Ab initio study of the Renner-Teller effect in the X∼ 2Πelectronic state of the OHF− anion

The Renner-Teller effect in the OHF− anion is investigated theoretically, based on ab initio MRCI calculations for the underlying potential energy surfaces. Jacobi coordinates have been employed for the kinetic energy, to allow for large-amplitude displacements of the nuclei. The results for the 3D vibronic energy levels and wavefunctions are presented and discussed, also in relation to 1D and 2D calculations, where only the angular or the radial degrees of freedom are considered. The impact of the (moderately weak) Renner-Teller coupling on the low-lying vibronic excitations is thus established for the first time for this system.