Electron degradation and thermalization in H2 gas.

Abstract

Thermalization and degradation of subexcitation electrons with initial energies of 1, 3, and 5 eV in H{sub 2} gas at a number density of 2.69 {times} 10{sup 19} cm{sup {minus}3} and a temperature of 300 K are studied through a numerical solution of the Boltzmann equation. The collision term in the Boltzmann equation includes contributions from elastic collisions as well as inelastic collisions, viz., collisions leading to rotational and vibrational excitation or deexcitation. The time evolution of the electron energy distribution function and of the cumulative degradation spectrum, as well as thermalization times, are calculated. Time-dependent yields or collision numbers for rotationally and vibrationally inelastic processes are calculated by using the cumulative degradation spectrum. We discuss extensively the present result for thermalization times in comparison with experimental data and other theoretical results. {copyright} {ital 1996 The American Physical Society.}