15min:

WILTON L. VIRGO AND TIMOTHY C. STEIMLE, Department of Chemistry and Biochemistry, Arizona State University, Tempe, AZ 85287-1604.

High resolution optical spectroscopy has been used to study a molecular beam of molybdenum carbide, MoC. The R_e(0) ( =18612.978 cm^-1) and Q_fe(1) ( =18611.872 cm^-1) branch features of the (0,0) [18.6]³ ₁-X^{3 -} system of ⁹⁸MoC were analyzed using Stark spectroscopy. Electric field induced splitting in the laser induced fluorescence (LIF) spectra was analyzed to measure permanent electric dipole moments of 2.69(2)D and 6.32(20)D for the [18.6]³ ₁ and X^{3 -} states, respectively. Excited state hyperfine structure has been observed for the first time in ⁹⁵MoC and ⁹⁷MoC. Experimental results will be compared to theoretical predictions, and the electronic structure will be discussed using a molecular orbital correlation model. The MoC dipole moments will be compared with those of other transition metal monocarbides. An interesting observation is that the ab initio calculations for second row transition metal monocarbides are more reliable than predictions for the first row carbides.