"Anomalous" Debye-Waller Factor for bccHe4

Abstract

The Debye-Waller factor for bcc ${}_{}{}^4{}_{}{}^{}\mathrm{He}$ is calculated at $T=0\mathrm{}$ on the basis of a Hartree-Jastrow ground-state wave function by means of a cluster-expansion technique and is found to be a Gaussian function of the wave-vector transfer to within 1%. We discuss a possible reason for the large deviations from Gaussian behavior observed in recent neutron inelastic-scattering experiments.