Electron impact excitation of the G ^1?^+_g state of H_2

Abstract

The optical excitation function for the G1Σ+g →B1Σ+u transition of the H2 spectrum has been determined for the electron impact energies in the range 0-500 eV and at H2 gas pressures ≤ 30 mtorr. Measurements of the absolute emission cross section for the λ = 4634 Å [G → B(0,0)P1,R2,R3] vibration-rotational line blend have been carried out at 200 eV incident electron energy. Measurements of the G1Σ+g(ν′ = 0) state radiative lifetime have also been carried out and yield a single-mode decay, with a lifetime of ∼30 ns. Both dc intensity and time-solved lifetime measurements are observed to be independent of H2 gas pressure and electron beam current over the regions ∼ 2 to 50 mtorr and 5 µA to 1 mA, respectively.