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

Comment on “Classical description of H(1s) andH∗(n=2) for cross-section calculations relevant to charge-exchange diagnostics”

Cariatore et al. [Phys. Rev. A 91, 042709 (2015)] have introduced a modification of the classical trajectory Monte Carlo (CTMC) method, specially conceived to provide an accurate representation of charge-exchange processes between highly charged ions and H(1s), H ∗ (n=2) . We point out that this new CTMC treatment is based on nonstable initial distributions for H ∗ (n=2) targets and an improper description of the H(1s) targetThis work has been partially supported by Ministerio de Economía y Competitividad (Spain) (Projects No. ENE2011-28200 and No. ENE2014-5432-R

Calculation of total cross sections and effective emission coefficients for B5 + collisions with ground-state and excited hydrogen

International audienceClassical and semiclassical calculations of nl-resolved charge exchange cross sections in B 5+ collisions with H(n i) are performed to compute effective emission coefficients for the n = 7 → n = 6 transition in B 4+ for plasma conditions typical of the ASDEX-U tokamak. For n i = 1, the value of the emission coefficient is larger than that obtained from ADAS database by a factor of two at energies of 10 keV/amu, but no differences are found at energies above 50 keV/amu. For n i = 2, our calculation yields emission coefficients close to those derived from ADAS data from low to high impact energies. The emission coefficients corresponding to B 5+ + H(n i = 3) collisions are of the same order of magnitude than those for n i = 2

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

Ab initio calculation of charge transfer in proton collisions with N 2

Total and partial charge transfer cross sections are calculated in collisions of protons with the nitrogen molecule at energies between 0.1 and 10 keV. Ab initio potential energy curves and nonadiabatic couplings have been obtained for a number of N2 bond lengths using a multireference configuration interaction method. The influence of the anisotropy of the target molecule is investigated. Results are compared with previous experimental and theoretical dataThis work has been supported by the Project ENE2007- 62934 of the Ministerio de Ciencia e Innovación (Spain). Allocation of computational time at the CCC of the Universidad Autónoma de Madrid is gratefully acknowledge

Ion-water collisions at intermediate energies

We employ the independent event electron model in the framework of the classical trajectory Monte Carlo method to compute ionization and capture cross sections for one- and two- electron processes in collisions of H+, He2+ and C6+ with water molecules at intermediate impact energies. Subsequente fragmentation processes are also considered, as well as the differential cross sections for electron emission, of paramount importance for ion beam therap

Classical calculation of total and differential cross sections for electron capture and ionization in proton - molecule collisions

The Classical Trajectory Monte Carlo method is applied to treat proton collisions with N2, CO and CH4 at collision energies 25< E < 2.5 × 103 keV. The calculation employs model potentials to describe the interaction of the active electron with the molecular core. General good agreement with available experimental data is foun

Hemiquantal treatment of low energy p+H2 collisions

We present calculations of charge exchange and vibrational excitation cross sections in low energy p+H2 collisions. These cross sections are obtained by means of an hemiquantal treatment which uses Diatomics In Molecules (DIM) diabatic wavefunctions of the H3+ molecule. The hemiquantal approach allows to distinguish the nonreactive, dissociative and nuclear exchange contributions to the electronic reaction path