The effect of vibrational state mixing on the predissociation lifetime of ν1 excited OC–HF

Abstract

Sub‐Doppler resolution infrared spectra have been obtained for the ν₁ band of OC–HF. For most of the observed rovibrational transitions the linewidths are found to have a Lorentzian component of 190±10 MHz FWHM, presumably resulting from the vibrational predissociation of the complex. In several cases, however, perturbations, due to either anharmonic or Coriolis coupling between the vibrational state corresponding to the excited HF stretch and other vibrational states of the molecule, have been observed in the spectrum. Where these perturbations are present the width of the transitions vary with the relative contributions from the two states involved. This is explained in terms of a simple perturbative treatment of the coupling in conjunction with a Golden Rule treatment of the vibrational predissociation process. Stark measurements have also been performed in order to determine the dipole moment of the complex in the vibrationally excited state, namely μ₁=2.545±0.008 D.