Classical treatment of ion-H2O collisions with a three-center model potential

Abstract

We present calculations of cross sections for one-and two-electron processes in collisions of H + , He 2+ , and C 6+with water molecules in the framework of the Franck-Condon approximation. We employ an independent-electron method and a classical trajectory Monte Carlo approach. Anisotropy effects related to the structure of the target are explicitly incorporated by using a three-center model potential to describe the electron-H 2 O + interaction. We derive scaling laws with respect to the projectile charge. We also estimate cross sections for molecular fragmentation subsequent to electron removal.

Ab initiotreatment of charge transfer in ion-molecule collisions based on one-electron wave functions

“…As ionization becomes important at higher energies, we have only performed FC calculations with η = 2. In this figure, we compare our results with two sets of experimental data [2,6] and with recent classical CTMC calculations [41]. Our results follow correctly the curve plotted by the experimental data for E 15 keV, but slightly underestimate this data for higher energies, probably due to the limited number of ionization channels.…”

“…9 we show the comparison between our SEC cross sections for impact energies in the range 1-110 keV, using MII (solid line in the figure), with several experimental data of [2,[5][6][7], and with previous ab initio calculations performed by Mada et al [12] and classical calculations by Illescas et al [41]. Results of MII were obtained using the vibrational sudden approximation previously detailed and combining the results obtained with different values of the cutoff parameter η of Eq.…”

Nonadiabatic Quantum Dynamics Predissociation of H2O+(B̃ 2B2)

“…In this context, several works [5][6][7] have estimated the branching ratios for production of the The good agreement between these semiempirical results and the experiments [9][10][11][12] indicates that the ions H + , OH + and O + are formed through a two-step mechanism that involves the ionization of H 2 O followed by the post-collisional fragmentation of H 2 O + .…”

Non-adiabatic interactions in charge transfer collisions

“…In particular, we are interested in collisions between ions and biomolecules, in relation to the action of ionizing radiation on the biological medium [7,20]. Different processes may be induced in such reactions, including: excitation and ionization of the target, fragmentation of the ionized biomolecule, and electron exchange from the incident ion toward the biomolecular system [21]. In experimental studies, fragmentation yield may be determined through analysis of the different fragments by mass spectroscopy [22].…”