Knowledge Bank

Fundamental intramolecular vibrational spectra have been used in conjunction with combination and hot bands to obtain intermolecular vibrational frequencies for $(HCN)2$ and HCN-HF in both the ground and excited intramolecular vibrational states. These spectra were recorded in the UNC-CH opto-thermal molecular beam apparatus at sub-Doppler resolution. Comparisons are made between these accurate values and those obtained from L-type doubling. Recent ab-initio calculations are also available for $(HCN)2$ for comparison.