Alba Jorge

Calculation of total cross sections for electron capture in collisions of Carbon ions with H(D,T)(1s)

The calculations of total cross sections of electron capture in collisions of Cq+ with H(1s) are reviewed. At low collision energies, new calculations have been performed, using molecular expansions, to analyze isotope effects. The Classical Trajectory Monte Carlo method have been also applied to discuss the accuracy of previous calculations and to extend the energy range of the available cross sections.

Electron capture and ionization processes in high-velocity Cn+ , C?Ar and Cn+ , C?He collisions

Single-electron and double-electron capture as well as projectile single-ionization and multiple-ionization processes in 125 keV u−1 C–He (n = 1–5) and C–Ar () collisions have been studied experimentally and theoretically. Helium target single-ionization and double-ionization cross sections are also reported for C–He (n = 1, 4) collisions in the 100–400 keV u−1 impact energy domain. These results are compared with predictions from the independent atom and electron (IAE) model developed for describing cluster–atom collisions. The ion/atom–atom probabilities required for the IAE simulations have been determined by classical trajectory Monte Carlo (CTMC) and semiclassical atomic orbital close coupling (SCAOCC) calculations for the Ar and He targets, respectively. For comparison, electron capture cross sections were also measured in C–He and C–Ar collisions. In general the agreement between experiment and IAE calculations has been found to be rather good, with the exception of double-electron capture leading to anionic C species.

Total and partial charge exchange and ionization cross sections for C6+ and N7+ colliding with H(n = 1,2)

The atomic processes of charge exchange and ionization in collisions between fully ionized ions (C6+, N7+) and atomic hydrogen (H(1s), H(n = 2)) are studied theoretically in the intermediate–high collision energy range (10–500 keV amu−1). The method employed is the so-called classical trajectory Monte Carlo method.

Ionization and Single and Double Electron Capture in Proton–Ar Collisions

Total cross sections for formation of H and H-, and electron production, in H+ + Ar collisions have been calculated at energies between 100 eV and 200 keV by employing two methods: for E < 10 keV, a semiclassical treatment with an expansion in a basis of electronic wave functions of the ArH+ quasimolecule and, for E > 10 keV, the switching-classical-trajectory-Monte Carlo method (s-CTMC). The semiclassical calculation involves transitions to molecular autoionizing states, calculated by applying a block-diagonalization technique. The s-CTMC method is adept to treat two-electron processes and yields total cross sections for H- formation in reasonably good agreement with the experimental data. Cross sections for electron- and H-production processes, which are dominated by one-electron transitions, are in good agreement with the experimental data.

Electron capture and ionization processes in high velocity Cn+, C-Ar and Cn+, C-He collisions

Single and double electron capture as well as projectile single and multiple ionization processes occurring in 125keV/u Cn+-He, Ar collisions have been studied experimentally and theoretically for 1 ≤ n ≤ 5. The Independent atom and electron (IAE) model has been used to describe the cluster-atom collision. The ion/atom-atom probabilities required for the IAE simulations have been determined by classical trajectory Monte Carlo (CTMC) and semiclassical atomic orbital close coupling (SCAOCC) calculations for the Ar and He targets respectively. In general the agreement between experiment and IAE simulations was good, with the exception of double electron capture leading to anionic C−n species.

3D numerical calculation of electron capture cross sections in Be4+ + H collisions

Electron capture in Be4+ + H collisions is studied at collision energies between 1 and 100 keV/u, as a benchmark to discuss the accuracy of different theoretical approaches. Partial cross sections, obtained by solving numerically the time-dependent Schrodinger equation, are compared to the corresponding results from close-coupling and classical trajectory Monte Carlo calculations.

Classical treatment of Li2++Ar and He2++Ar collisions

Classical Trajectory Monte Carlo calculations are carried out for Li2++Ar and He2++Ar collisions, motivated by recent experiments on these systems. Cross sections for electron capture, projectile electron loss and target multiple ionization processes are evaluated and compared to the experimental values in the 75-500 keV/amy impact energy range.

Scaling for state-selective charge exchange due to collisions of multicharged ions with hydrogen

In this article we evaluate state-resolved charge exchange cross sections for Be and projectiles colliding with atomic hydrogen employing two different methods: the classical trajectory Monte Carlo and the eikonal impulse approximations. These cross sections are used to extend previously derived scaling laws for n-, nl-, and nlm-distributions to highly excited final levels with covering energies in the range amu. Present total and partial capture cross sections are in agreement with available experimental and theoretical data for these collision systems. Besides, the proposed scaling rules are also verified by other theories, becoming a useful instrument for plasma research.

State-selective electron capture in collisions of C6+, N7+ with Hydrogen at intermediate energies

We present a joint study of the electron capture process in multicharged ions on atomic Hydrogen at intermediate energies. We have applied two methods, the Eikonal Impulse Approximation (EIA) and the hydrogenic-Classical Trajectory Monte Carlo (CTMC) method. Good agreement is found in both total and state-selective electron capture cross sections.