Knowledge Bank

The optothermal detection method has been used to obtain sub-doppler resolution infrared spectra for the HF stretching vibration of $H2-HF$. At the highest resolution obtained in this study, the homogeneous broadening $associated2$ with the finite lifetime of the excited vibrational state (27 ns) is just observable. Infrared Stark spectra have also been recorded from which the electric dipole moments in the ground (1.428D) and excited (1.512D) vibrational states have been determined. These results clearly show that the HF monomer unit undergoes wide amplitude bending in both the ground and vibrationally excited states and that the bending angle decreases upon vibrational excitation.