LASER SPECTROSCOPY OF CERIUM MONOFLUORIDE - LIGAND-FIELD ASSIGNMENTS OF SOME 4F5D6P[-4F5D6S TRANSITIONS

The techniques of selectively detected fluorescence excitation, disper sed fluorescence, and magnetic rotation spectroscopy have been applied to the CeF molecule and used to characterize one [17.6]4.5 electronic state in the similar to 2 eV region and three electronic states with T-0 < 2000 cm(-1):X(1)3.5 and (2)3.5 with Omega = 3.5 and (1)4.5 with Omega = 4.5. Two of these states, the [17.6]4.5 and X(1)3.5 states, ha d been observed previously [R. M. Clements and R. F. Barrow, J. Mel. S pectrosc. 107, 119 (1984); Y. Azuma, W. J. Childs, and K. L. Menningen , J. Mel. Spectrosc. 145, 413 (1991)]. Based on the pattern of Omega-v alues and the value of Delta G(1/2) approximate to 550 cm(-1), the thr ee low-lying states are assigned to the Ce+(4f5d(H-3)6sF- superconfigu ration. The upper state is assigned to the Ce+(4f5d(H-3)6pF- superconf iguration on the basis of computed ligand field monopole B-0(0)(nl, nl ) orbital destabilization energies and one-electron transition propens ity rules. (C) 1996 Academic Press, Inc.