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The x-ray spectra resulting from single-electron capture in charge-exchange collisions of Nel0+ with He and Ne atoms are investigated for the projectile energy of 4.54 keV/u using the two-center atomic-orbital close-coupling method. The calculated spectra of the Ne9+ ion produced in Ne10+ + He and Nel0+ + Ne election-capture collisions have, generally speaking, the same level of agreement with experimental measurements as those calculated previously by the classical trajectory Monte Carlo method, indicating that multi-electron-capture processes, particularly in the case of the Nel0+ 4- Ne system, significantly affect the considered spectra. The effects of two-electron capture on the spectral line intensity have been demonstrated qualitatively by using the binomial statistics and independent particle model for the target outer-shell electrons. The role of multi-electron-capture processes in the Nel0+ 4- Ne collision system needs further attention. [ABSTRACT FROM AUTHOR]

Polarization spectroscopy of He+(nl) ion produced in He2+-H(1s) collisions in a Debye plasma is studied by the two-center atomic orbital close-coupling (TC-AOCC) method in the energy range 1-200 keV/u. The atomic orbitals and electron binding energies of atomic states are calculated within the Debye-Hückel approximation of the screened Coulomb potential and used in the AOCC dynamics formalism to calculate the magnetic substate-selective electron-capture cross sections. It is demonstrated that the screening of Coulomb interactions affects the entire collision dynamics and the magnitude and energy behavior of m-state-selective cross sections. The changes in magnetic substate-selective electron-capture cross sections when the interaction screening varies introduce dramatic changes in the polarization spectroscopy with respect to the unscreened interaction case. The magnetic substate-selective electron-capture cross sections, as well as the polarization degrees for the 2p 2P3/2-1s 2S1/2,3p 2P3/2-2s 2S1/2,3d 2D5/2-2p 2P3/2, and 3d 2D3/2-2p 2P1/2 transitions in the He+ ion produced in this collision system, are presented and discussed for a number of representative screening parameter values. [ABSTRACT FROM AUTHOR]

State-selective and total single-electron-capture cross sections in collisions of H+ with the excited Li*(2p) atom have been investigated by using the full quantum-mechanical molecular orbital close-coupling (QMOCC) method in the energy range 0.001-3 keV/u and by the two-center atomic orbital close-coupling (TC-AOCC) method in the energy range 0.1-100 keV/u. The present results are also compared with data from other sources when available. It is found that the total and partial electron-capture cross sections are sensitive to the initial p-state charge cloud alignment, particularly in the low-energy region. [ABSTRACT FROM AUTHOR]

The radiative association processes for Na+ colliding with 87Rb(5s) atoms have been investigated by using the quantum-mechanical method. The total and partial cross sections that associate to the specific rovibrational states are calculated rigorously in the energy range of 10-13 - 1.2 × 10-2eV. The association cross sections display rich resonance structures. The ratios of rotationally resolved cross sections to total association cross sections and the ratios of vibrationally resolved cross sections to rotationally resolved cross sections are calculated and presented. For energies less than 10-9eV, association to X²Σ+ (J = 1) dominates over all other association states. As the energy increases, each resonance of the total cross sections is associated with the given angular component of specific bound states. In the energy range of 10-13-1.2×10-3eV, the vibrational states ν = 27 and ν = 28 are the most probable final states. The probability for the formation of molecular ion NaRb+ in the rovibrational states is discussed. The existence of Cooper minima in the radiative association cross sections is found and illustrated. [ABSTRACT FROM AUTHOR]

The time-dependent density functional theory is applied to investigate the charge transfer and electron-loss processes during He2+-Ar collisions in the energy range of 4-300 keV/amu. A coordinate space translation technique is employed to focus our investigation on some certain space of interest such as the regions around the projectile or target. It is shown that both charge transfer and electron-loss processes are important in the considered energy range. One-electron-capture processes dominate charge transfer with the cross sections one to two orders of magnitude larger than two-electron-capture cross sections. The ionization cross sections decrease with increasing the number of ionized electrons. The calculated cross sections are in excellent agreement with available experimental and theoretical results. Evolution of electron density is also presented to explore interactions between the electrons as well as the correlation between the projectile and target during the collisions. [ABSTRACT FROM AUTHOR]