The technique of Molecular Dynamics (MD) computer simulation is coupled with the interrelated theories of light scattering and atomic polarisability to develop and test models for the Raman scattering from alkali halide systems. The primary interest is in the spectrum and intensity of the scattering from melts, but scattering from crystals is also considered. Two computationally tractable models for the Raman scattering are developed. One, a qualitative model capable of reproducing light scattering lineshapes in Nal, is based on approximations to the quantum-mechanical transition rates for the scattering processes and relies on the shell model interionic potentials from lattice dynamics to give insight into the dynamics of ionic dipole moment fluctuations, from which the scattering behaviour is extracted. The second model is a quantitative one capable of reproducing absolute scattering intensities as well as lineshapes for NaCl melts. This model is based on a detailed parameterisaton of the variation of individual ion polarisabilities with the instantaneous local ionic configuration. The model parameters are extracted from the results of electronic structure calculations on ionic systems performed elsewhere. This model has additionally been applied with some success to NaCl crystal systems. The scattering behaviour of LiF has also been considered, although no experimental comparison is available. The primary failure of the second model is its inability to predict the correct depolarisation ratio for the scattering from NaCl; reasons for this are offered. In developing the models, computer simulation techniques and the light scattering and polarisability theories are reviewed, as are aspects of alkali halide systems, especially interionic potentials suitable for use in simulations. Numerous improvements and extensions to the models are suggested.

published_or_final_version / abstract / Physics / Doctoral / Doctor of Philosophy

published_or_final_version / Physics / Master / Master of Philosophy

Thesis (M. Phil.)--University of Hong Kong, 2009. / Includes bibliographical references (leaves 52-54). Also available online.

The interaction of a high power laser beam with the lattice of transparent optical materials induces internal strains in the latter. Attention is focused on optical materials of zinc blende structure and excitation at the 10.6-(mu)m wavelength of the laser. A lattice dynamical treatment is presented to obtain the laser induced internal strains in terms of the lattice Green's functions, the transverse effective charge and the Raman coefficient. The transverse effective charge and the Raman coefficient are then thoroughly discussed and discrepancies in previous works concerning these parameters are resolved. / The imperfect lattice Green's functions are utilized to calculate the expected magnitude of the actual strains induced in real crystals taking into account the effect of lattice point defects. The mechanical laser damage thresholds at the 10.6-(mu)m CO(,2) laser wavelength are then obtained specifically for SiC, GaAs, InSb, ZnS, ZnSe, and CdTe materials, in good agreement with the available measured values.

Thesis (Ph. D.)--University of Hong Kong, 2007. / Title proper from title frame. Also available in printed format.

Thesis (Ph. D.)--Auburn University, 2008. / Abstract. Vita. Includes bibliographical references (p. 140-142).

Thesis (M. Phil.)--University of Hong Kong, 2009. / Includes bibliographical references (leaves 52-54). Also available in print.

Thesis (Ph. D.)--University of Texas at Austin, 1998. / Vita. Includes bibliographical references (leaves 153-160). Available also in a digital version from Dissertation Abstracts.

Thesis (Ph. D.)--University of Idaho, 2006. / Abstract. "June 2006." "In liquefaction, the movement of particles is generally viewed as random and isotropic. A numerical study has been performed based on the hypothesis that as liquefaction occurs, initially randomly placed particles become organized into a lattice structure. As a result, the initial behavior may be isotropic, but there is a progressive movement to anisotropic behavior as cyclic shearing is applied. The study is performed under ideal conditions considering spherically shaped particles of the same size in pure shear. The results of the study showed that the particles organize to the same lattice structure regardless of friction coefficient or shear plane selection. Consequently, this study provides a tool for calibrating constitutive models related to liquefaction."--p. iii. Includes bibliographical references (leaves 45-51). Also available online in PDF format.