Ab initio and semiempirical estimates of PN valence state interactions

Abstract

Hartree-Fock wavefunctions for the valence states of PN arising from the lowest energy open shell configurations, 2 π 47 σ3 π and 2 π 37 σ 23 π, are generated and used in ab initio calculations of diagonal spin-orbit, off-diagonal spin-orbit, and rotation-electronic matrix elements. These results are compared with those from two semiempirical methods, one based on atomic orbital populations and the other dependent solely on atomic spin-orbit splittings. The latter method is found to be surprisingly successful in predicting the 3Δ spin-orbit constant for a series of isovalent molecules. Semiempirical estimates of the 3Δ and 3Π spin-orbit constants of AsN are given. The Hartree-Fock values of the a and b perturbation parameters are found to be 50 cm −1 and 0.60 (unitless), respectively. A previously reported perturbation in the A 1Π- X 1Σ + band system is shown to arise from a 3 Σ − ∼ 1 Π spin-orbit interaction.