Far-Infrared Spectra of Crystalline Benzene at 138°K and Intermolecular Forces

Abstract

Far-infrared spectra of crystalline benzene have been measured at low temperatures. The three bands assigned to the translational lattice vibrations have been found. The frequencies of these lattice vibrations, those of the Raman-active lattice vibrations and the frequency splittings of the infrared bands at 138°K have been consistently explained from the hydrogen—hydrogen and hydrogen—carbon interactions. The values obtained for these atom—atom interactions are correlated with the values of other intramolecular and intermolecular force constants and with the energy of internal rotation for n-butane.