Computation of Phonon Spectral Functions and GroundState Energy of Solid Helium. I. bcc Phase
Abstract
Computations incorporating the threephonon interaction process are presented of phonon spectral functions, yielding frequency and lifetime dispersion curves, for the bcc solid phase of both He^{3} and He^{4}. Comparison of the compressibilities obtained from groundstate energy and elastic constants as functions of molar volume quantify the effects of certain analytical approximations. A model calculation shows the sensitivity of elastic anisotropy and longwavelength dispersions to the precise form of the threephonon vertex.
 Publication:

Physical Review A
 Pub Date:
 May 1972
 DOI:
 10.1103/PhysRevA.5.2230
 Bibcode:
 1972PhRvA...5.2230K