Ab initio and experimental studies of the large-amplitude motion in BF2OH.

The ground state rotational spectrum of BF2OH was measured under high resolution by microwave Fourier transform spectroscopy (FTMW), and the small torsional splitting could be resolved for several lines. This splitting was analyzed using a phenomenological model previously developed for HNO3 [Coudert and Perrin, J. Mol. Spectrosc. 1995, 172, 352] and with the help of the geometries of the stationary points calculated ab initio. The torsional splitting was also calculated using the results of the calculations for the ground vibrational state, for the excited OH torsional states 91 and 92, and for the excited BOH bending state 41, and a satisfactory agreement with available experimental data was found.