Charge Transfer and Electron Production in Proton Collisions with Uracil: A Classical and Semiclassical Study

Cross sections for charge transfer and ionization in proton–uracil collisions are studied, for collision energies (Formula presented.) keV, using two computational models. At low energies, below 20 keV, the charge transfer total cross section is calculated employing a semiclassical close-coupling expansion in terms of the electronic functions of the supermolecule (H-uracil) (Formula presented.). At energies above 20 keV, a classical-trajectory Monte Carlo method is employed. The cross sections for charge transfer at low energies have not been previously reported and have high values of the order of 40 Å (Formula presented.), and, at the highest energies of the present calculation, they show good agreement with the previous results. The classical-trajectory Monte Carlo calculation provides a charge transfer and electron production cross section in reasonable agreement with the available experiments. The individual molecular orbital contributions to the total electron production and charge transfer cross sections are analyzed in terms of their energies; this permits the extension of the results to other molecular targets, provided the values of the corresponding orbital energies are know

Resonant Fragmentation of the Water Cation by Electron Impact: a Wave‐Packet Study

We have investigated the dissociation of a resonant state that can be formed in low energy electron scattering from H2O+. We have chosen the second triplet resonance above the (Formula presented.) (Formula presented.) state of H2O+ whose autoionization mainly produces H2O+ ((Formula presented.)). We have considered both dissociation of the resonant state itself, dissociative recombination (DR), or the dissociation of the H2O+ cation after autodetachment, dissociative excitation (DE). The time-evolution of a wave packet on the potential energy surfaces of the resonance and cationic states shows, for the initial conditions studied, that the probability for DR is about 38 % while the probability for DE is negligibleThis research was funded by Ministerio de Economía y Competitividad (Spain), project No. FIS2017-84684-R, Ministerio de Ciencia e Innovación (Spain), project No. PLEC2022-009256 and Comunidad de Madrid (Spain), project No. 2022/BMD-743

Estudio teórico de la dispersión de electrones por átomos en presencia de láseres de alta densidad

Tesis doctoral inédita leída en la Universidad Autónoma de Madrid, Facultad de Ciencias, Departamento de Química. Fecha de lectura: 16-03-199

Charge Transfer and Electron Production in Proton Collisions with Uracil: A Classical and Semiclassical Study

Cross sections for charge transfer and ionization in proton–uracil collisions are studied, for collision energies 0.05<E<2500 keV, using two computational models. At low energies, below 20 keV, the charge transfer total cross section is calculated employing a semiclassical close-coupling expansion in terms of the electronic functions of the supermolecule (H-uracil)+. At energies above 20 keV, a classical-trajectory Monte Carlo method is employed. The cross sections for charge transfer at low energies have not been previously reported and have high values of the order of 40 Å2, and, at the highest energies of the present calculation, they show good agreement with the previous results. The classical-trajectory Monte Carlo calculation provides a charge transfer and electron production cross section in reasonable agreement with the available experiments. The individual molecular orbital contributions to the total electron production and charge transfer cross sections are analyzed in terms of their energies; this permits the extension of the results to other molecular targets, provided the values of the corresponding orbital energies are known

Electron Capture from Molecular Hydrogen by Metastable Sn2+* Ions

Over a wide and partly overlapping energy range, the single-electron capture crosssections for collisions of metastable Sn2+(5s5p3Po) (Sn2+∗) ions with H2 molecules were measured(0.1–10 keV) and calculated (0.3–1000 keV). The semi-classical calculations use a close-couplingmethod on a basis of electronic wavefunctions of the (SnH2)2+ system. The experimental crosssections were extracted from double collisions in a crossed-beam experiment of Sn3+ with H2. Themeasured capture cross-sections for Sn2+∗show good agreement with the calculations between2 and 10 keV, but increase toward lower energies, whereas the calculations decrease. AdditionalLandau–Zener calculations were performed and show that the inclusion of spin-orbit splitting cannotexplain the large cross-sections at the lowest energies which we now assume to be likely due tovibrational effects in the molecular hydrogen target

Cover Feature: Resonant Fragmentation of the Water Cation by Electron Impact: a Wave‐Packet Study (ChemPhysChem 19/2023)

The Cover Feature illustrates the decay of a resonance state of the water molecule into a vibrationally excited water cation (autoionization) or to neutral fragments (dissociative recombination). The branching ratio between the two channels depends on the resonance propertie

Electron Capture from Molecular Hydrogen by Metastable Sn²⁺* Ions

Over a wide and partly overlapping energy range, the single-electron capture cross-sections for collisions of metastable Sn2+(5s5p Po3) (Sn2+∗) ions with H2 molecules were measured (0.1–10 keV) and calculated (0.3–1000 keV). The semi-classical calculations use a close-coupling method on a basis of electronic wavefunctions of the (SnH2)2+ system. The experimental cross-sections were extracted from double collisions in a crossed-beam experiment of Sn3+ with H2. The measured capture cross-sections for Sn2+∗ show good agreement with the calculations between 2 and 10 keV, but increase toward lower energies, whereas the calculations decrease. Additional Landau–Zener calculations were performed and show that the inclusion of spin-orbit splitting cannot explain the large cross-sections at the lowest energies which we now assume to be likely due to vibrational effects in the molecular hydrogen target