Ab initio calculation of the ground state and the first excited state system of Br including spin-orbit coupling and relativistic correction to the kinetic energy operator

Abstract

Ab initio calculations of the ground state ² P _u and the first excited state system ⁴ P_g /² P_g (4p →5s) of the bromine atom have been carried out in the framework of an MRD-CI study. The spin-orbit splitting of the ground state has been evaluated in first order perturbation theory; for the excited states a spin-hamiltonian matrix including the five multiplets in question has been diagonalized. In addition to calculations employing the non-relativistic operator for the kinetic energy a recently proposed matrix representation of the relativistic kinetic energy has been investigated.