Ab initio description of the fragmentation of H2O+(B2B2)

A quantum-dynamical study of the fragmentation of H2O+(B2B2) is carried out by using wave packet propagations on ab initio potential energy surfaces connected by nonadiabatic couplings assuming a Franck- Condon initial wave packet from the ground state of the water molecule. The simulations indicate that a conical intersection between the B2B2 and à 2A1 states of H2O+ allows the transfer of 80% of the initial wave packet within 30 fs, while the Renner-Teller coupling between the à 2A1 and B1 states determines the fragmentation branching rations in the ps timescal

Nonadiabatic fragmentation of H2O+ and isotopomers. Wave packet propagation using ab initio wavefunctions

The fragmentation of the water cation from its B 2B2 electronic state, allowing the participation of the X 2B1, Ã 2A1 and C 2B1 states in the process, is simulated using the extended capabilities of the collocation GridTDSE code to account for the nonadiabatic propagation of wave packets in several potential energy surfaces connected by nonadiabatic couplings. Molecular data are calculated ab initio. Two initial wave packets are considered to reproduce two different experiments. The isotopic effect in the fragmentation of D2O+ and HDO+ is also studied and the results show very good agreement with the experimental cleavage preference in the fragmentation of HDO+This work has been partially supported by Ministerio de Economía and Competitividad (Spain), project ENE2014-52432-

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

This document is the unedited author's version of a Submitted Work that was subsequently accepted for publication in The Journal of of Physical Chemistry Letters, copyright © American Chemical Society after peer review. To access the final edited and published work, see DOI: http://dx.doi.org/10.1021/jz5022894A quantum-mechanical study of the predissociation of H2O+(B˜ 2B2) is carried out by using wave packet propagations on ab initio potential energy surfaces connected by nonadiabatic couplings. The simulations show that within the first 30 fs, 80% of the initial wave packet is transferred from the B 2B2 to the A˜ 2A1 electronic state through a conical intersection. A much slower transfer (in the ps timescale) from the A˜ 2A1 to the X˜2B1 state due to a Renner-Teller coupling determines the fragmentation branching ratios, which are in accordance with the experimental measurementsThis work has been partially supported by projects ENE2007-62934 and ENE2011-28200 (Secretaría de Estado de I+D+i, Spain) and the European COST actions CM1204 (XLIC) and MP1002 (Nano-IBCT). The calculations have been performed at the Centro de Computación Científica of the UAM

Ionization and single and double electron capture in proton−Ar collisions

This document is the unedited Author’s version of a Submitted Work that was subsequently accepted for publication in The Journal of Physical Chemistry A, copyright © 2018American Chemical Society after peer review. To access the final edited and published work see http://doi.org/10.1021/acs.jpca.7b11769Total 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, 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 dataThis work has been partially supported by Ministerio de Economía and Competitividad (Spain), project no. ENE201452432-

Aggregation effects in proton collisions with water dimers

Charge transfer cross sections in proton collisions with water dimers are calculated using an ab initio method based on molecular orbitals of the system. Results are compared with their counterpart in proton-water collisions to gauge the importance of intermolecular interactions in the cross sectionsThis work has been supported by the project ENE2007-62934 of the Secretaría de Estado de Investigación, Desarrollo e Innovación (Spain). Allocation of computational time at the CCC of the Universidad Autónoma de Madrid is gratefully acknowledge

Charge exchange in proton collisions with the water dimer

We calculate the electron capture cross sections in collisions of protons with water dimers, using a simple ab initio approach. The formalism involves one-electron scattering wave functions and a statistical interpretation to evaluate many-particle cross sections. By comparing with proton-water collisions, we aim at identifying aggregation effects in the electron capture cross section

Ionization of water molecules by proton impact: Two nonperturbative studies of the electron-emission spectra

Two nonperturbative methods are applied to obtain total and singly differential (in the electron energy) cross sections of electron emission in proton collisions with H2O at impact energies in the range 10 keV ≤ Ep ≤ 5 MeV. Both methods, one classical and one semiclassical, combine an independent particle treatment with a multicenter model potential description of the target. The excellent agreement obtained with experimental data supports the usefulness of the approximations involved and encourages the study of more complex systemsThis work has been partially supported by Projects No. ENE2007-62934 and No. ENE2011-28200 (Secretaría de Estado de I+D+i, Spain

Ab initio treatment of ion-water molecule collisions with a three-center pseudo potential

We calculate electron capture cross sections in collisions of protons with water molecules, using two simple ab initio approaches. The formalism involves the calculation of one-electron scattering wave functions and the use of three-center pseudo potential to represent the electron H2O+ interaction. Several methods to obtain many-electron cross sections are considere