coherent atomic samples using laser cooling * Bose-Einstein condensation of a weakly-interacting gas * Zeeman and his contemporaries: Dutch physics around 1900 * Zeeman's great discovery * The Zeeman effect: A tool for atom manipulation * The Zeeman effect a century later: New insights into classical physics * QED effects in few-electron high-Z systems * Lamb shift experiments on high-Z one- and two-electron systems * Fundamental constants of nature * Response of atoms in photonic lattices * Hydrogen-like systems and quantum electrodynamics * New experiments with atomic lattices bound by light * Bloch oscillations of atoms in an optical potential * Quantum decoherence and inertial sensing with atom interferometers * Quantum effects in He clusters * Atoms in super-intense radiation fields * Wave packet dynamics of excited atomic electrons in intense laser fields * Nonlinear laser-electron scattering * Comparing the antiproton and proton and progress toward cold antihydrogen * Author Index

  17. Time-evolution of many active electrons in slow ion-atom collisions

    Energy Technology Data Exchange (ETDEWEB)

    Runge, K.; Micha, D.A.

    1996-05-01

    The previously developed Eikonal/Time-dependent Hartree-Fock method is applied to slow ionic and atomic collisions involving many active electrons. The electronic density matrix is written in a basis of traveling atomic orbitals including s, p, and d-type atomic basis functions. One- and two-electron integrals are calculated in a static basis and transformed to the traveling basis. Electronic orbital polarization parameters are calculated during the collision to determine the degree of electonic orientation and alignment as a function of time. This method is currently being applied to slow collisions of hydrogen, alkali, alkali earth and rare gas atoms and ions, to calculate the time evolution of electronic energy and charge transfer, as well as orbital polarization.

  18. Unified treatment of hadronic annihilation and protonium formation in slow collisions of antiprotons with hydrogen atoms

    Science.gov (United States)

    Sakimoto, Kazuhiro

    2013-07-01

    Antiproton (p¯) collisions with hydrogen atoms, resulting in the hadronic process of particle-antiparticle annihilation and the atomic process of protonium (p¯p) formation (or p¯ capture), are investigated theoretically. As the collision energy decreases, the collision time required for the p¯ capture becomes necessarily longer. Then, there is the possibility that the p¯-p annihilation occurs significantly before the p¯ capture process completes. In such a case, one can no longer consider the annihilation decay separately from the p¯ capture process. The present study develops a rigorous unified quantum-mechanical treatment of the annihilation and p¯ capture processes. For this purpose, an R-matrix approach for atomic collisions is extended to have complex-valued R-matrix elements allowing for the hadronic annihilation. Detailed calculations are carried out at low collision energies ranging from 10-8 to 10-1 eV, and the annihilation and the p¯ capture (total and product-state selected) cross sections are reported. Consideration is given to the difference between the direct annihilation occurring during the collision and the annihilation of p¯p occurring after the p¯ capture. The present annihilation process is also compared with the annihilation in two-body p¯+p collisions.

  19. Atoms, molecules and optical physics 1. Atomic physics and foundations of spectroscopy

    International Nuclear Information System (INIS)

    Unique, unified presentation of these partial fields and by this exclusive. With the highly reputed co-author Prof. Dr. Ingolf Volker Hertel. Eminent presentation makes it possible, together also over set connections. For bachelor/master and diploma curricula. The book applies primarily to graduate students of physics and physical chemistry until promotion. It offers a detailed introduction to the most important theme complexes of atomic and molecular physics and the methods of modern optical physics connected with this. In many selected partial fields it leads until the actual status of research. Simultaneously it also appeals to the active scientist and wants to be a standard work of the field. By the clearly stuctured chapters the reader is - starting from the foundations of quantum physics - step-wise made familiar with the most important phenomena and models of atomic and molecular physics and led wherever it is offered, to their actual developments in modern research. In the first part here present the to a certain degree canonical knowledge with the main topic structure of atoms and molecules and the competent spectroscopy is summarized. In the second part still being in work deepening knowledge for this is mediated, and selected chapters of modern optics, lase physics, cluster research, and scattering physics is treated, as well a short excursus in the world of cold atoms and molecules is given. At the whole both volumes of this textbook want to show to the interested reader that atomic, molecular, and optical physics, are still as usual an alive field of modern physical research

  20. Excitation and charge transfer in low-energy hydrogen atom collisions with neutral atoms: Theory, comparisons, and application to Ca

    CERN Document Server

    Barklem, Paul S

    2016-01-01

    A theoretical method for the estimation of cross sections and rates for excitation and charge transfer processes in low-energy hydrogen atom collisions with neutral atoms, based on an asymptotic two-electron model of ionic-covalent interactions in the neutral atom-hydrogen atom system, is presented. The calculation of potentials and non-adiabatic radial couplings using the method is demonstrated. The potentials are used together with the multi-channel Landau-Zener model to calculate cross sections and rate coefficients. The main feature of the method is that it employs asymptotically exact atomic wavefunctions, which can be determined from known atomic parameters. The method is applied to Li+H, Na+H, and Mg+H collisions, and the results compare well with existing detailed full-quantum calculations. The method is applied to the astrophysically important problem of Ca+H collisions, and rate coefficients are calculated for temperatures in the range 1000-20000 K.

  1. Dissociative excitation of cesium atom upon e-CsOH collisions

    International Nuclear Information System (INIS)

    The process of dissociative excitation of cesium atom in collisions with mono-kinetic molecules of cesium hydroxide is studied. It is established that behaviour of dissociative excitations the cesium atom in spectral series corresponds of to the grade dependence of cross sections on the main quantum number of the upper level. The values of constants, characterizing the behaviour of cross sections in the eight spectral series of the cesium atom are determined

  2. Investigation of the intermediate LK molecular orbital radiation in heavy ion-atom collisions

    International Nuclear Information System (INIS)

    The continuum consisting of an intensive low-energy and a high-energy components in heavy-ion atom collision systems with atomic numbers Z1, Z2 > 28 is studied. The aim of the study is to prove that the C1 continuum cannot be caused by ridiative electron capture (REC) being molecular orbital (MO) radiation to the 2ptau level. It is shown that the comparison of the C1 yields obtained in Kr+Nb asymmetric collisions in gas and solid targets is associated with the formation of vacancies in the lower-Z collision partner and can be interpreted as quasimolecular radiation to the 2ptau orbital level. The strong suppression of the C2 component in the gas target experimets indicates that the MO radiation to the 1stau orbit is emitted preferentially in the two-collision process in symmetric and near-symmetric systems with Z1, Z2 <= 41

  3. Analysis and manipulation of atomic and molecular collisions using laser light

    International Nuclear Information System (INIS)

    Optical collisions in a crossed beam experiment are examined for the atomic collision pairs LiHe, LiNe, NaNe. Differential cross sections are measured in order to probe the quality of quantum chemical calculated and spectroscopical determined molecular potentials. The linear polarization of the excitation laser is used to manipulate the contrast of the differential cross sections for NaNe. Using elliptical polarized light total control over the angular position and the contrast of the interference pattern is demonstrated. Differential cross sections for the collision pairs LiH2 and LiD2 show a pronounced oscillatory structure, which for the first time is observed for atom-molecule optical collisions. (orig.)

  4. Atomic, molecular, and optical physics electromagnetic radiation

    CERN Document Server

    Dunning, F B; Lucatorto, Thomas

    1997-01-01

    Combined with Volumes 29A and 29B, this volume is a comprehensive treatment of the key experimental methods of atomic, molecular, and optical physics, as well as an excellent experimental handbook for the field. Thewide availability of tunable lasers in the past several years has revolutionized the field and lead to the introduction of many new experimental methods that are covered in these volumes. Traditional methods are also included to ensure that the volumes will be a complete reference source for the field.

  5. K-Vacancy Production in the Collision of Highly Charged Relativistic Ions With Heavy Atoms

    OpenAIRE

    Khabibullaev, P. K.

    2000-01-01

    A general expression for the cross section of the inelastic collision of relativistic highly charged ion with heavy (relativistic) atoms is obtained using the generalized eikonal approximation. In the ultrarelativistic limit, the obtained formula coincides with a known exact one. As an application of the obtained result, probability and cross section of the K-vacany production in the U92+ - U91+ collision are calculated.

  6. Large Effects of Electric Fields on Atom-Molecule Collisions at Millikelvin Temperatures

    OpenAIRE

    Parazzoli, L. P.; Fitch, N J; Zuchowski, P.S.; Hutson, J. M.; Lewandowsk, H.J.

    2011-01-01

    Controlling interactions between cold molecules using external fields can elucidate the role of quantum mechanics in molecular collisions. We create a new experimental platform in which ultracold rubidium atoms and cold ammonia molecules are separately trapped by magnetic and electric fields and then combined to study collisions. We observe inelastic processes that are faster than expected from earlier field-free calculations. We use quantum scattering calculations to show that electric field...

  7. Bibliography on electron transfer processes in ion-ion/atom/molecule collisions. Updated 1997

    International Nuclear Information System (INIS)

    Following our previous compilations (IPPJ-AM-45 (1986), NIFS-DATA-7 (1990), NIFS-DATA-20 (1993)), bibliographic information on experimental and theoretical studies on electron transfer processes in ion-ion/atom/molecule collisions is up-dated. The references published through 1954-1996 are listed in the order of the publication year. For easy finding of the references for a combination of collision partners, a simple list is provided. (author)

  8. Bibliography on electron transfer processes in ion-ion/atom/molecule collisions, updated 1990

    International Nuclear Information System (INIS)

    Following a previous compilation, new bibliographic information on experimental and theoretical studies on electron transfer processes in ion-ion/atom/molecule collisions is up-dated. The references published through 1989 are surveyed. For easy finding references for particular combination of collision partners, a simple list is also provided. Furthermore, for convenience, a copy of the previous compilation (IPPJ-AM-45 (1986)) is included. (author) 1363 refs

  9. Bibliography on electron transfer processes in ion-ion/atom/molecule collisions. Updated 1997

    Energy Technology Data Exchange (ETDEWEB)

    Tawara, H.

    1997-04-01

    Following our previous compilations (IPPJ-AM-45 (1986), NIFS-DATA-7 (1990), NIFS-DATA-20 (1993)), bibliographic information on experimental and theoretical studies on electron transfer processes in ion-ion/atom/molecule collisions is up-dated. The references published through 1954-1996 are listed in the order of the publication year. For easy finding of the references for a combination of collision partners, a simple list is provided. (author)

  10. Collective processes in heavy-ion collisions with atomic nuclei. Dissipation of energy and angular momentum

    International Nuclear Information System (INIS)

    The collective processes in collision of heavy-ions with atomic nuclei are discussed. Measured data on the S+Ti collision at Esub(LAB)=105, 130 and 144 MeV have been analysed in terms of a ''fission-like'' processes which seem to be a special case of deep inelastic collisions whose total available kinetic energy is completely dissipated. Applying transport theory it was possible to introduce a ''clock'' for measuring the time scale of nuclear processes in collision of heavy-ions by measuring the FWHM of mass distribution of emitted reaction products. Experimental data on continuum gamma spectra from Cu+Au collision at Esub(LAB)=400 MeV are presented and the angular momentum dissipation in this reaction is discussed. (author)

  11. Ultracold atomic collisions in tight harmonic traps: Perturbation theory, ionization losses and application to metastable helium atoms

    CERN Document Server

    Beams, T J; Whittingham, I B

    2004-01-01

    Collisions between tightly confined atoms can lead to ionization and hence to loss of atoms from the trap. We develop second-order perturbation theory for a tensorial perturbation of a spherically symmetric system and the theory is then applied to processes mediated by the spin-dipole interaction. Redistribution and loss mechanisms are studied for the case of spin-polarized metastable helium atoms and results obtained for the five lowest s states in the trap and trapping frequencies ranging from 1 kHz to 10 MHz.

  12. Dynamical resonant electron capture in atom surface collisions: H- formation in H-Al(111) collisions

    Science.gov (United States)

    Borisov, A. G.; Teillet-Billy, D.; Gauyacq, J. P.

    1992-05-01

    The formation of H- ion by grazing-angle collisions of hydrogen on an Al(111) surface is investigated with the newly developed coupled angular mode method. The capture process involves a dynamical resonant process induced by the collision velocity. All the resonance properties of the H- level in front of an Al(111) surface are determined: position, width, and angular distribution of ejected electrons. The results are shown to account for the recent observations on H- formation by Wyputta, Zimny, and Winter.

  13. Theoretical study of electronic processes occurring in atom and molecule collisions: the non-perturbative approach

    International Nuclear Information System (INIS)

    This work is composed of 2 parts. The first part is dedicated to the study of ion collisions with atoms or molecules and the second part deals with electron-atom collisions in intense laser radiation. The 2 issues are not so independent as it seems since both involve diffusion processes or the dynamic of electronic structures of atoms and molecules in a non-perturbative framework. The first chapter describes the main collisional processes that happen in ion collisions with atoms and molecules. The eikonal method that is used to compute integral and differential cross-sections is presented in the second chapter. The third chapter reports the various concepts and methods used for studying the dynamics of quantum systems. The fourth chapter deals with the electronic capture in a mono-electronic molecular system and with the interference phenomena that may take place in the differential cross-sections. The fifth chapter studies the ionizing ion-molecule collisions with high impact energy, in such collisions very low amplitude interference structures have been observed experimentally. These structures can be explained by the multiple scattering of the wave packet representing the ejected electron by the 2 centers of the molecular target. The sixth chapter deals with ion-atom collisions in which 2 electrons are active for simple and double electronic capture. The second part of this work begins with chapter 7. The study of electron-atom collisions in intense laser radiation field implies to take into account 3 different interactions: first the interaction between the free electron and the atom, secondly the interaction between the laser field and the incident electron and thirdly, the interaction between the atom and the laser field. The seventh chapter presents a mathematical formalism able to describe the interaction of the atom with the laser field. This formalism is a non-perturbative approach based on the Floquet theorem. In chapter 8 we present an application to

  14. Lectures on ion-atom collisions from nonrelativistic to relativistic velocities

    CERN Document Server

    Eichler, Jörg

    2005-01-01

    Atomic collisions offer some unique opportunities to study atomic structure and reaction mechanisms in experiment and theory, especially for projectiles of high atomic number provided by modern accelerators. The book is meant as an introduction into the field and provides some basic theoretical understanding of the atomic processes occurring when a projectile hits another atom. It also furnishes the tools for a mathematical description, however, without going deeper into the technical details, which can be found in the literature given. With this aim, the focus is on reactions, in which only a single active electron participates. Collisional excitation, ionization and charge transfer are discussed for collision velocities ranging from slow to comparable to thespeed of light. For the highest projectile velocities, energy can be converted into mass, so that electron-positron pairs are created. In addition to the systematic treatment, a theoretical section specializes on electron-electroncorrelations and three...

  15. US-Japan Workshop on atomic-collision data for fusion

    International Nuclear Information System (INIS)

    This report, containing abstracts of each of the presentations and discussions, includes: brief talks on the applications of atomic data in tokamaks and in inertial confinement; reviews of the specific atomic collisions projects for fusion in Japan and the United States; discussions of how the data centers operate and manner of exchanging data; brief reviews of the status of electron-ion scattering and ion-atom scattering; discussions of criteria to be used in evaluating and selecting both experimental and theoretical data in these two areas; comparisons of data selected for each of six specific collision reactions which were evaluated by both groups prior to the workshop; brief reviews of activities in the related areas of atomic structure and plasma wall interactions; and a decision to pursue a joint or collaborative compilation of recommended cross sections for oxygen ions for electron impact excitation and electron capture from atomic hydrogen

  16. Single-collision studies of hot atom energy transfer and chemical reaction

    International Nuclear Information System (INIS)

    This report discusses research in the collision dynamics of translationally hot atoms, with funding with DOE for the project ''Single-Collision Studies of Hot Atom Energy Transfer and Chemical Reaction,'' Grant Number DE-FG03-85ER13453. The work reported here was done during the period September 9, 1988 through October 31, 1991. During this period this DOE-funded work has been focused on several different efforts: (1) experimental studies of the state-to-state dynamics of the H + RH → H2 R reactions where RH is CH4, C2H6, or C3H8, (2) theoretical (quasiclassical trajectory) studies of hot hydrogen atom collision dynamics, (3) the development of photochemical sources of translationally hot molecular free radicals and characterization of the high resolution CARS spectroscopy of molecular free radicals, (4) the implementation of stimulated Raman excitation (SRE) techniques for the preparation of vibrationally state-selected molecular reactants

  17. Atomic and nuclear physics an introduction

    CERN Document Server

    Littlefield, T A

    1979-01-01

    After the death of Dr. Littlefield it was decided that I should undertake the revision ofthe whole of Atomic and Nuclear Physics: an Introduction for the third edition, and it was soon apparent that major changes were necessary. I am confident that these changes would have had Dr. Littlefield's approval. The prime consideration for the present edition has been to modernize at a minimum cost. As much as possible of the second edition has therefore been retained, but where changes have been made they have been fairly drastic. Thus the chapters on fine structure, wave mechanics, the vector model of the atom, Pauli's principle and the Zeeman effect have been completely restructured. The chapters on nuclear models, cosmic rays, fusion systems and fundamental particles have been brought up to date while a new chapter on charm and the latest ideas on quarks has been included. It is hoped that the presentation of the last named will give readers a feeling that physics research can be full of adventure and surprises.

  18. Microtraps and Atom Chips: Toolboxes for Cold Atom Physics

    OpenAIRE

    Feenstra, L.; Andersson, L. M.; Schmiedmayer, J.

    2003-01-01

    Magnetic microtraps and Atom Chips are safe, small-scale, reliable and flexible tools to prepare ultra-cold and degenerate atom clouds as sources for various atom-optical experiments. We present an overview of the possibilities of the devices and indicate how a microtrap can be used to prepare and launch a Bose-Einstein condensate for use in an atom clock or an interferometer.

  19. Collision of Bare Ion Si14+ with the Same Z Slow-atom Si

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    We present the collision of bare ion Si14+ with the same Z slow-atom Si. It is shown that the cold-atom collisions are sensitive to the potential. In this paper, we present the cross sectiond for the most important transition from the 3p13d1 and 3p14d1 excited states. It is seen that there are large cross sections when the angle is larger than 80 degrees. With increasing energy, the cross section becomes decresasingly flat.PACS numbers:34.70.+e, 32.80. Fb

  20. Calculation of the ionization differential effective cross sections in fast ion-atom collisions

    CERN Document Server

    Kaminskij, A K

    2002-01-01

    The method of the calculations of the ionization effective cross sections d sigma/d OMEGA differential in the incident ion scattering angle is described in fast collisions of light ions and atoms. The calculated values of angular distributions of the ions Al, Mg (for the different values of charge and energy of ions) after their collisions with the Ne, Mg atoms being ionized are reported. The dependence of such angular distributions on the incident ion charge and energy and the initial state of ejected electron is investigated

  1. Measurements of scattering processes in negative ion - atom collisions. Technical progress report - year 1, April 1, 1995--March 31, 1996

    Energy Technology Data Exchange (ETDEWEB)

    Kvale, T.J.

    1995-12-01

    This Technical Progress Report describes the progress made on the research objectives during the past twelve months. The objective of this research project is to provide absolute cross section measurements of various scattering processes which occur in negative ion collisions with atomic (specifically, noble gas and atomic hydrogen) targets at intermediate energies. These processes include: elastic scattering, single- and double-electron detachment, and target-inelastic processes of excitation and ionization. Total cross sections for single- and double-electron detachment were recently published in Physical Review A from this research project. The researchers were successful this past year in acquiring the first cross section measurements of target excitation for H{sup -} impact on helium target atoms.

  2. Heavy quark physics in ep collisions at LEP+LHC

    International Nuclear Information System (INIS)

    We study electroweak production of heavy quarks - charm, beauty, and top - in deep inelastic electron-proton collisions at the proposed LEP+LHC collider at CERN. The assumed energy for the collisions is Ee=50 GeV, Ep=8000 GeV, providing an ep center of mass energy, √s≅1.26 TeV. We invoke the boson-gluon fusion model to estimate theoretical cross sections and distributions for the heavy quarks. Higher order QCD corrections are only approximately taken into account, by assuming a (normalization) K-factor of 2 for the charm and beauty quark production rates and incorporating the parton shower cascades. With these assumptions and the parameterization of Eichten et al. for the structure functions (EHLQ, set 1), we find the following cross sections: σ(ep→c+X)≅O(3 μb), σ(ep→b+X)≅O(40 nb), and σ(ep→t+X)≅4 pb for mt=120 GeV, decreasing to 0.5 pb for mt=250 GeV. These cross sections would provide O(6x109) charmed hadrons, O(8x107) beauty hadrons, and O(103) top hadrons, for an integrated ep luminosity of 1000 pb-1. The heavy quark rates in ep collisions are considerably smaller than the corresponding rates in pp collisions at LHC, with √s=16 TeV. This gives a clear advantage to pp collisions for top searches. However, for the charmed and beauty quarks only a tiny fraction of the cross sections in p+p→Q+X can be triggered in comparison to the corresponding cross sections in e+p→Q+X, resulting in comparable number of measured heavy quark events in the ep and pp mode. We sketch the energy-momentum profile of heavy quark events in ep collisions and illustrate the kind of analyses that experiments at the LEP+LHC collider would undertake to quantitatively study heavy quark physics. In particular, prospects of measuring the particle-antiparticle mixing parameter xs=ΔM/Γ for the Bs0-anti Bs0 meson system are evaluated, and search strategies for the top quark in ep collisions are presented. (orig.)

  3. Charge breeding investigation in EBIS/T and collision study of ions with cold atoms for HITRAP

    International Nuclear Information System (INIS)

    Highly charged ions (HCI) at low velocities or at rest are interesting systems for various atomic physics experiments. For investigations on HCI of heavy stable or radioactive nuclides the HITRAP (Highly charged Ion TRAP) decelerator facility has been set up at GSI to deliver cooled beams of HCI at an energy of 5 keV/q. The HCI are produced in a stripper foil at relativistic energies and are decelerated in several steps at ESR storage ring and HITRAP before they are delivered to experimental setups. One of the experiments is the investigation of multi-electron charge exchange in collisions of heavy HCI with cold atoms using novel MOTRIMS technique. Collision experiments on light ions from an ECR ion source colliding with cold atoms in a MOT have been performed and the results are described. An electron beam ion trap (EBIT) has been tested and optimized for commissioning of the HITRAP physics experiments. The process of charge breeding in the EBIT has been successfully studied with gaseous elements and with an alkaline element injected from an external ion source. (orig.)

  4. Charge breeding investigation in EBIS/T and collision study of ions with cold atoms for HITRAP

    Energy Technology Data Exchange (ETDEWEB)

    Sokolov, Alexey

    2010-01-29

    Highly charged ions (HCI) at low velocities or at rest are interesting systems for various atomic physics experiments. For investigations on HCI of heavy stable or radioactive nuclides the HITRAP (Highly charged Ion TRAP) decelerator facility has been set up at GSI to deliver cooled beams of HCI at an energy of 5 keV/q. The HCI are produced in a stripper foil at relativistic energies and are decelerated in several steps at ESR storage ring and HITRAP before they are delivered to experimental setups. One of the experiments is the investigation of multi-electron charge exchange in collisions of heavy HCI with cold atoms using novel MOTRIMS technique. Collision experiments on light ions from an ECR ion source colliding with cold atoms in a MOT have been performed and the results are described. An electron beam ion trap (EBIT) has been tested and optimized for commissioning of the HITRAP physics experiments. The process of charge breeding in the EBIT has been successfully studied with gaseous elements and with an alkaline element injected from an external ion source. (orig.)

  5. Non-thermal Dupree diffusivity and shielding effects on atomic collisions in Lorentzian turbulent plasmas

    Science.gov (United States)

    Lee, Myoung-Jae; Jung, Young-Dae

    2016-05-01

    The influence of non-thermal Dupree turbulence and the plasma shielding on the electron-ion collision is investigated in Lorentzian turbulent plasmas. The second-order eikonal analysis and the effective interaction potential including the Lorentzian far-field term are employed to obtain the eikonal scattering phase shift and the eikonal collision cross section as functions of the diffusion coefficient, impact parameter, collision energy, Debye length and spectral index of the astrophysical Lorentzian plasma. It is shown that the non-thermal effect suppresses the eikonal scattering phase shift. However, it enhances the eikonal collision cross section in astrophysical non-thermal turbulent plasmas. The effect of non-thermal turbulence on the eikonal atomic collision cross section is weakened with increasing collision energy. The variation of the atomic cross section due to the non-thermal Dupree turbulence is also discussed. This research was supported by Nuclear Fusion Research Program through NRF funded by the Ministry of Science, ICT & Future Planning (Grant No. 2015M1A7A1A01002786).

  6. 16. International Conference on Atomic Collisions in Solids. Book of abstracts

    International Nuclear Information System (INIS)

    In this conference book of abstracts the following topics are treated: The interaction of atomic, molecular or ion beams with surfaces of solid metals and crystals, scattering and collisions, ion bombardment, ion channeling, energy losses and charge exchange, thin films, secondary emission, the Auger effect, sputtering of particles and atomic and molecular clusters. Thereby not only experimental results are presented but also computerized simulation methods are applied. (Suda)

  7. Influence of the atomic-wall collision elasticity on the coherent population trapping resonance shape

    OpenAIRE

    Kazakov, G A; Litvinov, A. N.; Matisov, B. G.; Romanenko, V. I.; Yatsenko, L. P.; Romanenko, A. V.

    2011-01-01

    We studied theoretically a coherent population trapping resonance formation in cylindrical cell without buffer gas irradiated by a narrow laser beam. We take into account non-zero probabilities of elastic ("specular") and inelastic ("sticking") collision between the atom and the cell wall. We have developed a theoretical model based on averaging over the random Ramsey pulse sequences of times that atom spent in and out of the beam. It is shown that the shape of coherent population trapping re...

  8. Cross-sections for neutral atoms and molecules collisions with charged spherical nanoparticle

    CERN Document Server

    Shneider, M N

    2016-01-01

    The paper presents cross sections for collisions of neutral atoms/molecules with a charged nanoparticle, which is the source of the dipole potential. The accuracy of the orbital limited motion (OLM) approximation is estimated. It is shown that simple analytical formulas for the atoms/molecules and heat fluxes, obtained in the OLM approximation, give an error of not more than 15%, and are applicable in all reasonable range of nanoparticles and weakly ionized plasma parameters.

  9. Atomic physics at the advanced photon source

    International Nuclear Information System (INIS)

    Argonne's 7-GeV synchrotron light source (APS) is expected to commence operations for research early in FY 1996. The Basic Energy Sciences Synchrotron Research Center (BESSRC) is likewise expected to start its research programs at that time. As members of the BESSRC CAT (Collaborative Access Team), we are preparing, together with atomic physicists from the University of Western Michigan, the University of Tennessee, and University of Notre Dame, to initiate a series of atomic physics experiments that exploit the unique capabilities of the APS, especially its high brilliance for photon energies extending from about 3 keV to more than 50 keV. Most of our early work will be conducted on an undulator beam line and we are thus concentrating on various aspects of that beam line and its associated experimental areas. Our group has undertaken responsibilities in such areas as hutch design, evaluation of undulator performance, user policy, interfacing and instrumentation, etc. Initial experiments will probably utilize existing apparatus. We are, however, planning to move rapidly to more sophisticated measurements involving, for example, ion-beam targets, simultaneous laser excitation, and the spectroscopy of emitted photons

  10. Formation of heavy-Rydberg ion-pair states in Rydberg atom collisions with attaching targets

    Science.gov (United States)

    Wang, Changhao; Kelley, Michael; Buathong, Sitti; Dunning, F. Barry

    2014-05-01

    Electron transfer in collisions between K(np)Rydberg atoms and electron attaching molecules can lead to formation of heavy-Rydberg ion-pair states comprising a weakly-bound positive-negative ion pair orbiting at large internuclear separations. In the present work ion-pair states are created in a small collision cell and allowed to exit into an analysis region where their binding energy and velocity distributions are determined with the aid of electric-field-induced dissociation and a position sensitive detector. Ion pair production is analyzed using a Monte Carlo collision code that models both the initial Rydberg electron capture and the subsequent behavior of the product ion pair. The data demonstrate that collisions with SF6 and CCl4 lead to formation of long-lived ion pair states with a broad distribution of binding energies whose velocity distribution is strongly peaked in the forward direction. Research supported by the Robert A. Welch Foundation.

  11. Positronium formation and ionization in slow positron-hydrogen atom collisions

    Energy Technology Data Exchange (ETDEWEB)

    Janev, R.K. [International Atomic Energy Agency, PO Box 100, A-1400 Vienna (Austria); Solov' ev, E.A. [Research Centre for Energy and Informatics, Macedonian Academy of Sciences and Arts, PO Box 428, 9100 Skopje (Macedonia, The Former Yugoslav Republic of)

    1999-07-14

    The electron capture and ionization processes in slow collisions of positrons with hydrogen atoms are considered within the advanced adiabatic approach to atomic collisions. The mass asymmetry of the (p,e{sup -},e{sup +}) collision system is properly taken into account. The calculated positronium formation and ionization cross sections compare favourably with the available experimental data in the adiabatic energy region. It is shown that the potential energy curve of the 2p {sigma} molecular state supports a quasi-bound level of the three-particle (p,e{sup +},e{sup -}) system with an energy of -0.3 eV and decay width of 0.15 eV, approximately. (author)

  12. Cold collisions of N atoms and NH molecules in magnetic fields

    CERN Document Server

    Zuchowski, Piotr S \\

    2010-01-01

    We calculate the interaction potential between N atoms and NH molecules and use it to investigate cold and ultracold collisions important for sympathetic cooling. The ratio of elastic to inelastic cross sections is large over a wide range of collision energy and magnetic field for most isotopic combinations, so that sympathetic cooling of NH molecules by N atoms is a good prospect. However, there are important effects due to a p-wave shape resonance that may inhibit cooling in some cases. We show that scaling the reduced mass used in the collision is approximately equivalent to scaling the interaction potential. We then explore the dependence of the scattering properties on the reduced mass and explain the resonant effects observed using angular-momentum-insensitive quantum defect theory

  13. Atom interferometers and optical atomic clocks: New quantum sensors for fundamental physics experiments in space

    International Nuclear Information System (INIS)

    We present projects for future space missions using new quantum devices based on ultracold atoms. They will enable fundamental physics experiments testing quantum physics, physics beyond the standard model of fundamental particles and interactions, special relativity, gravitation and general relativity

  14. On cross sections of intercombination transitions between high-excited levels in electron-atom collisions

    International Nuclear Information System (INIS)

    The cross sections of intercombination transitions (ICT) between high-excited levels of atoms during the collisions of the latter with electrons are considered. A method is proposed for calculating ICT cross sections which are orbital quantum number totals. A comparison with the cross section calculated within the scope of quasiclassic approach is performed. Both methods yield close results

  15. ELECTRON-CAPTURE IN HIGHLY-CHARGED ION-ATOM COLLISIONS

    NARCIS (Netherlands)

    MORGENSTERN, R

    1993-01-01

    An attempt is made to identify the most important mechanisms responsible for the rearrangement of electrons during collisions between multiply charged ions and atoms at keV energies. It is discussed to which extent the influence of binding energy, angular momentum of heavy particles and electrons, a

  16. Relativistic effects in non-radiative electron capture in ion-atom collisions

    International Nuclear Information System (INIS)

    In this paper, a modified eikonal method (Blankenbecler-Goldberger) has been extended to perform calculations for the electron capture processes in relativistic ion-atom collisions. The results are compared with the first order Born approximation and the ordinary eikonal approximation. The relativistic effects are discussed. Some conclusions are drawn. (author)

  17. Orientational invariance of the rotational transition probability in the sudden approximation. [atom-molecule collisions

    Science.gov (United States)

    Stallcop, J. R.

    1974-01-01

    Semiclassical collisions of an atom with a rigid-rotor molecule are examined in the sudden approximation. The rotational transition probability is shown to be invariant with respect to the choice of orientation for the molecular coordinate system; this fact contradicts recently reported results of a computer analysis. The present analysis may lead to an improved interpretation of recent molecular beam measurements.

  18. Electron and X-ray emission in collisions of multiply charged ions and atoms

    International Nuclear Information System (INIS)

    The author presents experimental results of electron and X-ray emission following slow collisions of multiply charged ions and atoms. The aim of the investigation was to study the mechanisms which are responsible for the emission. (G.T.H.)

  19. High Rydberg atoms: newcomers to the atomic physics scene

    International Nuclear Information System (INIS)

    A description is given of high Rydberg atoms which have a greatly increased size due to their having been perturbed in certain ways. The production, detection, and research on these atoms are considered. The motivation for such studies, apart from their intrinsic interest, includes laser development, laser isotope separation, energy deposition in gases, plasma diagnostics, and radio astronomy

  20. Accurate abundance analysis of late-type stars: advances in atomic physics

    CERN Document Server

    Barklem, Paul S

    2016-01-01

    The measurement of stellar properties such as chemical compositions, masses and ages, through stellar spectra, is a fundamental problem in astrophysics. Progress in the understanding, calculation and measurement of atomic properties and processes relevant to the high-accuracy analysis of F-, G-, and K-type stellar spectra is reviewed, with particular emphasis on abundance analysis. This includes fundamental atomic data such as energy levels, wavelengths, and transition probabilities, as well as processes of photoionisation, collisional broadening and inelastic collisions. A recurring theme throughout the review is the interplay between theoretical atomic physics, laboratory measurements, and astrophysical modelling, all of which contribute to our understanding of atoms and atomic processes, as well as to modelling stellar spectra.

  1. Atomic parity violation, muon pair production in e{sup +}e{sup -} collisions, and detection of CDM WIMP. Physics related to the neutral vector boson D{sub 1}

    Energy Technology Data Exchange (ETDEWEB)

    Senju, Hirofumi [Physics Department, School of Design and Architecture, Nagoya City Univ., Nagoya (Japan)

    1999-11-01

    In our preon model there exists a neutral vector boson D{sub 1} which is an isoscalar partner of W(Z) in the vector boson octet. It is shown that the exchange of a D{sub 1} of about 1 TeV mass naturally explains a positive excess of the weak charge of atomic cesium recently observed. Other processes occurring through the D{sub 1} exchange are discussed, including the detection of CDM WIMP. (author)

  2. Atomic Spectroscopy and Collisions Using Slow Antiprotons \\\\ ASACUSA Collaboration

    CERN Multimedia

    Matsuda, Y; Lodi-rizzini, E; Kuroda, N; Schettino, G; Hori, M; Pirkl, W; Mascagna, V; Malbrunot, C L S; Yamazaki, Y; Eades, J; Simon, M; Massiczek, O; Sauerzopf, C; Breuker, H; Nagata, Y; Uggerhoj, U I; Mc cullough, R W; Toekesi, K M; Venturelli, L; Widmann, E; Zmeskal, J; Kanai, Y; Hayano, R; Knudsen, H; Kristiansen, H; Todoroki, K; Bartel, M A; Moller, S P; Charlton, M; Leali, M; Diermaier, M; Kolbinger, B

    2002-01-01

    ASACUSA (\\underline{A}tomic \\underline{S}pectroscopy \\underline{A}nd \\underline{C}ollisions \\underline{U}sing \\underline{S}low \\underline{A}ntiprotons) is a collaboration between a number of Japanese and European research institutions, with the goal of studying bound and continuum states of antiprotons with simple atoms.\\\\ Three phases of experimentation are planned for ASACUSA. In the first phase, we use the direct $\\overline{p}$ beam from AD at 5.3 MeV and concentrate on the laser and microwave spectroscopy of the metastable antiprotonic helium atom, $\\overline{p}$He$^+$, consisting of an electron and antiproton bound by the Coulomb force to the helium nucleus. Samples of these are readily created by bringing AD antiproton beam bunches to rest in helium gas. With the help of techniques developed at LEAR for resonating high precision laser beams with antiproton transitions in these atoms, ASACUSA achieved several of these first-phase objectives during a few short months of AD operation in 2000. Six atomic tr...

  3. Parameters for Cold Collisions of Lithium and Caesium Atoms

    Institute of Scientific and Technical Information of China (English)

    Jamieson M. J.; Ouerdane H.

    2011-01-01

    @@ We calculate the s-wave scattering length and effective range and the p-wave scattering volume for Li atoms interacting with 133CS atoms via the X∑ molecular potential.The length and volume are found by fitting the log-derivative of the zero energy wave function evaluated at short range to a long range expression that accounts for the leading van der Waals dispersion potential and then incorporating the remaining long range dispersion contributions to first order.The effective range is evaluated from a quadrature formula.The calculated parameters are checked from the zero energy limits of the scattering phase shifts.We comment on ill-conditioning in the calculated s-wave scattering length.%We calculate the s-wave scattering length and effective range and the p-wave scattering volume for 7Li atoms interacting with 133Cs atoms via the X1E+ molecular potential. The length and volume are found by fitting the log-derivative of the zero energy wave function evaluated at short range to a long range expression that accounts for the leading van der Waals dispersion potential and then incorporating the remaining long range dispersion contributions to first order. The effective range is evaluated from a quadrature formula. The calculated parameters are checked from the zero energy limits of the scattering phase shifts. We comment on ill-conditioning in the calculated s-wave scattering length.

  4. Trends in physics 1984

    International Nuclear Information System (INIS)

    Volume 1 of the conference proceedings contains plenary lectures and papers of sessions on non-linear plasma astrophysics, neutrino physics and astrophysics, hard hadron collisions, positron-electron collisions, and atomic and molecular physics. (J.P.)

  5. Protonium formation in slow collisions of antiprotons with hydrogen atoms

    Energy Technology Data Exchange (ETDEWEB)

    Sakimoto, Kazuhiro [Institute of Space and Astronautical Science, Yoshinodai, Sagamihara (Japan)]. E-mail: sakimoto@pub.isas.ac.jp

    2001-05-14

    Protonium formation p-bar+H{yields}p-barp+e is investigated theoretically at centre-of-mass collision energies less than E=10 eV. In previous studies on the break-up ionization p-bar+H{yields}p-bar+p+e, the present author introduced the direct numerical method using a discrete-variable-representation technique to solve the time-dependent (semiclassical) Schroedinger equation. The same method is applied to protonium formation. The reliability of the adiabatic molecular picture is examined for the calculation of the formation cross section. At very low energies, the centrifugal barrier plays an important role in the protonium formation as found in a variety of ion-molecule chemical reactions. (author)

  6. Protonium formation in slow collisions of antiprotons with hydrogen atoms

    International Nuclear Information System (INIS)

    Protonium formation p-bar+H→p-barp+e is investigated theoretically at centre-of-mass collision energies less than E=10 eV. In previous studies on the break-up ionization p-bar+H→p-bar+p+e, the present author introduced the direct numerical method using a discrete-variable-representation technique to solve the time-dependent (semiclassical) Schroedinger equation. The same method is applied to protonium formation. The reliability of the adiabatic molecular picture is examined for the calculation of the formation cross section. At very low energies, the centrifugal barrier plays an important role in the protonium formation as found in a variety of ion-molecule chemical reactions. (author)

  7. Photon emission spectroscopy of ion-atom collisions

    Energy Technology Data Exchange (ETDEWEB)

    Nystroem, B.

    1995-10-01

    Emission cross sections for the 1snp{sup 1}P{sub 1}-levels have been measured by photon emission spectroscopy for the collision systems He{sup +} + He at 10 keV and He{sup 2+} + He at 10-35 keV. Photon spectra of Krypton (Kr VIII) and Xenon (Xe V - IX) have also been obtained using 10q keV beams of Kr{sup q+} (q=7-9) and Xe{sup q+} (q=5-9) colliding with Helium and Argon. The Lifetimes of 3p{sup 2}P-levels in Na-like Nb are reported together with lifetime for the 3s3p{sup 3}P{sub 1}-level in Mg-like Ni, Kr, Y, Zr and Nb where this level has an intercombination transition to the ground state. 45 refs, 20 figs.

  8. Gilles Jobin Final residency lecture - Collision between dance and physics

    CERN Document Server

    CERN. Geneva; Doser, Michael; Dimou, Maria; Jobin, Gilles

    2012-01-01

    CERN, the Republic and Canton of Geneva, and the City of Geneva are delighted to invite you to the final public lecture about collisions between dance and physics by the first winner of Collide@CERN Geneva, the choreographer Gilles Jobin. The event marks the end of his residency and will be held at the CERN Globe of Science and Innovation on 6th November at 1800. Doors open at 17.30 Programme 18.00 - Opening address by Rolf-Dieter Heuer, CERN Director General, Ariane Koek, CERN Cultural Specialist, Sami Kanaan, Administrative Councilor in charge of the Department of Culture and Sport of the City of Geneva, and Charles Beer, Vice President of the State Council in charge of the Department of Education, Culture and Sport. 18.30 - Presentation by Gilles Jobin (Switzerland) of his residency experience at CERN with live demonstrations with his dancers 19.15 - Discussion on CERN as a Place of Collisions and Interventions between Dance and Physics with Gilles Jobin (Switzerland) and CERN scientists Maria Dimo...

  9. Atomic physics and non-equilibrium plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Weisheit, J.C.

    1986-04-25

    Three lectures comprise the report. The lecture, Atomic Structure, is primarily theoretical and covers four topics: (1) Non-relativistic one-electron atom, (2) Relativistic one-electron atom, (3) Non-relativistic many-electron atom, and (4) Relativistic many-electron atom. The lecture, Radiative and Collisional Transitions, considers the problem of transitions between atomic states caused by interactions with radiation or other particles. The lecture, Ionization Balance: Spectral Line Shapes, discusses collisional and radiative transitions when ionization and recombination processes are included. 24 figs., 11 tabs.

  10. Energy losses of fast heavy multiply charged structural ions in collisions with complex atoms

    Science.gov (United States)

    Matveev, V. I.; Sidorov, D. B.

    2007-07-01

    A nonperturbatve theory of energy losses of fast heavy multiply charged structural ions in collisions with neutral complex atoms is elaborated with allowance for simultaneous excitations of ionic and atomic electron shells. Formulas for the effective deceleration that are similar to the well-known Bethe-Bloch formulas are derived. By way of example, the energy lost by partially stripped U q+ ions (10 ≤ q ≤ 70) colliding with argon atoms and also the energy lost by Au, Pb, and Bi ions colliding with various targets are calculated. The results of calculation are compared with experimental data.

  11. PREFACE: XXIX International Conference on Photonic, Electronic, and Atomic Collisions (ICPEAC2015)

    Science.gov (United States)

    Díaz, C.; Rabadán, I.; García, G.; Méndez, L.; Martín, F.

    2015-09-01

    The 29th International Conference on Photonic, Electronic and Atomic Collisions (XXIX ICPEAC) was held at the Palacio de Congresos ''El Greco'', Toledo, Spain, on 22-28 July, 2015, and was organized by the Universidad Autónoma de Madrid (UAM) and the Consejo Superior de Investigaciones Científicas (CSIC). ICPEAC is held biannually and is one of the most important international conferences on atomic and molecular physics. The topic of the conference covers the recent progresses in photonic, electronic, and atomic collisions with matter. With a history back to 1958, ICPEAC came to Spain in 2015 for the very first time. UAM and CSIC had been preparing the conference for six years, ever since the ICPEAC International General Committee made the decision to hold the XXIX ICPEAC in Toledo. The conference gathered 670 participants from 52 countries and attracted 854 contributed papers for presentation in poster sessions. Among the latter, 754 are presented in issues 2-12 of this volume of the Journal of Physics Conference Series. In addition, five plenary lectures, including the opening one by the Nobel laureate Prof. Ahmed H. Zewail and the lectures by Prof. Maciej Lewenstein, Prof. Paul Scheier, Prof. Philip H. Bucksbaum, and Prof. Stephen J. Buckman, 62 progress reports and 26 special reports were presented following the decision of the ICPEAC International General Committee. Detailed write-ups of most of the latter are presented in issue 1 of this volume, constituting a comprehensive tangible record of the meeting. On the occasion of the International Year of Light (IYL2015) and with the support of the Fundación Española para la Ciencia y la Tecnología (FECYT), the program was completed with two public lectures delivered by the Nobel laureate Prof. Serge Haroche and the Príncipe de Asturias laureate Prof. Pedro M. Echenique on, respectively, ''Fifty years of laser revolutions in physics'rquot; and ''The sublime usefulness of useless science''. Also a

  12. Electron capture by fluorinated fullerene anions in collisions with Xe atoms

    DEFF Research Database (Denmark)

    Boltalina, OV; Hvelplund, P; Jørgensen, Thomas J. D.;

    2000-01-01

    Electron capture by 50-keV fluorinated fullerene anions (C60Fn- 18collisions with Xe atoms, The relative importance of nondissociative vs dissociative electron capture was found to depend strongly on the ion pro...... production method and on the number of attached F atoms. The absolute size of the cross section similar to 10(-16) cm(2) has been modeled within the over-the-barrier model......Electron capture by 50-keV fluorinated fullerene anions (C60Fn- 18collisions with Xe atoms, The relative importance of nondissociative vs dissociative electron capture was found to depend strongly on the ion...

  13. SASP '86: Symposium on atomic and surface physics

    International Nuclear Information System (INIS)

    71 papers are presented on subject matters indicated in the section headings: 1) Ion-neutral and neutral-neutral interactions in the gas phase; 2) Laser physics and photonics; 3) Electron collisions and electronic capture; 4) Ion-surface interaction and plasma-related effects; 5) Cluster physics. 70 thereof are of INIS interested and are treated separately. (G.Q.)

  14. Quantum theory of ultracold atom-ion collisions

    CERN Document Server

    Idziaszek, Zbigniew; Julienne, Paul S; Simoni, Andrea

    2008-01-01

    We study atom-ion scattering in the ultracold regime. To this aim, an analytical model based on the multichannel quantum defect formalism is developed and compared to close-coupled numerical calculations. We investigate the occurrence of magnetic Feshbach resonances focusing on the specific 40Ca+ - Na system. The presence of several resonances at experimentally accessible magnetic fields should allow the atom-ion interaction to be precisely tuned. A fully quantum-mechanical study of charge exchange processes shows that charge-exchange rates should remain small even in the presence of resonance effects. Most of our results can be cast in a system-independent form and are important for the realization of the charge-neutral ultracold systems.

  15. Coherence effects in heavy ion-atom collisions

    International Nuclear Information System (INIS)

    A new approach to charge capture and ionization by highly stripped projectiles is described and shown to explain cross section systematics through the periodic table. Oscillations in cross section with respect to charge state observed around atomic number 70 are explained as an f-wave resonance in the target electron-projectile scattering. The ratio of H2 to H cross sections for both light and heavy projectiles is shown to fit a two center coherent scattering model; independent scattering by the two centers is not a good assumption for velocities below 4 a.u. Similar coherence effects are predicted in stripping by molecular gases even in multi-electron processes where the independent atom model might be thought valid. Recent experiments on the forward peak of electrons ejected from the projectile show interesting structure which can be partly explained without invoking interference effects. 7 references

  16. Laser Assisted Free-Free Transition in Electron - Atom Collision

    Science.gov (United States)

    Sinha, C.; Bhatia, A. K.

    2011-01-01

    Free-free transition is studied for electron-Hydrogen atom system in ground state at very low incident energies in presence of an external homogeneous, monochromatic and linearly polarized laser field. The incident electron is considered to be dressed by the laser in a non perturbative manner by choosing the Volkov solutions in both the channels. The space part of the scattering wave function for the electron is solved numerically by taking into account the effect of electron exchange, short range as well as of the long range interactions. Laser assisted differential as well as elastic total cross sections are calculated for single photon absorption/emission in the soft photon limit, the laser intensity being much less than the atomic field intensity. A strong suppression is noted in the laser assisted cross sections as compared to the field free situations. Significant difference is noted in the singlet and the triplet cross sections.

  17. Parameters for Cold Collisions of Lithium and Caesium Atoms

    CERN Document Server

    Ouerdane, H

    2015-01-01

    We calculate the s-wave scattering length and effective range and the p-wave scattering volume for $^7$Li atoms interacting with $^{133}$Cs atoms via the X$^1\\Sigma^+_g$ molecular potential. The length and volume are found by fitting the log-derivative of the zero energy wave function evaluated at short range to a long range expression that accounts for the leading van der Waals dispersion potential and then incorporating the remaining long range dispersion contributions to first order. The effective range is evaluated from a quadrature formula. The calculated parameters are checked from the zero energy limits of the scattering phase shifts. We comment on ill-conditioning in the calculated s-wave scattering length.

  18. Coherence and correlation in electron-atom collisions

    Energy Technology Data Exchange (ETDEWEB)

    Slevin, J.A. (Saint Patrick' s Coll., Maynooth (Ireland)); Chwirot, S. (Uniwersytet Mikolaja Kopernika, Torun (Poland). Inst. Fizyki)

    1990-01-28

    Recent developments in the field of alignment and orientation studies of electron impact excitation of atoms are discussed. This article reviews experiments which have a well defined planar symmetry, i.e. in which the initial and final momenta of electrons are determined. The experimental results obtained by different groups during the last four years are presented after a brief theoretical introduction followed by a description of typical experimental arrangements. (author).

  19. Coherence and correlation in electron-atom collisions

    International Nuclear Information System (INIS)

    Recent developments in the field of alignment and orientation studies of electron impact excitation of atoms are discussed. This article reviews experiments which have a well defined planar symmetry, i.e. in which the initial and final momenta of electrons are determined. The experimental results obtained by different groups during the last four years are presented after a brief theoretical introduction followed by a description of typical experimental arrangements. (author)

  20. Experiments in atomic and applied physics using synchrotron radiation

    International Nuclear Information System (INIS)

    A diverse program in atomic and applied physics using x rays produced at the X-26 beam line at the Brookhaven National Synchrotron Light Source is in progress. The atomic physics program studies the properties of multiply-ionized atoms using the x rays for photo-excitation and ionization of neutral atoms and ion beams. The applied physics program builds on the techniques and results of the atomic physics work to develop new analytical techniques for elemental and chemical characterization of materials. The results are then used for a general experimental program in biomedical sciences, geo- and cosmochemistry, and materials sciences. The present status of the program is illustrated by describing selected experiments. Prospects for development of new experimental capabilities are discussed in terms of a heavy ion storage ring for atomic physics experiments and the feasibility of photoelectron microscopy for high spatial resolution analytical work. 21 refs., 11 figs., 2 tabs

  1. Electron collisions with atoms, ions, molecules, and surfaces: Fundamental science empowering advances in technology

    Science.gov (United States)

    Bartschat, Klaus; Kushner, Mark J.

    2016-06-01

    Electron collisions with atoms, ions, molecules, and surfaces are critically important to the understanding and modeling of low-temperature plasmas (LTPs), and so in the development of technologies based on LTPs. Recent progress in obtaining experimental benchmark data and the development of highly sophisticated computational methods is highlighted. With the cesium-based diode-pumped alkali laser and remote plasma etching of Si3N4 as examples, we demonstrate how accurate and comprehensive datasets for electron collisions enable complex modeling of plasma-using technologies that empower our high-technology-based society.

  2. Electron capture by impact of highly partially stripped ions on hydrogen atom in low collision energies

    International Nuclear Information System (INIS)

    Based on the reaction windows of electron capture obtained by using the two-state Landau-Zener model, the electron capture processes in collision of bare ions and highly partially stripped ions with hydrogen atoms are analysed. The capture cross sections predicted by multichannel Landau-Zener method are reliable if the cross points between the initial and final diabatic potential energy curves are located in the corresponding reaction windows. The calculations by the multichannel Landau-Zener method show that the present theoretical results are in accord with the analyses for slow C3+ + H and 5+ + H collisions

  3. Electron collisions with atoms, ions, molecules, and surfaces: Fundamental science empowering advances in technology.

    Science.gov (United States)

    Bartschat, Klaus; Kushner, Mark J

    2016-06-28

    Electron collisions with atoms, ions, molecules, and surfaces are critically important to the understanding and modeling of low-temperature plasmas (LTPs), and so in the development of technologies based on LTPs. Recent progress in obtaining experimental benchmark data and the development of highly sophisticated computational methods is highlighted. With the cesium-based diode-pumped alkali laser and remote plasma etching of Si3N4 as examples, we demonstrate how accurate and comprehensive datasets for electron collisions enable complex modeling of plasma-using technologies that empower our high-technology-based society. PMID:27317740

  4. Delta-ray production in ion-atom collisions

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, W.E.; Toburen, L.H.

    1980-07-01

    The stochastic energy concentrations randomly deposited in submicron volumes in and near the paths of charged particles is needed. Computational methods, especially Monte Carlo methods, required a comprehensive set of basic interaction cross sections for the primary and all secondary radiation products. Of particular importance for high LET radiations are the cross sections for the production of energetic secondary electrons, delta-rays, in primary ionizing events. In this paper, we review the present state of available data on the production of delta-rays by fast positive ions in collision with targets of biological interest. The systematics in the cross sections for proton ionization of molecular targets are discussed, indicating what scaling is possible and summarizing what can be concluded regarding the dependence of the mean delta-ray energies on the chemical makeup of the medium. A comparison of typical data is made with the binary-encounter approximation to illustrate the limitations of this theoretical treatment of the ionization process. A bibliography of relevant published works on this topic is included.

  5. Dynamical approach to the statistical average of atom-diatom collision

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The dynamical Lie algebraic method is used for the description of statistical mechanics of the atom-diatom collision. A main advantage of this method is that it can not only give the expression for evolution operator in terms of the group parameter, but also provide the expression for the density operator for a given system. The group parameters can be determined by solving a set of coupled nonlinear differential equations. Thus, the expression of the statistical average values is derived in terms of the density operator formalism in statistical mechanics. And we can use the time evolution operator to calculate the transition probability. The method is applied to the collision of H2 with He. Comparing the results with the experimental results, we can see that the dynamical Lie algebraic method is useful for describing the molecule collision.

  6. A simple nonbinary scattering model applicable to atomic collisions is crystals at 1ow energies

    DEFF Research Database (Denmark)

    Andersen, Hans Henrik; Sigmund, Peter

    1966-01-01

    the projectile and each ring atom is described by a Born-Mayer potential, and the scattering is assumed to be elastic and governed by the classical equations of motion. Because of symmetry, the problem can be reduced to plane motion of a particle in a potential of elliptic symmetry. The elliptic force field...... is approximated by a spherical one, which is dependent on the initial conditions of the individual scattering problem. For the spherical symmetrical potential, scattering angles and related quantities have been tabulated, but simple analytical approximations can be used too. As a result, one obtains...... the elliptic to the spherical potential are investigated. Special attention is paid to proper definitions of collision time and collision length which are important in collisions in crystals. Limitations to classical scattering arising from the uncertainty principle prove to be more serious than assumed...

  7. Direct probe of anisotropy in atom-molecule collisions via quantum scattering resonances

    CERN Document Server

    Klein, Ayelet; Skomorowski, Wojciech; Żuchowski, Piotr S; Pawlak, Mariusz; Janssen, Liesbeth M C; Moiseyev, Nimrod; van de Meerakker, Sebastiaan Y T; van der Avoird, Ad; Koch, Christiane P; Narevicius, Edvardas

    2016-01-01

    Anisotropy is a fundamental property of particle interactions. It occupies a central role in cold and ultra-cold molecular processes, where long range forces have been found to significantly depend on orientation in ultra-cold polar molecule collisions. Recent experiments have demonstrated the emergence of quantum phenomena such as scattering resonances in the cold collisions regime due to quantization of the intermolecular degrees of freedom. Although these states have been shown to be sensitive to interaction details, the effect of anisotropy on quantum resonances has eluded experimental observation so far. Here, we directly measure the anisotropy in atom-molecule interactions via quantum resonances by changing the quantum state of the internal molecular rotor. We observe that a quantum scattering resonance at a collision energy of $k_B$ x 270 mK appears in the Penning ionization of molecular hydrogen with metastable helium only if the molecule is rotationally excited. We use state of the art ab initio and ...

  8. Atomic hydrogen and fundamental physical constants

    International Nuclear Information System (INIS)

    Techniques are described which allow the study, in undergraduate laboratories, of the spectrum of atomic hydrogen. The Rydberg constant, the electron-proton mass ratio, and the fine-structure constant are evaluated from the measurements. The key to the series of experiments is a discharge tube in which atomic lines dominate over the molecular lines. (author)

  9. Inelastic scattering in atom-diatomic molecule collisions. I - Rotational transitions in the sudden approximation

    Science.gov (United States)

    Stallcop, J. R.

    1974-01-01

    The impact parameter method and the sudden approximation are applied to determine the total probability of inelastic rotational transitions arising from a collision of an atom and a homonuclear diatomic molecule at large impact parameters. An analytical approximation to this probability is found for conditions where the electron exchange or overlap forces dominate the scattering. An approximate upper bound to the range of impact parameters for which rotational scattering can be important is determined. In addition, an estimate of the total inelastic cross section is found at conditions for which a statistical model describes the scattering well. The results of this analysis are applied to Ar-O2 collisions and may be readily applied to other combinations of atoms and molecules.

  10. A high density target of ultracold atoms and momentum resolved measurements of ion-atom collisions

    OpenAIRE

    Götz, Simone Andrea

    2012-01-01

    In this thesis an ultracold high density target with high loading flux in combination with a recoil ion momentum spectrometer (RIMS) is presented. Trapped rubidium atoms serve as a high density target (up to 10¹¹ atoms/cm³) at a temperature of only 200 µK. The target is loaded from a two-dimensional magneto-optical trap (2D MOT), which delivers an atom beam with a brilliance of 8 x 10¹² atoms/(s*rad) and a longitudinal momentum spread of 0.25 a.u.. The great advantage of this source is that t...

  11. Atomic physics with highly charged ions. Progress report, 15 February 1985-14 February 1986

    International Nuclear Information System (INIS)

    The experimental program has three directions: the study of collisions of very low velocity, highly-charged secondary recoil ions with stationary gas atoms, the study of collisions of high velocity, highly-charged ions with stationary targets, and the study of the theoretical descriptions of atomic collisions and atomic structure properties of highly-charged ions. Brief reports of the progress in these areas are given

  12. Bibliography of atomic and molecular excitation in heavy particle collisions, 1950--1975

    Energy Technology Data Exchange (ETDEWEB)

    Hawthorne, S.W.; Thomas, E.W.; Barnett, C.F.; Crandall, D.H.; Gilbody, H.B.; Kirkpatrick, M.I.; McDaniel, E.W.; Phaneuf, R.A. (eds.)

    1979-02-01

    This annotated bibliography lists published work on atomic and molecular excitation in heavy particle collisions for the period 1950 to 1975. Sources include scientific journals, abstract compilations, conference proceedings, books, and reports. The bibliography is arranged alphabetically by author. Each entry indicates whether the work was experimental or theoretical, what energy range was covered, and what reactants were investigated. Following the bibliographical listing are indexes of reactions and authors.

  13. Bibliography of atomic and molecular excitation in heavy particle collisions, 1950--1975

    International Nuclear Information System (INIS)

    This annotated bibliography lists published work on atomic and molecular excitation in heavy particle collisions for the period 1950 to 1975. Sources include scientific journals, abstract compilations, conference proceedings, books, and reports. The bibliography is arranged alphabetically by author. Each entry indicates whether the work was experimental or theoretical, what energy range was covered, and what reactants were investigated. Following the bibliographical listing are indexes of reactions and authors

  14. Effects of ion-atom collisions on the propagation and damping of ion-acoustic waves

    DEFF Research Database (Denmark)

    Andersen, H.K.; D'Angelo, N.; Jensen, Vagn Orla;

    1968-01-01

    Experiments are described on ion-acoustic wave propagation and damping in alkali plasmas of various degrees of ionization. An increase of the ratio Te/Ti from 1 to approximately 3-4, caused by ion-atom collisions, results in a decrease of the (Landau) damping of the waves. At high gas pressure and....../or low wave frequency a "fluid" picture adequately describes the experimental results....

  15. Inelastic scattering in atom-diatomic molecule collisions. II - Effect of rotation on vibrational transition

    Science.gov (United States)

    Stallcop, J. R.

    1975-01-01

    Rotational and vibrational transitions in a diatomic molecule caused by collisions with an atom are analyzed by a semiclassical method for conditions where the rotational transitions can be handled well by the sudden approximation and the vibrational transitions belong to the adiabatic regime. The contribution to the vibrational transition probability from the correction, which takes the finite value of the spacing between rotational energy levels into account, is examined.-

  16. Quantum-mechanical theory including angular momenta analysis of atom-atom collisions in a laser field

    Science.gov (United States)

    Devries, P. L.; George, T. F.

    1978-01-01

    The problem of two atoms colliding in the presence of an intense radiation field, such as that of a laser, is investigated. The radiation field, which couples states of different electronic symmetry, is described by the number state representation while the electronic degrees of freedom (plus spin-orbit interaction) are discussed in terms of a diabatic representation. The total angular momentum of the field-free system and the angular momentum transferred by absorption (or emission) of a photon are explicitly considered in the derivation of the coupled scattering equations. A model calculation is discussed for the Xe + F collision system.

  17. Chemical reactivity of the compressed noble gas atoms and their reactivity dynamics during collisions with protons

    Indian Academy of Sciences (India)

    P K Chattaraj; B Maiti; U Sarkar

    2003-06-01

    Attempts are made to gain insights into the effect of confinement of noble gas atoms on their various reactivity indices. Systems become harder, less polarizable and difficult to excite as the compression increases. Ionization also causes similar effects. A quantum fluid density functional technique is adopted in order to study the dynamics of reactivity parameters during a collision between protons and He atoms in different electronic states for various projectile velocities and impact parameters. Dynamical variants of the principles of maximum hardness, minimum polarizability and maximum entropy are found to be operative.

  18. Application of the refined Born approximation to atom-rigid rotor collision

    International Nuclear Information System (INIS)

    Coupled equations obtained by Arthurs and Dalgarno for the collision of an atom with a rigid rotor have been solved with the help of the refined Born approximation in the case of a helium-atom-hydrogen-molecule scattering problem. An appriopriate choice of the trial function allowed us to find the solution with high accuracy. For several values of energy and several values of total angular-momentum quantum numbers we give the elements of the reactance matrix and partial cross sections. For comparison we also solved the problem by Gordon's numerical procedure. (author)

  19. Negative ion productions in high velocity collision between small carbon clusters and Helium atom target

    International Nuclear Information System (INIS)

    We measured absolute double capture cross section of Cn+ ions (n=1,5) colliding, at 2.3 and 2.6 a.u velocities, with an Helium target atom and the branching ratios of fragmentation of the so formed electronically excited anions Cn−*. We also measured absolute cross section for the electronic attachment on neutral Cn clusters colliding at same velocities with He atom. This is to our knowledge the first measurement of neutral-neutral charge exchange in high velocity collision.

  20. On the relativistic and nonrelativistic electron descriptions in high-energy atomic collisions

    Energy Technology Data Exchange (ETDEWEB)

    Voitkiv, A.B [Max-Planck-Institut fuer Kernphysik, Saupfercheckweg 1, 69117 Heidelberg (Germany)

    2007-07-28

    We consider the relativistic and nonrelativistic descriptions of an atomic electron in collisions with point-like charged projectiles moving at relativistic velocities. We discuss three different forms of the fully relativistic first-order transition amplitude. Using the Schroedinger-Pauli equation to describe the atomic electron we establish the correct form of the nonrelativistic first-order transition amplitude. We also show that the so-called semi-relativistic treatment, in which the Darwin states are used to describe the atomic electron, is in fact fully equivalent to the nonrelativistic consideration. The comparison of results obtained with the relativistic and nonrelativistic electron descriptions shows that the latter is accurate within 20-30% up to Z{sub a}{approx}< 50-60, where Z{sub a} is the atomic nuclear charge.

  1. On the relativistic and nonrelativistic electron descriptions in high-energy atomic collisions

    Science.gov (United States)

    Voitkiv, A. B.

    2007-07-01

    We consider the relativistic and nonrelativistic descriptions of an atomic electron in collisions with point-like charged projectiles moving at relativistic velocities. We discuss three different forms of the fully relativistic first-order transition amplitude. Using the Schrödinger-Pauli equation to describe the atomic electron we establish the correct form of the nonrelativistic first-order transition amplitude. We also show that the so-called semi-relativistic treatment, in which the Darwin states are used to describe the atomic electron, is in fact fully equivalent to the nonrelativistic consideration. The comparison of results obtained with the relativistic and nonrelativistic electron descriptions shows that the latter is accurate within 20-30% up to Za<~ 50-60, where Za is the atomic nuclear charge.

  2. Sub-Poissonian atom number fluctuations using light-assisted collisions

    CERN Document Server

    Sortais, Y R P; Bourgain, R; Browaeys, A

    2011-01-01

    We investigate experimentally the number statistics of a mesoscopic ensemble of cold atoms in a microscopic dipole trap, and find that the atom number fluctuations are reduced with respect to a Poisson distribution due to light-assisted two-body collisions. For numbers of atoms larger than 2, we measure a reduction factor (Fano factor) close to 0.75. We analyze this fact by a general stochastic model describing the competition between the loading of the trap from a reservoir of cold atoms and multi-body losses, which leads to a master equation. The model indicates that we have reached the ultimate level of reduction in number fluctuations achievable in our experimental regime.

  3. Van der Waals universality in homonuclear atom-dimer elastic collisions

    CERN Document Server

    Giannakeas, P

    2016-01-01

    The universal aspects of atom-dimer elastic collisions are investigated within the framework of Faddeev equations. The two-body interactions between the neutral atoms are approximated by the separable potential approach. Our analysis considers a pure van der Waals potential tail as well as soft-core van der Waals interactions permitting us in this manner to address the universally general features of atom-dimer resonant spectra. In particular, we show that the atom-dimer resonances are solely associated with the {\\it excited} Efimov states. Furthermore, the positions of the corresponding resonances for a soft-core potentials with more than 5 bound states are in good agreement with the corresponding results from an infinitely deep pure van der Waals tail potential.

  4. Collisions of low-energy antiprotons and protons with atoms and molecules

    Energy Technology Data Exchange (ETDEWEB)

    Luehr, Armin

    2010-02-18

    Antiproton (anti p) collisions have evolved to a powerful tool for the testing of dynamic electron correlations in atoms and molecules. While advances in the understanding of anti p collisions with the simplest one- and two-electron atoms, H and He, have been achieved experiment and theory did not agree for low-energy anti p+He collisions (<40 keV), stimulating a vivid theoretical activity. On the other hand, only very few theoretical anti p studies can be found considering molecular as well as other atomic targets, in contrast to proton (p) collisions. This is in particular true for anti p impacts on H{sub 2} despite its fundamental role in representing the simplest two-electron molecule. The obtained results may be useful for the anti p experiments at CERN (e.g., antihydrogen production) and in particular for the facility design of low-energy anti p storage rings (e.g., at FLAIR) where a precise knowledge of the anti p interaction with the dominant residual-gas molecule H{sub 2} is needed. In this work a nonperturbative, time-dependent numerical approach is developed which describes ionization and excitation of atoms or molecules by either anti p or p impact based on the impact-parameter method. A spectral close-coupling method is employed for solving the time-dependent Schroedinger equation in which the scattering wave function is expanded in (effective) one- or two-electron eigenstates of the target. This includes for the first time a full two-electron, two-center description of the H{sub 2} molecule in anti p collisions. The radial part of the one-electron eigenstates is expanded in B splines while the two-electron basis is obtained with a configurationinteraction approach. Calculations are performed for anti p collisions with H, H{sub 2}{sup +}, and H{sub 2} as well as with He and alkali-metal atoms Li, Na, K, and Rb. Additionally, data are obtained for p collisions with H{sub 2}, Li, Na, and K. The developed method is tested and validated by detailed

  5. Weisskopf--Wigner approximation in atomic physics

    International Nuclear Information System (INIS)

    Several approximations involved in the usual Weisskopf-Wigner treatment of the emission of light by an atom are investigated. The system considered is a recoilless, nonrelativistic hydrogen atom interacting with a quantized electromagnetic field, in dipole approximation (with a nonrelativistic cutoff in momentum space). Since only electric dipole waves interact with the atom, the Hamiltonian can be expressed in a simple one-dimensional form. The time evolution of the system is determined by resolvent operator techniques. The method goes beyond the analysis by Van Hove and Hugenholtz, allowing one to treat also fields of finite intensity in the infinite-volume limit. A comparison between this and other techniques is made

  6. Probing the Planck Scale in Low-Energy Atomic Physics

    OpenAIRE

    Bluhm, Robert

    2001-01-01

    Experiments in atomic physics have exceptional sensitivity to small shifts in energy in an atom, ion, or bound particle. They are particularly well suited to search for unique low-energy signatures of new physics, including effects that could originate from the Planck scale. A number of recent experiments have used CPT and Lorentz violation as a candidate signal of new physics originating from the Planck scale. A discussion of these experiments and their theoretical implications is presented.

  7. Combined ion and atom trap for low temperature ion-atom physics

    OpenAIRE

    Ravi, K.; LEE, Seunghyun; Sharma, Arijit; Werth, G.; Rangwala, S. A.

    2010-01-01

    We report an experimental apparatus and technique which simultaneously traps ions and cold atoms with spatial overlap. Such an apparatus is motivated by the study of ion-atom processes at temperatures ranging from hot to ultra-cold. This area is a largely unexplored domain of physics with cold trapped atoms. In this article we discuss the general design considerations for combining these two traps and present our experimental setup. The ion trap and atom traps are characterized independently ...

  8. Atomic physics: computer calculations and theoretical analysis

    OpenAIRE

    Drukarev, E. G.

    2004-01-01

    It is demonstrated, how the theoretical analysis preceding the numerical calculations helps to calculate the energy of the ground state of helium atom, and enables to avoid qualitative errors in the calculations of the characteristics of the double photoionization.

  9. Atomic physics: A milestone in quantum computing

    Science.gov (United States)

    Bartlett, Stephen D.

    2016-08-01

    Quantum computers require many quantum bits to perform complex calculations, but devices with more than a few bits are difficult to program. A device based on five atomic quantum bits shows a way forward. See Letter p.63

  10. Atomic physics and radiation processes in plasmas

    International Nuclear Information System (INIS)

    It is pointed out that atomic and molecular (A/M) processes play important roles in divertor plasmas but the problems related to these processes are not yet studied quantitatively. Recently new subjects related to A/M processes such as plasma- vapor interaction during plasma disruption are presented. This is a brief summary of our discussions. Our recent results of the calculations for the line emissions of carbon atoms in edge plasmas are also included. (J.P.N.)

  11. Tight Binding Models in Cold Atoms Physics

    Science.gov (United States)

    Zakrzewski, J.

    2007-05-01

    Cold atomic gases placed in optical lattice potentials offer a unique tool to study simple tight binding models. Both the standard cases known from the condensed matter theory as well as novel situations may be addressed. Cold atoms setting allows for a precise control of parameters of the systems discussed, stimulating new questions and problems. The attempts to treat disorder in a controlled fashion are addressed in detail.

  12. The infancy of atomic physics Hercules in his cradle

    CERN Document Server

    Keller, Alex

    2006-01-01

    Atomic physics is a mighty Hercules that dominates modern civilization, promising immense reserves of power but threatening catastrophic war and radioactive pollution. The story of the atom's discovery and the development of techniques to harness its energy offers fascinating insights into the forces behind twenty-first-century technology. This compelling history portrays the human faces and lives behind the beginnings of atomic science.The Infancy of Atomic Physics ranges from experiments in the 1880s by William Crookes and others to the era just after the First World War, when Rutherford's f

  13. Fundamentals of Atomic and Nuclear Physics. Chapter 1

    International Nuclear Information System (INIS)

    Knowledge of the structure of the atom, elementary nuclear physics, the nature of electromagnetic radiation and the production of X rays is fundamental to the understanding of the physics of medical imaging and radiation protection. This, the first chapter of the handbook, summarizes those aspects of these areas which, being part of the foundation of modern physics, underpin the remainder of the book

  14. PREFACE: 8th Asian International Seminar on Atomic and Molecular Physics (AISAMP)

    Science.gov (United States)

    Williams, Jim F.; Buckman, Steve; Bieske, Evan J.

    2009-09-01

    These proceedings arose from the 8th Asian International Seminar on Atomic and Molecular Physics (AISAMP) which was held at the University of Western Australia 24-28 November 2008. The history of AISAMP (Takayanagi and Matsuzawa 2002) recognizes its origin from the Japan-China meeting of 1985, and the first use of the name 'The First Asian International Seminar on Atomic and Molecular Physics (AISAMP)' in 1992. The initial attendees, Japan and China, were joined subsequently by scientists from Korea, Taiwan, India, Australia and recently by Malaysia, Thailand, Vietnam, Turkey Iran, UK and USA. The main purpose of the biennial AISAMP series is to create a wide forum for exchanging ideas and information among atomic and molecular scientists and to promote international collaboration. The scope of the AISAMP8 meeting included pure, strategic and applied research involving atomic and molecular structure and processes in all forms of matter and antimatter. For 2008 the AISAMP conference incorporated the Australian Atomic and Molecular Physics and Quantum Chemistry meeting. The topics for AISAMP8 embraced themes from earlier AISAMP meetings and reflected new interests, in atomic and molecular structures, spectroscopy and collisions; atomic and molecular physics with laser or synchrotron radiation; quantum information processing using atoms and molecules; atoms and molecules in surface physics, nanotechnology, biophysics, atmospheric physics and other interdisciplinary studies. The implementation of the AISAMP themes, as well as the international representation of research interests, is indicated both in the contents list of these published manuscripts as well as in the program for the meeting. Altogether, 184 presentations were made at the 8th AISAMP, including Invited Talks and Contributed Poster Presentations, of which 60 appear in the present Proceedings after review by expert referees in accordance with the usual practice of Journal of Physics: Conference Series of

  15. Will Allis Prize for the Study of Ionized Gases Lecture: Electron and Photon Collisions with Atoms and Molecules

    Science.gov (United States)

    Burke, Philip G.

    2012-06-01

    After a brief historical introduction this talk will review the broad range of collision processes involving electron and photon collisions with atoms and molecules that are now being considered. Their application in the analysis of astronomical spectra, atmospheric observations and laboratory plasmas will be considered. The talk will review the R-matrix computational method which has been widely used by international collaborations and by other scientists in the field to obtain accurate scattering amplitudes and cross sections of importance in these applications. Results of some recent calculations of electron and photon collisions with atoms and molecules will be presented. In conclusion some challenges for future research will be briefly discussed.

  16. A method for the calculation of collision strengths for complex atomic structures based on Slater parameter optimisation

    International Nuclear Information System (INIS)

    This report presents details of a new method to enable the computation of collision strengths for complex ions which is adapted from long established optimisation techniques previously applied to the calculation of atomic structures and oscillator strengths. The procedure involves the adjustment of Slater parameters so that they determine improved energy levels and eigenvectors. They provide a basis for collision strength calculations in ions where ab initio computations break down or result in reducible errors. This application is demonstrated through modifications of the DISTORTED WAVE collision code and SUPERSTRUCTURE atomic-structure code which interface via a transformation code JAJOM which processes their output. (author)

  17. Collisions of low-energy antiprotons and protons with atoms and molecules

    International Nuclear Information System (INIS)

    Antiproton (anti p) collisions have evolved to a powerful tool for the testing of dynamic electron correlations in atoms and molecules. While advances in the understanding of anti p collisions with the simplest one- and two-electron atoms, H and He, have been achieved experiment and theory did not agree for low-energy anti p+He collisions (2 despite its fundamental role in representing the simplest two-electron molecule. The obtained results may be useful for the anti p experiments at CERN (e.g., antihydrogen production) and in particular for the facility design of low-energy anti p storage rings (e.g., at FLAIR) where a precise knowledge of the anti p interaction with the dominant residual-gas molecule H2 is needed. In this work a nonperturbative, time-dependent numerical approach is developed which describes ionization and excitation of atoms or molecules by either anti p or p impact based on the impact-parameter method. A spectral close-coupling method is employed for solving the time-dependent Schroedinger equation in which the scattering wave function is expanded in (effective) one- or two-electron eigenstates of the target. This includes for the first time a full two-electron, two-center description of the H2 molecule in anti p collisions. The radial part of the one-electron eigenstates is expanded in B splines while the two-electron basis is obtained with a configurationinteraction approach. Calculations are performed for anti p collisions with H, H2+, and H2 as well as with He and alkali-metal atoms Li, Na, K, and Rb. Additionally, data are obtained for p collisions with H2, Li, Na, and K. The developed method is tested and validated by detailed comparison of the present findings for p impacts and for anti p+He collisions with literature data. On the other hand, total and differential cross sections for ionization and excitation of the targets by anti p impact complement the sparse literature data of this kind. Results gained from different targets as well

  18. Hyperfine-frequency shifts of alkali-metal atoms during long-range collisions

    CERN Document Server

    McGuyer, B H

    2013-01-01

    Collisions with chemically inert atoms or molecules change the hyperfine coupling of an alkali-metal atom through the hyperfine-shift interaction. This interaction is responsible for the pressure shifts of the microwave resonances of alkali-metal atoms in buffer gases, is an important spin interaction in alkali-metal--noble-gas van der Waals molecules, and is anticipated to enable the magnetoassociation of ultracold molecules such as RbSr. An improved estimate is presented for the long-range asymptote of this interaction for Na, K, Rb, and Cs. To test the results, the change in hyperfine coupling due to a static electric field is estimated and reasonable agreement is found.

  19. Atomic site sensitive processes in low energy ion-dimer collisions

    CERN Document Server

    Iskandar, W; Leredde, A; Fléchard, X; Gervais, B; Guillous, S; Hennecart, D; Méry, A; Rangama, J; Zhou, C L; Shiromaru, H; Cassimi, A

    2014-01-01

    Electron capture processes for low energy Ar9+ ions colliding on Ar2 dimer targets are investigated, focusing attention on charge sharing as a function of molecule orientation and impact parameter. A preference in charge-asymmetric dissociation channels is observed, with a strong correlation between the projectile scattering angle and the molecular ion orientation. The measurements provide here clear evidences that projectiles distinguish each atom in the target and, that electron capture from near-site atom is favored. Monte Carlo calculations based on the classical over-the-barrier model, with dimer targets represented as two independent atoms, are compared to the data. They give a new insight into the dynamics of the collision by providing, for the di erent electron capture channels, the two-dimensional probability maps p(~b), where ~b is the impact parameter vector in the molecular frame.

  20. Characterization of charge-exchange collisions between ultracold $\\rm{^6Li}$ atoms and $\\rm{^{40}Ca^+}$ ions

    CERN Document Server

    Saito, R; Sasakawa, M; Nakai, R; Raoult, M; Silva, H Da; Dulieu, O; Mukaiyama, T

    2016-01-01

    We investigate the energy dependence and the internal-state dependence of the charge-exchange collision cross sections in a mixture of $^6$Li atoms and $^{40}$Ca$^+$ ions in the collision energy range from 0.2 mK to 1 K. Deliberately excited ion micromotion is used to control the collision energy of atoms and ions. The energy dependence of the charge-exchange collision cross section obeys the Langevin model in the temperature range of the current experiment, and the measured magnitude of the cross section is correlated to the internal state of the $^{40}$Ca$^+$ ions. Revealing the relationship between the charge-exchange collision cross sections and the interaction potentials is an important step toward the realization of the full quantum control of the chemical reactions at an ultralow temperature regime.

  1. Characteristic X-ray emission in close collisions between heavy ions and atoms

    International Nuclear Information System (INIS)

    In this paper an attempt is given to answer the question of how far the inner-shell vacancy production in very heavy ion-atom collisions is influenced by the electronic configuration of the projectile prepared prior to the collision producing the observed vacancy. The variation of this configuration has been induced by changing the primary charge state of the projectile, the target density and thickness or by inverting the collision system. It turns out from the performed analysis of the experimental data that the excitation of even most strongly bound MO's can be easily dependent on these factors which have been ignored until now, especially in discussions of the 1sσ or 2pσ vacancy production at ZUA > 130. Experiments performed for the first time with gaseous targets for such heavy systems show very convincingly the influence of the outer-shell configuration on the vacancy production in inner shells. The analysis of the data has been performed in terms of electronic transitions among MO's transiently formed during the collision. In many cases a satisfactory agreement between theoretical predictions and experiment has been achieved. (orig./HSI)

  2. Highly charged atomic physics at HIRFL-CSR

    International Nuclear Information System (INIS)

    HIRFL-CSR is a proposed electron cooling storage ring optimized to accelerate and store beams of highly charged heavy ions. Several possibilities for advanced atomic physics studies are discussed, such as studies of electron-ion, ion-atoms, photon-ion-electron interactions and high resolution spectroscopy

  3. Status and perspectives of atomic physics research at GSI: The new GSI accelerator project

    Energy Technology Data Exchange (ETDEWEB)

    Stoehlker, Th. E-mail: t.stoehlker@gsi.de; Backe, H.; Beyer, H.F.; Bosch, F.; Braeuning-Demian, A.; Hagmann, S.; Ionescu, D.C.; Jungmann, K.; Kluge, H.-J.; Kozhuharov, C.; Kuehl, Th.; Liesen, D.; Mann, R.; Mokler, P.H.; Quint, W

    2003-05-01

    A short overview on the results of atomic physics research at the storage ring ESR is given followed by a presentation of the envisioned atomic physics program at the planned new GSI facility. The proposed new GSI facility will provide highest intensities of relativistic beams of both stable and unstable heavy nuclei - up to a Lorentz factor of 24. At those relativistic velocities, the energies of optical transitions, such as for lasers, are boosted into the X-ray region and the high-charge state ions generate electric and magnetic fields of exceptional strength. Together with high beam intensities a range of important experiments can be anticipated, for example electronic transitions in relativistic heavy-ion collisions such as dynamically induced e{sup +}e{sup -} pairs, test of quantum electrodynamics (QED) in strong fields, and ions and electrons in ultra-high intensity femtosecond laser fields.

  4. Technique for measuring the frequency of slow electron collisions with atoms and molecules

    International Nuclear Information System (INIS)

    The described technique was applied for registering the frequency of slow electrons collisions with molecules and atoms of substances. The registering is carried out through superpositioning of crossing high-frequency electrical and adjustable constant magnetic fields over the investigated media, through inserting in this media electrons with the necessary energy and by registering the forms of the curve that characterizes the electron-cyclotron resonance, by which a judgement can be made about the collision frequency. To lower the electrical field frequency, to simplify the apparatus and widen the nomenclature of the investigated substances a stationary flux of electrons is inserted in the investigated media with the help of thermoionic cathode, for example, hence the resonance curve of the electron power reaching the collector is registered. The described technique can be applied for investigating the plasma parameters. (author)

  5. Ion-metal and ion-atom collisions instant replays and mean-field theories

    International Nuclear Information System (INIS)

    In this paper, we describe the results of our general long-term programmatic goal of investigating the strengths and weaknesses of time-dependent mean-field theories for collisions. We have made some progress in: (a) obtaining a better formulation of the theory, which has the exact full Schroedinger equation as one limit and permits appropriate classical treatment of heavy particles correctly coupled to the quantally treated electrons; (b) restructuring our numerical treatment to make it fully three-dimensional, improve accuracy and decrease cycle time, so that larger problems more in keeping with the mean-field concept can be treated; and (c) incorporating the electrons in the conduction band of a metal into our quantal treatment, making possible the description of collisions of atoms and ions with solids. Numerical results for protons tranversing a thin metallic foil, among other examples, are presented and discussed

  6. Computer simulations of atomic collisions in solids with special emphasis on sputtering

    International Nuclear Information System (INIS)

    Computer simulations of atomic collisions in solids are traditionally divided into fully interacting or molecular dynamics (MD) simulations on the one side and simulations based on the binary collision approximation (BCA) on the other. The historical development of both branches is followed and other dichotomies viz. between static and dynamic target models and between models using crystalline and amorphous targets are introduced. The influence of the main input parameters, viz. interatomic potentials, surface- and bulk-binding energies and inelasticity is discussed before selected results are treated. Here, results for non-linear effects, clusters, fluctuations and for angular distributions are presented. The review is concluded with a discussion of the influence of computer developments on future simulations. With 392 refs

  7. Coordinate space translation technique for simulation of electronic process in the ion-atom collision.

    Science.gov (United States)

    Wang, Feng; Hong, Xuhai; Wang, Jian; Kim, Kwang S

    2011-04-21

    Recently we developed a theoretical model of ion-atom collisions, which was made on the basis of a time-dependent density functional theory description of the electron dynamics and a classical treatment of the heavy particle motion. Taking advantage of the real-space grid method, we introduce a "coordinate space translation" technique to allow one to focus on a certain space of interest such as the region around the projectile or the target. Benchmark calculations are given for collisions between proton and oxygen over a wide range of impact energy. To extract the probability of charge transfer, the formulation of Lüdde and Dreizler [J. Phys. B 16, 3973 (1983)] has been generalized to ensemble-averaging application in the particular case of O((3)P). Charge transfer total cross sections are calculated, showing fairly good agreements between experimental data and present theoretical results.

  8. Two centre problems in relativistic atomic physics

    OpenAIRE

    McConnell, Sean R.

    2012-01-01

    The work contained within this thesis is concerned with the explanation and usage of a set of theoretical procedures for the study of static and dynamic two–centre problems in the relativistic framework of Dirac’s equation. Two distinctly different theories for handling time–dependent atomic interactions are reviewed, namely semi–classical perturbation theory and a non–perturbative numerical technique based on the coupled channel equation to directly solve the time–dependent, two–centre Dirac...

  9. Atoms and molecules interacting with light atomic physics for the laser era

    CERN Document Server

    Straten, Peter van der

    2016-01-01

    This in-depth textbook with a focus on atom-light interactions prepares students for research in a fast-growing and dynamic field. Intended to accompany the laser-induced revolution in atomic physics, it is a comprehensive text for the emerging era in atomic, molecular and optical science. Utilising an intuitive and physical approach, the text describes two-level atom transitions, including appendices on Ramsey spectroscopy, adiabatic rapid passage and entanglement. With a unique focus on optical interactions, the authors present multi-level atomic transitions with dipole selection rules, and M1/E2 and multiphoton transitions. Conventional structure topics are discussed in some detail, beginning with the hydrogen atom and these are interspersed with material rarely found in textbooks such as intuitive descriptions of quantum defects. The final chapters examine modern applications and include many references to current research literature. The numerous exercises and multiple appendices throughout enable advanc...

  10. Jet Physics in Heavy Ion Collisions with Compact Muon Solenoid detector at the LHC

    CERN Document Server

    Lokhtin, I P

    2006-01-01

    The status of CMS jet simulations and physics analysis in heavy ion collisions is presented. Jet reconstruction and high transverse momentum particle tracking in the high multiplicity environment of heavy ion collisions at the LHC using the CMS calorimetry and tracking system are described. The Monte Carlo tools used to simulate jet quenching are discussed.

  11. Physical meaning of the multiplicities of emitted nucleons in hadron-nucleus collisions

    Science.gov (United States)

    Strugalski, Z.

    1985-01-01

    The analysis of experimental data on hadron-nucleus collisions at energies from about 2 up to about 400 GeV was performed in order to discover a physical meaning of the multiplicity of emitted nucleons. Simple relations between the multiplicities and the thickness of the nuclear matter layer involved in collisions were obtained.

  12. Multichannel quantum-defect theory for ultracold atom-ion collisions

    Science.gov (United States)

    Idziaszek, Zbigniew; Simoni, Andrea; Calarco, Tommaso; Julienne, Paul S.

    2011-08-01

    We develop an analytical model for ultracold atom-ion collisions using the multichannel quantum-defect formalism. The model is based on analytical solutions of the r-4 long-range potential and on the application of a frame transformation between asymptotic and molecular bases. This approach allows the description of atom-ion interaction in the ultracold domain in terms of only three parameters: the singlet and triplet scattering lengths, assumed to be independent of the relative motion angular momentum, and the lead dispersion coefficient of the asymptotic potential. We also introduce corrections to the scattering lengths that improve the accuracy of our quantum-defect model for higher-order partial waves, a particularly important result for an accurate description of shape and Feshbach resonances at finite temperature. The theory is applied to the system composed of a 40Ca+ ion and a Na atom, and compared with numerical coupled-channel calculations carried out using ab initio potentials. For this particular system, we investigate the spectrum of bound states, the rate of charge-transfer processes and the collision rates in the presence of magnetic Feshbach resonances at zero and finite temperature.

  13. Multichannel quantum-defect theory for ultracold atom-ion collisions

    Energy Technology Data Exchange (ETDEWEB)

    Idziaszek, Zbigniew [Faculty of Physics, University of Warsaw, 00-681 Warsaw (Poland); Simoni, Andrea [Institut de Physique de Rennes, UMR 6251 du CNRS and Universite de Rennes 1, 35042 Rennes Cedex (France); Calarco, Tommaso [Institute of Quantum Information Processing, University of Ulm, D-89069 Ulm (Germany); Julienne, Paul S, E-mail: idziaszek@fuw.edu.pl [Joint Quantum Institute, NIST and the University of Maryland, Gaithersburg, MD 20899-8423 (United States)

    2011-08-15

    We develop an analytical model for ultracold atom-ion collisions using the multichannel quantum-defect formalism. The model is based on analytical solutions of the r{sup -4} long-range potential and on the application of a frame transformation between asymptotic and molecular bases. This approach allows the description of atom-ion interaction in the ultracold domain in terms of only three parameters: the singlet and triplet scattering lengths, assumed to be independent of the relative motion angular momentum, and the lead dispersion coefficient of the asymptotic potential. We also introduce corrections to the scattering lengths that improve the accuracy of our quantum-defect model for higher-order partial waves, a particularly important result for an accurate description of shape and Feshbach resonances at finite temperature. The theory is applied to the system composed of a {sup 40}Ca{sup +} ion and a Na atom, and compared with numerical coupled-channel calculations carried out using ab initio potentials. For this particular system, we investigate the spectrum of bound states, the rate of charge-transfer processes and the collision rates in the presence of magnetic Feshbach resonances at zero and finite temperature.

  14. Cold collisions of an open-shell S-state atom with a (2)Pi molecule : N(S-4) colliding with OH in a magnetic field.

    OpenAIRE

    Skomorowski, Wojciech; Gonzalez-Martinez, Maykel L.; Moszynski, Robert; Hutson, Jeremy M.

    2011-01-01

    We present quantum-theoretical studies of collisions between an open-shell S-state atom and a ^2Pi-state molecule in the presence of a magnetic field. We analyze the collisional Hamiltonian and discuss possible mechanisms for inelastic collisions in such systems. The theory is applied to the collisions of the nitrogen atom (^4S) with the OH molecule, with both collision partners initially in fully spin-stretched (magnetically trappable) states, assuming that the interaction takes place exclus...

  15. 12th Rencontres du Vietnam: 36th International symposium on Physics in Collision

    CERN Document Server

    2016-01-01

    The XXXVI international symposium on Physics in Collision (PIC) is a conference whose focus is to update key topics in elementary particle physics in which new results have been published within the last year or are reasonably expected to be so before the symposium. The aim of the presentations is to encourage informal discussions of new experimental results and their implications. The topics at the symposium cover a wide range of physics subjects from experimental and theoretical accelerator-based particle physics to astroparticle physics. Specifically, the meeting topics include Electroweak phenomena, neutrino physics, QCD, heavy flavor physics, heavy ion physics, Higgs physics, Searches for BSM physics, and astroparticle physics.

  16. Distorted wave theories for dressed-ion-atom collisions with GSZ projectile potentials

    Energy Technology Data Exchange (ETDEWEB)

    Monti, J M; Rivarola, R D [Instituto de Fisica Rosario (CONICET-UNR) and Facultad de Ciencias Exactas, IngenierIa y Agrimensura, Universidad Nacional de Rosario, Avenida Pellegrini 250, 2000 Rosario (Argentina); Fainstein, P D, E-mail: monti@ifir-conicet.gov.ar [Comision Nacional de EnergIa Atomica, Centro Atomico Bariloche, 8400 San Carlos de Bariloche (Argentina)

    2011-10-14

    The continuum distorted wave and the continuum distorted wave-eikonal initial state approximations for electron emission in ion-atom collisions are generalized to the case of dressed projectiles. The interaction between the dressed projectile and the active electron is represented by the analytic Green-Sellin-Zachor (GSZ) potential. Doubly differential cross sections as a function of the emitted electron energy and angle are computed. The region of the binary encounter peak is analysed in detail. Interference structures appear in agreement with the experimental data and are interpreted as arising from the coherent interference between short- and long-range scattering amplitudes.

  17. Projectile X-ray emission in relativistic ion-atom collisions

    OpenAIRE

    Salem, Shadi

    2010-01-01

    This work reports on the study of the projectile x-ray emission in relativistic ion-atom collisions. Excitation of K-shell in He-like uranium ions, electron capture into H-like uranium ions and Simultaneous ionization and excitation of initially He-like uranium ions have been studied using the experimental storage ring at GSI. Information about the population of the excited states for the H- and He-like uranium ions, can be obtained by measuring the angular distribution of the decay radiation...

  18. Spin-Exchange Collisions of the Ground State of Cs Atoms in a High Magnetic Field

    Institute of Scientific and Technical Information of China (English)

    FU Li-Ping; LUO Jun; ZENG Xi-Zhi

    2000-01-01

    Cs atoms were optically pumped with a Ti:sapphire laser in a magnetic field of 1.516 T. Steady absorption spectra and populations of Zeeman sublevels of the ground state of Cs in N2 gas at various pressures (5, 40, and 80 Torr)were obtained. The results show that in a high magnetic field, the combined electron-nuclear spin transition(flip-flop transition), which is mainly induced by the collision modification δa( J.I)of hyperfine interaction, is an important relaxation mechanism at high buffer-gas pressures.

  19. δ-electron spectroscopy and the atomic clock effect in heavy-ion collisions

    International Nuclear Information System (INIS)

    The properties of strongly bound electrons in superheavy quasimolecular systems with combined nuclear charge numbers Z = ZP + ZT ≥ 110 are investigated. The emission of δ-electrons may serve as an atomic clock for nuclear reactions which is associated with the large overlap of the electron probability density with the nuclear interior. Excitation and emission rates of inner-shell electrons in collisions of very heavy ions with beam energies at or above the nuclear Coulomb barrier depend explicitly on details of the nuclear dynamics. Theoretical and experimental results are reviewed. (orig.)

  20. Supercomputers and the future of computational atomic scattering physics

    International Nuclear Information System (INIS)

    The advent of the supercomputer has opened new vistas for the computational atomic physicist. Problems of hitherto unparalleled complexity are now being examined using these new machines, and important connections with other fields of physics are being established. This talk briefly reviews some of the most important trends in computational scattering physics and suggests some exciting possibilities for the future. 7 refs., 2 figs

  1. [The physics of laser polarized muonic atoms

    International Nuclear Information System (INIS)

    This past research period we carried out a successful experiment at LAMPF in collaboration with Syracuse University in which we used lasers to produce polarized muonic 3He. Samples of nuclear polarized 3He were produced by spin-exchange with optically pumped rubidium vapor. Unpolarized muons were stopped in the gas, and became polarized due to their hyperfine interaction with the 3He nucleus. We determined that a muon polarization of ∼8% results with a 3He target polarization of 100%. The high statistical accuracy of our result gives us a firm handle on a theoretical question of great importance to future work involving muons and polarized 3He. Currently, we are working toward a new experiment at LAMPF, for which we have just submitted a proposal requesting running time this coming summer. The experiment utilizes a new technique for producing polarized muonic 3He, a technique we believe has the potential for producing practical polarizations that in principle could be as high as 75%, and in practice may exceed 25--50%. We call this new technique direct spin-exchange (DSE) because it is based on spin-exchange collisions between neutral muonic helium and an optically pumped vapor of Rb. It is direct because, in contrast to the technique we used last summer, the 3He nucleus is not involved in the spin-exchange process. We have proposed the use of DSE to study the induced pseudoscalar form factor of 3He. Finally, we describe an experiment to measure the spin dependent structure function of the neutron at SLAC. Princeton played an important role in the design and proposal of this experiment, including hosting a meeting to explore the technical feasibility of the polarized 3He target

  2. Atomic physics with highly charged ions

    International Nuclear Information System (INIS)

    The past year has been a busy one for all three accelerators, the LINAC, EBIS and the tandem. The EBIS continues to deliver beams of highly charged ions around the clock for the study of low energy collisions with gases and surfaces. The electron beam energy has been upgraded to 10 keV, and intensities of highly charged species such as Xe44+ have been greatly increased. The tandem, the traditional source of highly charged Binary encounter electron production at zero degrees were studied for medium Z (Si,Cl,Cu) projectiles. Recoil momentum spectroscopy has been used to separate the contributions to collisional ionization of one-electron ions (C5+, O7+, F8+) from the nucleus and the electrons of a He target. Marked structure in the binary encounter electron spectra for Cuq+ on H2 targets has been measured for moderate velocity projectiles. Electron capture by slow multiply charged (EBIS) projectiles from laser excited targets has been carried out. Cross sections for capture from Na(3s) and Na*(3p) have been measured for velocities between 0.1 and 1 au. The extension of these experiments to laser excited Rydberg targets is proceeding. Electron capture cross sections and average Q values for Ar16+ on He at velocities between 0.23 and 1.67 au have been measured. The charge state distribution of the He recoils following large angle scattering of C4+ and C6+ ions at 7.5 keV/u has been measured. Cross sections have been measured for up to sextuple capture from C60 (buckminsterfullerene) by highly charged slow projectiles. Coupled channel calculations for double capture from He by slow multicharge ions have been carried out

  3. Current Topics in Atomic, Molecular and Optical Physics

    Science.gov (United States)

    Sinha, Chandana; Bhattacharyya, Shib Shankar

    Preface -- Ultrafast dynamics of nano and mesoscopic systems driven by asymmetric electromagnetic pulses / A. Matos-Abiague, A. S. Moskalenko and J. Berakdar -- One-dimensional non-linear oscillators as models for atoms and molecules under intense laser fields / A. Wadehra and B. M. Deb -- Experimenting with topological states of Bose-Einstein condensates / C. Raman -- Laser cooling and trapping of Rb atoms / S. Chakraborty ... [et al.] -- Pair-correlation in Bose-Einstein condensate and fermi superfluid of atomic gases / B. Deb -- Properties of trapped Bose gas in the large-gas-parameter regime / A. Banerjee -- A Feynman-Kac path integral study of Rb gas / S. Datta -- Mean field theory for interacting spin-1 bosons on a lattice / R. V. Pai, K. Sheshadri and R. Pandit -- Mixed internal-external state approach for quantum computation with neutral atoms on atom chips / E. Charron ... [et al.] -- Ultrafast pulse shaping developments for quantum computation / S. K. Karthick Kumar and D. Goswami -- Quantum information transfer in atom-photon interactions in a cavity / A. S. Majumdar, N. Nayak and B. Ghosh -- Liouville density evolution in billiards and the quantum connection / D. Biswas -- MRCPA: theory and application to highly correlating system / K. Tanaka -- Calculation of negative ion shape resonances using coupled cluster theory / Y. Sajeev and S. Pal -- Optical frequency standard with Sr+: a theoretical many-body approach / C. Sur ... [et al.] -- Fast heavy ion collisions with H[symbol] molecules and young type interference / L. C. Tribedi and D. Misra -- Estimation of ion kinetic energies from time-of-flight and momentum spectra / B. Bapat -- Third-order optical susceptibility of metal nanocluster-glass 28 composites / B. Ghosh and P. Chakraborty -- Study of atom-surface interaction using magnetic atom mirror / A. K. Mohapatra.

  4. Evidence for new physics in high energy neutrino collisions

    International Nuclear Information System (INIS)

    For many years it has been recognised that neutrinos are a rather unique tool for studying particle interactions at very high energies. The neutrino is a simple point-like particle that only interacts weakly and thus provides the opportunity to investigate 'new' phenomena in weak interaction at high energies. New and as yet undiscovered particles may be produced by neutrinos and may be observed in high energy collisons, for example W-bosons or heavy leptons. If the target consists of hadrons these collisions may yield basic information about the structure of hadrons. Experimental work at Caltech Fermilab is described, the object of which is a search for new phenomena arising from neutrino investigations. A class of neutrino interactions has been discovered involving two muons in the final state, not readily explainable, although so far most results tend to fit the predictions of a simple quark-parton model. The main purpose here is to comment on this work. The most striking features are that both muons are relatively energetic, the two muons are of opposite sign, the μ-is more energetic than the μ+, and the energy observed in the interaction is very large. It has been established that both muons are prompt, and the question is discussed as to whether matters can be explained by decays of known short-lived particles yielding leptons - this is found to be untenable. The most likely explanation seems to be the production of a new particle. One possibility is that something new in the weak interaction is produced, for example, a new heavy lepton. Another possibility is that a new state is formed in the hadron system, and it is thought that a new hadronic state of mass 2 to 4 GeV is responsible. It is concluded that recent observations of 2μ events induced by neutrinos definitely imply new and as yet unexplained physics. (U.K.)

  5. The Common Elements of Atomic and Hadronic Physics

    CERN Document Server

    Brodsky, Stanley J

    2015-01-01

    Atomic physics and hadronic physics are both governed by the Yang Mills gauge theory Lagrangian; in fact, Abelian quantum electrodynamics can be regarded as the zero-color limit of quantum chromodynamics. I review a number of areas where the techniques of atomic physics can provide important insight into hadronic eigenstates in QCD. For example, the Dirac-Coulomb equation, which predicts the spectroscopy and structure of hydrogenic atoms, has an analog in hadron physics in the form of frame-independent light-front relativistic equations of motion consistent with light-front holography which give a remarkable first approximation to the spectroscopy, dynamics, and structure of light hadrons. The production of antihydrogen in flight can provide important insight into the dynamics of hadron production in QCD at the amplitude level. The renormalization scale for the running coupling is unambiguously set in QED; an analogous procedure sets the renormalization scales in QCD, leading to scheme-independent scale-fixed...

  6. Spin-orbit interactions and quantum spin dynamics in cold ion-atom collisions

    CERN Document Server

    Tscherbul, Timur V; Buchachenko, Alexei A

    2015-01-01

    We present accurate ab initio and quantum scattering calculations on a prototypical hybrid ion-atom system Yb$^+$-Rb, recently suggested as a promising candidate for the experimental study of open quantum systems, quantum information processing, and quantum simulation. We identify the second-oder spin-orbit (SO) interaction as the dominant source of hyperfine relaxation and decoherence in cold Yb$^+$-Rb collisions. Our results are in good agreement with recent experimental observations [L. Ratschbacher et al., Phys. Rev. Lett. 110, 160402 (2013)] of hyperfine relaxation rates of trapped Yb$^+$ immersed in an ultracold Rb gas. The calculated rates are 4 times smaller than predicted by the Langevin capture theory and display a weak $T^{-0.3}$ temperature dependence, indicating significant deviations from statistical behavior. Our analysis underscores the deleterious nature of the SO interaction and implies that light ion-atom combinations such as Yb$^+$-Li should be used to minimize hyperfine relaxation and dec...

  7. Production of relativistic positronium in collisions of photons and electrons with nuclei and atoms

    CERN Document Server

    Gevorkyan, S R; Schiller, A; Serbo, V G; Tarasov, A V

    1998-01-01

    We consider the production of ultrarelativistic positronium (Ps) in $\\gamma A is an atom or a nucleus with charge $Ze$. For the photoproduction of para- and ortho-Ps and the electroproduction of para-Ps we obtain the most complete description compared with previous works. It includes high order $Z \\alpha$ corrections and polarization effects. The accuracy of the obtained cross sections is determined by omitted terms of the order of the inverse Ps Lorentz factor squared. The studied high order multi-photon electroproduction of ortho-Ps dominates for the collision of electrons with heavy atoms over the bremsstrahlung production from the electron via a virtual photon proposed by Holvik and Olsen. Our results complete and correct the studies of those authors.

  8. The dependence of scattering length on van derWaals interaction and reduced mass of the system in two-atomic collision at cold energies

    Indian Academy of Sciences (India)

    RAY HASI

    2016-07-01

    The static exchange model (SEM) and the modified static exchange model (MSEM) recently introduced by Ray in {\\it Pramana – J. Phys.} 83, 907 (2014) are used to study the elastic collision between two hydrogen-like atoms when both are in ground states by considering the system as a four-body Coulomb system in the centre of mass frame, in which all the Coulomb interaction terms in direct and exchange channels are treated exactly. The SEM includes the non-adiabatic short-range effect due to electron exchange. The MSEM added init, the long-range effect due to induced dynamic dipole polarizabilities between the atoms e.g., the van der Waals interaction. Applying the SEM code in different H-like two-atomic systems, a reduced mass $(\\mu)$ dependence on the scattering length is observed. Again, applying the MSEM code on H(1s)–H(1s) elastic scattering and varying the minimum values of interatomic distance $R_0$, the dependence of scattering length on the effective interatomic potential consistent with the existing physics is observed. Both these basic findings in low and cold energy atomic collision physics are quite useful and are being reported for the first time.

  9. Cold and controlled molecular collisions: a bridge from quantum physics to organic chemistry

    International Nuclear Information System (INIS)

    The fundamental dynamics of molecular collisions and reactions have challenged researchers for many years. This continues to drive the development of more informative experiments and more precise theoretical descriptions in physical chemistry and chemical physics. I will discuss two collision processes that we have studied with different techniques in my group. The first one is a fully quantum state-resolved inelastic collision, which we have achieved to study in a low-temperature ion trap. The second one is the elementary nucleophilic substitution reaction, for which we have been able to image and analyse several different reaction mechanisms. (author)

  10. Advances in atomic, molecular, and optical physics

    CERN Document Server

    Bederson, Benjamin

    1995-01-01

    Praise for Previous Volumes"This volume maintains the authoritative standards of the series...The editors and publishers are to be congratulated"- M.S. CHILD in PHYSICS BULLETIN"Maintains the high standards of earlier volumes in the series...All the series are written by experts in the field, and their summaries are most timely...Strongly recommended."- G. HERZBERG in AMERICAN SCIENTIST

  11. Advances in atomic, molecular, and optical physics

    CERN Document Server

    Bederson, Benjamin

    1997-01-01

    Praise for the Series""This volume maintains the authoritative standards of the series...The editors and publishers are to be congratulated.""--M.S. Child in Physics Bulletin""Maintains the high standards of earlier volumes in the series...All the articles are written by experts in the field, and their summaries are most timely...Strongly recommended.""--G. Herzberg in American Scientist

  12. Atomic Layer Thermopile Materials: Physics and Application

    Directory of Open Access Journals (Sweden)

    P. X. Zhang

    2008-01-01

    Full Text Available New types of thermoelectric materials characterized by highly anisotropic Fermi surfaces and thus anisotropic Seebeck coefficients are reviewed. Early studies revealed that there is an induced voltage in high TC oxide superconductors when the surface of the films is exposed to short light pulses. Subsequent investigations proved that the effect is due to anisotropic components of the Seebeck tensor, and the type of materials is referred to atomic layer thermopile (ALT. Our recent studies indicate that multilayer thin films at the nanoscale demonstrate enhanced ALT properties. This is in agreement with the prediction in seeking the larger figure of merit (ZT thermoelectric materials in nanostructures. The study of ALT materials provides both deep insight of anisotropic transport property of these materials and at the same time potential materials for applications, such as light detector and microcooler. By measuring the ALT properties under various perturbations, it is found that the information on anisotropic transport properties can be provided. The information sometimes is not easily obtained by other tools due to the nanoscale phase coexistence in these materials. Also, some remained open questions and future development in this research direction have been well discussed.

  13. Orbital-angular-momentum change in sodium Rydbery atoms induced by collisions with slow ions

    Energy Technology Data Exchange (ETDEWEB)

    Smith, D.B.

    1987-01-01

    This dissertation describes the experimental measurement of angular-momentum change in sodium Rydberg-state atoms induced by collisions with slow Na/sup +/ ions. For these measurements an existing crossed-beam apparatus was modified by the addition of two ion sources, one a thermionic emitter, the other a duoplasmatron. In the experiments, Na atoms were laser-excited to Rydberg nd-levels (principal quantum numbers n = 21 to 29) and were exposed to a Na/sup +/ ion beam (energies 29 to 590 eV from the thermionic emitter) in a crossed-beam experiment. A method was devised for a direct measurement of the ion-beam current density in the interaction region. During an interaction time of approximately 3 ..mu..sec, collisions occurred in which the initial orbital-angular-momentum l was increased by an amount ..delta..l greater than or equal to 1. The distribution of final nl states was analyzed by selective field ionization (SFI). The cross section was measured as a function of velocity in the region v = 0.2 to 0.7, where the reduced velocity v is the ratio of incident-ion and orbital-electron velocities.

  14. Wave-packet continuum-discretization approach to ion-atom collisions: Nonrearrangement scattering

    Science.gov (United States)

    Abdurakhmanov, I. B.; Kadyrov, A. S.; Bray, I.

    2016-08-01

    A general single-center close-coupling approach based on a continuum-discretization procedure is developed to calculate excitation and ionization processes in ion-atom collisions. The continuous spectrum of the target is discretized using stationary wave packets constructed from the Coulomb wave functions, the eigenstates of the target Hamiltonian. Such continuum discretization allows one to generate pseudostates with arbitrary energies and distribution. These features are ideal for detailed differential ionization studies. The approach starts from the semiclassical three-body Schrödinger equation for the scattering wave function and leads to a set of coupled differential equations for the transition probability amplitudes. To demonstrate its utility the method is applied to calculate collisions of antiprotons with atomic hydrogen. A comprehensive set of benchmark results from integrated to fully differential cross sections for antiproton-impact ionization of hydrogen in the energy range from 1 keV to 1 MeV is provided. Contrary to previous predictions, we find that at low incident energies the singly differential cross section has a maximum away from the zero emission energy. This feature could not be seen without a fine discretization of the low-energy part of the continuum.

  15. Atoms in Flight: The Remarkable Connections between Atomic and Hadronic Physics

    Energy Technology Data Exchange (ETDEWEB)

    Brodsky, Stanley J.; /SLAC

    2012-02-16

    Atomic physics and hadron physics are both based on Yang Mills gauge theory; in fact, quantum electrodynamics can be regarded as the zero-color limit of quantum chromodynamics. I review a number of areas where the techniques of atomic physics provide important insight into the theory of hadrons in QCD. For example, the Dirac-Coulomb equation, which predicts the spectroscopy and structure of hydrogenic atoms, has an analog in hadron physics in the form of light-front relativistic equations of motion which give a remarkable first approximation to the spectroscopy, dynamics, and structure of light hadrons. The renormalization scale for the running coupling, which is unambiguously set in QED, leads to a method for setting the renormalization scale in QCD. The production of atoms in flight provides a method for computing the formation of hadrons at the amplitude level. Conversely, many techniques which have been developed for hadron physics, such as scaling laws, evolution equations, and light-front quantization have equal utility for atomic physics, especially in the relativistic domain. I also present a new perspective for understanding the contributions to the cosmological constant from QED and QCD.

  16. The Common Elements of Atomic and Hadronic Physics

    Energy Technology Data Exchange (ETDEWEB)

    Brodsky, Stanley J. [SLAC National Accelerator Lab., Menlo Park, CA (United States)

    2015-02-26

    Atomic physics and hadronic physics are both governed by the Yang Mills gauge theory Lagrangian; in fact, Abelian quantum electrodynamics can be regarded as the zero-color limit of quantum chromodynamics. I review a number of areas where the techniques of atomic physics can provide important insight into hadronic eigenstates in QCD. For example, the Dirac-Coulomb equation, which predicts the spectroscopy and structure of hydrogenic atoms, has an analog in hadron physics in the form of frame-independent light-front relativistic equations of motion consistent with light-front holography which give a remarkable first approximation to the spectroscopy, dynamics, and structure of light hadrons. The production of antihydrogen in flight can provide important insight into the dynamics of hadron production in QCD at the amplitude level. The renormalization scale for the running coupling is unambiguously set in QED; an analogous procedure sets the renormalization scales in QCD, leading to scheme-independent scale-fixed predictions. Conversely, many techniques which have been developed for hadron physics, such as scaling laws, evolution equations, the quark-interchange process and light-front quantization have important applicants for atomic physics and photon science, especially in the relativistic domain.

  17. Atomic collision studies at moderate projectile velocities using highly charged, decelerated heavy ions from the GSI-UNILAC

    International Nuclear Information System (INIS)

    Beams of highly ionized, very heavy atoms at moderate velocities have been produced at the UNILAC using the acceleration-stripping-deceleration method. The available ion species range from Kr33+ to U66+ in the energy region between 2 and 5 MeV/u. A survey on first experiments at GSI using these moderate velocity, few electron, heavy ion beams is given. The effectiveness of the method is demonstrated for Xesup(q+)-Xe collision experiments with 41 <= q <= 45. Results on vacancy transfer between inner quasimolecular levels for close collisions, and on distant collision electron capture are reported. (orig.)

  18. Opportunities for atomic physics with hard synchrotron radiation

    International Nuclear Information System (INIS)

    The construction of third-generation synchrotron radiation facilities places atomic and molecular scientists at the threshold of extraordinary opportunities. Areas of potential interest for the APS in atomic physics are: (1) exploration of relativistic and QED effects which become prominent in inner shells and at high Z; (2) total photon interaction cross sections; (3) scattering; (4) fluorescence; (5) photo- and Auger-electron spectrometries; and (6) ion spectrometry. A special regime in which the APS will lend access to unprecedented exploration is atomic inner-shell phenomena

  19. Atomic physics with new synchrotron radiation: Report from the Japanese working group

    International Nuclear Information System (INIS)

    The construction of a new photon facility, SPring-8, is being started this year in Harima, Japan, and the first photon beam is to be supplied to users in 1998. As a next generation photon source, this facility will rely mainly upon insertion devices like the APS. The source has two characteristic features. One is that the photon flux is very powerful. In atomic physics target density is often very dilute, and, in many cases, coincidence measurement is desirable to get more definite conclusions. Only with the advent of an intense photon source such studies become tractable and will compensate a thin target density. Another feature is that it can yield photons as high as one hundred or two hundred keV. Since the K-edge of uranium is about 120 keV, the new source can be used to ionize even the innermost shell of the heaviest element. In order to discuss the possible projects in the field of atomic physics with these new photon sources, a group was organized in December 1988. The following themes have been discussed (multiply charged ion is abbreviated to MCI): (1) spectroscopy of atoms and molecules; (2) photoionization of ions (inclusive of MCI); (3) MCI-trap (spectroscopy of MCI, cold MCI plasma); (4) collisions of very slow MCI; (5) electronic and atomic structures of microclusters; and (6) plasma

  20. Correlated charge changing ion-atom collisions: Progress report for the period February 15, 1987-March 14, 1988

    International Nuclear Information System (INIS)

    This report summarizes the progress and accomplishments in accelerator atomic physics research supported by DOE grant DE-FG02-87ER13778 for a period of 13 months from February 15, 1987 through March 14, 1988. The general scope of this work involves the experimental investigation of fundamental atomic interactions in collisions of highly charged projectiles with neutral targets, with a particular emphasis on two-electron interactions. Inner-shell processes involving excitation, ionization, and charge transfer are investigated using coincidence techniques in which projectile charge-changing events are associated with x-ray emission, target recoil ions, or electron emission. New measurements were conducted using accelerators at the Lawrence Berkeley Laboratory, Argonne National Laboratory, Hahn-Meitner-Institut (Berlin), and Western Michigan University. The work at Hahn-Meitner resulted from a collaboration initiated while J. A. T. was on research leave from Western Michigan University during the 1986-1987 academic year. The principal new results obtained during the past year using each of the three coincidence techniques are summarized below. A major emphasis of all these investigations is to determine the role of electron correlation in two- (and multiple-) electron interactions

  1. Cern academic training programme 2011: Selected Topics in the Physics of Heavy Ion Collisions

    CERN Multimedia

    PH Department

    2011-01-01

    LECTURE SERIES 14, 15 & 16 March 2011 Selected Topics in the Physics of Heavy Ion Collisions 11:00-12:00 - Bldg. 222-R-001 - Filtration Plant In these lectures, I discuss some classes of measurements accessible in heavy ion collisions at the LHC. How can these observables be measured, to what extent can they be calculated, and what do they tell us about the dense mesoscopic system created during the collision? In the first lecture, I shall focus in particular on measurements that constrain the spatio-temporal picture of the collisions and that measure centrality, orientations and extensions. In the subsequent lectures, I then discuss on how classes of measurements allow one to characterize collective phenomena, and to what extent these measurements can constrain the properties of matter produced in heavy ion collisions. Organiser: Maureen Prola-Tessaur/PH-EDU  

  2. On the calculation of cross-sections for electron neutral atom collisions in the Born approximation to the reactance matrix

    International Nuclear Information System (INIS)

    Born partial wave integrals are considered for electron-neutral atom collisions. It is shown that for relatively general atomic wave functions these may be evaluated analytically. These form the Born reactance matrix Rsub(B) and can be used to calculate the collision strengths in the approximations Ωsup(I), Ωsup(II). It is shown how to modify Ωsup(I) to take some account of exchange using the simple Ochkur approximation. A result is presented for the coupling coefficients that occur in Seaton's multiplication theorem for spherical Bessel functions. (author)

  3. Near-threshold photoionization of hydrogenlike uranium studied in ion-atom collisions via the time-reversed process.

    Science.gov (United States)

    Stöhlker, T; Ma, X; Ludziejewski, T; Beyer, H F; Bosch, F; Brinzanescu, O; Dunford, R W; Eichler, J; Hagmann, S; Ichihara, A; Kozhuharov, C; Krämer, A; Liesen, D; Mokler, P H; Stachura, Z; Swiat, P; Warczak, A

    2001-02-01

    Radiative electron capture, the time-reversed photoionization process occurring in ion-atom collisions, provides presently the only access to photoionization studies for very highly charged ions. By applying the deceleration mode of the ESR storage ring, we studied this process in low-energy collisions of bare uranium ions with low- Z target atoms. This technique allows us to extend the current information about photoionization to much lower energies than those accessible for neutral heavy elements in the direct reaction channel. The results prove that for high- Z systems, higher-order multipole contributions and magnetic corrections persist even at energies close to the threshold.

  4. Near-threshold photoionization of hydrogenlike uranium studied in ion-atom collisions via the time-reversed process.

    Science.gov (United States)

    Stöhlker, T; Ma, X; Ludziejewski, T; Beyer, H F; Bosch, F; Brinzanescu, O; Dunford, R W; Eichler, J; Hagmann, S; Ichihara, A; Kozhuharov, C; Krämer, A; Liesen, D; Mokler, P H; Stachura, Z; Swiat, P; Warczak, A

    2001-02-01

    Radiative electron capture, the time-reversed photoionization process occurring in ion-atom collisions, provides presently the only access to photoionization studies for very highly charged ions. By applying the deceleration mode of the ESR storage ring, we studied this process in low-energy collisions of bare uranium ions with low- Z target atoms. This technique allows us to extend the current information about photoionization to much lower energies than those accessible for neutral heavy elements in the direct reaction channel. The results prove that for high- Z systems, higher-order multipole contributions and magnetic corrections persist even at energies close to the threshold. PMID:11177990

  5. Preon Model and a Possible New Physics in ep Collisions

    Science.gov (United States)

    Senju, H.

    1993-03-01

    The properties of predicted new particles in a preon-subpreon model are discussed. The model contains several new particles which could be detected in the near future. It is shown that ep colliders are especially adequate to study properties of a few of them. Production cross sections and signatures in ep collisions are discussed.

  6. Preon model and a possible new physics in ep collisions

    Energy Technology Data Exchange (ETDEWEB)

    Senju, Hirofumi (Nagoya Municipal Women' s Coll. (Japan))

    1993-03-01

    The properties of predicted new particles in a preon-subpreon model are discussed. The model contains several new particles which could be detected in the near future. It is shown that ep colliders are especially adequate to study properties of a few of them. Production cross sections and signatures in ep collisions are discussed. (author).

  7. Jet and photon physics in pp collisions at the LHC

    CERN Document Server

    Ciulli, Vitaliano

    2016-01-01

    Jets and photons production in proton-proton collisions at the Large Hadron Collider at CERN are key processes to test predictions of Quantum Chromodynamics and constraint the parton distribution functions of the proton. In this paper the most recent measurements from the LHC Collaborations are reviewed.

  8. Advances and challenges in electron-molecule scattering physics-A Report of the 14th International Symposium on Electron-Molecule Collisions and Swarms

    Energy Technology Data Exchange (ETDEWEB)

    Khakoo, M A [Department of Physics, California State University, Fullerton, CA 92831 (United States); Lima, M A P [Departamento de Eletronica Quantica, Instituto de Fisica ' Gleb Wataghin' -UNICAMP, Caixa Postal 6165, 13083-970 Campinas (Brazil); Tennyson, J [Department of Physics and Astronomy, University College, Gower Street, London WC1E 6BT (United Kingdom)

    2006-07-15

    A report is presented of the 13th International Symposium on Electron-Molecule Collisions Physics (Instituto de Fisica, Unicamp, Campinas, Brazil, 27-30 July 2005). This workshop covered low-energy electron interactions with atoms, molecules and condensed matter systems. Several important aspects of this symposium were to bring together theory and experimental advances in this field for gaseous targets as well as showcasing the increasing diversity of electron-molecule collision applications in condensed matter and biological applications. A summary session was held wherein were discussed aspects of the future of the field, including the development of new theoretical and experimental capabilities.

  9. Zeeman Relaxation of Cold Atomic Iron and Nickel in Collisions with 3He

    CERN Document Server

    Johnson, Cort; Brahms, Nathan; Doyle, John M; Kleppner, Daniel; Greytak, Thomas J

    2010-01-01

    We have measured the ratio of the diffusion cross-section to the angular momentum reorientation cross-section in the colliding Fe-3He and Ni-3He systems. Nickel (Ni) and iron (Fe) atoms are introduced via laser ablation into a cryogenically cooled experimental cell containing cold (< 1 K) 3He buffer gas. Elastic collisions rapidly cool the translational temperature of the ablated atoms to the helium temperature. The cross-section ratio is extracted by measuring the decays of the atomic Zeeman sublevels. For our experimental conditions, thermal energy is comparable to the Zeeman splitting. As a result, thermal excitations between Zeeman sublevels significantly impact the observed decay. To determine the cross-section ratio accurately, we introduce a model of Zeeman state dynamics that includes thermal excitations. We find the cross-section ratio for Ni-3He = 5 x 10^3 and Fe-3He <= 3 x 10^3 at 0.75 K in a 0.8 T magnetic field. These measurements are interpreted in the context of submerged shell suppressio...

  10. Multichannel quantum-defect theory for ultracold atom-ion collisions

    CERN Document Server

    Idziaszek, Zbigniew; Calarco, Tommaso; Julienne, Paul S

    2011-01-01

    We develop an analytical model for ultracold atom-ion collisions using the multichannel quantum-defect formalism. The model is based on the analytical solutions of the r^-4 long-range potential and on the application of a frame transformation between asymptotic and molecular bases. This approach allows the description of the atom-ion interaction in the ultracold domain in terms of three parameters only: the singlet and triplet scattering lengths, assumed to be independent of the relative motion angular momentum, and the lead dispersion coefficient of the asymptotic potential. We also introduce corrections to the scattering lengths that improve the accuracy of our quantum-defect model for higher order partial waves, a particularly important result for an accurate description of shape and Feshbach resonances at finite temperature. The theory is applied to the system composed of a 40Ca+ ion and a Na atom, and compared to numerical coupled-channel calculations carried out using ab initio potentials. For this part...

  11. Theoretical Femtosecond Physics Atoms and Molecules in Strong Laser Fields

    CERN Document Server

    Grossmann, Frank

    2008-01-01

    Theoretical femtosecond physics is a new field of research. Theoretical investigations of atoms and molecules interacting with pulsed or continuous wave lasers of up to atomic field strengths are leading to an understanding of many challenging experimental discoveries. Laser-matter interaction is treated on a nonperturbative level in the book using approximate and numerical solutions of the time-dependent Schrödinger equation. The light field is treated classically. Physical phenomena, ranging from ionization of atoms to the ionization and dissociation of molecules and the control of chemical reactions are presented and discussed. Theoretical background for experiments with strong and short laser pulses is given. Several exercises are included in the main text. Some detailed calculations are performed in the appendices.

  12. ATOMIC PHYSICS, AN AUTOINSTRUCTIONAL PROGRAM, VOLUME 4, SUPPLEMENT.

    Science.gov (United States)

    DETERLINE, WILLIAM A.; KLAUS, DAVID J.

    THE AUTOINSTRUCTIONAL MATERIALS IN THIS TEXT WERE PREPARED FOR USE IN AN EXPERIMENTAL STUDY, OFFERING SELF-TUTORING MATERIAL FOR LEARNING ATOMIC PHYSICS. THE TOPICS COVERED ARE (1) RADIATION USES AND NUCLEAR FISSION, (2) NUCLEAR REACTORS, (3) ENERGY FROM NUCLEAR REACTORS, (4) NUCLEAR EXPLOSIONS AND FUSION, (5) A COMPREHENSIVE REVIEW, AND (6) A…

  13. Quantum Shock waves and Population Inversion in Collisions of Ultracold Atomic Clouds

    Science.gov (United States)

    Peotta, Sebastiano; di Ventra, Massimiliano

    2014-03-01

    Using Time-Dependent Density Matrix Renormalization Group (TDMRG) we study the collision of one-dimensional atomic clouds confined in a harmonic trap and evolving with the Lieb-Liniger Hamiltonian. It is observed that the motion is essentially periodic with the clouds bouncing elastically in agreement with the results of the ``quantum Newton cradle'' experiment of Kinoshita et al. [Nature 440, 900 (2006)]. We compare the results for the density profile against a hydrodynamic description with the pressure term taken from the Bethe Ansatz solution of the Lieb-Liniger model. We find that hydrodynamics can describe the breathing mode of a harmonically trapped cloud for arbitrary long times while it breaks down almost immediately for the collision of two clouds due to the formation of shock waves (gradient catastrophe). Concomitantly with the shock waves formation we observe a local energy distribution typical of population inversion, i.e., an effective negative temperature. Our results are an important step towards understanding the hydrodynamics of quantum many-body systems out of equilibrium and the role of integrability in their dynamics. This work has been supported by DOE under Grant No. DE-FG02-05ER46204.

  14. Rovibrationally Inelastic Atom-Molecule Collision Cross Sections from a Hard Sphere Model

    Science.gov (United States)

    Lashner, Jacob; Stewart, Brian

    2016-05-01

    Hard-shell models have long been used to elucidate the principal features of molecular energy transfer and exchange reaction in the A + BC system. Nevertheless, no three-dimensional hard-shell calculation of inelastic collision cross sections has been reported. This work aims to fill that void. A particular motivation comes from our experimental results, which show the importance of equatorial impacts in the vibrational excitation process. Working with the simple hard-sphere model, we incorporated secondary impacts, defined as those in which A strikes C after striking B. Such collisions are important in systems such as Li2 - X, in which vibrational energy transfer occurs principally through side impacts. We discuss the complexity this adds to the model and present fully three-dimensional cross sections for rovibrational excitation of an initially stationary molecule in the homonuclear A + B2 system, examining the cross section as a function of the masses and radii of the atoms. We show how the features in the cross section evolve as these parameters are varied and calculate the contribution of secondary (near-equatorial) impacts to the dynamics. We compare with recent measurements in our laboratory and with the results of quasiclassical trajectories.

  15. Recent theoretical studies of slow collisions between plasma impurity ions and H or He atoms

    Energy Technology Data Exchange (ETDEWEB)

    Fritsch, W. [Hahn-Meitner-Institut Berlin GmbH (Germany). Bereich Theoretische Physik; Tawara, H.

    1997-01-01

    We review recent progress in theoretical studies of slow collisions between light plasma impurity ions and atomic hydrogen or helium. We start with a brief overview of theory work that has been done by various groups in the past. We then proceed to discuss work that is published in the last two years. For the systems of Be{sup 2+}-He, Be{sup 4+}-He and C{sup 5+}-He we present yet unpublished work of our own. All of this work broadens our knowledge about systems that are of interest for the fusion community. Some of the new information is found to be at variance with what is known from other sources and hence needs further analysis. (author)

  16. Proceedings of the 2nd joint seminar on atomic collisions and heavy ion induced nuclear reactions

    International Nuclear Information System (INIS)

    The meeting of the 2nd joint seminar on atomic collisions and heavy ion induced nuclear reactions was held at the University of Tokyo, May 13 and 14, 1982. The aim of this seminar has been not only to recognize the common problems lying between above two research fields, but also to obtain an overview of the theoretical and experimental approaches to clear the current problems. In the seminar, more than 50 participants gathered and presented 16 papers. These are two general reviews and fourteen comprehensive surveys on topical subjects which have been developed very intensively in recent years. The editors would like to thank all participants for their assistance and cooperation in making possible a publication of these proceedings. (author)

  17. Charge transfer and ionization in proton-alkali atoms collisions with and without electric field

    International Nuclear Information System (INIS)

    The classical trajectory Monte Carlo simulation has been used to investigate the collisions of protons with alkali metal atoms in their ground state. Model interaction potential has been used to describe the electron-ionic core interaction. The cross sections for the capture and ionization in the energy range 1-100 keV/amu have been calculated and compared with the available experimental and theoretical results. The effects of the presence of a strong static electric field in different geometrical features on the capture and ionization cross sections have also been investigated. It has been found that the electric field causes the cross section for the capture to decrease while for the ionization enhance dramatically. Many of the null field features are retained. The analyses of the final state n, l-distribution in the electron capture process reveals H(2p) to be the most populated level in both the cases, with and without electric field. (author)

  18. Many-electron stripping in collisions between atoms and heavy ions

    International Nuclear Information System (INIS)

    Recent experiments suggest that a highly stripped ion can remove up to 10 electrons in a single collision with a neutral atom or molecule. It is shown that this process can take place through the coherent superposition of the heavy ion's electric field at different times, in a way analogous to multiphoton ionisation by intense radiation fields. For relatively fast ions, a simple theory is developed and results are presented for a variety of cases. The theory is in reasonable agreement with measured cross sections for 1s-vacancy production in Ne by Clsup(z+) ions at 50 MeV (2 02 for effective charges 10 7+ (1s2s2p 4P) may be as large as 0.1 πa02. The dependence of these cross sections on energy is complicated but their variation with Z at a fixed energy is usually rather gentle. (author)

  19. Cold collisions of polyatomic molecular radicals with S-state atoms in a magnetic field: An ab initio study of He + CH2(X) collisions

    OpenAIRE

    Tscherbul, T.V.; Grinev, T. A.; Yu, H.-G.; Dalgarno, A.; Klos, Jacek; Ma, Lifang; Alexander, Millard H.

    2012-01-01

    We develop a rigorous quantum mechanical theory for collisions of polyatomic molecular radicals with S-state atoms in the presence of an external magnetic field. The theory is based on a fully uncoupled space-fixed basis set representation of the multichannel scattering wavefunction. Explicit expressions are presented for the matrix elements of the scattering Hamiltonian for spin-1/2 and spin-1 polyatomic molecular radicals interacting with structureless targets. The theory is applied to calc...

  20. B physics at CDF - the Beauty of hadron collisions

    International Nuclear Information System (INIS)

    The CDF experiment at the Tevatron pp-bar collider established that extensive and detailed exploration of the b-quark dynamics is possible in hadron collisions, with results competitive and supplementary to those from e+e- colliders. This provides an unique, rich, and highly rewarding program that is currently reaching full maturity. I report a few recent world-leading results on rare decays, CP-violation in Bs0 mixing, and b→s penguin decays.

  1. B physics at CDF - the Beauty of hadron collisions

    International Nuclear Information System (INIS)

    The CDF experiment at the Tevatron p(bar p) collider established that extensive and detailed exploration of the b-quark dynamics is possible in hadron collisions, with results competitive and supplementary to those from e+e- colliders. This provides an unique, rich, and highly rewarding program that is currently reaching full maturity. I report a few recent world-leading results on rare decays, CP-violation in Bs0 mixing, and b → s penguin decays.

  2. Physical meaning of the yields from hadron-nucleon, hadron-nucleus, and nucleus-nucleus collisions observed in experiments

    International Nuclear Information System (INIS)

    A physical meaning of the outcomes from hadronic and nuclear collision processes at high energies is presented, as prompted experimentally. The fast and slow stages in hadron-nucleus collisions are distinguished. Hadrons are produced via intermediate objects observed in hadron-nucleus collisions. The intermediate objects may be treated as the groups of quarks or the quark bags. 37 refs

  3. Cold collisions of polyatomic molecular radicals with S-state atoms in a magnetic field: An ab initio study of He + CH2(X) collisions

    CERN Document Server

    Tscherbul, T V; Yu, H -G; Dalgarno, A; Klos, Jacek; Ma, Lifang; Alexander, Millard H; 10.1063/1.4748258

    2012-01-01

    We develop a rigorous quantum mechanical theory for collisions of polyatomic molecular radicals with S-state atoms in the presence of an external magnetic field. The theory is based on a fully uncoupled space-fixed basis set representation of the multichannel scattering wavefunction. Explicit expressions are presented for the matrix elements of the scattering Hamiltonian for spin-1/2 and spin-1 polyatomic molecular radicals interacting with structureless targets. The theory is applied to calculate the cross sections and thermal rate constants for spin relaxation in low-temperature collisions of the prototypical organic molecule methylene [CH2(X)] with He atoms. To this end, two highly accurate three-dimensional potential energy surfaces (PESs) of the He-CH2(X) complex are developed using the state-of-the-art CCSD(T) method and large basis sets. Both PESs exhibit shallow minima and are weakly anisotropic. Our calculations show that spin relaxation in collisions of CH2, CHD, and CD2 molecules with He atoms occu...

  4. Future atomic physics researches at HIRFL-CSR

    International Nuclear Information System (INIS)

    A new storage ring system, HIRFL-CSR, is now in construction in the National Laboratory of Heavy Ion Research Facility of Lanzhou, China. The new facility consists of a main ring (CSRm) and an experimental ring (CSRe). With the flexibility of the production and the investigation of highly charged ions and radioactive ion beams the new HIRFL-CSR facility will make many frontier atomic physics researches possible in near future. The future physics researches at the HIRFL-CSR are now under consideration. In this paper an overview of the HIRFL-CSR project is given, and the main atomic physics programs to be carried at the HIRFL-CSR are presented. (orig.)

  5. Atomic physics of strongly correlated systems. Progress report, 1 August 1980-31 July 1981

    International Nuclear Information System (INIS)

    Studies of electron correlations of doubly-excited electrons in hyperspherical coordinates, and differential and total cross sections for charge transfer and ionization in fast ion-atom collisions are reported

  6. Atomic scattering in the diffraction limit: electron transfer in keV Li+-Na(3s, 3p) collisions

    DEFF Research Database (Denmark)

    Poel, Mike van der; Nielsen, C.V.; Rybaltover, M.;

    2002-01-01

    of the de Broglie wavelength lambda(dB) = 150 fm at a velocity v = 0.20 au and the effective atomic diameter for electron capture 2R = 20 au. Parallel AO and MO semiclassical coupled-channel calculations of the Na(3s, 3p) --> Li(2s, 2p) state-to-state collision amplitudes have been performed, and quantum...

  7. Atomic density functions: atomic physics calculations analyzed with methods from quantum chemistry

    CERN Document Server

    Borgoo, Alex; Geerlings, P

    2011-01-01

    This contribution reviews a selection of findings on atomic density functions and discusses ways for reading chemical information from them. First an expression for the density function for atoms in the multi-configuration Hartree--Fock scheme is established. The spherical harmonic content of the density function and ways to restore the spherical symmetry in a general open-shell case are treated. The evaluation of the density function is illustrated in a few examples. In the second part of the paper, atomic density functions are analyzed using quantum similarity measures. The comparison of atomic density functions is shown to be useful to obtain physical and chemical information. Finally, concepts from information theory are introduced and adopted for the comparison of density functions. In particular, based on the Kullback--Leibler form, a functional is constructed that reveals the periodicity in Mendeleev's table. Finally a quantum similarity measure is constructed, based on the integrand of the Kullback--L...

  8. Do atoms and anti-atoms obey the same laws of physics?

    CERN Multimedia

    Jeffrey Hangst

    2010-01-01

    ALPHA physicists have recently succeeded in trapping anti-atoms for the first time. Being able to hold on to the simplest atoms of antimatter is an important step towards the collaboration’s ultimate goal: precision spectroscopic comparison of hydrogen and antihydrogen. The question they are seeking to answer: do atoms and anti-atoms obey the same laws of physics? The Standard Model says that they must.   The ALPHA Collaboration celebrates the successful results. The ALPHA collaboration has taken it up a gear and trapped 38 atoms of antihydrogen for the first time. Antihydrogen atoms have been mass-produced at the Antiproton Decelerator (AD) since 2002, when ATHENA (ALPHA’s predecessor) and ATRAP learned how to mix clouds of antiprotons and positrons at cryogenic temperatures. However, these anti-atoms were not confined, and flew off in a few microseconds to meet their fate: annihilation with matter in the walls of the experiment. ALPHA uses antiprotons produced at...

  9. B physics at CDF - the Beauty of hadron collisions

    Energy Technology Data Exchange (ETDEWEB)

    Tonelli, Diego

    2010-11-01

    The CDF experiment at the Tevatron p{bar p} collider established that extensive and detailed exploration of the b-quark dynamics is possible in hadron collisions, with results competitive and supplementary to those from e{sup +}e{sup -} colliders. This provides an unique, rich, and highly rewarding program that is currently reaching full maturity. I report a few recent world-leading results on rare decays, CP-violation in B{sub s}{sup 0} mixing, and b {yields} s penguin decays.

  10. B physics at CDF - the Beauty of hadron collisions

    Energy Technology Data Exchange (ETDEWEB)

    Tonelli, D. [Fermilab, P.O. Box 500, Batavia, IL, 60510 (United States)

    2010-12-15

    The CDF experiment at the Tevatron pp-bar collider established that extensive and detailed exploration of the b-quark dynamics is possible in hadron collisions, with results competitive and supplementary to those from e{sup +}e{sup -} colliders. This provides an unique, rich, and highly rewarding program that is currently reaching full maturity. I report a few recent world-leading results on rare decays, CP-violation in B{sub s}{sup 0} mixing, and b{yields}s penguin decays.

  11. Cross section database for collision processes of helium atom with charged particles. 1. Electron impact processes

    International Nuclear Information System (INIS)

    A comprehensive and critically assessed cross section database for the inelastic collision processes of ground state and excited helium atoms colliding with electrons, protons and multiply-charged ions has been prepared at the Data and Planning Center at NIFS. The present report describes the first part of the database containing the recommended data for electron impact excitation and ionization of neutral helium. An states (atomic terms) with n ≤ 4 are treated individually while the states with n > 4 are considered degenerate. For the processes involving transitions to and from n > 4 levels, suitable cross section scaling relations are presented. For a large number of electron impact transitions, both from the ground and excited states, new convergent close coupling (CCC) calculations were performed to achieve a high accuracy of the data. The evaluated/recommended cross section data are presented by analytic fit functions which preserve the correct asymptotic behavior of the cross sections. The cross sections are also displayed in a graphical form. (author)

  12. The effect of van der Waals forces in two-atomic elastic collision

    CERN Document Server

    Ray, Hasi

    2013-01-01

    The effect of van der Waals interaction on two-atomic collision is studied for elastic scattering at colder energies. A modified static exchange model (MSEM) is used to determine the s-wave elastic phase shift and the corresponding amplitude square. The model includes the effect of dipole-dipole long-range van der Waals interaction in addition to the short-range electron-exchange force. Both are stronger at colder energies. The effective range theory is used to determine the scattering lengths and effective ranges. A system containing one positronium and one hydrogen e.g. the Ps-H system is chosen for the present study since both Ps and H are ideal atoms having only one electron; at the same time Ps is light so that the convergence in partial wave analysis is easier and it has a very high polarizability to make the van der Waals interaction stronger. In addition, the studies are made in search of Feshbach resonances using a very large number of mesh points. The observed interesting behavior with the variation...

  13. Cold collisions of polyatomic molecular radicals with S-state atoms in a magnetic field: An ab initio study of He + CH2(X~) collisions

    Science.gov (United States)

    Tscherbul, T. V.; Grinev, T. A.; Yu, H.-G.; Dalgarno, A.; Kłos, Jacek; Ma, Lifang; Alexander, Millard H.

    2012-09-01

    We develop a rigorous quantum mechanical theory for collisions of polyatomic molecular radicals with S-state atoms in the presence of an external magnetic field. The theory is based on a fully uncoupled space-fixed basis set representation of the multichannel scattering wave function. Explicit expressions are presented for the matrix elements of the scattering Hamiltonian for spin-1/2 and spin-1 polyatomic molecular radicals interacting with structureless targets. The theory is applied to calculate the cross sections and thermal rate constants for spin relaxation in low-temperature collisions of the prototypical organic molecule methylene [CH_2(tilde{X}^3B_1)] with He atoms. To this end, two accurate three-dimensional potential energy surfaces (PESs) of the He-CH_2(tilde{X}^3B_1) complex are developed using the state-of-the-art coupled-cluster method including single and double excitations along with a perturbative correction for triple excitations and large basis sets. Both PESs exhibit shallow minima and are weakly anisotropic. Our calculations show that spin relaxation in collisions of CH2, CHD, and CD2 molecules with He atoms occurs at a much slower rate than elastic scattering over a large range of temperatures (1 μK-1 K) and magnetic fields (0.01-1 T), suggesting excellent prospects for cryogenic helium buffer-gas cooling of ground-state ortho-CH_2(tilde{X}^3B_1) molecules in a magnetic trap. Furthermore, we find that ortho-CH2 undergoes collision-induced spin relaxation much more slowly than para-CH2, which indicates that magnetic trapping can be used to separate nuclear spin isomers of open-shell polyatomic molecules.

  14. Cold collisions of polyatomic molecular radicals with S-state atoms in a magnetic field: an ab initio study of He + CH2(X) collisions.

    Science.gov (United States)

    Tscherbul, T V; Grinev, T A; Yu, H-G; Dalgarno, A; Kłos, Jacek; Ma, Lifang; Alexander, Millard H

    2012-09-14

    We develop a rigorous quantum mechanical theory for collisions of polyatomic molecular radicals with S-state atoms in the presence of an external magnetic field. The theory is based on a fully uncoupled space-fixed basis set representation of the multichannel scattering wave function. Explicit expressions are presented for the matrix elements of the scattering Hamiltonian for spin-1/2 and spin-1 polyatomic molecular radicals interacting with structureless targets. The theory is applied to calculate the cross sections and thermal rate constants for spin relaxation in low-temperature collisions of the prototypical organic molecule methylene [CH(2)(X(3)B(1))] with He atoms. To this end, two accurate three-dimensional potential energy surfaces (PESs) of the He-CH(2)(X(3)B(1)) complex are developed using the state-of-the-art coupled-cluster method including single and double excitations along with a perturbative correction for triple excitations and large basis sets. Both PESs exhibit shallow minima and are weakly anisotropic. Our calculations show that spin relaxation in collisions of CH(2), CHD, and CD(2) molecules with He atoms occurs at a much slower rate than elastic scattering over a large range of temperatures (1 μK-1 K) and magnetic fields (0.01-1 T), suggesting excellent prospects for cryogenic helium buffer-gas cooling of ground-state ortho-CH(2)(X(3)B(1)) molecules in a magnetic trap. Furthermore, we find that ortho-CH(2) undergoes collision-induced spin relaxation much more slowly than para-CH(2), which indicates that magnetic trapping can be used to separate nuclear spin isomers of open-shell polyatomic molecules. PMID:22979854

  15. Coupled-Channel Investigation of the Collision of Protons and Antiprotons with Hydrogen- Like Atoms in the 2s States

    Institute of Scientific and Technical Information of China (English)

    Reda S. Tantawi

    2003-01-01

    The influence of the electric charge of both the projectile and the target nucleus on the cross section of the inelastic collision of protons and antiprotons with atoms is investigated at energies ranging from i to 2500 KeV. The impact parameter method is used to analyse the cross sections of the excitation of the n = 3 states of H atom and He+, Li2+ ions being initially in the excited 2s states. The calculated cross sections for hydrogen atoms are compared with the other theoretical results based on coupled-channels methods.

  16. Laser spectroscopy with nanometric gas cells distance dependence of atom-surface interaction and collisions under confinement

    CERN Document Server

    Hamdi, I; Yarovitski, A; Dutier, G; Maurin, I; Saltiel, S; Li, Y; Lezama, A; Vartapetyan, T; Sarkisyan, D; Gorza, M P; Fichet, M; Bloch, D; Ducloy, M; Hamdi, Ismah\\`{e}ne; Todorov, Petko; Yarovitski, Alexander; Dutier, Gabriel; Maurin, Isabelle; Saltiel, Solomon; Li, Yuanyuan; Lezama, Arturo; Varzhapetyan, Tigran; Sarkisyan, David; Gorza, Marie-Pascale; Fichet, Mich\\`{e}le; Bloch, Daniel; Ducloy, Martial

    2005-01-01

    The high sensitivity of Laser Spectroscopy has made possible the exploration of atomic resonances in newly designed "nanometric" gas cells, whose local thickness varies from 20nm to more than 1000 nm. Following the initial observation of the optical analogous of the coherent Dicke microwave narrowing, the newest prospects include the exploration of long-range atom surface van der Waals interaction with spatial resolution in an unprecedented range of distances, modification of atom dielectric resonant coupling under the influence of the coupling between the two neighbouring dielectric media, and even the possible modification of interatomic collisions processes under the effect of confinement.

  17. Processes involving electron capture and multiple ionization in collisions of fast H+ and He2+ ions with lead atoms

    Science.gov (United States)

    McCartney, P. C. E.; Shah, M. B.; Geddes, J.; Gilbody, H. B.

    1999-12-01

    A crossed-beam technique incorporating time-of-flight analysis and coincidence counting of the collision products has been used to study Pbq+ formation with q up to 8 in collisions between ground-state Pb atoms and H+ and He2+ ions within the range 50-600 keV amu-1. The separate cross sections for simple charge transfer, transfer ionization, and pure ionization leading to the formation of Pbq+ ions have been obtained and the relative importance of these processes has been established. Accurate measurements and rigorous theoretical descriptions of these multielectron processes in such heavy atoms are difficult and data are still very limited. The present measurements have been designed to extend our previous studies of multiple ionization of a few selected heavy metal atoms and to provide a further check on the extent to which the main collision processes can be described quantitatively in terms of simple models based on an independent electron description. In our previous work with Fe, Cu, and Ga atoms using the same experimental approach, we were able to describe the formation of multiply charged ions through both transfer ionization and pure ionization with a high degree of success using an independent electron model. However, the present results for Pb show that the success of this simple approach is much more limited for these much heavier atoms.

  18. Introducing many-body physics using atomic spectroscopy

    CERN Document Server

    Krebs, Dietrich; Santra, Robin

    2013-01-01

    Atoms constitute relatively simple many-body systems, making them suitable objects for developing an understanding of basic aspects of many-body physics. Photoabsorption spectroscopy is a prominent method to study the electronic structure of atoms and the inherent many-body interactions. In this article the impact of many-body effects on well-known spectroscopic features such as Rydberg series, Fano resonances, Cooper minima, and giant resonances is studied, and related many-body phenomena in other fields are outlined. To calculate photoabsorption cross sections the time-dependent configuration interaction singles (TDCIS) model is employed. The conceptual clearness of TDCIS in combination with the compactness of atomic systems allows for a pedagogical introduction to many-body phenomena.

  19. Fragmentation of neutral carbon clusters formed by high velocity atomic collision; Fragmentation d'agregats de carbone neutres formes par collision atomique a haute vitesse

    Energy Technology Data Exchange (ETDEWEB)

    Martinet, G

    2004-05-01

    The aim of this work is to understand the fragmentation of small neutral carbon clusters formed by high velocity atomic collision on atomic gas. In this experiment, the main way of deexcitation of neutral clusters formed by electron capture with ionic species is the fragmentation. To measure the channels of fragmentation, a new detection tool based on shape analysis of current pulse delivered by semiconductor detectors has been developed. For the first time, all branching ratios of neutral carbon clusters are measured in an unambiguous way for clusters size up to 10 atoms. The measurements have been compared to a statistical model in microcanonical ensemble (Microcanonical Metropolis Monte Carlo). In this model, various structural properties of carbon clusters are required. These data have been calculated with Density Functional Theory (DFT-B3LYP) to find the geometries of the clusters and then with Coupled Clusters (CCSD(T)) formalism to obtain dissociation energies and other quantities needed to compute fragmentation calculations. The experimental branching ratios have been compared to the fragmentation model which has allowed to find an energy distribution deposited in the collision. Finally, specific cluster effect has been found namely a large population of excited states. This behaviour is completely different of the atomic carbon case for which the electron capture in the ground states predominates. (author)

  20. A high resolution X-ray crystal spectrometer to study electron and heavy-ion impact atomic collisions

    Indian Academy of Sciences (India)

    Ajay Kumar; D Misra; A H Kelkar; U R Kadhane; K V Thulasiram; Lokesh C Tribedi

    2007-06-01

    We have studied fast ion–atom and electron–atom collision processes using a reconditioned high resolution X-ray spectrometer. The X-rays, generated by the collisions, are dispersed by a curved ADP crystal (Johansson geometry) and detected by a gas proportional counter. A self-written LabVIEW based program has been used to give precise and controlled movement to the crystal and for data acquisition. The performance was tested by detecting the K diagram and satellite lines of several elements. The K satellite lines of Al have been studied in collision with 3–12 keV electrons and 40 MeV C4+ ions. In ion collisions as large as four L-vacancies are created simultaneously with the K-vacancy, compared to two satellites in case of the e-impact. In addition, we have measured the X-rays from H-, He- and Li-like Si ions which arise due to the electron loss/capture process in highly charged 80 MeV Si7+ ions in collision with thin carbon foil. Approximate charge state distribution has been obtained using this new technique.

  1. Electron emission in collisions of fast highly charged bare ions with helium atoms

    Science.gov (United States)

    Mondal, Abhoy; Mandal, Chittranjan; Purkait, Malay

    2016-01-01

    We have studied the electron emission from ground state helium atom in collision with fast bare heavy ions at intermediate and high incident energies. In the present study, we have applied the present three-body formalism of the three Coulomb wave (3C-3B) model and the previously adopted four-body formalism of the three Coulomb wave (3C-4B). To represent the active electron in the helium atom in the 3C-3B model, the initial bound state wavefunction is chosen to be hydrogenic with an effective nuclear charge. The wavefunction for the ejected electron in the exit channel has been approximated to be a Coulomb continuum wavefunction with same effective nuclear charge. Effectively the continuum-continuum correlation effect has been considered in the present investigation. Here we have calculated the energy and angular distribution of double differential cross sections (DDCS) at low and high energy electron emission from helium atom. The large forward-backward asymmetry is observed in the angular distribution which is explained in terms of the two-center effect (TCE). Our theoretical results are compared with available experimental results as well as other theoretical calculations based on the plain wave Born approximation (PWBA), continuum-distorted wave (CDW) approximation, continuum-distorted wave eikonal-initial state (CDW-EIS) approximation, and the corresponding values obtained from the 3C-4B model [S. Jana, R. Samanta, M. Purkait, Phys. Scr. 88, 055301 (2013)] respectively. It is observed that the four-body version of the present investigation produces results which are in better agreement with experimental observations for all cases.

  2. Atomic and molecular physics at INDUS-1: plans and prospects

    International Nuclear Information System (INIS)

    This paper will give a brief description of the INDUS-1 source, details of the proposed beam lines, the present status of the beam lines and atomic and molecular physics experiments planned to be carried out on these beam lines. It will also include some of the future plans for utilisation of INDUS-1 and INDUS-2, a higher energy (2 GeV) machine

  3. Atomic physics experiments with trapped and cooled highly charged ions

    OpenAIRE

    Kluge, H.-J.; Quint, W; Winters, D. F. A

    2007-01-01

    Trapping and cooling techniques have become very important for many fundamental experiments in atomic physics. When applied to highly charged ions confined in Penning traps, these procedures are very effective for testing quantum electrodynamics in extreme electromagnetic fields produced by heavy highly charged ions such as uranium U$^{91+}$. In addition, fundamental constants or nuclear ground state properties can be determined with high accuracy in these simple systems. Finally, by studying...

  4. Physical, Atomic and Thermal Properties of Biofield Treated Lithium Powder

    OpenAIRE

    Trivedi, Mahendra Kumar

    2015-01-01

    Lithium has gained extensive attention in medical science due to mood stabilizing activity. The objective of the present study was to evaluate the impact of biofield treatment on physical, atomic, and thermal properties of lithium powder. The lithium powder was divided into two parts i.e., control and treatment. Control part was remained as untreated and treatment part received Mr. Trivedi’s biofield treatment. Subsequently, control and treated lithium powder samples were characterized ...

  5. Perfect/complete scattering experiments. Probing quantum mechanics on atomic and molecular collisions and coincidences

    Energy Technology Data Exchange (ETDEWEB)

    Lohmann, Bernd [Muenster Univ. (Germany). Inst. fuer Theoretische Physik 1; Grum-Grzhimailo, Alexei N. [Moscow State Univ. (Russian Federation). Skobeltsyn Inst. of Nuclear Physics; Kleinpoppen, Hans

    2013-07-01

    Derives parameters for electrons, photons, atoms, ions, molecules calculated from theory. Delivers the quantum mechanical knowledge of atomic and molecular physics. Presents state-of-the-art experiments in atomic and molecular physics and related theoretical approaches. The main goal of this book is to elucidate what kind of experiment must be performed in order to determine the full set of independent parameters which can be extracted and calculated from theory, where electrons, photons, atoms, ions, molecules, or molecular ions may serve as the interacting constituents of matter. The feasibility of such perfect' and-or 'complete' experiments, providing the complete quantum mechanical knowledge of the process, is associated with the enormous potential of modern research techniques, both, in experiment and theory. It is even difficult to overestimate the role of theory in setting of the complete experiment, starting with the fact that an experiment can be complete only within a certain theoretical framework, and ending with the direct prescription of what, and in what conditions should be measured to make the experiment 'complete'. The language of the related theory is the language of quantum mechanical amplitudes and their relative phases. This book captures the spirit of research in the direction of the complete experiment in atomic and molecular physics, considering some of the basic quantum processes: scattering, Auger decay and photo-ionization. It includes a description of the experimental methods used to realize, step by step, the complete experiment up to the level of the amplitudes and phases. The corresponding arsenal includes, beyond determining the total cross section, the observation of angle and spin resolved quantities, photon polarization and correlation parameters, measurements applying coincidence techniques, preparing initially polarized targets, and even more sophisticated methods. The 'complete' experiment is

  6. Perfect/complete scattering experiments. Probing quantum mechanics on atomic and molecular collisions and coincidences

    International Nuclear Information System (INIS)

    Derives parameters for electrons, photons, atoms, ions, molecules calculated from theory. Delivers the quantum mechanical knowledge of atomic and molecular physics. Presents state-of-the-art experiments in atomic and molecular physics and related theoretical approaches. The main goal of this book is to elucidate what kind of experiment must be performed in order to determine the full set of independent parameters which can be extracted and calculated from theory, where electrons, photons, atoms, ions, molecules, or molecular ions may serve as the interacting constituents of matter. The feasibility of such perfect' and-or 'complete' experiments, providing the complete quantum mechanical knowledge of the process, is associated with the enormous potential of modern research techniques, both, in experiment and theory. It is even difficult to overestimate the role of theory in setting of the complete experiment, starting with the fact that an experiment can be complete only within a certain theoretical framework, and ending with the direct prescription of what, and in what conditions should be measured to make the experiment 'complete'. The language of the related theory is the language of quantum mechanical amplitudes and their relative phases. This book captures the spirit of research in the direction of the complete experiment in atomic and molecular physics, considering some of the basic quantum processes: scattering, Auger decay and photo-ionization. It includes a description of the experimental methods used to realize, step by step, the complete experiment up to the level of the amplitudes and phases. The corresponding arsenal includes, beyond determining the total cross section, the observation of angle and spin resolved quantities, photon polarization and correlation parameters, measurements applying coincidence techniques, preparing initially polarized targets, and even more sophisticated methods. The 'complete' experiment is, until today, hardly to perform

  7. Theoretical femtosecond physics atoms and molecules in strong laser fields

    CERN Document Server

    Grossmann, Frank

    2013-01-01

    Theoretical investigations of atoms and molecules interacting with pulsed or continuous wave lasers up to atomic field strengths on the order of 10^16 W/cm² are leading to an understanding of many challenging experimental discoveries. This book deals with the basics of femtosecond physics and goes up to the latest applications of new phenomena. The book presents an introduction to laser physics with mode-locking and pulsed laser operation. The solution of the time-dependent Schrödinger equation is discussed both analytically and numerically. The basis for the non-perturbative treatment of laser-matter interaction in the book is the numerical solution of the time-dependent Schrödinger equation. The light field is treated classically, and different possible gauges are discussed. Physical phenonema, ranging from Rabi-oscillations in two-level systems to the ionization of atoms, the generation of high harmonics, the ionization and dissociation of molecules as well as the control of chemical reactions are pre...

  8. Production of heavy ion beams for atomic physics studies

    International Nuclear Information System (INIS)

    A laboratory for research in atomic physics of ions has been set up around a 2 MV tandem Van de Graaff accelerator designed and built indegenously. Mass analysed negatively charged heavy ion beams from a directly extracted duoplasmatron ion source are injected through various ion-optical elements into the accelerating tube. A gas stripper at the high voltage dome changes the negative ions into positive ions which are subsequently accelerated. The high energy end of the accelerator consists of quadrupole focussing magnets and an analysing magnet. A pair of insulated tantalum slits provide corona feedback and stabilize the energy of the accelerator. A beam resolution of 5 keV at 1 MeV proton energy has been measured. A number of experiments are presently being planned to utilize the accelerator in the field of basic research in atomic physics. These include beam-foil spectroscopic measurements involving detection of decay photon/electrons, ion-induced X-ray emission, analytical applications and radiation damage studies. Electron spectrometers which are in the stage of testing include cylindrical mirror analyser and parallel plate analyser. On the accelerator front, efforts are underway to develop a new sputter ion source and computer automation for improving stability and reliability. The salient features of the accelerator and the instrumentation developed for carrying out experiments in atomic physics are reported. (author). 14 refs., 17 figs

  9. Moscow State University physics alumni and the Soviet Atomic Project

    International Nuclear Information System (INIS)

    In this paper, two closely related themes are addressed: (1) the role that M V Lomonosov Moscow State University (MSU) played in training specialists in physics for the Soviet Atomic Project, and (2) what its alumni contributed to the development of thermonuclear weapons. In its earlier stages, the Soviet Atomic Project was in acute need of qualified personnel, without whom building nuclear and thermonuclear weapons would be an impossible task, and MSU became a key higher educational institution grappled with the training problem. The first part of the paper discusses the efforts of the leading Soviet scientists and leaders of FMD (First Main Directorate) to organize the training of specialists in nuclear physics at the MSU Physics Department and, on the other hand, to create a new Physics and Technology Department at the university. As a result, a number of Soviet Government's resolutions were prepared and issued, part of which are presented in the paper and give an idea of the large-scale challenges this sphere of education was facing at the time. Information is presented for the first time on the early MSU Physics Department graduates in the structure of matter, being employed in the FMD organizations and enterprises from 1948 to 1951. The second part discusses the contribution to the development of thermonuclear weapons by the teams of scientists led by Academicians I E Tamm, A N Tikhonov, and I M Frank, and including MSU physics alumni. The paper will be useful to anyone interested in the history of Russian physics. (from the history of physics)

  10. Measurement of Absolute Atomic Collision Cross Section with Helium Using 87Rb Atoms Confined in Magneto-Optic and Magnetic Traps

    Institute of Scientific and Technical Information of China (English)

    WANG Ji-Cheng; ZHOU Ke-Ya; WANG Yue-Yuan; LIAO Qing-Hong; LIU Shu-Tian

    2011-01-01

    We present the measurements and calculations of the absolute total collision cross sections for a room-temperature gas of helium using 87 Rb atoms confined in either a magneto-optic or a magnetic quadrupole trap. The loss rates from the magneto-optic trap and the pure magnetic trap are compared and show significant differences. The collision cross sections as a function of trap depth for helium gas are obtained. These findings are significant for extracting the information about the different cross sections when the trap depth is changed.%@@ We present the measurements and calculations of the absolute total collision cross sections for a room-temperature gas of helium using 87Rb atoms confined in either a magneto-optic or a magnetic quadrupole trap.The loss rates from the magneto-optic trap and the pure magnetic trap are compared and show significant differences.The collision cross sections as a function of trap depth for helium gas are obtained.These findings are significant for extracting the information about the different cross sections when the trap depth is changed.

  11. Theory of heavy ion collision physics in hadron therapy

    CERN Document Server

    2013-01-01

    Advances in Quantum Chemistry presents surveys of current topics in this rapidly developing field that has emerged at the cross section of the historically established areas of mathematics, physics, chemistry, and biology. It features detailed reviews written by leading international researchers. This volume focuses on the theory of heavy ion physics in medicine.

  12. Ionization and excitation of Rydberg states in collisions of fast metastable helium atoms with He, Ne, and N2

    International Nuclear Information System (INIS)

    The experimental values of the cross sections of elementary collision processes involving neutral atoms and covering the energy range 01.-1,000 keV are of interest because they can be used to model some phenomena which occur under laboratory conditions and in outer space, and also to check the precision of various models and methods used in the theory of atomic collisions. The latter task is particularly important at moderate collision energies (usually below 100 keV) where the Born approximation for the cross sections of collisional processes gives results greatly at variance with the experimental data and the precision of the more complex theoretical methods being developed at present requires a careful experimental check. Here, the cross sections for ionization and excitation into Rydberg states (n = 21-27) were determined for fast (accelerated to 3.9 keV) metastable helium atoms colliding with He, Ne, and N2. An analysis of the collisionally excited helium atoms in terms of their principal quantum number was carried out using for the ionization by an electric field a system capable of separation in accordance with n and was calibrated using signals from Rydberg states excited selectively by laser radiation

  13. High energy heavy ion collisions from the view point of the 'strong field physics'

    International Nuclear Information System (INIS)

    In the high energy heavy ion collisions at the facilities like RHIC and LHC, two strongest fields in the present universe are generated. First of all, a very strong electromagnetic field is generated, though its duration is very short due to the very high speed collisions of nuclei and the large electric charges. On the other hand, the nuclei are described as the high density saturation gluon state just before the moment of the collision and the high density gluon is released by the collision. A very strong color electromagnetic field is generated. The color glass condensate (CGC) is a reasonable picture. In this text, dynamics of the GLASMA (Glass + plasma), the new physics brought about by those 'strong fields', are introduced and are explained how the yet unsolved problems of the heavy ion collisions are going to be investigated on the new view point. The mechanism of the apparitions of the strong electromagnetic field and the strong color electromagnetic field are explained at first. The heavy ion collisions can be described as the process CGC to develop into QGP. As the phenomena under the strong electromagnetic field and the heavy ion collisions, their synchrotron radiations, the photon birefringence, the photon decay, the splitting of photons and the chiral phase transitions under high field are picked up. Concerning the strong color electromagnetic field dynamics and the heavy ion collisions, the plasma flux tube dynamics, the color magnetic flux tube, the color electric flux tube and the coexisting case of the color electric field and magnetic field are presented. (S. Funahashi)

  14. Atomic physics at the Advanced Photon Source: Workshop report

    International Nuclear Information System (INIS)

    The first Workshop on Atomic Physics at the Advanced Photon Source was held at Argonne National Laboratory on March 29--30, 1990. The unprecedented brightness of the Advanced Photon Source (APS) in the hard X-ray region is expected to make possible a vast array of new research opportunities for the atomic-physics community. Starting with discussions of the history and current status of the field, presentations were made on various future directions for research with hard X-rays interacting with atoms, ions, clusters, and solids. Also important were the discussions on the design and status of the four next-generation rings coming on line during the 1990's: the ALS 1.6 GeV ring at Berkeley; the ESRF 6.0-GeV ring at Grenoble (1993); the APS 7.0-GeV ring at Argonne (1995); and the SPring-8 8.0-GeV ring in Japan (1998). The participation of more than one hundred scientists from domestic as well as foreign institutions demonstrated a strong interest in this field. We plan to organize follow-up workshops in the future emphasizing specific research topics

  15. New methods for quantum mechanical calculations of inelastic atom-molecule collisions and electron scattering

    International Nuclear Information System (INIS)

    New methods for the accurate quantum mechanical treatment of inelastic atom-molecule collisions and electron scattering are considered. The advantages of expanding the system wave function in adiabatic basis functions are emphasized. For a model collinear He-H2 system, the advantages of using vibrationally adiabatic basis functions in close coupling calculations of vibrationally elastic and inelastic transition probabilities are shown. For this system the detailed dynamics of multiquantum transitions is also considered, and the significance of various reactance matrix elements is probed. The close coupling method with conventional, l-dominant, and rotationally and orbitally adiabatic basis functions is applied to rotationally inelastic electron-molecule scattering in the laboratory frame. Electron-N2 scattering is treated in the rigid rotator approximation at total energy E = 30 eV and total angular momentum J = 5. The l-dominant bases afford a useful approximation, but dramatically more accurate results can be obtained with even smaller adiabatic bases. The accuracy and efficiency of close coupling calculations using conventional, l-dominant, adiabatic, and adiabatic l-dominant bases in rotationally inelastic atom-molecule scattering are compared. He-HF is treated in the rigid-rotator approximation at E = 0.05 and 0.017 eV for J = 4, 12, and 20. The effect of various reactance matrix elements on the partial cross sections is shown. S-, p-, and d-wave inelastic e-H scattering is treated in the 1s-2s close coupling approximation. The effects of electron exchange can be successfully approximated by replacing the nonlocal exchange potentials with approximate energy-dependent local potentials

  16. Three-body dynamical interference in electron and positron collision with positronium atom

    Directory of Open Access Journals (Sweden)

    E Ghanbari Adivi

    2010-12-01

    Full Text Available In this project, the Faddeev-Watson-Lovelace (FWL formalism is generalized to large scattering angles. The angular range includes 0-180 degrees. Using this method, the charge transfer differential cross-sections are calculated, in a second-order approximation, for collision of energetic positrons and electrons with neutral positronium atoms. In this approximation, the rearrangement amplitude contains two first-order and three second-order partial amplitudes. The first first-order term is the Born amplitude in a first-order approximation. The second one corresponds to capturing the transferred particle without perturbing the state of this particle. This term, in fact, describes a knock-on process. Since the masses of the particles and the absolute values of their charges are equal, one expects that the second-order terms be similar in magnitude. This aspect causes the instructive interference of the partial amplitudes in some angles and destructive interference in some others. However, it is predicted that these amplitudes have local maxima in direction of the recoiling of the projectile. In order to investigate this situation, the second-order partial amplitudes are calculated and their relations with the parity of the initial and final states of the scattering system are analyzed. In particular, the role of dynamical interference of these partial amplitudes in creation of the kinematical peak and the peak corresponding to the knock-on scattering in angular distribution of the differential cross sections is investigated.

  17. Collision between two ortho-positronium (Ps) atoms: A four-body Coulomb problem

    Indian Academy of Sciences (India)

    RAY HASI

    2016-05-01

    The elastic collision between two ortho-positronium (e.g. $S = 1$) atoms is studied using an {\\it ab-initio} static exchange model (SEM) in the centre of mass (CM) frame by considering the system as a four-body Coulomb problem where all the Coulomb interaction terms in the direct and exchange channels are treated exactly. A coupled channel methodology in momentum space is used to solve Lippman–Schwinger equation following the integral approach. A new SEM code is developed in which the Born–Oppenheimer (BO) scattering amplitude acts as input to derive the SEM amplitude adapting the partial wave analysis. The $s$-, $p$- and $d$-wave elastic phase shifts and the corresponding partial cross-sections for the spin alignment $S = 0$, i.e., singlet (+) and $S = 2$, i.e., triplet (−) states are studied. An augmented Born approximation is used to includethe contribution of higher partial waves more accurately to determine the total/integrated elastic cross-section $(\\sigma)$, the quenching cross-section (σq) and ortho-to-para conversion ratio $(\\sigma/\\sigma q)$. The effective range theory is used to determine the scattering lengths and effective ranges in the s-wave elastic scattering. The theory includes the non-adiabatic short-range effects due to exchange.

  18. Pion correlations as a function of atomic mass in heavy ion collisions

    International Nuclear Information System (INIS)

    The method of two pion interferometry was used to obtain source-size and lifetime parameters for the pions produced in heavy ion collisions. The systems used were 1.70 · A GeV 56Fe + Fe, 1.82 · A GeV 40Ar + KCl and 1.54 · A GeV 93Nb + Nb, allowing for a search for dependences on the atomic number. Two acceptances (centered, in the lab., at ∼ 0 degrees and 45 degrees) were used for each system, allowing a search for dependences on the viewing angle. The correlation functions were calculated by comparing the data samples to background (or reference) samples made using the method of event mixing, where pions from different events are combined to produce a data sample in which the Bose-Einstein correlation effect is absent. The effect of the correlation function on the background samples is calculated, and a method for weighting the events to remove the residual correlation effect is presented. The effect of the spectrometer design on the measured correlation functions is discussed, as are methods for correcting for these effects during the data analysis. 58 refs., 39 figs., 18 tabs

  19. Influence of external magnetic and laser radiation fields on Feshbach resonances in collision of atoms

    CERN Document Server

    Gazazyan, E A; Chaltykyan, V O

    2012-01-01

    We study collision of two atoms with formation of Feshbach resonance at combined interaction with the external magnetic field and laser radiation. In cases of one- and two-photon resonances of laser radiation with two discrete vibrational molecular levels, we show that Feshbach resonances appear at interaction of external magnetic field with dressed states formed via Autler-Townes effect. In addition, in case of one-photon resonance the lower vibrational molecular state is coupled by laser radiation with the continuum of the elastic channel and forms laser-induced Feshbach resonance via both Autler-Townes effect and LICS mechanism. We study the combined process of formation of Feshbach resonances; this enables the control of Feshbach resonance by varying the magnetic field and intensity and frequency of laser radiation. We obtain the cross-sections of elastic and inelastic scattering and show that quenching of resonance occurs at the energy equal to that of the systems ground state. Dependence of the cross-se...

  20. Excitation of atoms and molecules in collisions with fast, highly charged ions: Progress report for the period January 1, 1988 to February 28, 1989

    International Nuclear Information System (INIS)

    This report summarizes progress in research supported by DOE Grant FG05-84ER13262 during the period January 1, 1988 to February 29, 1989. The research program continues to emphasize the investigation of multielectron ionization and capture processes in fast heavy-ion collisions. Several major projects were completed this year and a number of new ones begun. Among the completed projects were an investigation of resonant multielectron transfer to double K-vacancy states in solid oxygen compounds, and a study of collisional quenching of 23P and 24P states in 33 MeV two- and three-electron Mg ions. New projects include a systematic investigation of the projectile charge dependence of cross sections for Ar recoil-ion production in 1 MeV/amu oxygen ion collisions production, and a design study for an atomic physics beam line to be connected to an electron-cyclotron-resonance (ECR) ion source. Work on molecular fragmentation in heavy-ion collisions continued

  1. Ionization and charge transfer in high-energy ion-atom collisions

    International Nuclear Information System (INIS)

    Electron capture and loss by fast highly charged ions in a gas target, and ionization of the target by passage of the fast projectile beam, are fundamental processes in atomic physics. These processes, along with excitation, can be experimentally studied separately (''singles'') or together (''coincidence''). This paper is a review of recent results on singles measurements for electron capture and loss and for target ionization, for velocities which are generally high relative to the active electron, including recent ionization measurements for a nearly relativistic projectile. 11 refs., 6 figs

  2. Suppression of angular momentum transfer in cold collisions of transition metal atoms in ground States with nonzero orbital angular momentum.

    Science.gov (United States)

    Hancox, Cindy I; Doret, S Charles; Hummon, Matthew T; Krems, Roman V; Doyle, John M

    2005-01-14

    The Zeeman relaxation rate in cold collisions of Ti(3d(2)4s(2) 3F2) with He is measured. We find that collisional transfer of angular momentum is dramatically suppressed due to the presence of the filled 4s(2) shell. The degree of electronic interaction anisotropy, which is responsible for Zeeman relaxation, is estimated to be about 200 times smaller in the Ti-He complex than in He complexes with typical non-S-state atoms.

  3. Single and double electron capture cross sections in keV-collisions between fully stripped ions with helium atom

    OpenAIRE

    Ibaaz, Aicha; Dubois, Alain

    2015-01-01

    International audience We present cross section calculations for single-, double-capture, and double capture to auto-ionizing states occurring in the course of collisions between fully stripped ions Aq+ (q≤10) and helium atom at impact energies ranging from 0.25 to 625 keV/u. These calculations were performed by applying a semiclassical nonperturbative close coupling approach, based on the expansion of the scattering wave function into asymptotic bielectronic states with proper translation...

  4. Molecular theory of K-vacancy production in heavy-ion-atom collisions at small impact parameters

    International Nuclear Information System (INIS)

    1 s sigma vacancy production is calculated by approximating the 1 s sigma molecular wave function with an atomic 1s wave function for a charge Z(R) centered at a distance h(R) from the heavier nucleus. h(R) and Z(R) are determined by minimizing the 1 s sigma electronic energy. Previous calculations with the atomic semi-classsical approximation (h = 0, Z(R) = Z2, the target atomic number) showed that the probability of making Cu K vacancies in 0.5- to 2-MeV/a.m.u. H+, D+, and He+ + Cu collisions can be written as P(theta) = A(1 + B cos theta), where theta is the scattering angle and A and B are constants for theta approx. > 100. Although the recoil and dipole excitation contributions to P(theta) (which interfere destructively in the atomic theory) are independently smaller in the molecular calculations, similar B values are obtained. (orig.)

  5. Resonance Radiation and Excited Atoms

    Science.gov (United States)

    Mitchell, Allan C. G.; Zemansky, Mark W.

    2009-06-01

    1. Introduction; 2. Physical and chemical effects connected with resonance radiation; 3. Absorption lines and measurements of the lifetime of the resonance state; 4. Collision processes involving excited atoms; 5. The polarization of resonance radiation; Appendix; Index.

  6. Atom Interferometry for Fundamental Physics and Gravity Measurements in Space

    Science.gov (United States)

    Kohel, James M.

    2012-01-01

    Laser-cooled atoms are used as freefall test masses. The gravitational acceleration on atoms is measured by atom-wave interferometry. The fundamental concept behind atom interferometry is the quantum mechanical particle-wave duality. One can exploit the wave-like nature of atoms to construct an atom interferometer based on matter waves analogous to laser interferometers.

  7. Recent advances in Rydberg physics using alkaline-earth atoms

    Science.gov (United States)

    Dunning, F. B.; Killian, T. C.; Yoshida, S.; Burgdörfer, J.

    2016-06-01

    In this brief review, the opportunities that the alkaline-earth elements offer for studying new aspects of Rydberg physics are discussed. For example, the bosonic alkaline-earth isotopes have zero nuclear spin which eliminates many of the complexities present in alkali Rydberg atoms, permitting simpler and more direct comparison between theory and experiment. The presence of two valence electrons allows the production of singlet and triplet Rydberg states that can exhibit a variety of attractive or repulsive interactions. The availability of weak intercombination lines is advantageous for laser cooling and for applications such as Rydberg dressing. Excitation of one electron to a Rydberg state leaves behind an optically active core ion allowing, for high-L states, the optical imaging of Rydberg atoms and their (spatial) manipulation using light scattering. The second valence electron offers the possibility of engineering long-lived doubly excited states such as planetary atoms. Recent advances in both theory and experiment are highlighted together with a number of possible directions for the future.

  8. Atomic, Molecular, and Optical Physics Workshop Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Armstrong, Jr., Lloyd [University of Southern California

    1997-09-21

    This document contains the final reports from the five panels that comprised a Workshop held to explore future directions, scientific impacts and technological connections of research in Atomic, Molecular and Optical Physics. This workshop was sponsored by the Department of Energy, Office of Basic Energy Sciences, Chemical Sciences Division and was held at the Westfields International Conference Center in Chantilly, Virginia on September 21-24, 1997. The workshop was chaired by Lloyd Armstrong, Jr., University of Southern California and the five panels focused on the following topics: Panel A: Interactions of Atoms and Molecules with Photons - Low Field Daniel Kleppner (Massachusetts Institute of Technology), chair Panel B: Interactions of Atoms and Molecules with Photons - High Field Phil Bucksbaum (University of Michigan), chair Panel C: Surface Interactions with Photons, Electrons, Ions, Atoms and Molecules J. Wayne Rabalais (University of Houston), chair Panel D: Theory of Structure and Dynamics Chris Greene (University of Colorado), chair Panel E: Nano- and Mesocopic Structures Paul Alivisatos (Lawrence Berkeley National Laboratory), chair The choice of focus areas reflects areas of significant interest to DOE/BES but is clearly not intended to span all fields encompassed by the designation of atomic, molecular and optical physics, nor even all areas that would be considered for review and funding under DOE’s AMOP program. In a similar vein, not all research that might be suggested under these topics in this report would be appropriate for consideration by DOE’s AMOP program. The workshop format included overview presentations from each of the panel chairs, followed by an intensive series of panel discussion sessions held over a two-day period. The panels were comprised of scientists from the U. S. and abroad, many of whom are not supported by DOE’s AMOP Program. This workshop was held in lieu of the customary “Contractors Meeting” held annually for

  9. Projectile X-ray emission in relativistic ion-atom collisions

    Energy Technology Data Exchange (ETDEWEB)

    Salem, Shadi Mohammad Ibrahim

    2010-03-16

    This work reports on the study of the projectile X-ray emission in relativistic ion-atom collisions. Excitation of K-shell in He-like uranium ions, electron capture into H-like uranium ions and Simultaneous ionization and excitation of initially He-like uranium ions have been studied using the experimental storage ring at GSI. For the K{sub {alpha}}{sub 1} and K{sub {alpha}}{sub 2} transitions originating from the excitation of the He-like uranium ions, no alignment was observed. In contrast, the Ly{sub {alpha}}{sub 1} radiation from the simultaneous ionization-excitation process of the He-like uranium ions shows a clear alignment. The experimental value leads to the inclusion of a magnetic term in the interaction potential. The capture process of target electrons into the highly-charged heavy ions was studied using H-like uranium ions at an incident energy of 220 MeV/u, impinging on N{sub 2} gas-target. It was shown that, the strongly aligned electrons captured in 2p{sub 3/2} level couple with the available 1s{sub 1/2} electron which shows no initial directional preference. The magnetic sub-state population of the 2p{sub 3/2} electron is redistributed according to the coupling rules to the magnetic sub-states of the relevant two-electron states. This leads to the large anisotropy in the corresponding individual ground state transitions contributing to the K{sub {alpha}}{sub 1} emission. From the K{sub {alpha}}{sub 1}/K{sub {alpha}}{sub 2} ratio, the current results show that the incoherent addition of the E1 and M2 transition components yield to an almost isotropic emission of the total K{sub {alpha}}{sub 1}. In contrast to the radiative electron capture, the experimental results for the K-shell single excitation of He-like uranium ions indicate that only the {sup 1}P{sub 1} level contributes to the K{sub {alpha}}{sub 1} transition. For this case, the anisotropy parameter {beta}{sub 20} was found to be -0.20{+-}0.03. This work also reports on the study of a two

  10. Aneesur Rahman Prize for Computational Physics Talk: Black Hole Collisions

    Science.gov (United States)

    Pretorius, Frans

    2010-02-01

    The class of spacetimes describing the merger of two black holes contain some of the most fascinating solutions to the equations of general relativity. In this talk I will review what has been learnt about the binary black hole problem over the past several years from numerical simulations of the Einstein field equations, focusing on the more ``extreme'' solutions obtained in the high velocity limit. This is of possible relevance to LHC and cosmic ray physics in certain proposed large extra dimension scenarios. Some of the interesting results include the near-Planck scale luminosity in radiated gravitational waves, recoil velocities of on the order of ten thousand kilometers per second or larger, zoom-whirl orbital motion, the formation of near-extremal Kerr black holes, and that in the ultra relativistic limit the internal nature of the colliding object, whether black holes or not, seemingly becomes irrelevant. )

  11. Rearrangement reactions in ion-ion and ion-atom collisions: results and problems

    Energy Technology Data Exchange (ETDEWEB)

    Presnyakov, L.P. [Lebedev Physical Institute, Moscow (Russian Federation); Tawara, H.

    1997-01-01

    Recent experimental and theoretical results are discussed for ionic collisions with large cross sections at intermediate and small energies of the relative motion. Single- and double-electron removal from H{sup -} ions in slow collisions with other ions is considered in more details. The theoretical methods are discussed from the viewpoint of general requirements of scattering theory. (author)

  12. Applications of many-body physics to relativistic heavy ion collisions

    Science.gov (United States)

    Fillion-Gourdeau, Francois

    In this dissertation, many-body physics techniques are used to study and improve ideas related to the description of heavy ion collisions at very high energy. The first part of the thesis concerns the production of tensor mesons in proton-proton (pp) collisions. An effective theory where the f2 meson couples to the energy-momentum tensor is proposed and a comparison of the inclusive cross-section computed in the collinear factorization, the k⊥-factorization and the color glass condensate is performed. A study of the phenomenology in pp collisions then shows a strong dependence on the parametrization of the unintegrated distribution function. The conclusion is that f2 meson production can be utilized to improve the understanding of the proton wave-function. In the second part, a similar investigation is performed by analysing the production cross-section of the eta' meson in pp and proton-nucleus (pA) collisions. The nucleus and proton are described by the CGC and the k⊥ -factorization respectively. A new technique for the computation of Wilson lines---color charge densities correlators in the McLerran-Venugopalan model is developped. The phenomenology shows that the cross-section in pA collisions is very sensitive to the value of the saturation scale, a crucial ingredient of the CGC picture. In the third part of the thesis, the collision term of the Boltzmann equation is derived from first principles at all orders and for any number of participating particles, starting from the full out-of-equilibrium quantum field theory and using the multiple scattering expansion. Finally, the emission of photons from a non-abelian strong classical field is investigated. A formalism based on Schwinger-Keldysh propagators relating the production rate of photons to the retarded solution of the Dirac equation in a background field is presented.

  13. Davisson-Germer Prize in Atomic or Surface Physics Lecture: Exploring Flatland with Cold Atoms

    Science.gov (United States)

    Dalibard, Jean

    2012-06-01

    A two-dimensional Bose fluid is a remarkably rich many-body system, which allows one to revisit several features of quantum statistical physics. Firstly, the role of thermal fluctuations is enhanced compared to the 3D case, which destroys the ordered state associated with Bose-Einstein condensation. However interactions between particles can still cause a superfluid transition, thanks to the Berezinskii-Kosterlitz-Thouless mechanism. Secondly, a weakly interacting Bose fluid in 2D must be scale-invariant, a remarkable feature that manifests itself in the very simple form taken by the equation of state of the fluid. In this talk I will present recent experimental progress in the investigation of 2D atomic gases, which provide a nice illustration of the main features of low dimensional many-body physics.

  14. Non-negligible collisions of alkali atoms with background gas in buffer-gas-free cells coated with paraffin

    Science.gov (United States)

    Sekiguchi, Naota; Hatakeyama, Atsushi

    2016-04-01

    We measured the rate of velocity-changing collisions (VCCs) between alkali atoms and background gas in buffer-gas-free anti-relaxation-coated cells. The average VCC rate in paraffin-coated rubidium vapor cells prepared in this work was 1× 106 hbox {s}^{-1}, which corresponds to 1 mm in the mean free path of rubidium atoms. This short mean free path indicates that the background gas is not negligible in the sense that alkali atoms do not travel freely between the cell walls. In addition, we found that a heating process known as "ripening" increases the VCC rate, and also confirmed that ripening improves the anti-relaxation performance of the coatings.

  15. Modified oscillator approach to ultracold collisions in tight harmonic traps General model and application to metastable helium atoms

    CERN Document Server

    Peach, G; Beams, T J; Peach, Gillian; Whittingham, Ian B; Beams, Timothy J

    2002-01-01

    A novel modified oscillator method of calculating energy eigenvalues for colliding ultracold atoms tightly confined in harmonic potentials is presented and applied to trapped spin-polarized metastable helium atoms. The perturbed harmonic oscillator problem is characterized by a long asymptotic region beyond the effective range of the interatomic potential, and a very efficient method for integrating inwards through this outer region is developed. The calculated eigenvalues for states with $l=0$ agree closely with those computed directly from the radial Schr\\"{o}dinger equation for the trapped atoms using a discrete variable method, and with those computed self-consistently from an energy-dependent effective scattering length. Finally, the self-consistent method is generalized to collisions with $l \

  16. Experimental investigation of the formation of negative hydrogen ions in collisions between positive ions and atomic or molecular targets

    International Nuclear Information System (INIS)

    The formation of the negative hydrogen ion (H-) in collisions between a positive ion and a neutral atomic or molecular target is studied experimentally at impact energies of a few keV. The doubly-differential cross sections for H- formation are measured as a function of the kinetic energy and emission angle for the collision systems OH+ + Ar and O+ + H2O at 412 eV/a.m.u. These H- ions can be emitted at high energies (keV) in hard quasi-elastic two-body collisions involving a large momentum transfer to the H center. However, H- anions are preferentially emitted at low energy (eV) due to soft many-body (≥ 2) collisions resulting in a low momentum transfer. The formation of H- ions by electron capture follows excitation or ionization of the molecule. The molecular fragmentation dynamics is modeled to simulate the emission of H- ions. The overall good agreement between the simulation and the experiment leads to the understanding of most of the experimental observations. (author)

  17. Retraction notice to "Measurements of total absolute collision cross section of ultracold Rb atom using magneto-optic and pure magnetic traps" [Chinese Optics Letters 9, 060201 (2011)

    Institute of Scientific and Technical Information of China (English)

    Jicheng Wang; Yueyuan Wang; Yueke Wang; Guangyu Fang; Shutian Liu

    2011-01-01

    This article "Measurements of total absolute collision cross section of ultracold Rb atom using magneto-optic and pure magnetic traps",which was published on Chinese Optics Letters (9,060201 (2011)) has been retracted at the request of the authors.Reason:The first author,Jicheng Wang,participated in a related research in Professor Kirk Madison's group in the Department of Physics & Astronomy at the University of British Columbia,Canada from September 2008 to February 2010.Some of the experimental data have not been authorized for publication,even though they have been consented to be used by Jicheng Wang in his own research.The authors apologize to Professor K.Madison for misunderstanding,and to Chinese Optics Letters and the readers of Chinese Optics Letters for any inconvenience this mistake may have caused.

  18. I.I. Rabi Prize in Atomic, Molecular and Optical Physics Talk: Novel Quantum Physics in Few- and Many-body Atomic Systems

    Science.gov (United States)

    Chin, Cheng

    2011-05-01

    Recent cold atom researches are reaching out far beyond the realm that was conventionally viewed as atomic physics. Many long standing issues in other physics disciplines or in Gedanken-experiments are nowadays common targets of cold atom physicists. Two prominent examples will be discussed in this talk: BEC-BCS crossover and Efimov physics. Here, cold atoms are employed to emulate electrons in superconductors, and nucleons in nuclear reactions, respectively. The ability to emulate exotic or thought systems using cold atoms stems from the precisely determined, simple, and tunable interaction properties of cold atoms. New experimental tools have also been devised toward an ultimate goal: a complete control and a complete characterization of a few- or many-body quantum system. We are tantalizingly close to this major milestone, and will soon open new venues to explore new quantum phenomena that may (or may not!) exist in scientists' dreams.

  19. Collisions recorded by the CMS detector on 7 May 2016 at the start of the year's physics run

    CERN Multimedia

    Mc Cauley, Thomas

    2016-01-01

    The collisions were recorded from the first so-called "stable beams" of the year, data from which are used by CMS for physics analyses. This marks the beginning of the 2016 data-collection operations.

  20. Difference-frequency combs in cold atom physics

    CERN Document Server

    Kliese, Russell; Puppe, Thomas; Rohde, Felix; Sell, Alexander; Zach, Armin; Leisching, Patrick; Kaenders, Wilhelm; Keegan, Niamh C; Bounds, Alistair D; Bridge, Elizabeth M; Leonard, Jack; Adams, Charles S; Cornish, Simon L; Jones, Matthew P A

    2016-01-01

    Optical frequency combs provide the clockwork to relate optical frequencies to radio frequencies. Hence, combs allow to measure optical frequencies with respect to a radio frequency where the accuracy is limited only by the reference signal. In order to provide a stable link between the radio and optical frequencies, the two parameters of the frequency comb must be fixed: the carrier envelope offset frequency $f_{\\rm ceo}$ and the pulse repetition-rate $f_{\\rm rep}$. We have developed the first optical frequency comb based on difference frequency generation (DFG) that eliminates $f_{\\rm ceo}$ by design - specifically tailored for applications in cold atom physics. An $f_{\\rm ceo}$-free spectrum at 1550 nm is generated from a super continuum spanning more than an optical octave. Established amplification and frequency conversion techniques based on reliable telecom fiber technology allow generation of multiple wavelength outputs. In this paper we discuss the frequency comb design, characterization, and optical...

  1. Atomic Physics in the Quest for Fusion Energy and ITER

    Energy Technology Data Exchange (ETDEWEB)

    Charles H. Skinner

    2008-02-27

    The urgent quest for new energy sources has led developed countries, representing over half of the world population, to collaborate on demonstrating the scientific and technological feasibility of magnetic fusion through the construction and operation of ITER. Data on high-Z ions will be important in this quest. Tungsten plasma facing components have the necessary low erosion rates and low tritium retention but the high radiative efficiency of tungsten ions leads to stringent restrictions on the concentration of tungsten ions in the burning plasma. The influx of tungsten to the burning plasma will need to be diagnosed, understood and stringently controlled. Expanded knowledge of the atomic physics of neutral and ionized tungsten will be important to monitor impurity influxes and derive tungsten concentrations. Also, inert gases such as argon and xenon will be used to dissipate the heat flux flowing to the divertor. This article will summarize the spectroscopic diagnostics planned for ITER and outline areas where additional data is needed.

  2. Atomic physics experiments with trapped and cooled highly charged ions

    CERN Document Server

    Kluge, H -J; Winters, D F A

    2007-01-01

    Trapping and cooling techniques have become very important for many fundamental experiments in atomic physics. When applied to highly charged ions confined in Penning traps, these procedures are very effective for testing quantum electrodynamics in extreme electromagnetic fields produced by heavy highly charged ions such as uranium U$^{91+}$. In addition, fundamental constants or nuclear ground state properties can be determined with high accuracy in these simple systems. Finally, by studying a single trapped radioactive ion, its nuclear decay can be studied in detail by observing the disappearance of the signal of the mother and the appearance of that of the daughter isotope. Such experiments on highly charged ions at extremely low energy will become possible by the HITRAP facility which is currently being built up at GSI. Also the future Facility for Antiproton and Ion Research (FAIR) will be briefly described which is expected to be operational by 2014.

  3. Probing non-Hermitian physics with flying atoms

    Science.gov (United States)

    Wen, Jianming; Xiao, Yanhong; Peng, Peng; Cao, Wanxia; Shen, Ce; Qu, Weizhi; Jiang, Liang

    2016-05-01

    Non-Hermtian optical systems with parity-time (PT) symmetry provide new means for light manipulation and control. To date, most of experimental demonstrations on PT symmetry rely on advanced nanotechnologies and sophisticated fabrication techniques to manmade solid-state materials. Here, we report the first experimental realization of optical anti-PT symmetry, a counterpart of conventional PT symmetry, in a warm atomic-vapor cell. By exploiting rapid coherence transport via flying atoms, we observe essential features of anti-PT symmetry with an unprecedented precision on phase-transition threshold. Moreover, our system allows nonlocal interference of two spatially-separated fields as well as anti-PT assisted four-wave mixing. Besides, another intriguing feature offered by the system is refractionless (or unit-refraction) light propagation. Our results thus represent a significant advance in non-Hermitian physics by bridging a firm connection with the AMO field, where novel phenomena and applications in quantum and nonlinear optics aided by (anti-)PT symmetry can be anticipated.

  4. Nuclear effects in atomic and solid state physics

    Energy Technology Data Exchange (ETDEWEB)

    Belov, Nikolay

    2015-04-15

    Various nuclear effects in atomic systems and in a particular type of solids, namely, in unconventional superconductors, are investigated. The first process considered, internal pair conversion in heavy ions, can play an important role in numerous scattering processes to be examined at existing or upcoming high-energy heavy-ion-accelerator facilities. The rate of nuclear excitation and thus the number of created pairs is found here to be strongly increased by ion planar channeling through a crystal. The time-reversed process of pair conversion, nuclear excitation by resonant positron annihilation, provides an alternative mechanism of positron-matter interaction and constitutes a state-selective way to excite nuclei which is complementary to photo- and Coulomb excitation. Furthermore, weak-interaction effects are examined in the context of parity violation in unconventional p-wave superconductors. We suggest schemes to efficiently enhance the effect and to enable its future experimental study. The considered effects represent new phenomena at the interface of atomic and nuclear physics and quantum electrodynamics, and provide effective ways to investigate fundamental interactions.

  5. Investigating the effect of electric field on ionization cross sections in antiproton–hydrogen/deuterium atoms collisions

    International Nuclear Information System (INIS)

    The Classical Trajectory Monte Carlo (CTMC) method has been used to investigate the effects of aligned electric field on the ionization cross sections in antiproton and hydrogen atoms collisions. The cross sections for the ionization of hydrogen/deuterium collision with antiproton in the energy range 10–500 keV/amu have been calculated and compared with the available experiment and theoretical results. The ionization cross sections are in reasonable agreement with the recently reported experimental and theoretical results. Isotope effect in the ionization cross section is reported to be negligible. The effects of the external electric field are seen to be quite prominent. Differential cross sections for ionization at the scattering angle up to 0.1° are also reported in this paper.

  6. Directional `superradiant' collisions: bosonic amplification of atom pairs emitted from an elongated Bose-Einstein condensate

    OpenAIRE

    Vardi, A.; Moore, M. G.

    2002-01-01

    We study spontaneous directionality in the bosonic amplification of atom pairs emitted from an elongated Bose-Einstein condensate (BEC), an effect analogous to `superradiant' emission of atom-photon pairs. Using a simplified model, we make analytic predictions regarding directional effects for both atom-atom and atom-photon emission. These are confirmed by numerical mean-field simulations, demonstrating the the feasibility of nearly perfect directional emission along the condensate axis. The ...

  7. Measurements of scattering processes in negative ion-atom collisions. Technical progress report, 1 September 1991--31 August 1992

    Energy Technology Data Exchange (ETDEWEB)

    Kvale, T.J.

    1992-04-01

    This Technical Progress Report describes the progress made on the research objectives during the past twelve months. This research project is designed to provide measurements of various scattering processes which occur in H{sup {minus}} collisions with atomic (specifically, noble gas and atomic hydrogen) targets at intermediate energies. These processes include: elastic scattering,single- and double-electron detachment, and target excitation/ionization. For the elastic and target inelastic processes where H{sup {minus}} is scattered intact, the experimental technique of Ion Energy-Loss Spectroscopy (IELS) will be employed to identify the final target state(s). In most of the above processes, cross sections are unknown both experimentally and theoretically. The measurements in progress will provide either experimentally-determined cross sections or set upper limits to those cross sections. In either case, these measurements will be stringent tests of our understanding in energetic negative ion-atom collisions. This series of experiments required the construction of a new facility and the initial ion beam was accelerated through the apparatus in April 1991.

  8. Measurements of scattering processes in negative ion-atom collisions. Technical progress report, 1 September 1992--31 August 1993

    Energy Technology Data Exchange (ETDEWEB)

    Kvale, T.J.

    1993-05-01

    This Technical Progress Report describes the progress made on the research objectives during the past twelve months. This research project is designed to provide measurements of various scattering processes which occur in H{sup {minus}} collisions with atomic (specifically, noble gas and atomic hydrogen) targets at intermediate energies. These processes include elastic scattering, single- and double-electron detachment, and target excitation/ionization. For the elastic and target inelastic processes where H{sup {minus}} is scattered intact, the experimental technique of Ion Energy-Loss Spectroscopy (IELS) will be employed to identify the final target state(s). In most of the above processes, cross sections are unknown both experimentally and theoretically. The measurements in progress will provide either experimentally determined cross sections or set upper limits to those cross sections. In either case, these measurements will be stringent tests of our understanding in energetic negative ion - atom collisions. In addition secondary negative particle emission yields for H{sup 0} on Cu in the 3 to 50 keV range are shown.

  9. The dependence of scattering length on van der Waals interaction and on the reduced-mass of the system in two-atomic collision at cold energies

    CERN Document Server

    Ray, Hasi

    2015-01-01

    The static-exchange model (SEM) and the modified static-exchange model (MSEM) recently introduced by Ray [1] is applied to study the elastic collision between two hydrogen-like atoms when both are in ground states considering the system as a four-body Coulomb problem in the center of mass frame, in which all the Coulomb interaction terms in direct and exchange channels are treated exactly. The SEM includes the non-adiabatic short-range effect due to electron-exchange. The MSEM added in it, the long-range effect due to induced dynamic dipole polarizabilities between the atoms e.g. the Van der Waals interaction. Applying the SEM code in different H-like two-atomic systems, a reduced mass dependence on scattering length is observed. Again applying the MSEM code on H(1s)-H(1s) elastic scattering and varying the minimum values of interatomic distance, the dependence of scattering length on the effective interatomic potential consistent with the existing physics are observed. Both these basic findings in low and co...

  10. Direct probe of anisotropy in atom-molecule collisions via quantum scattering resonances

    OpenAIRE

    Klein, Ayelet; Shagam, Yuval; Skomorowski, Wojciech; Żuchowski, Piotr. S.; Pawlak, Mariusz; Janssen, Liesbeth M. C.; Moiseyev, Nimrod; van de Meerakker, Sebastiaan Y. T.; van der Avoird, Ad; Koch, Christiane P.; Narevicius, Edvardas

    2016-01-01

    Anisotropy is a fundamental property of particle interactions. It occupies a central role in cold and ultra-cold molecular processes, where long range forces have been found to significantly depend on orientation in ultra-cold polar molecule collisions. Recent experiments have demonstrated the emergence of quantum phenomena such as scattering resonances in the cold collisions regime due to quantization of the intermolecular degrees of freedom. Although these states have been shown to be sensi...

  11. Search for New Physics Using Jets in Proton-Proton Collisions

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00338702

    In this thesis a search for New Physics in events with two jets is presented. These events are produced in proton-proton collisions at the Large Hadron Collider (LHC) at the European Organization for Nuclear Research (CERN) close to the lake Geneva in Switzerland. These collisions have been recorded with the ATLAS experiment, a large multi-purpose particle detector that is placed at one of four points in the LHC where the proton beams are brought to collision. The theory to describe the processes of particle physics, the Standard Model, was able to describe all measurements made so far. Apart from this amazing agreement, the Standard Model does not give an answer to some fundamental questions. How can gravity be described within the Standard Model? What is the mysterious form of matter that has not been seen, but 26 % of the universe are made of? Why are neutrinos massive? Models answering some of these questions lead to the prediction of additional particles, that have not be seen before. A search for new p...

  12. Scattering of NH{sub 3} and ND{sub 3} with rare gas atoms at low collision energy

    Energy Technology Data Exchange (ETDEWEB)

    Loreau, J., E-mail: jloreau@ulb.ac.be [Service de Chimie Quantique et Photophysique, Université Libre de Bruxelles (ULB) CP 160/09, 50 av. F.D. Roosevelt, 1050 Brussels (Belgium); Avoird, A. van der, E-mail: A.vanderAvoird@theochem.ru.nl [Theoretical Chemistry, Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen (Netherlands)

    2015-11-14

    We present a theoretical study of elastic and rotationally inelastic collisions of NH{sub 3} and ND{sub 3} with rare gas atoms (He, Ne, Ar, Kr, Xe) at low energy. Quantum close-coupling calculations have been performed for energies between 0.001 and 300 cm{sup −1}. We focus on collisions in which NH{sub 3} is initially in the upper state of the inversion doublet with j = 1, k = 1, which is the most relevant in an experimental context as it can be trapped electrostatically and Stark-decelerated. We discuss the presence of resonances in the elastic and inelastic cross sections, as well as the trends in the inelastic cross sections along the rare gas series and the differences between NH{sub 3} and ND{sub 3} as a colliding partner. We also demonstrate the importance of explicitly taking into account the umbrella (inversion) motion of NH{sub 3} in order to obtain accurate scattering cross sections at low collision energy. Finally, we investigate the possibility of sympathetic cooling of ammonia using cold or ultracold rare gas atoms. We show that some systems exhibit a large ratio of elastic to inelastic cross sections in the cold regime, which is promising for sympathetic cooling experiments. The close-coupling calculations are based on previously reported ab initio potential energy surfaces for NH{sub 3}–He and NH{sub 3}–Ar, as well as on new, four-dimensional, potential energy surfaces for the interaction of ammonia with Ne, Kr, and Xe, which were computed using the coupled-cluster method and large basis sets. We compare the properties of the potential energy surfaces corresponding to the interaction of ammonia with the various rare gas atoms.

  13. Physics of polarized scattering at multi-level atomic systems

    CERN Document Server

    Stenflo, Jan

    2015-01-01

    The symmetric peak observed in linear polarization in the core of the solar sodium D$_1$ line at 5896 \\AA\\ has remained enigmatic since its discovery nearly two decades ago. One reason is that the theory of polarized scattering has not been experimentally tested for multi-level atomic systems in the relevant parameter domains, although the theory is continually being used for the interpretation of astrophysical observations. A laboratory experiment that was set up a decade ago to find out whether the D$_1$ enigma is a problem of solar physics or quantum physics revealed that the D$_1$ system has a rich polarization structure in situations where standard scattering theory predicts zero polarization, even when optical pumping of the $m$ state populations of the hyperfine-split ground state is accounted for. Here we show that the laboratory results can be modeled in great quantitative detail if the theory is extended to include the coherences in both the initial and final states of the scattering process. Radiat...

  14. Anisotropy and linear polarization of radiative processes in energetic ion-atom collisions; Untersuchung zur Anisotropie und linearen Polarisation radiativer Prozesse in energiereichen Ion-Atom-Stoessen

    Energy Technology Data Exchange (ETDEWEB)

    Weber, Guenter

    2010-06-16

    In the present thesis the linear polarization of radiation emitted in energetic ion-atom collisions at the ESR storage ring was measured by applying a novel type of position, timing and energy sensitive X-ray detector as a Compton polarimeter. In contrast to previous measurements, that mainly concentrate on studies of the spectral and angular distribution, the new detectors allowed the first polarization study of the Ly-{alpha}{sub 1} radiation (2p{sub 3/2}{yields}1s{sub 1/2}) in U{sup 91+}. Owing to the high precision of the polarimeters applied here, the experimental results indicate a significant depolarization of the Ly-{alpha}{sub 1} radiation caused by the interference of the E1 and M2 transition branches. Moreover, the current investigation shows that measurements of the linear polarization in combination with angular distribution studies provide a model-independent probe for the ratio of the E1 and M2 transition amplitudes and, consequently, of the corresponding transition probabilities. In addition, a first measurement of the linear polarization as well as an angular distribution study of the electron-nucleus Bremsstrahlung arising from ion-atom collisions was performed. The experimental results obtained were compared to exact relativistic calculations and, in case of the Bremsstrahlung, to a semirelativistic treatment. In general, good agreement was found between theoretical predictions and experimental findings. (orig.)

  15. Atomic physics with highly charged ions. Progress report, FY 1989--91

    Energy Technology Data Exchange (ETDEWEB)

    Richard, P.

    1991-08-01

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

  16. First research coordination meeting on atomic collision data for diagnostics of magnetic fusion plasmas, Vienna, 21-25 June 1982

    International Nuclear Information System (INIS)

    Proceedings of the first meeting of the participants in the IAEA Coordinated Research Programme on atomic collision data for diagnostics of magnetically confined fusion plasmas, convened by the IAEA Nuclear Data Section on 21 - 25 June 1982, at IAEA Headquarters in Vienna. The meeting participants reviewed the status of electron excitation, electron ionization and charge transfer data for selected fusion relevant elements, made specific recommendations on the use of these existing data, and identified those data which needed to be measured or calculated. (author)

  17. Precision measurements of cross sections of inelastic processes realized in collisions of alkali metal ions with atoms of rare gases

    CERN Document Server

    Lomsadze, R A; Mosulishvili, N O; Kezerashvili, R Ya

    2015-01-01

    This work presents a multifaceted experimental study of collisions of Na$^{+}$ and K$^{+}$ ions in the energy range 0.5 -- 10 keV with He and Ar atoms. Absolute cross sections for charge-exchange, ionization, stripping and excitation were measured using a refined version of the transfer electric field method, angle- and energy-dependent collection of product ions, energy loss, and optical spectroscopy. The experimental data and the schematic correlation diagrams have been employed to analyze and determine the mechanisms for these processes.

  18. Suppression of angular momentum transfer in cold collisions of transition metal atoms in ground States with nonzero orbital angular momentum.

    Science.gov (United States)

    Hancox, Cindy I; Doret, S Charles; Hummon, Matthew T; Krems, Roman V; Doyle, John M

    2005-01-14

    The Zeeman relaxation rate in cold collisions of Ti(3d(2)4s(2) 3F2) with He is measured. We find that collisional transfer of angular momentum is dramatically suppressed due to the presence of the filled 4s(2) shell. The degree of electronic interaction anisotropy, which is responsible for Zeeman relaxation, is estimated to be about 200 times smaller in the Ti-He complex than in He complexes with typical non-S-state atoms. PMID:15698077

  19. Fast and Power Efficient Sensor Arbitration: Physical Layer Collision Recovery of Passive RFID Tags

    CERN Document Server

    Fyhn, Karsten; Popovski, Petar; Scaglione, Anna; Larsen, Torben

    2010-01-01

    This work concerns physical layer collision recovery for cheap sensors with allowed variations in frequency and delay of their communications. The work is presented as a generic framework and demonstrated using UHF RFID tag technology. Previous work in this area has not provided recovery for more than two tags, which is shown to be possible in this work. Also presented is a novel mathematical model of the tag signal, incorporating the allowed variations in frequency and delay. The main motivation is seen in the observation that random variations in frequency and delay make the collided signals of different tags separable. The collision recovery is done by estimating the sensor specific variation in frequency and delay and using these estimates in a successive interference cancellation algorithm and a maximum likelihood sequence decoder, to iteratively reconstruct a sensor signal and remove it from the received signal. Numerical simulations show that the estimates and proposed algorithm are effective in recove...

  20. Changes in behavior of some physical quantities as signals of phase transitions in relativistic nuclear collisions

    CERN Document Server

    Jipa, A; Argintaru, D; Grigore, C; Felea, D; Zgura, I S; Zaharia, R; Costantin, F; Stan, E; Ristea, O; Ristea, C; Taban, G

    2003-01-01

    The nuclear collisions at intermediate and high energies offer conditions for different phase transitions in nuclear matter. The present work considers the behaviour of some physical quantities - multiplicity, cross section, particle production ratio - to investigate the possibility of evidencing phase transitions in different experiments at energies between 0.8 A GeV and 200 A GeV, in Laboratory System. Some connections with the most recent results from experiments performed at Relativistic Heavy Ion Collider from Brookhaven National Laboratory and the possibility to introduce the rest mass dependence on the nuclear density are addressed in the paper. New interesting behaviour of the multiplicity and cross section in central and peripheral collisions are reported too. (authors)

  1. Simultaneous K plus L shell ionized atoms during heavy-ion collision process

    Indian Academy of Sciences (India)

    G A V Ramana Murty; G J Naga Raju; V Vijayan; T Ranjan Rautray; B Seetharami Reddy; S Lakshminarayana; K L Narasimham; S Bhuloka Reddy

    2004-06-01

    The fraction of simultaneous K plus L shell ionized atoms is estimated in Fe, Co and Cu elements using carbon ions at different projectile energies. The present results indicate that the fraction of simultaneous K plus L shell ionization probability decreases with increase in projectile energy as well as with increase in the atomic number of the targets atoms.

  2. Measurements of scattering processes in negative ion: Atom collisions. Technical progress report, 1 September 1991--31 December 1994

    Energy Technology Data Exchange (ETDEWEB)

    Kvale, T.J.

    1994-09-27

    This report describes the progress made on the research objectives during the past three years of the grant. This research project is designed to study various scattering processes which occur in H{sup {minus}} collisions with atomic (specifically, noble gas and atomic hydrogen) targets in the intermediate energy region. These processes include: elastic scattering, single- and double-electron detachment, and target excitation/ionization. For the elastic and target inelastic processes where H{sup {minus}} is scattered intact, the experimental technique of Ion Energy-Loss Spectroscopy (IELS) will be employed to identify the final target state(s). In most of the above processes, cross sections are unknown both experimentally and theoretically. The measurements will provide total cross sections (TCS) initially, and once the angular positioning apparatus is installed, will provide angular differential cross sections (ADCS).

  3. Renormalization shielding and eikonal analysis on the atomic collision in dense partially ionized hydrogen plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sung Soo [Department of Applied Mathematics, Hanyang University, Ansan, Kyunggi-Do 426-791 (Korea, Republic of); Jung, Young-Dae [Department of Applied Physics and Department of Bionanotechnology, Hanyang University, Ansan, Kyunggi-Do 426-791 (Korea, Republic of); Department of Physics, Applied Physics, and Astronomy, Rensselaer Polytechnic Institute, 110 Eighth Street, Troy, New York 12180-3590 (United States)

    2013-12-15

    The renormalization plasma screening effects on the electron-ion collision are investigated in dense partially ionized hydrogen plasmas. The Hamilton-Jacobi and eikonal methods with the effective interaction potential are employed to obtain the eikonal scattering phase shift and eikonal cross section for the electron-ion collision. It is found that the influence of renormalization screening strongly suppresses the eikonal scattering phase shift as well as the eikonal cross section, especially, for small impact parameter regions. In addition, the renormalization screening effect reduces the total eikonal cross section in all energy domains. The variation of the renormalization effects on the electron-ion collision in dense partially ionized hydrogen plasmas is also discussed.

  4. The collision between two positronium (Ps) atoms: the exact evaluation of a four-body Coulomb problem

    CERN Document Server

    Ray, Hasi

    2014-01-01

    The collision between two positronium (Ps) atoms is a four-body Coulomb problem with all the particles of equal masses. It is very difficult to compute the Born-Oppenheimer (BO) scattering amplitude involving the nine-dimensional integrals with four Coulomb interaction terms between the atoms. It is extremely difficult in the electron-electron correlation term to include the exchange or antisymmetry between two system electrons exactly. Earlier the Ps and H system was easily approximated as a three-body problem, due to the light mass of Ps the center of mass of the system was confined in the H-nucleus. A simple substitution of variables using no approximation has enabled to evaluate the electron-electron Coulomb exchange-correlation term exactly in such a four-center problem in the center of mass frame involving a nine dimensional integral. The present code of Ps-Ps collision using an ab-initio and exact static-exchange model (SEM) that uses the BO amplitude as input, can reproduce exactly the same data of Ps...

  5. Collisions of electrons with hydrogen atoms I. Package outline and high energy code

    Science.gov (United States)

    Benda, Jakub; Houfek, Karel

    2014-11-01

    Being motivated by the applied researchers’ persisting need for accurate scattering data for the collisions of electrons with hydrogen atoms, we developed a computer package-Hex-that is designed to provide trustworthy results for all basic discrete and continuous processes within non-relativistic framework. The package consists of several computational modules that implement different methods, valid for specific energy regimes. Results of the modules are kept in a common database in the unified form of low-level scattering data (partial-wave T-matrices) and accessed by an interface program which is able to produce various derived quantities like e.g. differential and integral cross sections. This article is the first one of a series of articles that are concerned with the implementation and testing of the modules. Here we give an overview of their structure and present (a) the command-line interface program hex-db that can be also easily compiled into a derived code or used as a backend for a web-page form and (b) simple illustrative module specialized for high energies, hex-dwba, that implements distorted and plane wave Born approximation. Catalogue identifier: AETH_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AETH_v1_0.html Program obtainable from: CPC Program library, Queen’s University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data etc.: 30367 No. of bytes in distributed program, including test data etc.: 232032 Distribution format: tar.gz Programming language: C++11 Operating system: Any system with a C++11 compiler (e.g. GCC 4.8.1; tested on OpenSUSE 13.1 and Windows 8). RAM: Test run 3 MiB. CPC Library Classification: 2.4 Electron scattering External libraries:GSL [49], FFTW3[52], SQLite3 [46]. All of the libraries are open-source and maintained. Nature of problem: Extraction of derived (observable) quantities from partial

  6. High temperature facility for atomic physics studies. Final report

    International Nuclear Information System (INIS)

    The results of a program designed to develop a laser heated plasma sample for atomic physics studies in the 30 to 100 eV range of electron temperature and the 3 x 1017 to 1018 cm-3 range in electron density are presented. The approach used was discussed in detail in Mathematical Sciences Northwest, Inc., (MSNW) Proposal 1660, that is, the laser breakdown mode of heating in a slow solenoid. An extensive rework of the plasma sample facility was done in order to use this mode of heating. Specifically, a new solenoid magnet was constructed to allow higher field operation and the plasma chamber was modified to allow the use of puff filling orifices and small bore tube liners. The vacuum system and focussing optics were changed to allow the use of an on-axis Cassagranian system capable of focussing the laser radiation to a nearly diffraction limited spot as is necessary when heating through a small aperture. The 10 liter CO2 laser optics were charged to an unstable oscillator configuration and additional windows were provided into the optical cavity for alignment purposes

  7. A Slater parameter optimisation interface for the CIV3 atomic structure code and its possible use with the R-matrix close coupling collision code

    International Nuclear Information System (INIS)

    Details are here provided of amendments to the atomic structure code CIV3 which allow the optional adjustment of Slater parameters and average energies of configurations so that they result in improved energy levels and eigenvectors. It is also indicated how, in principle, the resultant improved eigenvectors can be utilised by the R-matrix collision code, thus providing an optimised target for close coupling collision strength calculations. An analogous computational method was recently reported for distorted wave collision strength calculations and applied to Fe XIII. The general method is suitable for the computation of collision strengths for complex ions and in some cases can then provide a basis for collision strength calculations in ions where ab initio computations break down or result in unnecessarily large errors. (author)

  8. Benchmarking atomic physics models for magnetically confined fusion plasma physics experiments

    International Nuclear Information System (INIS)

    In present magnetically confined fusion devices, high and intermediate Z impurities are either puffed into the plasma for divertor radiative cooling experiments or are sputtered from the high Z plasma facing armor. The beneficial cooling of the edge as well as the detrimental radiative losses from the core of these impurities can be properly understood only if the atomic physics used in the modeling of the cooling curves is very accurate. To this end, a comprehensive experimental and theoretical analysis of some relevant impurities is undertaken. Gases (Ne, Ar, Kr, and Xe) are puffed and nongases are introduced through laser ablation into the FTU tokamak plasma. The charge state distributions and total density of these impurities are determined from spatial scans of several photometrically calibrated vacuum ultraviolet and x-ray spectrographs (3 - 1600 Angstrom), the multiple ionization state transport code transport code (MIST) and a collisional radiative model. The radiative power losses are measured with bolometery, and the emissivity profiles were measured by a visible bremsstrahlung array. The ionization balance, excitation physics, and the radiative cooling curves are computed from the Hebrew University Lawrence Livermore atomic code (HULLAC) and are benchmarked by these experiments. (Supported by U.S. DOE Grant No. DE-FG02-86ER53214 at JHU and Contract No. W-7405-ENG-48 at LLNL.) copyright 1999 American Institute of Physics

  9. Atomic and molecular physics, physicochemical properties of biologically important structure, and high-voltage research

    International Nuclear Information System (INIS)

    Research in atomic and molecular physics is reported. Studies included: experimental evidence for the existence of a Ramsauer-Townsend minimum in liquid methane and liquid argon; discovery of a Ramsauer-Townsend minimum in gaseous ethane and propane; motion of thermal electrons in n-alkane vapors; electron mobilities in high pressure gases; electron capture and drift in liquid media; electron attachment to molecules in dense gases; attachment of slow electrons to hexafluorobenzene; fragmentation of atmospheric halocarbons under electron impact; negative ion resonances and threshold electron excitation spectra of organic molecules; theoretical studies of negative-ion resonance states of organic molecules; kinetics of electron capture by sulfur hexafluoride in solution; interactions of slow electrons with benzene and benzene derivatives; Stokes and anti-Stokes fluorescence of 1 : 12-benzoperylene in solution; photoionization of molecules in liquid media; construction of high-voltage breakdown apparatus for gaseous insulation studies; measurements of the breakdown strengths of gaseous insulators and their relation to basic electron-collision processes; accuracy of the breakdown voltage measurements; and assembling basic data on electronegative gases of significance to breakdown

  10. l- and n-changing collisions during interaction of a pulsed beam of Li Rydberg atoms with CO2

    Science.gov (United States)

    Dubreuil, B.; Harnafi, M.

    1989-07-01

    The pulsed Li atomic beam produced in our experiment is based on controlled transversely-excited-atmospheric CO2 laser-induced ablation of a Li metal target. The atomic beam is propagated in vacuum or in CO2 gas at low pressure. Atoms in the beam are probed by laser-induced fluorescence spectroscopy. This allows the determination of time-of-flight and velocity distributions. Li Rydberg states (n=5-13) are populated in the beam by two-step pulsed-laser excitation. The excited atoms interact with CO2 molecules. l- and n-changing cross sections are deduced from the time evolution of the resonant or collision-induced fluorescence following this selective excitation. l-changing cross sections of the order of 104 AṦ are measured; they increase with n as opposed to the plateau observed for Li* colliding with a diatomic molecule. This behavior is qualitatively well explained in the framework of the free-electron model. n-->n' changing processes with large cross sections (10-100 AṦ) are also observed even in the case of large electronic energy change (ΔEnn'>103 cm-1). These results can be interpreted in terms of resonant-electronic to vibrational energy transfers between Li Rydberg states and CO2 vibrational modes.

  11. l- and n-changing collisions during interaction of a pulsed beam of Li Rydberg atoms with CO2

    International Nuclear Information System (INIS)

    The pulsed Li atomic beam produced in our experiment is based on controlled transversely-excited-atmospheric CO2 laser-induced ablation of a Li metal target. The atomic beam is propagated in vacuum or in CO2 gas at low pressure. Atoms in the beam are probed by laser-induced fluorescence spectroscopy. This allows the determination of time-of-flight and velocity distributions. Li Rydberg states (n=5--13) are populated in the beam by two-step pulsed-laser excitation. The excited atoms interact with CO2 molecules. l- and n-changing cross sections are deduced from the time evolution of the resonant or collision-induced fluorescence following this selective excitation. l-changing cross sections of the order of 104 A2 are measured; they increase with n as opposed to the plateau observed for Li/sup */ colliding with a diatomic molecule. This behavior is qualitatively well explained in the framework of the free-electron model. n yields n' changing processes with large cross sections (10--100 A2) are also observed even in the case of large electronic energy change (ΔE/sub nn'/>103 cm/sup -1/). These results can be interpreted in terms of resonant-electronic to vibrational energy transfers between Li Rydberg states and CO2 vibrational modes

  12. Transmutations of atomic nuclei in hadron-nuclei nuclear collisions at GeV energies

    International Nuclear Information System (INIS)

    In hadron-nuclei nuclear collisions nuclei change their mass numbers A and the charge numbers Z. The mechanism of transmutation of a target nucleus was prompted experimentally and is described in this work. The information about the nuclei transmutation may be a basis for elaboration of the method of nuclei changes in beams of hadrons from accelerators

  13. On the behavior of scattering phases in collisions of electrons with multi-atomic objects

    CERN Document Server

    Amusia, M Ya

    2015-01-01

    We have studied the energy dependence of several first scattering phases with multi-atomic object. As concrete examples representing the general trends endohedrals Neon inside C60 and Argon inside C60 are considered. It appeared that the presence of an inner atom, either Ne or Ar, qualitatively affects the scattering phases, in spite of the fact that the fullerene consists of 60 carbon atoms, while the atom staffed inside is only one. Calculations are performed in the one-electron Hartree-Fock (HF) and random phase approximation with exchange (RPAE) for the inner atom while the fullerenes shell is substituted by static potential without and with the polarization potential. It appeared that the total endohedral scattering phase is simply a sum of atomic, Ne or Ar, and fullerenes C60 phases, contrary to the intuitive assumption that the total phases on C60 and Neon inside C60 or Ar inside C60 has to be the same.

  14. Design, fabrication and characterization of tunable external cavity diode laser and atom trapping chips for atomic physics

    Science.gov (United States)

    Chuang, Ho-Chiao

    External cavity diode laser systems (ECDLs) have been well documented for their suitability in the fields of laser cooling and atom trapping, and are now widely used in optical and atomic physics. A particularly simple implementation of this idea uses feedback from a diffraction grating mounted in the Littrow configuration and the typical size of this laser is quite large (120mmx90mmx90mm). For atom optics, the current atom trapping chips are not in a feedthrough configuration, which makes the chips to glass cell assembly process complicated and the wires and solder areas vulnerable, resulting in an unreliable vacuum seal. Recent experimental realizations of atom optical devices such as atomic waveguides, beam splitters, and on-chip Bose-Einstein condensate (BEC) sources have opened a new field for the development of more complex devices such as, e.g., BEC-based atom transistor. This work focuses on micro/nano fabrication techniques to build three different devices for the miniature BEC system. The research work focuses on the development of new ECDLs, a novel fabrication process of feedthrough atom trapping chips for atomic optics and a fabrication process for atom transistor chips. In the ECDLs part, we describe a new method for constructing a smaller external-cavity diode laser by use of a micromachined silicon flexure and a VHG (Volume Holographic Grating). It is much smaller, inexpensive and easy to build because it is based on simple modifications of a few commercial optical and mechanical components but with a specific silicon flexure design enabled by micro-fabrication technology for the laser frequency tuning. In the feedthrough chips part, we present a novel fabrication process for feedthrough atom trapping chips in atomic condensate optics cells using the copper electroplating to seal the vias. The advantages of using feedthrough atom trapping chips are the simple microfabrication process and reduction of the overall chip area bonded on the glass atom

  15. Status and perspectives of atomic physics research at GSI : The new GSI accelerator project

    NARCIS (Netherlands)

    Stolker, T; Backe, H; Beyer, HF; Brauning-Demian, A; Hagmann, S; Ionescu, DC; Jungmann, K; Kluge, HJ; Kozhuharov, C; Kuhl, T; Liesen, D; Mann, R; Mokler, PH; Quint, W; Bosch, F.M.

    2003-01-01

    A short overview on the results of atomic physics research at the storage ring ESR is given followed by a presentation of the envisioned atomic physics program at the planned new GSI facility. The proposed new GSI facility will provide highest intensities of relativistic beams of both stable and uns

  16. Fisher-like atomic divergences: Mathematical grounds and physical applications

    Science.gov (United States)

    Martín, A. L.; Angulo, J. C.; Antolín, J.

    2013-11-01

    Two different local divergence measures, the Fisher (FD) and the Jensen-Fisher (JFD) ones, are compared in this work by applying them to atomic one-particle densities in position and momentum spaces. They are defined in terms of the absolute and the relative Fisher information functionals. The analysis here afforded includes not only neutral atoms, but also singly-charged cations. The results are interpreted and justified according to (i) shell-filling patterns, (ii) short- and long-range behaviors of the atomic densities, and (iii) the value of the atomic ionization potential. The strengths of the FD measure, as compared to the JFD one, are emphasized.

  17. Monte Carlo event generators in atomic collisions: A new tool to tackle the few-body dynamics

    Science.gov (United States)

    Ciappina, M. F.; Kirchner, T.; Schulz, M.

    2010-04-01

    We present a set of routines to produce theoretical event files, for both single and double ionization of atoms by ion impact, based on a Monte Carlo event generator (MCEG) scheme. Such event files are the theoretical counterpart of the data obtained from a kinematically complete experiment; i.e. they contain the momentum components of all collision fragments for a large number of ionization events. Among the advantages of working with theoretical event files is the possibility to incorporate the conditions present in a real experiment, such as the uncertainties in the measured quantities. Additionally, by manipulating them it is possible to generate any type of cross sections, specially those that are usually too complicated to compute with conventional methods due to a lack of symmetry. Consequently, the numerical effort of such calculations is dramatically reduced. We show examples for both single and double ionization, with special emphasis on a new data analysis tool, called four-body Dalitz plots, developed very recently. Program summaryProgram title: MCEG Catalogue identifier: AEFV_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEFV_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 2695 No. of bytes in distributed program, including test data, etc.: 18 501 Distribution format: tar.gz Programming language: FORTRAN 77 with parallelization directives using scripting Computer: Single machines using Linux and Linux servers/clusters (with cores with any clock speed, cache memory and bits in a word) Operating system: Linux (any version and flavor) and FORTRAN 77 compilers Has the code been vectorised or parallelized?: Yes RAM: 64-128 kBytes (the codes are very cpu intensive) Classification: 2.6 Nature of problem: The code deals with single and double

  18. Pre-service physics teachers' ideas on size, visibility and structure of the atom

    International Nuclear Information System (INIS)

    Understanding the atom gives the opportunity to both understand and conceptually unify the various domains of science, such as physics, chemistry, biology, astronomy and geology. Among these disciplines, physics teachers are expected to be particularly well educated in this topic. It is important that pre-service physics teachers know what sort of theories regarding the atom they will bring into their own classrooms. Six tasks were developed, comprising size, visibility and structure of the atom. These tasks carried out by pre-service physics teachers were examined by content analysis and six categories were determined. These are size, visibility, subatomic particles, atom models, electron orbit and electron features. Pre-service physics teachers' ideas about the atom were clarified under these categories.

  19. Benchmarking atomic physics models for magnetically confined fusion plasma physics experiments

    Science.gov (United States)

    May, M. J.; Finkenthal, M.; Soukhanovskii, V.; Stutman, D.; Moos, H. W.; Pacella, D.; Mazzitelli, G.; Fournier, K.; Goldstein, W.; Gregory, B.

    1999-01-01

    In present magnetically confined fusion devices, high and intermediate Z impurities are either puffed into the plasma for divertor radiative cooling experiments or are sputtered from the high Z plasma facing armor. The beneficial cooling of the edge as well as the detrimental radiative losses from the core of these impurities can be properly understood only if the atomic physics used in the modeling of the cooling curves is very accurate. To this end, a comprehensive experimental and theoretical analysis of some relevant impurities is undertaken. Gases (Ne, Ar, Kr, and Xe) are puffed and nongases are introduced through laser ablation into the FTU tokamak plasma. The charge state distributions and total density of these impurities are determined from spatial scans of several photometrically calibrated vacuum ultraviolet and x-ray spectrographs (3-1600 Å), the multiple ionization state transport code transport code (MIST) and a collisional radiative model. The radiative power losses are measured with bolometery, and the emissivity profiles were measured by a visible bremsstrahlung array. The ionization balance, excitation physics, and the radiative cooling curves are computed from the Hebrew University Lawrence Livermore atomic code (HULLAC) and are benchmarked by these experiments. (Supported by U.S. DOE Grant No. DE-FG02-86ER53214 at JHU and Contract No. W-7405-ENG-48 at LLNL.)

  20. Three—body collisions involving Na(3P),Rb(5S) and buffer gas atoms

    Institute of Scientific and Technical Information of China (English)

    沈异凡; 李万兴; 等

    1996-01-01

    Energy pooling in the Na-Rb vapor mixture has been investigated.While some kind of buffer gas is introduced into the cell the peculiar features appear.The buffer gas enhances the energy transfer betwwen Na(3P) and Rb(5S),which can be detected through the effects induced on the highly excited states populated by the Na(3P)/Rb(5P) and Rb(5P)/Rb(5P) collisions.

  1. FITTING OF 3D REACTION SURFACE OF THREE-ATOMIC SYSTEM IN THE NATURAL COLLISION COORDINATES

    OpenAIRE

    Gevorkyan, A.; Grigoryan, T.; Nalbandyan, M.; Hovhannisyan, V.; Nyman, G

    2010-01-01

    The objective of this investigation is to prove the possibility of representation of the 3 interaction between particles in various reacting three-body systems by analytical function with a set of adjusting parameters in natural collision coordinates. Realization of this idea implies the procedure of fitting 3 numerical data by 3 analytical function or more precisely, calculation of adjusting parameters in mentioned analytical function. In the work Levenberg Marquardt algorithm is used on the...

  2. Many-body processes in atomic and molecular physics

    International Nuclear Information System (INIS)

    This report discusses the following topics: Dynamics of Multiphoton Excitation in Rydberg Atoms; Nonlinear Schrodinger Equation and Dissipative Quantum Dynamics in Periodic Fields; Density Matrix Formulation of Complex Geometric Phases in Dissipative Systems; and A. C. Stark Shifts of Excited States of Atoms in Strong Fields

  3. Proceedings of the workshop on atomic physics with fast heavy-ion beams

    International Nuclear Information System (INIS)

    The Workshop on Atomic Physics with Fast Heavy-Ion Beams was held in the Physics Division, Argonne National Laboratory on January 20 and 21, 1983. The meeting brought together approx. 50 practitioners in the field of accelerator-based atomic physics. The workshop was held to focus attention on possible areas of atomic physics research which would benefit from use of the newest generation of accelerators designed to produce intense high-quality beams of fast heavy ions. Abstracts of individual paper were prepared separately for the data base

  4. Ion-neutral chemistry at ultralow energies: Dynamics of reactive collisions between laser-cooled Ca^+ ions and Rb atoms in an ion-atom hybrid trap

    CERN Document Server

    Hall, Felix H J; Hegi, Gregor; Raoult, Maurice; Aymar, Mireille; Dulieu, Olivier; Willitsch, Stefan

    2013-01-01

    Cold chemical reactions between laser-cooled Ca^+ ions and Rb atoms were studied in an ion-atom hybrid trap. Reaction rate constants were determined in the range of collision energies /k_B = 20 mK-20 K. The lowest energies were achieved in experiments using single localized Ca^+ ions. Product branching ratios were studied using resonant-excitation mass spectrometry. The dynamics of the reactive processes in this system (non-radiative and radiative charge transfer as well as radiative association leading to the formation of CaRb^+ molecular ions) have been analyzed using high-level quantum-chemical calculations of the potential energy curves of CaRb^+ and quantum-scattering calculations for the radiative channels. For the present low-energy scattering experiments, it is shown that the energy dependence of the reaction rate constants is governed by long-range interactions in line with the classical Langevin model, but their magnitude is determined by short-range non-adiabatic and radiative couplings which only ...

  5. Atom Skimmers and Atom Lasers Utilizing Them

    Science.gov (United States)

    Hulet, Randall; Tollett, Jeff; Franke, Kurt; Moss, Steve; Sackett, Charles; Gerton, Jordan; Ghaffari, Bita; McAlexander, W.; Strecker, K.; Homan, D.

    2005-01-01

    Atom skimmers are devices that act as low-pass velocity filters for atoms in thermal atomic beams. An atom skimmer operating in conjunction with a suitable thermal atomic-beam source (e.g., an oven in which cesium is heated) can serve as a source of slow atoms for a magneto-optical trap or other apparatus in an atomic-physics experiment. Phenomena that are studied in such apparatuses include Bose-Einstein condensation of atomic gases, spectra of trapped atoms, and collisions of slowly moving atoms. An atom skimmer includes a curved, low-thermal-conduction tube that leads from the outlet of a thermal atomic-beam source to the inlet of a magneto-optical trap or other device in which the selected low-velocity atoms are to be used. Permanent rare-earth magnets are placed around the tube in a yoke of high-magnetic-permeability material to establish a quadrupole or octupole magnetic field leading from the source to the trap. The atoms are attracted to the locus of minimum magnetic-field intensity in the middle of the tube, and the gradient of the magnetic field provides centripetal force that guides the atoms around the curve along the axis of the tube. The threshold velocity for guiding is dictated by the gradient of the magnetic field and the radius of curvature of the tube. Atoms moving at lesser velocities are successfully guided; faster atoms strike the tube wall and are lost from the beam.

  6. Relative level excitation in ion-atom collisions as a function of the orbital angular momentum quantum number

    International Nuclear Information System (INIS)

    In a previous study of projectile Rydberg state excitations in the collisions Be+, Mg+-He at 10-75 keV it was found, for a fixed value of the principal quantum number n, that the ratio of the s, p, and d level cross sections was close to 1:3:5, whereas the f and g level cross sections drop to approximately the same value as for s levels. Blaney and Berry (1976) found essentially the same increase in cross section for electron transfer into excited Li I states in the Li+-H2 collision. In contrast to this behavior, beam-foil excitations oscillate as a function of the orbital angular momentum quantum number with maxima at odd values of l (p, f,...) and minima at even l (s, d, g,...). Since no model is available to describe these features, the measurements have been extended to other systems to test their general validity. A large conjugated molecule (benzene) was chosen as target gas in one experiment to bridge the gap between ion-atom and ion-foil excitations. The data presented here have all been obtained by optical spectrometry. A quasi molecular approach is used to explain the results. (Auth.)

  7. Improved adiabatic calculation of muonic-hydrogen-atom cross sections. II. Hyperfine transitions and elastic scattering in symmetric collisions

    International Nuclear Information System (INIS)

    The improved adiabatic representation is used in calculations of elastic and hyperfine-transition cross sections for symmetric collisions of pμ, dμ, and tμ with bare p, d, and t nuclei and with H, D, and T atoms, respectively. The cross sections for dμ+d and tμ+t are in excellent agreement with other recent determinations, while those for pμ+p are about 30% larger at low energies. The electronic screening is calculated nonperturbatively and found to be about 30% smaller in magnitude than the previously calculated value at large internuclear distances, and to deviate considerably from the asymptotic form in the molecular region. The resulting screened elastic cross sections are up to 60% smaller than those obtained using the old screening potential. The reactance matrices, needed for calculations of molecular-target effects, are given in tables

  8. Quantum-kinetic modeling of electron release in low-energy surface collisions of atoms and molecules

    Energy Technology Data Exchange (ETDEWEB)

    Marbach, Johannes

    2012-09-20

    In this work we present a theoretical description of electron release in the collision of atomic and molecular projectiles with metallic and especially dielectric surfaces. The associated electron yield, the secondary electron emission coefficient, is an important input parameter for numerical simulations of dielectric barrier discharges and other bounded low-temperature gas discharges. The available reference data for emission coefficients is, however, very sparse and often uncertain, especially for molecular projectiles. With the present work we aim to contribute to the filling of these gaps by providing a flexible and easy-to-use model that allows for a convenient calculation of the emission coefficient and related quantities for a wide range of projectile-surface systems and the most dominant reaction channels.

  9. Studying Atomic Physics Using the Nighttime Atmosphere as a Laboratory

    Science.gov (United States)

    Sharpee, B. D.; Slanger, T. G.; Huestis, D. L.; Cosby, P. C.

    2006-01-01

    A summary of our recent work using terrestrial nightglow spectra, obtained from astronomical instrumentation, to directly measure, or evaluate theoretical values for fundamental parameters of astrophysically important atomic lines.

  10. Casimir effects in atomic, molecular, and optical physics

    CERN Document Server

    Babb, James F

    2010-01-01

    The long-range interaction between two atoms and the long-range interaction between an ion and an electron are compared at small and large intersystem separations. The vacuum dressed atom formalism is applied and found to provide a framework for interpretation of the similarities between the two cases. The van der Waals forces or Casimir-Polder potentials are used to obtain insight into relativistic and higher multipolar terms.

  11. Heavy Flavor Physics in Heavy-Ion Collisions with STAR Heavy Flavor Tracker

    Science.gov (United States)

    Zhang, Yifei

    2010-02-01

    Heavy quarks are a unique tool to probe the strongly interacting matter created in relativistic heavy-ion collisions at RHIC energies. Due to their large mass, energetic heavy quarks are predicted to lose less energy than light quarks by gluon radiation when they traverse a Quark-Gluon Plasma. In contrast, recent measurements of non-photonic electrons from heavy quark decays at high transverse momentum (pT) show a jet quenching level similar to that of the light hadrons. Heavy quark are produced mainly at early stage in heavy-ion collisions, thus they are proposed to probe the QCD medium and to be sensitive to bulk medium properties. Ultimately, their flow behavior may help establish whether light quarks thermalize. Therefore, topological reconstruction of D-mesons and identification of electrons from charm and bottom decays are crucial to understand the heavy flavor production and their in medium properties. The Heavy Flavor Tracker (HFT) is a micro-vertex detector utilizing active pixel sensors and silicon strip technology. The HFT will significantly extend the physics reach of the STAR experiment for precise measurement of charmed and bottom hadrons. We present a performance study with full detector on the open charm nuclear modification factor, elliptic flow v2 and λc measurement as well as the measurement of bottom mesons via a semi-leptonic decay. )

  12. Quasi-free scattering in the ionization and destruction of hydrogen and helium Rydberg atoms in collision with neutral targets

    International Nuclear Information System (INIS)

    Hydrogen and helium Rydberg atoms (H** and He**), with principal quantum number n ranging from 10 to 20, have been used in collision experiments from 1 to 40 keV/amu. These were produced by electron capture in a charge-exchange cell and analyzed by ionization in a modulated electric field combined with phase-sensitive detection. Three experiments have been conducted. In the first, spectra of the band of H and He Rydberg states from electron capture were produced by the modulated field technique and compared. Considerable differences were found between the two. Both types of spectra were analyzed with calculations of Stark energies and field ionization rates. Attempts were made to simulate the spectra using this information and some assumptions about the state distribution produced in the electron capture. In the second experiment, destruction cross sections for H** incident on N2, Ar, and SF6 were measured. This was a further test of the independent-particle model for Rydberg atom scattering; in this model, the atom is destroyed by quasi-free scattering of either the ionic core or the outer electron. Already proven valid for n = 20-35, this has been extended to n as low as 10, as measurements with n = 10 showed full compliance with the model. In the third experiment, not only destruction cross sections but also ionization cross sections for H** and He** incident on Xe, AR, and N2 were measured. The ionization measurement is a more sensitive test of the quasi-free scattering of the Rydberg electron. This was especially important for the Xe and Ar targets, which exhibits a Ramsauer-Townsend minimum in their free-electron scattering cross sections. The quasi-free Rydberg electron should reproduce these data. Unmistakable deviations from the quasi-free prediction were seen in Xe and N2 but not in Ar. This represents the first measurement of a breakdown of the Independent Particle Model for fast Rydberg atom scattering

  13. Introduction to the physics of matter basic atomic, molecular, and solid-state physics

    CERN Document Server

    Manini, Nicola

    2014-01-01

    This book offers an up-to-date, compact presentation of basic topics in the physics of matter, from atoms to molecules to solids, including elements of statistical mechanics. The adiabatic separation of the motion of electrons and nuclei in matter and its spectroscopic implications are outlined for molecules and recalled regularly in the study of the dynamics of gases and solids. Numerous experiments are described and more than 160 figures give a clear visual impression of the main concepts. Sufficient detail of mathematical derivations is provided to enable students to follow easily. The focus is on present-day understanding and especially on phenomena fitting various independent-particle models. The historical development of this understanding, and phenomena such as magnetism and superconductivity, where interparticle interactions and nonadiabatic effects play a crucial role, are mostly omitted. A final outlook section stimulates the curiosity of the reader to pursue the study of such advanced topics in gra...

  14. Atomic data on inelastic processes in low-energy beryllium-hydrogen collisions

    Science.gov (United States)

    Yakovleva, Svetlana A.; Voronov, Yaroslav V.; Belyaev, Andrey K.

    2016-08-01

    Aims: Inelastic processes in low-energy Be + H and Be+ + H- collisions are treated for the states from the ground and up to the ionic state with the aim to provide rate coefficients needed for non-local thermodynamic equilibrium (non-LTE) modeling of beryllium spectra in cool stellar atmospheres. Methods: The electronic molecular structure is determined by using a recently proposed model quantum approach that is based on an asymptotic method. Nonadiabatic nuclear dynamics is treated by means of multichannel formulas, based on the Landau-Zener model for nonadiabatic transition probabilities. Results: The cross sections and the rate coefficients for inelastic processes in Be + H and Be+ + H- collisions are calculated for all transitions between 13 low-lying covalent states plus the ionic state. It is shown that the highest rate coefficient values correspond to the mutual neutralization processes with the final states Be(2s3s 1S), Be(2s3p 1,3P), Be(2s3d 3D). These processes, as well as some of the excitation, de-excitation and ion-pair formation processes, are likely to be important for non-LTE modeling. Tables A.1-A.10 are also available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/593/A27

  15. Applications of resonance ionization spectroscopy in atomic and molecular physics

    International Nuclear Information System (INIS)

    We examine topics of current interest in which we feel the use of RIS can yield significant contributions. To this end we discuss several previous studies as examples of the methods involved and then suggest a variety of specific experiments, the performance of which, we endeavor to show, should be possible with present-day technology. The areas of consideration are: (1) laser excitation with relatively broad bandwidth lasers; (2) measurements of photoionization cross sections; and (3) studies of collision and transport processes. Particular attention is given to the inert gases and to diatomic molecules

  16. Division of Atomic Physics. Lund Institute of Technology. Progress Report 1993-1994

    International Nuclear Information System (INIS)

    The Division of Atomic Physics is responsible for basic physics teaching in all engineering disciplines and for specialized teaching in Optics, Atomic Physics, Spectroscopy, Laser Physics, and Non-Linear Optics. Research activities are mainly carried out in the fields of basic and applied spectroscopy, largely based on the use of lasers. Projects in the following areas are reported: Basic Atomic Physics - Atomic physics with high power laser radiation; Laser spectroscopic investigations of atomic and ionic excited states in the short-wavelength region; Laser spectroscopy in the visible; Theoretical Atomic Physics; Applied Optics and Quantum Electronics -High resolution spectroscopy; Photon echoes in Rare Earth Ion Doped Crystals; diode laser Spectroscopy; Environmental Remote Sensing -Tropospheric Ozone Lidar; Measurement of gases of geophysical origin; Industrial and Urban Pollution Measurements; Laser induced fluorescence of vegetation and water; Applications in Medicine and Biology - Tissue diagnostic using Laser-induced fluorescence; Photodynamic Therapy; Measurement of Optical Properties of Tissue with applications to Diagnostics; Two Photon Excited fluorescence Microscopy; Capillary Electrophoresis; New Techniques; Industrial Applications - Optical spectroscopy in Metallurgy; Physics of Electric Breakdown in Dielectric liquids; Optical Spectroscopy of Paper

  17. Division of Atomic Physics. Lund Institute of Technology. Progress Report 1993-1994

    Energy Technology Data Exchange (ETDEWEB)

    Wahlstroem, C.G. [ed.

    1995-12-31

    The Division of Atomic Physics is responsible for basic physics teaching in all engineering disciplines and for specialized teaching in Optics, Atomic Physics, Spectroscopy, Laser Physics, and Non-Linear Optics. Research activities are mainly carried out in the fields of basic and applied spectroscopy, largely based on the use of lasers. Projects in the following areas are reported: Basic Atomic Physics - Atomic physics with high power laser radiation; Laser spectroscopic investigations of atomic and ionic excited states in the short-wavelength region; Laser spectroscopy in the visible; Theoretical Atomic Physics; Applied Optics and Quantum Electronics -High resolution spectroscopy; Photon echoes in Rare Earth Ion Doped Crystals; diode laser Spectroscopy; Environmental Remote Sensing -Tropospheric Ozone Lidar; Measurement of gases of geophysical origin; Industrial and Urban Pollution Measurements; Laser induced fluorescence of vegetation and water; Applications in Medicine and Biology - Tissue diagnostic using Laser-induced fluorescence; Photodynamic Therapy; Measurement of Optical Properties of Tissue with applications to Diagnostics; Two Photon Excited fluorescence Microscopy; Capillary Electrophoresis; New Techniques; Industrial Applications - Optical spectroscopy in Metallurgy; Physics of Electric Breakdown in Dielectric liquids; Optical Spectroscopy of Paper.

  18. Resonant coherent ionization in grazing ion/atom-surface collisions at high velocities

    Energy Technology Data Exchange (ETDEWEB)

    Garcia de Abajo, F.J. (Dept. de Ciencias de la Computacion e Inteligencia Artificial, Facultad de Informatica, Univ. del Pais Vasco, San Sebastian (Spain)); Pitarke, J.M. (Materia Kondentsatuaren Fisika Saila, Zientzi Fakultatea, Euskal Herriko Univ., Bilbo (Spain))

    1994-05-01

    The resonant coherent interaction of a fast ion/atom with an oriented crystal surface under grazing incidence conditions is shown to contribute significantly to ionize the probe for high enough velocities and motion along a random direction. The dependence of this process on both the distance to the surface and the velocity of the projectile is studied in detail. We focus on the case of hydrogen moving with a velocity above 2 a.u. Comparison with other mechanisms of charge transfer, such as capture from inner shells of the target atoms, permits us to draw some conclusions about the charge state of the outgoing projectiles. (orig.)

  19. Antiproton and proton collisions with the alkali-metal atoms Li, Na, and K

    DEFF Research Database (Denmark)

    Lühr, Armin Christian; Saenz, Alejandro

    2008-01-01

    Single-electron ionization and excitation cross sections as well as cross sections for excitation into the first excited p state of the alkali-metal atoms Li(2s), Na(3s), and K(4s) colliding with antiprotons and protons were calculated using a time-dependent channel-coupling approach. For antipro......Single-electron ionization and excitation cross sections as well as cross sections for excitation into the first excited p state of the alkali-metal atoms Li(2s), Na(3s), and K(4s) colliding with antiprotons and protons were calculated using a time-dependent channel-coupling approach...

  20. Ultimate Statistical Physics: fluorescence of a single atom

    CERN Document Server

    Pomeau, Yves; Ginibre, Jean

    2016-01-01

    We discuss the statistics of emission of photons by a single atom or ion illuminated by a laser beam at the frequency of quasi-resonance between two energy levels, a situation that corresponds to real experiments. We extend this to the case of two laser beams resonant with the energy differences between two excited levels and the ground state (three level atom in V-configuration). We use a novel approach of this type of problem by considering Kolmogorov equation for the probability distribution of the atomic state which takes into account first the deterministic evolution of this state under the effect of the incoming laser beam and the random emission of photons during the spontaneous decay of the excited state(s) to the ground state. This approach yields solvable equations in the two level atom case. For the three level atom case we set the problem and define clearly its frame. The results obtained are valid both in the opposite limits of rare and of frequent spontaneous decay, compared to the period of the...

  1. Pre-Service Physics Teachers' Ideas on Size, Visibility and Structure of the Atom

    Science.gov (United States)

    Unlu, Pervin

    2010-01-01

    Understanding the atom gives the opportunity to both understand and conceptually unify the various domains of science, such as physics, chemistry, biology, astronomy and geology. Among these disciplines, physics teachers are expected to be particularly well educated in this topic. It is important that pre-service physics teachers know what sort of…

  2. Close-Coupling R-Matrix Approach to Simulating Ion-Atom Collisions for Accelerator Applications

    CERN Document Server

    Stoltz, Peter

    2005-01-01

    We have implemented an R-matrix close coupling approach to calculate capture, ionization, stripping and excitation cross-sections for 0.5 to 8.0 MeV K+ incident on Ar. This is relevant to the High Current Experiment at Lawrence Berkley National Laboratory. These cross sections are used to model accelerator particle dynamics where background gasses can interfere with beam quality. This code is a semi-classical approach that uses quantum mechanics to describe the particle interactions and uses classical mechanics to describe the nuclei trajectories. We compare a hydrogenic approximation for K+ with a pseudo-potential approach. Further we are developing a variational approach to quickly determine the best pseudo-potential parameters. Since many R-Matrix computationalists use this pseudo-potential approach, this approach will be useful for helping generate cross sections for any collision system.

  3. Relativistic effect in inelastic collision of electron with atom or ion

    International Nuclear Information System (INIS)

    Based on relativistic Born approximation theory, we have calculated the relativistic and non-relativistic generalized oscillator strengthens (GOS) of the Li-likes iso-electron sequence. The difference between the two calculations shows the relativistic effect of both the target and impact electron in the inelastic collision process. For low Z target (e.g. Li), the relativistic effect is negligible. For the 2s-3p transition of Au+'76, the relativistic GOS is 27.1% smaller than the non-relativistic one. At high impact energy, the contribution of transverse term of GOS to the differential cross section is important at certain angle. At extremely high impact energy (e.g. 106, 107 eV), the transverse term of GOS becomes dominant at forward small angle and such forward peak makes overwhelming contribution to the total inelastic cross section

  4. Regular and Chaotic Quantum Dynamic in Atom-Diatom Reactive Collisions

    CERN Document Server

    Gevorkyan, A S; Nyman, G H; Bogdanov, Alexander V.; Gevorkyan, Ashot S.; Nyman, Gunnar

    2006-01-01

    A new micro-irreversible 3D theory of quantum multichannel scattering in the three-body system is developed. The quantum approach is constructed on the generating trajectory tubes which allow taking into account influence of classical non-integrability on the dynamical quantum system. It was shown that when the volume of classical chaos in phase space is larger than quantum sell in the main object of quantum system the wavefunction generates chaos (quantum chaos). The probability of quantum transitions is constructed for this case. On the example of collinear collision of Li+(FH) -> (LiF)+H system is carried out the numerical calculation and was shown that in the system is generated quantum (wave) chaos.

  5. Radiative electron capture studied in relativistic heavy-ion atom collisions

    International Nuclear Information System (INIS)

    The process of Radiative Electron Capture (REC) in relativistic collisions of high-Z ions with low-Z gaseous and solid targets is studied experimentally and theoretically. The observed X-ray spectra are analysed with respect to photon angular distributions as well as to total K-REC cross sections. The experimental results for angle-differential cross sections are well-reproduced by exact relativistic calculations which yield significant deviations from standard sin2θ distributions. Total cross sections for K-REC are shown to follow a simple scaling rule obtained from exact relativistic calculations as well as from a non-relativistic dipole approximation. The agreement between these different theoretical approaches must be regarded as fortuitous, but it lends support to the use of the non-relativistic approach for practical purposes. (orig.)

  6. Possible future experiments in atomic physics utilizing synchrotron radiation

    International Nuclear Information System (INIS)

    The survey is limited to processes in which a single photon is absorbed and either photon attenuation is measured or the end products following absorption are detected. Furthermore, only interactions with free atoms (or positive ions) in their ground states are considered

  7. The 'atom-splitting' moment of synthetic biology: Nuclear physics and synthetic biology share common features

    OpenAIRE

    Valentine, Alex J; Kleinert, Aleysia; Verdier, Jerome

    2012-01-01

    Synthetic biology and nuclear physics share many commonalities in terms of public perception and funding. Synthetic biologists could learn valuable lessons from the history of the atomic bomb and nuclear power.

  8. Charge exchange transition probability for collisions between unlike ions and atoms within the adiabatic approximation

    Science.gov (United States)

    Xu, Y. J.; Khandelwal, G. S.; Wilson, John W.

    1989-01-01

    A simple formula for the transition probability for electron exchange between unlike ions and atoms is established within the adiabatic approximation by employing the Linear Combination of Atomic Orbitals (LCAO) method. The formula also involves an adiabatic parameter, introduced by Massey, and thus the difficulties arising from the internal energy defect and the adiabatic approximation are avoided. Specific reactions Li(+++) + H to Li(++) + H(+) and Be(4+) + H to Be(3+) + H(+) are considered as examples. The calculated capture cross section results of the present work are compared with the experimental data and with the calculation of other authors over the velocity range of 10(7) cm/sec to 10(8) cm/sec.

  9. Collision free generation of highly ionized atomic species with 193 nm radiation

    Energy Technology Data Exchange (ETDEWEB)

    Luk, T.S.; Pummer, H.; Boyer, K.; Shahidi, M.; Egger, H.; Rhodes, C.K.

    1983-01-01

    The generation of highly ionized iodine (3+), xenon (5+), and mercury (4+) atoms at pressures of approx. 10/sup -6/ Torr and laser intensities of approx. 10/sup 14/ W/cm/sup 2/ at 193 nm is described. A minimum energy in excess of 170 eV, corresponding to greater than or equal to 27 photons, is required to produce Xe/sup 5 +/.

  10. Dynamics of carbon-hydrogen and carbon-methyl exchanges in the collision of 3P atomic carbon with propene

    Science.gov (United States)

    Lee, Shih-Huang; Chen, Wei-Kan; Chin, Chih-Hao; Huang, Wen-Jian

    2013-11-01

    We investigated the dynamics of the reaction of 3P atomic carbon with propene (C3H6) at reactant collision energy 3.8 kcal mol-1 in a crossed molecular-beam apparatus using synchrotron vacuum-ultraviolet ionization. Products C4H5, C4H4, C3H3, and CH3 were observed and attributed to exit channels C4H5 + H, C4H4 + 2H, and C3H3 + CH3; their translational-energy distributions and angular distributions were derived from the measurements of product time-of-flight spectra. Following the addition of a 3P carbon atom to the C=C bond of propene, cyclic complex c-H2C(C)CHCH3 undergoes two separate stereoisomerization mechanisms to form intermediates E- and Z-H2CCCHCH3. Both the isomers of H2CCCHCH3 in turns decompose to C4H5 + H and C3H3 + CH3. A portion of C4H5 that has enough internal energy further decomposes to C4H4 + H. The three exit channels C4H5 + H, C4H4 + 2H, and C3H3 + CH3 have average translational energy releases 13.5, 3.2, and 15.2 kcal mol-1, respectively, corresponding to fractions 0.26, 0.41, and 0.26 of available energy deposited to the translational degrees of freedom. The H-loss and 2H-loss channels have nearly isotropic angular distributions with a slight preference at the forward direction particularly for the 2H-loss channel. In contrast, the CH3-loss channel has a forward and backward peaked angular distribution with an enhancement at the forward direction. Comparisons with reactions of 3P carbon atoms with ethene, vinyl fluoride, and vinyl chloride are stated.

  11. The Influence of Physical and Physiological Cues on Atomic Force Microscopy-Based Cell Stiffness Assessment

    OpenAIRE

    Yu-Wei Chiou; Hsiu-Kuan Lin; Ming-Jer Tang; Hsi-Hui Lin; Ming-Long Yeh

    2013-01-01

    Atomic force microscopy provides a novel technique for differentiating the mechanical properties of various cell types. Cell elasticity is abundantly used to represent the structural strength of cells in different conditions. In this study, we are interested in whether physical or physiological cues affect cell elasticity in Atomic force microscopy (AFM)-based assessments. The physical cues include the geometry of the AFM tips, the indenting force and the operating temperature of the AFM. All...

  12. Research in atomic and applied physics using a 6-GeV synchrotron source

    International Nuclear Information System (INIS)

    The Division of Atomic and Applied Physics in the Department of Applied Science at Brookhaven National Laboratory conducts a broad program of research using ion beams and synchrotron radiation for experiments in atomic physics and nuclear analytical techniques and applications. Many of the experiments would benefit greatly from the use of high energy, high intensity photon beams from a 6-GeV synchrotron source. A survey of some of the specific scientific possibilities is presented

  13. Atomic and molecular physics and data activities for astrophysics at Oak Ridge National Laboratory

    International Nuclear Information System (INIS)

    The atomic astrophysics group at ORNL produces, collects, evaluates, and disseminates atomic and molecular data relevant to astrophysics and actively models various astrophysical environments utilizing this information. With the advent of the World Wide Web, these data are also being placed on-line to facilitate their use by end-users. In this brief report, the group's recent activities in data production and in modeling are highlighted. For example, the authors describe recent calculations of elastic and transport cross sections relevant to ionospheric and heliospheric studies, charge transfer between metal ions and metal atoms and novel supernova nebular spectra modeling, ion-molecule collision data relevant to planetary atmospheres and comets, and data for early universe modeling

  14. Relativistic calculations of the K-K charge transfer and K-vacancy production probabilities in low-energy ion-atom collisions

    CERN Document Server

    Tupitsyn, I I; Shabaev, V M; Bondarev, A I; Deyneka, G B; Maltsev, I A; Hagmann, S; Plunien, G; Stoehlker, Th

    2011-01-01

    The previously developed technique for evaluation of charge-transfer and electron-excitation processes in low-energy heavy-ion collisions [I.I. Tupitsyn et al., Phys. Rev. A 82, 042701(2010)] is extended to collisions of ions with neutral atoms. The method employs the active electron approximation, in which only the active electron participates in the charge transfer and excitation processes while the passive electrons provide the screening DFT potential. The time-dependent Dirac wave function of the active electron is represented as a linear combination of atomic-like Dirac-Fock-Sturm orbitals, localized at the ions (atoms). The screening DFT potential is calculated using the overlapping densities of each ions (atoms), derived from the atomic orbitals of the passive electrons. The atomic orbitals are generated by solving numerically the one-center Dirac-Fock and Dirac-Fock-Sturm equations by means of a finite-difference approach with the potential taken as the sum of the exact reference ion (atom) Dirac-Fock...

  15. Atoms, molecules, and optical physics 2. Molecules and photons, spectroscopy and scattering physics; Atome, Molekuele und optische Physik 2. Molekuele und Photonen, Spektroskopie und Streuphysik

    Energy Technology Data Exchange (ETDEWEB)

    Hertel, Ingolf V.; Schulz, C.P. [Max-Born-Institut fuer Nichlineare Optik und Kurzzeitspektroskopie, Berlin (Germany)

    2010-07-01

    These textbooks apply first of all to graduate students of physics and physical chemistry until the promotion. They want to a certain degree mediate the canonical knowledge of atomic and molecular physics and introduce to foundations of modern optica and quantum optics. In many selected partial fields they lead (together with a planned third volume) up to the actual status of research. So also the active scientist is addressed. By clearly structurated chapters the reader is - starting from the foundations of quantum physics, stepwise made familiar with the most important phenomena, models, and measuring methods. Thereby the focus lies on the experiment and its interpretation - the necessary theory is introduced from this point of view compactly and occasionally also something laxly. The first part is concentrated to the structure of the atoms and an introduction in modern methods of spectroscopy. In the present second part it deals with the structure of molecules and their spectroscopy as well as with scattering physics, which treats - complementarly to the bound molecular states - the continuum. Finally selected chapters of laser physics, modern optics, and quantum optics are treated. Thereby atomic, molecular, and optical physics is proved as a undiminishedly alive, highly productive branch of modern physics. It provides simultaneously for many further partial fields of physics and other natural-scientific disciplines indispensable foundations. [German] Diese Lehrbuecher wenden sich in erster Linie an fortgeschrittene Studierende der Physik und der Physikalischen Chemie bis hin zur Promotion. Sie wollen gewissermassen das kanonische Wissen der Atom- und Molekuelphysik vermitteln und in Grundlagen der modernen Optik und Quantenoptik einfuehren. In vielen ausgewaehlten Teilgebieten fuehren sie (zusammen mit einem geplanten dritten Band) bis hin zum aktuellen Stand der Forschung. So wird auch der aktive Wissenschaftler angesprochen. Durch klar strukturierte Kapitel

  16. Computational challenges in atomic, molecular and optical physics.

    Science.gov (United States)

    Taylor, Kenneth T

    2002-06-15

    Six challenges are discussed. These are the laser-driven helium atom; the laser-driven hydrogen molecule and hydrogen molecular ion; electron scattering (with ionization) from one-electron atoms; the vibrational and rotational structure of molecules such as H(3)(+) and water at their dissociation limits; laser-heated clusters; and quantum degeneracy and Bose-Einstein condensation. The first four concern fundamental few-body systems where use of high-performance computing (HPC) is currently making possible accurate modelling from first principles. This leads to reliable predictions and support for laboratory experiment as well as true understanding of the dynamics. Important aspects of these challenges addressable only via a terascale facility are set out. Such a facility makes the last two challenges in the above list meaningfully accessible for the first time, and the scientific interest together with the prospective role for HPC in these is emphasized.

  17. Python GUI Scripting Interface for Running Atomic Physics Applications

    OpenAIRE

    Tahat, Amani; Tahat, Mofleh

    2011-01-01

    We create a Python GUI scripting interface working under Windows in addition to (UNIX/Linux). The GUI has been built around the Python open-source programming language. We use the Python's GUI library that so called Python Mega Widgets (PMW) and based on Tkinter Python module (http://www.freenetpages.co.uk/hp/alan.gauld/tutgui.htm). The new GUI was motivated primarily by the desire of more updated operations, more flexibility incorporating future and current improvements in producing atomic d...

  18. Towards Relativistic Atomic Physics and Post-Minkowskian Gravitational Waves

    OpenAIRE

    Luca LusannaINFN

    2009-01-01

    A review is given of the formulation of relativistic atomic theory, in which there is an explicit realization of the Poincare' generators, both in the inertial and in the non-inertial rest-frame instant form of dynamics in Minkowski space-time. This implies the need to solve the problem of the relativistic center of mass of an isolated system and to describe the transitions from different conventions for clock synchronization, namely for the identifications of instantaneous ...

  19. Hydrogen Atom Collision Processes in Cool Stellar Atmospheres: Effects on Spectral Line Strengths and Measured Chemical Abundances in Old Stars

    International Nuclear Information System (INIS)

    The precise measurement of the chemical composition of stars is a fundamental problem relevant to many areas of astrophysics. State-of-the-art approaches attempt to unite accurate descriptions of microphysics, non-local thermodynamic equilibrium (non-LTE) line formation and 3D hydrodynamical model atmospheres. In this paper I review progress in understanding inelastic collisions of hydrogen atoms with other species and their influence on spectral line formation and derived abundances in stellar atmospheres. These collisions are a major source of uncertainty in non-LTE modelling of spectral lines and abundance determinations, especially for old, metal-poor stars, which are unique tracers of the early evolution of our galaxy. Full quantum scattering calculations of direct excitation processes X(nl) + H ↔ X(n'l') + H and charge transfer processes X(nl) + H ↔ X+ + H− have been done for Li, Na and Mg [1,2,3] based on detailed quantum chemical data, e.g. [4]. Rate coefficients have been calculated and applied to non-LTE modelling of spectral lines in stellar atmospheres [5,6,7,8,9]. In all cases we find that charge transfer processes from the first excited S-state are very important, and the processes affect measured abundances for Li, Na and Mg in some stars by as much as 60%. Effects vary with stellar parameters (e.g. temperature, luminosity, metal content) and so these processes are important not only for accurate absolute abundances, but also for relative abundances among dissimilar stars.

  20. Atomic and molecular physics in the gas phase

    Energy Technology Data Exchange (ETDEWEB)

    Toburen, L.H.

    1990-09-01

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

  1. Atomic collision experiments utilizing low-velocity, highly-charged ion beams

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, B.M.; Jones, K.W.; Meron, M.

    1982-01-01

    Intense beams of highly-stripped ions are now routinely produced at low velocities using the Brookhaven dual MP-tandens in a unique four-stage accel/decel mode. This mode of operation combines three stages of acceleration, stripping at high energy, and one stage of deceleration to near-zero velocity. To date, experiments have used 10-100 nA beams of bare and few-electron heavy ions at energies as low as 0.2 MeV/amu, and upgrades of the facility should push the lower limit below 0.1 MeV/amu. Recent experiments, such as measurements of charge transfer and x-ray production for S/sup 6-16+/ on He and Ar at 6 to 20 MeV and P(b) measurements for MO x-rays produced in Cl/sup 16 +/ + Ar collisions at 20, 10, and 5 MeV have demonstrated the usefulness of highly-stripped, low-velocity projectiles. These experiments and a few possibilities for future experiments are discussed.

  2. Excitation of atoms and molecules in collisions with highly charged ions

    International Nuclear Information System (INIS)

    A study of the double ionization of He by high-energy N7+ ions was extended up in energy to 40 MeV/amu. Coincidence time-of-flight studies of multicharged N2, O2, and CO molecular ions produced in collisions with 97-MeV Ar14+ ions were completed. Analysis of the total kinetic energy distributions and comparison with the available data for CO2+ and CO3+ from synchrotron radiation experiments led to the conclusion that ionization by Ar-ion impact populates states having considerably higher excitation energies than those accessed by photoionization. The dissociation fractions for CO1+ and CO2+ molecular ions, and the branching ratios for the most prominent charge division channels of CO2+ through CO7+ were determined from time-of-flight singles and coincidence data. An experiment designed to investigate the orientation dependence of dissociative multielectron ionization of molecules by heavy ion impact was completed. Measurements of the cross sections for K-shell ionization of intermediate-Z elements by 30-MeV/amu H, N, Ne, and Ar ions were completed. The cross sections were determined for solid targets of Z = 13, 22, 26, 29, 32, 40, 42, 46, and 50 by recording the spectra of K x rays with a Si(Li) spectrometer

  3. Electronic quenching of OH A 2Σ+ induced by collisions with Kr atoms.

    Science.gov (United States)

    Lehman, Julia H; Lester, Marsha I; Kłos, Jacek; Alexander, Millard H; Dagdigian, Paul J; Herráez-Aguilar, Diego; Aoiz, F Javier; Brouard, Mark; Chadwick, Helen; Perkins, Tom; Seamons, Scott A

    2013-12-19

    Electronic quenching of OH A (2)Σ(+) by Kr was investigated through experimental studies of the collision cross sections and the OH X (2)Π product state distribution. The quenching cross sections decrease with increasing rotational excitation in the excited OH A (2)Σ(+) electronic state. The OH X (2)Π products of quenching exhibit a significant degree of rotational excitation but minimal vibrational excitation. Complementary theoretical studies of the OH (A (2)Σ(+), X (2)Π) + Kr potential energy surfaces (PESs), nonadiabatic coupling, and quasiclassical trajectory calculations were carried out to elucidate the quenching dynamics. Accurate PESs for the two lowest diabatic states of A' symmetry were computed along with the angularly dependent coupling between them. Coupling in nearly linear HO-Kr configurations provides the mechanism for the observed electronic quenching. A deep attractive well on the OH A (2)Σ(+) + Kr PES facilitates access to this region of strong coupling. Surface-hopping quasiclassical trajectory calculations yielded quenching cross sections and a OH X (2)Π product rotational distribution in good accord with experimental observations.

  4. Atomic collision experiments utilizing low-velocity, highly-charged ion beams

    International Nuclear Information System (INIS)

    Intense beams of highly-stripped ions are now routinely produced at low velocities using the Brookhaven dual MP-tandems in a unique four-stage accel/decel mode. This mode of operation combines three stages of acceleration, stripping at high energy, and one stage of deceleration to near-zero velocity. To date, experiments have used 10-100 nA beams of bare and few-electron heavy ions at energies as low as 0.2 MeV/amu, and upgrades of the facility should push the lower limit below 0.1 MeV/amu. Recent experiments, such as measurements of charge transfer and x-ray production for S6-16+ on He and Ar at 6-20 MeV and P(b) measurements for MO x-rays produced in Cl16+ + Ar collisions at 20, 10 and 5 MeV have demonstrated the usefulness of highly-stripped, low-velocity projectiles. These experiments and a few possibilities for future experiments are discussed

  5. Quantum mechanical theory of a structured atom-diatom collision system - A + BC/1-Sigma/

    Science.gov (United States)

    Devries, P. L.; George, T. F.

    1977-01-01

    The problem of a 2-p state atom colliding with a singlet sigma state diatom, which involves multiple potential surfaces, is investigated. Within a diabatic representation for the electronic degrees of freedom (plus spin-orbit interaction), coupled scattering equations are derived in both space-fixed and body-fixed coordinate systems. Coefficients, analogous to Percival-Seaton coefficients, are obtained. Approximations to the exact equations, including angular momenta decoupling approximations, are discussed for both the space-fixed and body-fixed formalisms.

  6. Electron capture and ionization for ion-Rydberg atom collisions in a magnetic field

    International Nuclear Information System (INIS)

    Within the classical trajectory Monte Carlo (CTMC) model, we calculate electron transfer and ionization cross sections for 1.3-130 eV amu-1 singly charged ions colliding with Rydberg atoms in the presence of a laboratory-strength magnetic field of 4 tesla. A new method for generating a stationary microcanonical ensemble for a quasi-integrable initial-state Hamiltonian is presented. The calculated cross sections show signatures of electron capture and ionization mechanisms for the field-free case, e.g. multiple swaps and saddle-point electrons; their structure as well as their magnitude, however, are strongly modified by the presence of the magnetic field. (Author)

  7. Production of relativistic positronium in collisions of photons and electrons with nuclei and atoms

    OpenAIRE

    Gevorkyan, S. R.; Kuraev, E. A.; Schiller, A.; Serbo, V. G.; Tarasov, A. V.

    1998-01-01

    We consider the production of ultrarelativistic positronium (Ps) in $\\gamma A \\to Ps + A$ and $e A \\to Ps + e A$ processes where $A$ is an atom or a nucleus with charge $Ze$. For the photoproduction of para- and ortho-Ps and the electroproduction of para-Ps we obtain the most complete description compared with previous works. It includes high order $Z \\alpha$ corrections and polarization effects. The accuracy of the obtained cross sections is determined by omitted terms of the order of the in...

  8. An empirical curve describing the ionization cross-sections in atomic collisions involving heavy ions

    International Nuclear Information System (INIS)

    In a recent paper, a fifth order polynomial curve was presented which fits very well to the existing experimental data on K-shell ionization cross-sections induced by protons. It is a universal curve, in the sense that it includes target atoms of any Z number at any projectile (proton) energy. In principle, it is possible to fit in the same curve the cross-sections obtained with any ion as a projectile, by means of a scaling law derived from the plane wave Born approximation (PWBA) and the binary encounter approximation (BEA) models. Experimental data with deuterons, alpha particles and 3He ions were fit into the same curve, with a good agreement. The agreement was poorer for experimental cross-sections obtained with heavier ions, like 12C, 14N and 40Ar. The discrepancies are attributable to several aspects of the ion-atom interaction, not considered in the derivation of such scaling law. The ECPSSR model has been more successful on predicting the cross-sections for heavy ions. Within the considerations in the ECPSSR and other models, arguments are given to explain the former discrepancies and suggestions are made to generalize the scaling law to fit the heavy ion data in a single curve

  9. Exciting interdisciplinary physics quarks and gluons, atomic nuclei, relativity and cosmology, biological systems

    CERN Document Server

    2013-01-01

    Nuclear physics is an exciting, broadly faceted field. It spans a wide range of topics, reaching from nuclear structure physics to high-energy physics, astrophysics and medical physics (heavy ion tumor therapy).  New developments are presented in this volume and the status of research is reviewed. A major focus is put on nuclear structure physics, dealing with superheavy elements and with various forms of exotic nuclei: strange nuclei, very neutron rich nuclei, nuclei of antimatter. Also quantum electrodynamics of strong fields is addressed, which is linked to the occurrence of giant nuclear systems in, e.g., U+U collisions. At high energies nuclear physics joins with elementary particle physics. Various chapters address the theory of elementary matter at high densities and temperature, in particular the quark gluon plasma which is predicted by quantum chromodynamics (QCD) to occur in high-energy heavy ion collisions. In the field of nuclear astrophysics, the properties of neutron stars and quark stars are d...

  10. Atomic-scale nanowires: physical and electronic structure

    International Nuclear Information System (INIS)

    The technology to build and study nanowires with sizes ranging from individual atoms to tens of nanometres has been developing rapidly over the last few years. We survey the motivation behind these developments, and summarize the basics behind quantized conduction. Several of the different experimental techniques and materials systems used in the creation of nanowires are examined, and the range of theoretical methods developed both for examining open systems (especially their conduction properties) and for modelling large systems are considered. We present various noteworthy example results from the field, before concluding with a look at future directions. (topical review)

  11. Absolute Doubly Differential Cross Sections for Ejection of Electrons in - and Five-Body Collisions of 20 TO 114-KEV Protons on Atomic and Molecular Hydrogen.

    Science.gov (United States)

    Kerby, George W., III

    A crossed-beam experiment was performed to detect ejected electrons from ground-state atomic and molecular hydrogen after collisions with 20- to 114-keV protons. Because a pure atomic hydrogen target is not readily attainable, a method has been devised which yields atomic to molecular hydrogen doubly differential cross section (DDCS) ratios. Since the molecular hydrogen DDCS's were independently measured, the atomic cross sections could be directly calculated. Absolute cross sections differential in electron energy and angle were measured for electron energies ranging from 1.5 to 400 eV and scattering angles from 15^circ to 165^circ with respect to the fast beam. Electrons and ions were energy analyzed by an electrostatic hemispherical analyzer, which has an energy resolution of 5% and is rotatable in the scattering plane about the collision center. Atomic hydrogen is produced by a radio-frequency discharge of the type devised by J. Slevin. Hydrogen gas effuses from a 1 mm diameter nozzle in a nearly cos theta distribution. The projectile beam intersects the thermal gas targets 4 mm below the tip of the nozzle. Dissociation fractions of 74% and atomic hydrogen densities of 7 times 10 ^{11} cm^ {-3} were typical. The fraction of dissociated hydrogen was measured by detecting the reduced 9-eV ion signal from the molecular target when the RF is on. This characteristic ion signal originates from the coulomb breakup of the molecule and dissociative channels of excited H _sp{2}{+}. An auxiliary experiment was performed to determine the target densities with the aid of a low-resolution magnetic mass spectrometer after the slow recoil ions were extracted from the collision volume by a weak electric field. Comparisons of the atomic cross sections are made with theories such as the classical-trajectory Monte Carlo (CTMC) method, the plane-wave Born approximation (PWBA) and the continuum-distorted-wave eikonal-initial-state (CDW-EIS) approximation.

  12. Handbook of theoretical atomic physics. Data for photon absorption, electron scattering, and vacancies decay

    Energy Technology Data Exchange (ETDEWEB)

    Amusia, Miron [Hebrew Univ., Jerusalem (Israel). Racah Inst. of Physics; Ioffe Physico-Technical Inst., St. Petersburg (Russian Federation); Chernysheva, Larissa [Ioffe Physico-Technical Inst., St. Petersburg (Russian Federation); Yarzhemsky, Victor [Kurnakov Institute of General and Inorganic Chemistry, Moscow (Russian Federation)

    2012-07-01

    The aim of this book is to present highly accurate and extensive theoretical Atomic data and to give a survey of selected calculational methods for atomic physics, used to obtain these data. The book presents the results of calculations of cross sections and probabilities of a broad variety of atomic processes with participation of photons and electrons, namely on photoabsorption, electron scattering and accompanying effects. Included are data for photoabsorption and electron scattering cross-sections and probabilities of vacancy decay formed for a large number of atoms and ions. Attention is also given to photoionization and vacancy decay in endohedrals and to positron-atom scattering. The book is richly illustrated. The methods used are one-electron Hartree-Fock and the technique of Feynman diagrams that permits to include many-electron correlations. This is done in the frames of the Random Phase approximation with exchange and the many-body perturbation theory. Newly obtained and previously collected atomic data are presented. The atomic data are useful for investigating the electronic structure and physical processes in solids and liquids, molecules and clusters, astronomical objects, solar and planet atmospheres and atomic nucleus. Deep understanding of chemical reactions and processes is reached by deep and accurate knowledge of atomic structure and processes with participation of atoms. This book is useful for theorists performing research in different domains of contemporary physics, chemistry and biology, technologists working on production of new materials and for experimentalists performing research in the field of photon and electron interaction with atoms, molecules, solid bodies and liquids.

  13. Physical behaviors of impure atoms during relaxation of impure NiAl-based alloy grain boundary

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The Monte Carlo simulation with the energetics described by the embedded atom method has been employed to mainly study physical behaviors of boron atoms during relaxation of the Ni3Al-x at.% B grain boundary. During relaxation of impure Ni3Al grain boundaries, we suggest that for different types of impure atoms(Mg, B, Cr and Zr atoms etc.), as the segregating species, they have the different behaviors, but as the inducing species, they have the same behaviors, i.e. they all induce Ni atoms to substitute Al atoms. Calculations show that at the equilibrium, when x(the B bulk concentration) increases from 0.1 to 0.9 , the peak concentration of B increases, correspondently, the peak concentration of Ni maximizes but the valley concentration of Al minimizes, at x = 0.5. The calculations also show the approximate saturation of Ni at the grain boundary at x = 0.5.

  14. Atomic and plasma-material interaction data for fusion. V. 8. Elastic and related transport cross sections for collisions among isotopomers of H+ + H, H+ + H2, H+ + He, H + H, and H + H2

    International Nuclear Information System (INIS)

    The Volume 8 of the 'Atomic and Plasma-Material Interaction Data for Fusion' provides an exhaustive source of information on elastic scattering, momentum transfer and viscosity cross sections for collisions of hydrogenic ions, atoms and molecules, and their isotopes, in the energy range pertinent to fusion reactor divertor plasmas and extending (in its low-energy part) to collision conditions that are relevant for astrophysics. Hydrogen ion-helium atom collisions are also included. The reported cross sections are obtained from extensive quantum-mechanical calculations and can be regarded as having very high accuracy

  15. International Conference 'Current Problems in Nuclear Physics and Atomic Energy'. May 29 - Jun 03 2006. Book of Abstracts

    International Nuclear Information System (INIS)

    The collective processes in atomic nuclei, nuclear reactions and processes with exotic nuclei, rare nuclear processes, relativistic nuclear physics, neutron physics, physics of nuclear reactors, problems of atomic energy and reactors of the future, applied nuclear physics and technique of experiments was discussed in this conference

  16. Screening and antiscreening by projectile electrons in high-velocity atomic collisions

    International Nuclear Information System (INIS)

    The scattering amplitude for a projectile of nuclear charge Z1 carrying N electrons colliding with an atomic target with charge Z2, evaluated in the first Born approximation using hydrogenic wave functions, is compared with recent experimental results. In the present approximation where the minimum momentum transfer t/sub min/ is considered to be approximately independent of the final state of the projectile, the differential cross sections separate into a product of one term that depends only on the target times the square Z21(t) of an effective projectile charge. Here an analytic expression for Z21(t) is given for 2, 1, and 0 electrons. Some total ionization cross-section ratios are also given

  17. Calculation of the elastic collision properties of Na and Li atoms at ultracold temperature

    Institute of Scientific and Technical Information of China (English)

    Zhang Ji-Cai; Zhang Ying; Du Bing-Ge; Sun Jin-Feng

    2009-01-01

    This paper firstly reports a theoretical study of elastic scattering properties in a mixture of 23Na and 7Li atoms at cold and ultracold temperatures in detail.Based on the new constructed accurate singlet X1∑+g and the triplet a3∑+u states interatomic potentials for 23Na7Li mixture,it calculates the scattering lengths and the effective ranges by three computational methods,and obtains good agreements.Using the mass scaling method,it also calculates 23Na6Li scattering lengths and s-wave and total elastic cross sections,whose rich resonance structures were found and interpreted in terms of quasibound diatomic levels trapped behind a centrifugal barrier.

  18. LHC First Physics : First collisions in the LHC's experiments, afternoon of March the 30th, 2010

    CERN Multimedia

    CERN Video Productions

    2010-01-01

    We did it! The first high-energy collisions were achieved at 13.06 today at all four points of the LHC ring. Collisions occurred after a few attempts at injecting and ramping beams in the morning. Before the collisions, there was a mixture of excitement, expectation, fear and apprehension in the CERN Control Centre. Nobody had ever attempted to make two proton beams collide at 3.5 TeV before. Only Nature produces collisions like this routinely, in the processes that yield cosmic radiation, but in a way that makes it very difficult to extract meaningful data.

  19. Atomic physics with highly-charged ions at the future FAIR facility: A status report

    Energy Technology Data Exchange (ETDEWEB)

    Stoehlker, Th. [Gesellschaft fuer Schwerionenforschung (GSI), Darmstadt (Germany) and Institut fuer Kernphysik, University of Frankfurt (Germany)]. E-mail: t.stoehlker@gsi.de; Beyer, H.F. [Gesellschaft fuer Schwerionenforschung (GSI), Darmstadt (Germany); Braeuning, H. [Gesellschaft fuer Schwerionenforschung (GSI), Darmstadt (Germany); Braeuning-Demian, A. [Gesellschaft fuer Schwerionenforschung (GSI), Darmstadt (Germany); Brandau, C. [Gesellschaft fuer Schwerionenforschung (GSI), Darmstadt (Germany); Hagmann, S. [Institut fuer Kernphysik, University of Frankfurt (Germany); Kozhuharov, C. [Gesellschaft fuer Schwerionenforschung (GSI), Darmstadt (Germany); Kluge, H.J. [Gesellschaft fuer Schwerionenforschung (GSI), Darmstadt (Germany); Kuehl, Th. [Gesellschaft fuer Schwerionenforschung (GSI), Darmstadt (Germany); Liesen, D. [Gesellschaft fuer Schwerionenforschung (GSI), Darmstadt (Germany); Mann, R. [Gesellschaft fuer Schwerionenforschung (GSI), Darmstadt (Germany); Noertershaeuser, W. [Gesellschaft fuer Schwerionenforschung (GSI), Darmstadt (Germany); Quint, W. [Gesellschaft fuer Schwerionenforschung (GSI), Darmstadt (Germany); Schramm, U. [LMU, Munich (Germany); Schuch, R. [Stockholm University, Stockholm (Sweden)

    2007-08-15

    Key features of the future international accelerator Facility for Antiproton and Ion Research (FAIR) offer a range of new and challenging opportunities for atomic physics research in the realm of highly-charged heavy ions and exotic nuclei. Centred on use of FAIR, the Stored Particle Atomic Physics Research Collaboration (SPARC), organized in working groups, has been formed. A short report on the tasks and activities of the various SPARC working groups, devoted to the realization of experimental equipments and set-ups required to reach the physics goals is given.

  20. Atomic physics with highly-charged ions at the future FAIR facility. A status report

    Energy Technology Data Exchange (ETDEWEB)

    Stoehlker, T. [Gesellschaft fuer Schwerionenforschung, Darmstadt (Germany)]|[Frankfurt Univ. (Germany). Inst. fuer Kernphysik; Beyer, H.F.; Braeuning, H. [Gesellschaft fuer Schwerionenforschung, Darmstadt (DE)] (and others)

    2006-11-15

    The key features of the future international accelerator Facility for Antiproton and Ion Research (FAIR) offer a range of new and challenging opportunities for atomic physics research in the realm of highly-charged heavy ions and exotic nuclei. Centred on use of FAIR, the Stored Particle Atomic Physics Research Collaboration (SPARC), organized in working groups, has been formed. A short report on the tasks and activities of the various SPARC working groups, devoted to the realization of experimental equipments and setups required to reach the physics goals is given. (orig.)