K. ATHANASSENAS, C. T. KINGSTON, A. J. MERER AND J. R. D. PEERS, Chemistry Department, University of British Columbia, 2036 Main Mall, Vancouver, BC, Canada V6T 1Z1; M. BARNES, The Fluid Life Corporation, 9619 42nd Avenue, Edmonton, AB, Canada T6E 5R2; D. A. GILLETT, Lambda Physik, Inc., 3201 West Commercial Boulevard, Fort Lauderdale, FL 33309; G. F. METHA, School of Chemistry, University of Sydney, Building F11, Sydney, New South Wales 2006, Australia; L. C. O'BRIEN, Department of Chemistry, Southern Illinois University at Edwardsville, Edwardsville, IL 62026-1652.

Fluorescence excitation spectra of gaseous TaCH and TaCD have been recorded following reaction of laser-ablated tantalum with CH4 or CD4 under jet-cooled molecular beam conditions. A total of 27 bands of TaCH and 18 of TaCD were observed in the visible region. High resolution spectra reveal the X0+ ground state to have the substitution structure r0(Ta-C)=1.7714 Å and r0(C-H)=1.080 Å. Since the X0+ state has no orbital or spin angular momentum, we observe only quadrupole splitting due to the 181Ta nucleus (I=7/2). Resolved fluorescence studies have given the TaCH ground state vibrational frequencies nu2(bend)=640 cm-1 and nu3(Ta-C stretch)=960 cm-1. Analysis is currently underway on an \Omega =0+ state at 16391.9 cm-1 and an \Omega =1 state at 16376.0 cm-1. Through mixing with the \Omega =1 state, the upper \Omega =0+ state has acquired some magnetic hyperfine character.