Accession Number : AD0868328

Title :   Low Temperature Behavior of a Pure Dipole-Dipole System,

Corporate Author : NAVAL ORDNANCE LAB WHITE OAK MD

Personal Author(s) : O'Keeffe, David J.

Report Date : 24 MAR 1970

Pagination or Media Count : 86

Abstract : The Van Vleck moment expansion is applied to a pure dipole system. On the basis of the long range nature of the forces sequences of diagrams are selected that give the dominant contributions in the lattice sums. A selection of diagrams contributing to the entropy and susceptibility are displayed. There are three different summations to be performed for each type of diagram: the trace over the spin variables; the lattice summation and the summation over the Cartesian coordinates. The second was performed on the computer and the last summation was obtained by means of the Kramers-Wannier diagonalization. In order to obtain the contributions of diagrams of higher order a Fourier transform was employed. The calculations were performed for Cerous Magnesium Nitrate using a g-factor that is zero along the c-axis. The results are compared with experiments. (Author)

Descriptors :   (*PARAMAGNETIC MATERIALS, DIPOLE MOMENTS), CRYSTAL LATTICES, TEMPERATURE, CESIUM COMPOUNDS, MAGNESIUM COMPOUNDS, NITRATES, THESES.

Subject Categories : Physical Chemistry
      Solid State Physics

Distribution Statement : APPROVED FOR PUBLIC RELEASE