Intermolecular Potential and Ferroelectric Transitions in Hydrogen Halides

Abstract

A semiempirical molecular field approximation has been developed for the solid hydrogen halides. Including only the first- and second-order terms of the spherical harmonics expansion, the intermolecular potential may be characterized by two arbitrary parameters. The parameters were then evaluated from the infrared data. With this intermolecular potential, it is then possible to estimate the dielectric and NMR correlation times, the ferroelectric transition temperature, the heat of transition, etc. These calculations are in fair agreement with the experimental data. The correlation effects may be more important for ferroelectrics than for ferromagnets.