Classical and quantal calculations on electron capture.

  • 1.32 MB
  • 4215 Downloads
  • English
by
The Physical Object
Pagination1 v
ID Numbers
Open LibraryOL19928056M

In the case of capture by protons (H +) for impact energies from 30 keV to 4 MeV, the calculated cross sections agree rather well with the corresponding measured values per gas atom for capture from N 2 and O 2.

According to this classical model, capture from the 2s subshells of O and N each contributes appreciably for most impact energies, with 2s-orbital capture dominating 2p capture above 2 MeV. We present theoretical calculations of electron capture cross-sections for ion-atom and ion-molecule collisions in the intermediate impact energy range.

The results stem from intensive computations based on quantal, semiclassical and classical approaches. Abstract. Classical binary encounter methods and distorted-wave perturbation theory are employed to calculate the continuum electron capture cross section.

Results obtained for the impact of fast fully stripped ions of carbon, helium and hydrogen upon helium atoms Cited by: 1. Classical binary encounter methods and distorted-wave perturbation theory are employed to calculate the continuum electron capture cross section. Results obtained for the impact of fast fully stripped ions of carbon, helium and hydrogen upon helium atoms are compared with experimental measurements.

The results stem from intensive computations based on quantal, semiclassical and classical approaches. We focus our attention on (i) electron transfer cross-sections for quasi-one-electron ion–atom/molecule systems and (ii) energy distributions of the fragments produced in multiply charged ion–H 2 collisions.

The results from the different approaches are compared systematically, also with Cited by: 2. The classical-trajectory Monte Carlo method has been used to calculate the single-electron capture and impact-ionization cross sections for collisions between fully stripped ions (H+ to O+8) and.

A classical model is used to study electron capture and single ionization (SI) following H + + Ar collisions at projectile energies varying from to 40 keV. In the present model, the Ar electrons are treated independently from each other, and only the 3s and 3p electrons are supposed to be captured by the by: 2.

The accuracy of classical trajectory Monte Carlo treatments of electron capture is studied, by focusing on collisions on H(1s) targets by Li3+ and Ne10+ projectiles, treated in a separate paper. ELECTRON CAPTURE BY PROTONS IN IN AN ELECTRIC FIELD HYDROGEN SUMMARY The evaluation of the capture cross section in the Brinkman Kramers ap- proximation with the hydrogen atom wave function in parabolic coordinates is much simpler than this wave function in spherical Size: KB.

estimates of electron capture cross sections at few MeVs per nucleon as well as for multi-electron ions. Required accuracy in such estimates necessitates detailed and involved quantum-mechanical calculations or expensive numerical simulations.

For ENA modeling and similar purposes, a semi-classical approach offers a middle-ground : A. Barghouty. The terminal transport coefficients for the same gas confined in a quantum wire are also calculated using the Landauer-Buttiker formalism.

Both calculations are valid in a quantum wire structure when its width w is much greater than the Fermi wavelength and its length l is much greater than the classical Author: P. Butcher. Abstract Differential collision results based on classical (CTMC) and quantal (AOCC) calculations for single-electron capture in collisions of He 2+ projectiles with oriented Na(3p-1) atoms are compared at three intermediate impact energies (velocities ofand au).Good agreement between the two methods is reported with respect to the total capture probability, differential cross.

Electron-capture times due to the electron-electron (e-e), electron-hole (e-h), and electron-polar optical phonon (e-pop.

Download Classical and quantal calculations on electron capture. PDF

interactions are calculated in the GaAs quantum well ~QW. with electron and hole densities cm 2. The calculated capture times oscillate as a function of the QW width with the same period but with different amplitudes.

CiteSeerX - Document Details (Isaac Councill, Lee Giles, Pradeep Teregowda): Abstract. Partial radiative capture cross sections for very low energy (classical method of Fourier components.

Comparisons of these cross sections are made with quantum mechanical calculations. If one uses the "classical radius of the electron" and the known total angular momentum of the electron, it is easy to calculate that a point on the equator of the electron is moving at about times the speed of light.

The first is the accurate calculation, beyond theBorn–Oppenheimerapproximation,ofthepotentialenergy curves (PECs) and their non-adiabatic couplings for the quasi molecular ion formed during the collision, and the second is the quantal or classical nuclear dynamics on the coupled PECs.

For elementary reactions such as the electron transfer inCited by: 7. Ionization, excitation and electron capture are elementary processes in atomic and molecular collisions, also important in applications ranging from the modelling of the propagation of fast Cited by: 2.

Description Classical and quantal calculations on electron capture. PDF

In 17, classical and semiclassical calculations have been performed for energies between 1 and keV/amu. Pérez et al. 18 reported the only low-energy calculations.

In that work, a classical trajectory Monte Carlo method was used to obtain electron-capture cross sections between 1 eV/amu and keV/amu.

This paper is organized as follows. Quantum theory deals in probability, while classical physics, the one we all learned in HS, deals with deterministic cause and effect.

The Bohr model, for example, is the classical electron in orbit like a planet model. We can calculate both its location in the orbit and its velocity as it revolves around in the orbit. Mapping of electron capture probability to obtain differential cross sections via a deflection function.

The full curves in the deflection function and in the differential cross sections are obtained from quantal calculations while the same quantities calculated by the semiclassical method are shown as. ing multiply charged ions [11].

Some CTMC calculations [14, 15] of electron capture by singly charged ions from oriented elliptical Rydberg atoms have been performed. These results were in agreement with the experimental data of Ehrenreich et al.

Details Classical and quantal calculations on electron capture. EPUB

[8]. The classical trajectory Monte Carlo (CTMC) method is a successful model for ion. electron capture via the charge-exchange collisions in plasma.

For the classical conflgurations with sin-gle electron, orbital momenta quantum numbers high and close to their maximum values, electron paths are well approximated by circular orbits.

These or-bits turn out unstable, and this corresponds to the metastable quantum states. Another study, included in this work, is a series of angular differential cross section measurements for single-electron capture to MeV kinetic energy protons from He that enabled us to systematically investigate the classically allowed non-radiative electron capture process in fast collisions predicted by L.

Thomas in Author: Magnus Gudmundsson. Processes involved in slow collisions between highly charged ions (HCI) and neutral targets are presented. First, the mechanisms responsible for double electron capture are discussed. We show that, while the electron-nucleus interaction is expected to be dominant at projectile velocities of about a.u., the electron-electron interaction plays a decisive role during the collision and gains Cited by: 3.

Many-Electron Calculations of Partial Photoionization Cross Sections for Rare Gas Atoms; Electron Capture and Loss Experiments at Relativistic Energies; The Quantum World of Ultra-Cold Atoms and Light Book I: Foundations of Quantum Optics.

"This thesis focuses on how classical mechanics can be used to help determine the collision dynamics of simple ion-atom collision systems. It was once thought that all particle collisions must be calculated via quantum mechanics in order to obtain meaningful results.

The problem with quantum mechanical calculations is that each state and sub-state of a collision system must be specified prior Author: Kevin Ray Cornelius.

A full theoretical treatment including an ab-initio molecular calculation of the potential energy curves and couplings followed by a semi-classical collision dynamics has been performed for the one-electron capture by S3+ ions in collision with atomic hydrogen.

The present paper completes a previous letter [9] and displays the full results concerning this process in order to provide a detailed Cited by:   Quantum coherence between quantum bits (qubits) placed in entangled states is what physicists are seeking to exploit in quantum computers.

But qubits are typically cooled to within a fraction of a degree of absolute zero, and even then, coherence survives only for brief instants, among just a handful of bits, before decoherence sets in due to.

For ENA modeling and similar purposes, a semi-classical approach offers a middle-ground approach. Kuang's semiclassical formalism to calculate electron-capture cross sections for single and multi-electron ions is an elegant and efficient method, but has so far been applied to limited and specific laboratory measurements and at somewhat lower Author: A.

Barghouty. In solid-state physics, the free electron model is a simple model for the behaviour of charge carriers in a metallic solid. It was developed inprincipally by Arnold Sommerfeld, who combined the classical Drude model with quantum mechanical Fermi–Dirac statistics and hence it is also known as the Drude–Sommerfeld model.

Given its simplicity, it is surprisingly successful in. Covers all topics, including wave particle duality, Schrodinger's cat, EPR / Bell inequality, and the relationship between measurement and entanglement. Quantum Mechanics and Quantum .However, for a quantum well laser optimized to operate at an electron capture resonance, semiclassical calculations blind to the resonance structure would underestimate the capture rate, while Golden-Rule calculations, which assume complete phase coherence, could somewhat overestimate by: Abstract.

The coherence parameters of excited states formed in collisions of atoms with electrons, positrons, protons and antiprotons are calculated using the Classical Trajectory Monte Carlo (CTMC) method and the results are compared to those obtained from the quantal distorted wave and close-coupling : N.

Toshima, C. D. Lin.