TE'07		10min5:12

L. A. KALEDIN, A. L. KALEDIN AND M. C. HEAVEN, Department of Chemistry, Emory University, Atlanta, GA 30322.

The laser absorption spectrum of the LaF⁺ molecular ion has been observed for the first time. Gas phase LaF was obtained by heating a mixture of a 0.2 g of La metal and 0.3 g of LaF₃ powder to 1900 K. LaF⁺ ions were produced by passing a 25 kHz discharge (80-100W, 0.5A peak current) through the vapor. Under these conditions the Tantalum heating tube used to vaporize the sample also acted as a hollow cathode. 138 lines of the ² _2.5-² _1.5 (0,0) band were recorded. This band system was observed previously in the emission spectrum of LaF⁺. Accurate term energies are (in cm^-1):

TABLE

Ligand field theory models were used to provide the configurational assignment for the LaF⁺ electronic states. The symmetry for the ground state of the LaF⁺ molecular ion has been reassigned as X² .

Work supported by AFOSR under grant F19628-90-C-025.