Doroshenko I. The V-structure of liquid monohydric alcohols from the data on vibrational spectroscopy

The work is devoted to the determining of the structure peculiarities of liquid monohydric alcohols (methanol and ethanol), physical parameters of the clusters, which form this structure, and the character of vibrational relaxation in these alcohols. Quantum-chemical calculations of the associates forming the structure of liquid methanol were made. Their optimal space geometry, forming energy and electrical parameters were calculated. It was determined, that the structure of liquid methanol is formed mainly by cyclic trimers and tetramers. The changes in the molecule geometry of methanol, which occur at the molecular association, were studied. The Raman profiles in methanol and ethanol were investigated in the temperature region of the condensed phase existing (160 – 340 K). The dynamical stability of the structure of liquid monohydric alcohols in the investigated temperature region was registered. The correlation analysis of the Raman spectra of methyl alcohol was made. The time of vibrational relaxation was calculated. The broadening of the vibrational bands in the spectra of alcohols can be explained by the process of hydrogen bond dissociation.