On the high-frequency spectrum of elastic and thermal oscillations in liquids

The spectrum of high-frequency elastic and thermal oscillations in liquids is investigated by the method of paired interactions. An explicit form is found for high-frequency elastic and thermal moduli expressed in terms of the molecular parameters of the medium. A statistical system of identical particles interacting pairwise is examined and described in terms of a spherically symmetrical potential. Contributions made by energy fluctuations are taken into account in the eigenfunctions for longitudinal density excitations, but not in the spectrum of the associated elastic waves.