15min:

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

The optical Stark effect in the (0,0) A² -X^{2 +} band systems of a yttrium monosulfide, YS , supersonic molecular beam sample have been analyzed to produce permanent electric dipole moments, µ, for the A² _3/2, and A² _1/2 states of 5.9(2) D, and 6.8(1) D, respectively. Fine structure splitting in the field free A² _3/2-X^{2 +} and A² _1/2-X^{2 +} spectra were analyzed to produce the magnetic hyperfine spectroscopic parameters a = -36(6) MHz, c = 111(7) MHz, and d = -107(6) MHz for the A² state. Transition frequencies of the low rotational lines in the (0,0) A² _r-X^{2 +} band system were measured and analyzed to produce the first complete set of fine structure parameters for the A² _r state.