THE MILLIMETER/SUBMILLIMETER SPECTRUM OF CUSH($\tilde{X}^{1}A'$): INVESTIGATION OF THE TRANSITION METAL SULFUR BOND

Author Institution: Department of Chemistry, Department of Astronomy, and Steward Observatory, University of ArizonaThe pure rotational spectra of $^{63}CuSH$ and $^{65}CuSH$ and its deuterated isotopomers were recorded using millimeter/submillimeter-wave direct absorption techniques. The molecule was produced by reacting copper vapor with $H_{2}S$ in the presence of d.c. discharge. Transitions ranging from $J = 24 \rightarrow 25$ to $J = 50 \rightarrow 51$ spanning the region of 262 - 538 GHz were measured for $^{63}CuSH$ and $^{65}CuSH$, as well as transitions $J = 32 \rightarrow 33$ to $J = 39 \rightarrow 40$ 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 $r_{0}$ structure, have been determined for the molecule. This study shows that the molecule is bent with a Cu-S-H angle of $\Theta = 93.6^{0}$, and therefore is different from CuOH, which has a Cu-O-H angle of $\Theta = 110.1^{0}$. This striking variation in geometry likely results from a lack of hybridization in the CuSH molecule