Journal of Chemical Physics, Vol.101, No.5, 3581-3587, 1994
The Doubly-Excited 1-(3)-Sigma(G)(-) State of Li-7(2)
This paper reports the first experimental observation of the doubly excited valence (2p+2p)(3) Sigma(g) state of Li-7(2). We used cw perturbation-facilitated optical-optical double resonance (PFOODR) fluorescence excitation and resolved fluorescence spectroscopic techniques. All the observed levels have been detected through perturbations by the 2.(IIg)-I-3 state. The deperturbed primary molecular constants of this 1 (3) Sigma(g)(-) state are T-e=34 045.354(43) cm(-1), omega(e)=216.820(37) cm(-1), B-e=0.673 69(47) cm(-1), R(e)=2.670 81(94) Angstrom and D-e=4279.306(43) cm(-1). The equilibrium internuclear distance of the 1 (3) Sigma(g)(-) state is smaller than that of the X (1) Sigma(g)(+) ground state.
Keywords:POTENTIAL-ENERGY CURVES;ELECTRONIC-STRUCTURE;FINE-STRUCTURE;SPECTROSCOPY;PERTURBATIONS;LI-6(2);LI2