NEUTRON INELASTIC SCATTERING FROM SOLID HCl

Abstract

High resolution neutron inelastic scattering spectra in the region below $250 cm^{-1}$ have been obtained from solid HCl at temperatures corresponding to the low temperature ferroelectric phase, the high temperature disordered phase and the recently $reported^{1}$ (120$^\circ K$--98.4$^\circ K$) intermediate phase. These data were obtained utilizing a time-of-flight spectrometer with a crystal monochromator. The resolution of this instrument is sufficient to enable previously unresolved structure to be observed. The low temperature phase data are compared to cross-sections calculated by using a full lattice dynamical $model^{2}$ and good agreement is obtained.