Temperature study of resonance intermolecular interaction in the aliphatic crystals using spectra of IR absorption

Abstract

In this work, on the example of odd-numbered normal paraffins and α-olefins we propose a mechanism which explains the temperature dependence of the amgnitud eof Davydov splitting Δυ1,2 of the bands of scissoring and rocking vibrations of methylene chains of long-chain compounds with frequencies 1456 and 720 cm-1, respectively. This mechanism is connected with damping of the intramolecular vibrational excitons in crystals due to their interactin with orientational defects of the lattice which emerge as a result of excitation of librational-rotational degrees of freedom of organic molecules in the region of the phase transition of order-orientaional disorder type. Good agreement was observed bewteen theoretical and experimental results.