The spin-orbit coupling of the [formula omitted] and 43Π states in KCs: Observation and deperturbation

Abstract

Energies of 1655 rovibrational levels of the mutually perturbed 61Σ+ and 43Π0+ states in KCs were measured in a series of experiments employing polarization labelling spectroscopy technique. The experimental term values of the 61Σ+∼43Π0+ complex in KCs were used in coupled-channels deperturbation analysis which took explicitly into account the spin-orbit coupling of the 61Σ+ and 43Π0+ states. The empirical deperturbation treatment was supported by ab initio electronic structure calculation of adiabatic potentials of the interacting states and of the corresponding spin-orbit coupling matrix element as a function of internuclear distance.