Accession Number : ADA296728

Title :   Point-Charge Analysis of Symmetry-Preserving Charge Compensation and Vacancies in the Fluorapatites Ca5(PO4)3F and Sr5(PO4)3F.

Descriptive Note : Interim rept. Oct 93-Oct 94,

Corporate Author : ARMY RESEARCH LAB ADELPHI MD

Personal Author(s) : Morrison, Clyde A.

PDF Url : ADA296728

Report Date : JUN 1995

Pagination or Media Count : 20

Abstract : A single point-charge model was used to investigate four types of charge compensation and two types of vacancies for the M2 site in M5(PO4)3F (M = Ca, Sr). Two effective charges were chosen for the oxygen in the (PO4)(3-) complex. A set of crystal-field components, A(sub nm), was obtained for each assumed compensation or vacancy, and the crystal-field parameters, B(sub nm), for Nd(3+) were calculated for each type. The resulting energy levels for Nd(3+) were then calculated and the results for each type compared, showing a rather complicated result for the (L,S)j multiplets higher in energy than the (4)F3/2 multiplet of Nd(3+). Unsuccessful attempts were made to perform a simple correlation analysis, such as the rotational invariants of the crystal-field parameters and the width of the energy splittings of the 4Ij and (4)F3/2 multiplets of Nd(3+) for each case considered. A calculation for the M1 site is included, and the energy splittings of the 4Ij and (4)F3/2 are shown to be comparable to the energy splittings for the M2 sites. jg p.3

Descriptors :   *CALCIUM, *CRYSTALS, *SYMMETRY, *VACANCIES(CRYSTAL DEFECTS), *COMPENSATION, *STRONTIUM, *PHOSPHATES, TRANSITION METALS, PARAMETERS, OXYGEN, CORRELATION, SPLITTING, RARE EARTH COMPOUNDS, NEODYMIUM, ENERGY LEVELS.

Subject Categories : Inorganic Chemistry
      Physical Chemistry
      Crystallography
      Atomic and Molecular Physics and Spectroscopy

Distribution Statement : APPROVED FOR PUBLIC RELEASE