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Lattice Dynamics Of Naf, Arnold Karo, John R. Hardy
Lattice Dynamics Of Naf, Arnold Karo, John R. Hardy
John R. Hardy Papers
The results of an extended calculation of the normal modes of the NaF lattice are presented. Three models have been considered : a "rigid-ion" (RI) model, a "deformation-dipole" model with central F--F- short- range interactions (DDNNN), and a “deformation-dipole" model including both central F--F- interactions and a noncentral component in the first-neighbor, short-range interactions [DDNNN(NC)]. For each of these models we have derived frequency spectra for both 300 and 0°K input parameters, the associated dispersion curves for symmetry directions, Debye characteristic temperatures ΘD, moment functions ωD(n), and the …
Lattice Dynamics And Second-Order Raman Spectrum Of Naf, John R. Hardy, A. M. Karo, I. W. Morrison, C. T. Sennett, J. P. Russell
Lattice Dynamics And Second-Order Raman Spectrum Of Naf, John R. Hardy, A. M. Karo, I. W. Morrison, C. T. Sennett, J. P. Russell
John R. Hardy Papers
The second-order Raman spectrum of NaF has been measured using an argon laser source. For a light beam incident along the [010] direction, polarized along the [001] direction, and viewed along the [100] direction, the scattered radiation is almost completely polarized. It is shown theoretically that it is possible to account for the polarization and the detailed shape of the observed spectrum within the experimental resolution using a Raman polarizability tensor whose second derivatives with respect to nuclear displacements depend only on the positions of first neighbors in the crystal, provided one uses the phonon frequencies derived from a deformation …
Application Of The Method Of Lattice Statics To Vacancies In Na, K, Rb, And Cs, John W. Flocken, John R. Hardy
Application Of The Method Of Lattice Statics To Vacancies In Na, K, Rb, And Cs, John W. Flocken, John R. Hardy
John R. Hardy Papers
We have calculated the lattice distortion produced by a single vacancy in Na, K, Rb, and Cs. The calculations have been carried out using the technique of lattice statics, which is based on the Fourier transformation of the direct-space equilibrium equations, making consistent use of discrete lattice theory. Three distinct types of potential have been used to describe the interactions between the host atoms. The first of these applies only to sodium, and contains an ion-electron-ion term derived from the measured phonon dispersion curves. The second applies only to potassium, and has been similarly obtained. The third is based on …