Calculation of vibrational excitation of N₂ by electron impact at 5-50 eV using extended-basis-set Hartree-Fock wavefunctions

The cross sections 0 to 0, 0 to 1 and 1 to 2 for vibrational excitation of N₂ by electron impact at 5, 10, 20, 30 and 50 eV are calculated in a static-exchange-polarisation model. The calculations are based on the Hartree-Fock target wavefunctions of Cade, Sales and Wahl (1966) for the static potential and for the Hara (1967) free-electron-gas exchange potential. Target charge polarisation is included by the effective polarisation potential of Morrison and Collins (1978), scaled as a function of internuclear distance by the polarisabilities. The calculated cross sections are well converged with respect to channels. The results show clearly both the low-energy Pi _g resonance and the intermediate-energy Sigma _u resonance.