Dependence of electron-impact dissociative excitation cross sections on the initial vibrational quantum number in H2 and D2 molecules: X 1 Sigma g+-->B 1 Sigma u+ and X 1 Sigma g+-->C 1 Pi u transitions.

Electron-impact excitation cross sections have been calculated using the impact-parameter method for X ¹Σg⁺{→}B ¹Σᵤ⁺ and X ¹Σg⁺{→}C ¹Πᵤ transitions for both H₂ and D₂ molecules as a function of incident energy and of vibrational quantum number vᵢ. The results show that the cross sections initially increase monotonically with increasing vᵢ and follow the opposite trend for higher vᵢ values.