Cross Sections and Swarm Coefficients for H+, H2+, H3+, H, H2, and H− in H2 for Energies from 0.1 eV to 10 keV

Abstract

Graphical and tabulated data and the associated bibliography are presented for cross sections for elastic, excitation and ionization collisions of H+, H2+, H3+, H, H2, and H− with H2 at laboratory energies from 0.1 to 10 keV. Where appropriate, drift velocities and reaction or excitation coefficients are calculated from the cross sections and recommended for use in analyses of swarm experiments and electrical discharges. In the case of H+ in H2, cross sections for momentum transfer, rotational excitation, vibrational excitation, charge transfer, electronic excitation, and ionization are recommended. Energy-loss or stopping-power coefficients calculated from these cross sections are much smaller than obtained from stopping-power theory. There are no relevant energy-loss experiments for H+ in H2. Drift velocity calculations predict runaway for H+ in H2 for electric field to gas density ratios E/n greater than 700 Td, where 1 Td (townsend)=10−21 V m2. For H2+ in H2, the cross sections include H3+ formation, charge transfer, vibrational and electronic excitation, and ionization. Drift velocities and average cross sections are calculated for E/n≥1 kTd. For H3+ in H2, cross sections for momentum transfer, various charge transfer processes, electronic excitation, and ionization and drift velocities are recommended. In the case of H in H2, cross sections for momentum transfer, rotational excitation, vibrational excitation, charge transfer, H− formation, electronic excitation, and ionization are recommended. For H2 in H2, cross sections for momentum transfer, rotational excitation, vibrational excitation, charge transfer, electronic excitation, and ionization are recommended. In the case of H− in H2, cross sections for momentum transfer, electron detachment, and ionization are recommended and calculated drift velocities are compared with experiment. Collisions of electronically excited states with H2 are not included.