Theoretical study of the electronic spectrum of ammonia: Generalized oscillator strength calculations for the A-X transition

Abstract

A series of ab initio CI calculations is reported for the electronic spectrum of ammonia. The generalized oscillator strength for the A-X n→3s Rydberg transition is computed as a function of the square of the momentum transfer vector in electron impact studies and the results are found to be in good agreement with the corresponding measured data. Vertical and adiabatic transition energies are also reported for a series of low-energy Rydberg transitions involving 3p, 3d, 4s and 4p upper orbitals and these results are also found to compare well with the corresponding experimental findings. Optical φ values for the latter transitions have also been computed.