Non-dissociative ionization cross section of the electronically excited H2 and D2 with atomic-limit principal quantum number n = 3 and 4

Electron-impact cross sections for non-dissociative ionization via the ground vibrational level (v=0) of the electronically excited H2 and D2 with atomic-limit principal quantum number n = 3–4, including HH¯1Σg+, B′1Σu+, D1Πu, GK1Σg+, I1Πg, J1Δg, O1Σg+, B′′B¯1Σu+, D′1Πu, P1Σg+, R1Πg, S1Δg, h3Σg+, e3Σu+, d3Πu, g3Σg+, i3Πg, j3Δg, f3Σu+, k3Πu, r3Πg, and s3Δg, are calculated by Gryzinski method in the present study. The cross sections for these states show a significant dependence on the threshold energy. The isotope effect of the cross sections for H2 and D2 is discussed. The computed cross sections of the electronic states with n = 1–4 from threshold up to 10 keV are fitted. The corresponding Maxwellian rate coefficients are derived from those cross sections with electron temperature from 1 to 10 eV.