15min:

CAROLYN S. BRAUER, GALEN SEDO, ERIK M. GRUMSTRUP AND KENNETH R. LEOPOLD, Department of Chemistry, University of Minnesota, Minneapolis, MN 55455; MARK D. MARSHALL AND HELEN O. LEUNG, Department of Chemistry, Amherst College, Amherst, MA 01002-5000.

The radical complex OH-H₂O has been observed by rotational spectroscopy. Spectra for ¹⁶OH-¹⁶OH₂O and ¹⁸OH-¹⁸OH₂ have been analyzed using a two-state model which accounts for nuclear motion on both the ²A' and ²A'' potential surfaces. Partial quenching of the OH orbital angular momentum dramatically affects the rotational spectra, and the ²A'-²A'' energy separation, , is determined to be -146.50744(42) cm^-1. The ground state of the complex has approximately 86% ²A' character and the vibrationally averaged OH-OH₂ hydrogen bond distance is 1.952 Å. The magnetic hyperfine constants for the OH proton in the complex are significantly altered from monomer values.