High Resolution FTIR Overtone Spectra and Hydrogen Bond Dissociation Dynamics in (HF)2

Abstract

The first successful observation of the HF-stretching overtone spectra assigned to the hydrogen bonded HF-dimer in the near infrared region from 7100 to 8100 cm^-1 is reported. Partially pressure broadened bands with linewidths of 0.16 cm^-1 and less were found, which imply vibrational predissociation lifetimes of more than 30 ps. This result is discussed in terms of the efficient vibrationally adiabatic decoupling of the high frequency vibrations and the resulting limitations of quasi-equilibrium theories of unimolecular reactions.