Phys. Rev. 168, 43 (1968)j report a calculation for Fe ' which is qualitatively similar to the present system. Although the KP method was used, a subsequent calculation by D. Ikenberry (private communication) using the MP Dalgarno method gave almost exact agreement, shell by shell, with the EP calculation. The estimates of the corrections discussed for the EP method should therefore apply to the present MP calcul. ation.A quantum theory of ferroelectricity in Rochelle salt is developed which is an extension of the two-sublattice model of Mitsui. The isotope effects on deuteration are explained in a natural way, and the spontaneous polarization, the polarization of the two sublattices, and the dielectric constant are obtained as functions of temperature.The dynamics of the system is investigated for the case of deuterated Rochelle salt and is found to exhibit a twomode relaxational behavior. The correlation time of one of these two modes is proportional to the static dielectric constant and thus exhibits a critical slowing-down on approaching the two Curie temperatures in agreement with the experimental data.

No abstract

No abstract

The two-body dispersion interactions between multipoles of the hydrogen atoms have been worked out using [2,1] and [3,2] Padé approximants and generalized Casimir–Polder integral formulas. Energy coefficients which appear in the expression for the interaction energy of E2 (H–H), obtained up to the term R−16, are in agreement with those of Dalgarno and Meath.

No abstract