These effects of spin–orbit coupling, core–valence correlation and scalar relativistic correction on spectroscopic calculations for PN+ cation

The potential energy curves (PECs) of 9 Λ-S states (X 2 Σ + , 1 4 Σ + , 1 6 Σ + , A 2 Π, 1 4 Π, 1 6 Π, 1 4 Δ, 1 4 Σ − , 2 4 Π) and corresponding 28 Ω states of PN + cation are calculated by the complete active space self-consistent field (CASSCF), which is followed by the internally contracted multireference configuration interaction (icMRCI) with Davidson modification. The calculation is taken into account these effects of spin–orbit coupling, core–valence correlation and scalar relativistic correction. These are found that the 2 4 Π, 1 6 Π and 1 4 Σ − states possess double wells and two avoided crossings occur between the 1 6 Π and 2 6 Π states, the 2 4 Π and 3 4 Π states. Based on the PECs, the spectroscopic parameters are evaluated. And the transitions (transition dipole moments, Franck–Condon Factors and radiative lifetimes) from 1 6 Π −1/2 and 2 4 Π −1/2 (the first well of the two states) to the ground state X 2 Σ + 1/2 are obtained in this paper. These effects of spin–orbit coupling, core–valence correlation and scalar relativistic correction on the spectroscopic calculations are analyzed.