Dependence of Electron-Impact Excitation Cross-Sections on the Initial Vibrational Quantum Number in H-2 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 X1SIGMA(g)+-->B1SIGMA(u)+ and X1SIGMA(g)+-->C1PI(u) transitions for both H-2 and D2 molecules as a function of incident energy and of vibrational quantum number v(i). The results show that the cross sections initially increase monotonically with increasing v(i) and follow the opposite trend for higher v(i) values.