ABINITIO STUDIES ON THE HYDROGEN-BONDED COMPLEXES BETWEEN HYDROGEN-FLUORIDE AND HYDROXYLAMINE

The minimum-energy geometries for the complexes between hydrogen fluoride and hydroxylamine (HF)1H2NOH and (HF)2H2NOH were studied at the Hartree-Fock level and also at the second-order level in many-body perturbation theory (MBPT(2)) in order to estimate the effects of electronic correlation. The novel ring structures observed recently for these hydrogen-bonded complexes were confirmed. The 1:1 complex contains a loosely bound ring structure with a strong N-H F bond and weak long HF-HO bond. An association enthalpy of about -6 to -9 kcal/mol is predicted. For the 1:2 complex, a second HF molecule is inserted into the ring between the first HF moiety and the HO group. This complex exhibits three strong hydrogen bonds and a correspondingly larger association enthalpy of approximately -17 to -19 kcal/mol. The harmonic vibrational analysis at the MBPT(2) level supports most of the assumptions made in the analysis of the FTIR studies.