The infrared spectrum and internal rotation barrier in HF–BF 3

Abstract

The rotationally resolved infrared spectrum of the HF stretch fundamental in combination with one quantum of internal rotation excitation has been investigated for the HF–BF 3 complex using a color-center-laser optothermal molecular-beam spectrometer. The infrared band origin is red-shifted by 3.9 cm −1 from the HF monomer origin. The magnitude of the Coriolis interaction in the m=±1 internal rotor state observed in combination with the HF stretch gives a barrier to internal rotation of 54 cm −1 in the HF stretch excited state.