Knowledge Bank

The radical complex OH-H$2$O has been observed by rotational spectroscopy. Spectra for $1$$6$OH-$1$$6$OH$2$O and $1$$8$OH-$1$$8$OH$2$ have been analyzed using a two-state model which accounts for nuclear motion on both the $2$A and $2$A potential surfaces. Partial quenching of the OH orbital angular momentum dramatically affects the rotational spectra, and the $2$A-$2$A energy separation, $\rho$, is determined to be -146.50744(42) \wn. The ground state of the complex has approximately 86{%} $2$A character and the vibrationally averaged OH-OH$2$ hydrogen bond distance is 1.952 \AA. The magnetic hyperfine constants for the OH proton in the complex are significantly altered from monomer values.