Extensive theoretical study on the excited states of the PCI+ molecule including spin-orbit coupling

The entire 23 A-S states of the PCI+ molecule have been studied by using the high-level relativistic MRCI+Q method with full-electron aug-cc-pCVQZ-DK basis set. The potential energy curves(PECs) and wavefunctions of the states have been calculated. From the PECs, the spectroscopic constants of the bound states are also determined, and the good agreements could be found with the experiments. The high density region of states exhibits many PECs' crossings, which lead to complicated interaction of the states. Here, the interactions arising from the dipolar interaction and spin-orbit coupling (SOC) effect have been discussed in detail. Under the influence of the SOC effect, the A(2)Pi state is perturbed by the 1(4)Sigma(-) state. Considering the SOC effect, total 45 Omega states are generated from the original 23 Lambda-S states. The transition properties are also predicted, including the transition dipole moments, Franck-Condon factors, and radiative lifetimes. The lifetimes of the transitions A(2)Pi(1/2)-X-2 Pi(1/2) and A(2)Pi(3/2)-X-2 Pi(3/2) are determined to be 478.9 ns and 487.0 ns(nu'=0), respectively. (C) 2017 Elsevier Ltd. All rights reserved.