Liaison Hydrogene en Phase Liquide et Spectrometrie Raman. I: Alcools liquides purs

The vOH (OD) bands of some liquid alcohols (three primary, two secondary and one tertiary), have been studied over a wide temperature range with regard to: (i) band position as a function of temperature, (ii) band intensity and depolarization ratio as a function of temperature and physical state. From studies of (i), the long chain polymer structure is confirmed; and the diagonal and interaction force constants FOH and ƒOH are calcualated between 295 K and the melting point. From studies of (ii), it is shown that the intensity in the liquid phase is temperature independent as long as autoassociation is preponderant: however from relative intensity measurements (gas to liquid) the scattering activity {article}{empty}{document}(45 α '2 + 7 γ^ '2 ){document} is seen to increase by a factor of two as a result of autoassociation; and the depolarization ratio increases by a factor of two from dilute solution to pure liquid. These results are discussed in the light of the bond polarizability theory; it is concluded that the α′l/α′p ratio for the OH band changes considerably on formation of an hydrogen bond. This can be explained in terms of the Orville Thomas pulsed cloud model.