15min:

A. J. JANCZYK AND L. M. ZIURYS, Department of Chemistry, Department of Astronomy, and Steward Observatory, University of Arizona, Tucson, AZ, 85721.

The pure rotational spectra of ⁶³CuSH and ⁶⁵CuSH and its deuterated isotopomers were recorded using millimeter/submillimeter-wave direct absorption techniques. The molecule was produced by reacting copper vapor with H₂S in the presence of d.c. discharge. Transitions ranging from J = 24 25 to J = 50 51 spanning the region of 262 - 538 GHz were measured for ⁶³CuSH and ⁶⁵CuSH, as well as transitions J = 32 33 to J = 39 40 for the deuterated species. The spectra showed extensive K_a ladder structure for all species, which is consistent with the molecule being an asymmetric top. Rotational constants, as well as an r₀ structure, have been determined for the molecule. This study shows that the molecule is bent with a Cu-S-H angle of = 93.6^o, and therefore is different from CuOH, which has a Cu-O-H angle of =110.1^o. This striking variation in geometry likely results from a lack of hybridization in the CuSH molecule.