Theoretical study on potential energy curves and spectroscopy properties of ground and low-lying excited electronic states of BrCl+

Abstract

The calculations on the potential energy curves and spectroscopic constants of the ground and low-lying excited states of BrCl+, one of the important molecular ions in environment science, have been performed by using the multireference configuration interaction method at high level of theory in quantum chemistry. Through analyses of the effects of the spin-orbit coupling interaction on the electronic structures and spectroscopic properties, the multiconfiguration characteristic of the X2Π ground state and low-lying excited states was established. The spin-orbit coupling splitting energy of the X2Π ground state was calculated to be 1814 cm−1, close to the experimental value 2070 cm−1. The spin-orbit coupling splitting energy of the 2Π(II) exited state was predicted to be 766 cm−1. The transition dipole moments and Frank-Condon factors of the 3/2(III)-X3/2 and 1/2(III)-1/2(I) transitions were estimated, and the radiative lifetimes of the two transitions were briefly discussed.