Accession Number : AD0648461

Title :   INFRARED LATTICE VIBRATIONS OF SINGLE CRYSTAL LITHIUM HYDRIDE AND SOME OF ITS ISOTOPIC DERIVATIVES.

Descriptive Note : Technical rept.,

Corporate Author : PENNSYLVANIA STATE UNIV UNIVERSITY PARK DEPT OF PHYSICS

Personal Author(s) : Brodsky,H. M. ; Burstein,E.

Report Date : FEB 1967

Pagination or Media Count : 41

Abstract : The infrared reflection spectra of single crystal lithium hydride, lithium deuteride, lithium-6 hydride, and lithium-7 hydride have been measured and analyzed. The long wavelength limits of the optical lattice vibrational frequencies have been determined and used to find the static dielectric constants and Szigeti effective charges of all the isotopic variations studied. It is found that the square of the longitudinal (or transverse) frequency is inversely proportional to the reduced mass of the ion pairs forming the crystal. The Szigeti effective charge for LiH, e sub s(*) = (0.53 plus or minus 0.02) e, is qualitatively accounted for by the Dick and Overhauser shell model for the vibrating ions. A slight isotope effect on the e sub s (*) is noted in LiD and the difference in effective charges is interpretable within the framework of the shell model. (Author)

Descriptors :   (*LITHIUM COMPOUNDS, CRYSTAL STRUCTURE), (*SINGLE CRYSTALS, LITHIUM COMPOUNDS), HYDRIDES, DEUTERIUM COMPOUNDS, PHONONS, INFRARED SPECTRA, EQUATIONS OF MOTION, INTERACTIONS

Subject Categories : Crystallography
      Atomic and Molecular Physics and Spectroscopy

Distribution Statement : APPROVED FOR PUBLIC RELEASE