The low-lying electronic states X3Σ-, a1Δ and b1Σ+of PO-, NS-and PS-according to MRD-CI calculations

Abstract

Large-scale MRD-CI computations have been carried out on the pi 4 pi *2 states X 3 Sigma -, a 1 Delta and b 11 Sigma + of PO-, NS- and PS-, using extended AO basis sets. The a 1 Delta state of NS- is found to be stable upon electron attachment, as experimentally known for the similar state of PO-. For both NS- and PO-, the zero vibrational level of the b 1 Sigma + state is predicted to be slightly more stable than the ground state of the corresponding neutral molecule, while both singlet states of PS- are placed well below X 2 Pi of neutral PS. The electron affinity of PS is estimated to be 1.60+or-0.10 eV. Spectroscopic parameters and Franck-Condon factors for electron detachment are given for NS- and PS-. The dipole moments for the ground state of the neutral molecules and all negative-ion states, are reported.