SUBMILLIMETER SPECTROSCOPY OF ZnOH (X$^{2}$A$^{\prime }$): STRUCTURE AND BONDING IN 3d HYDROXIDE SPECIES

Author Institution: Department of Chemistry, Department of Astronomy, and Steward Observatory, University of Arizona, Tucson, AZ, 85721The ZnOH radical (X$^{2}$A$^{\prime }$) has been observed in the laboratory using mm/sub-mm direct-absorption techniques. This is the first gas-phase laboratory spectroscopic study of this radical. ZnOH was produced by reacting zinc vapor with H$_2$O or H$_2$O$_2$ under DC discharge conditions. Multiple rotational transitions have been recorded in the 400-540 GHz range that clearly exhibit K-ladder structure, indicative of a bent molecule. the pattern has been observed in three zinc isotopologues: $^{64}$ZnOH, $^{66}$ZnOH, and $^{68}$ZnOH. Each line consists of spin-rotation doublets with a splitting of $\sim$180-190 MHz, characteristic of zinc. The data are currently being analyzed and rotational and spin-rotation constants will be presented. The bent geometry suggests predominantly covalent bonding between zinc and oxygen