Interactions between the sextet states of FeCl

Abstract

Remarkable features ( Omega dependence of effective B values, non-equidistant spin-orbit separations, observations of Lambda -type doubling effects) found in analysing ultraviolet bands of FeCl are interpreted as arising from interactions between the sextet states of the (3d64s)Fe+ complex (for the X6 Delta ground state) and of the (3d64p pi )Fe+ complex (for the excited 6 Phi and 6 Pi states). Ab initio calculations are used to ascertain the nature of the observed transition (which are shown to be 4s-4p ion-like excitations) and to determine plausible values of the off-diagonal parameters involved in the energy matrices of the sextet states. Given these values a deperturbation analysis is carried out. The Lambda -type splittings observed in the X6 Delta 1/2, X6 Delta -1/2 and 6 Phi 1/2 components are quantitatively interpreted.