The infrared spectrum and internal rotation barrier in HF-BF3

The rotationally resolved infrared spectrum of the HF stretch fundamental i n combination with one quantum of internal rotation excitation has been inv estigated for the HF-BF3 complex using a color-center-laser optothermal mol ecular-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 st retch gives a barrier to internal rotation of 54 cm(-1) in the HF stretch e xcited state. (C) 2000 Elsevier Science B.V. All rights reserved.