Direct coupled-channels deperturbation analysis of the A(1)Σ(+) ∼ b(3)Π complex in LiCs with experimental accuracy.

Abstract

We have carried out the direct deperturbation analysis of about 780 rovibronic term values of the strongly spin-orbit (SO) coupled A(1)Σ(+) and b(3)Π states of the (7)Li(133)Cs molecule recorded by polarization labelling spectroscopy technique. The explicit A(1)Σ(+) ∼ b(3)ΠΩ=0,1,2 coupled-channels treatment allowed us to reproduce 95% experimental term values with a standard deviation of 0.05 cm(-1) which is close to the accuracy of the present experiment. The initial potential energy curves (PECs) of the mutually perturbed states and SO matrix elements were ab initio evaluated in the basis of the spin-averaged wave functions. The empirically refined PECs and SO functions, along with the theoretical transition dipole moments, were used to predict energy and radiative properties of the A ∼ b complex for low J levels of both (7)Li(133)Cs and (6)Li(133)Cs isotopologues. The reasonable candidates for the stimulated Raman transitions between initial Feshbach resonance states, the mixed levels of the A ∼ b complex, and absolute ground X(1)Σ(+) (v = 0 and J = 0) state were identified.