DOPPLER-FREE SPECTROSCOPY OF KLI

The B (1) Pi-X (1) Sigma(+) band system of the (KLi)-K-39-Li-7 molecul e was investigated by Doppler-free polarization spectroscopy in a heat -pipe oven. Precise molecular constants for levels upsilon = 0-3 in th e ground X (1) Sigma(+) state and levels upsilon = 0-2 in the excited B (1) Pi state were determined. The e-parity components in all three v ibrational levels of the B state were found to be subject to rotationa l perturbations, assigned to interaction with the C (1) Sigma(+) state . The deperturbation analysis provided preliminary constants of the pe rturbing C slate and values of the coupling matrix elements. (C) 1997 American Institute of Physics.