The experimental determination of vibrational transition moments for HF dimer

The vibrational transition moments for the proton acceptor and proton donor HF stretches in (HF)2 have been measured by vibrational predissociation spectroscopy under saturated conditions in a molecular beam using mass spectrometric detection. The proton acceptor transition moment shows only slight enhancement (∼10%) over the HF monomer value of 0.0997 D. The proton donor transition moment is substantially enhanced by a factor of ∼2, as a result of hydrogen bonding. The enhancements are in excellent agreement with predictions from ab initio calculations.