Knowledge Bank

Far infrared spectra of HCI and DCI dissolved in a variety of inert and interacting solvents have been recorded from $35cm-1$ to $300cm-1$. A broad absorption band devoid of any rotational structure was observed. The integrated intensity of the broad band was measured and compared with the theoretical gas phase intensity. The intensity and frequency characteristics of the band show that the band has more of the rotational-like characteristics for the less interacting solvents. The far infrared spectra of symmetric top molecules like $NH3,ND2,CH3F,CH3F,CH3Cl,CH3CN$ are also observed in a variety of solvents. A broad absorption band devoid of any discrete structure was observed. Intensity measurement as a function of concentration and temperature shows that these absorptions are due to momomeric species of the solute. Intensity measurement further shows that for $NH3$ and $ND3$ the motion can be described as rotation-like.