Ab initio R-matrix/multichannel quantum defect theory study of nitric oxide

Ab initio R-matrix techniques are combined with multi-channel quantum defect theory to determine the properties of arbitrarily highly excited electronic states of nitric oxide. Results are obtained for I = 0-4 channels associated with the four lowest NO+ target channels, namely (1)Sigma(+), E-3(+), (3)Pi and (3)Delta. Energy and bond length variations of the quantum defect functions for all target states are reported. Certain small surface amplitude R-matrix poles also serve to determine the energies of valence states. Diabatic potential curves for Rydberg states converging to the (1)Sigma(+) and (3)Sigma(+) target states and for the valence states are presented. Systematic jumps in the psigma quantum defects for all target states as the bond length increases beyond R = 2.5 an are attributed to Rydbergization of the antibonding 2psigma* molecular orbital.