The Study of some thermoelastic and thermodynamic properties of alkali halides using Woodcock potential

GAZI UNIVERSITY INSTITUTE OF SCIENCE AND TECHNOLOGY THE STUDY OF SOME THERMOELASTIC AND THERMODYNAMIC PROPERTIES OF ALKALI HALIDES USING WOODCOCK POTENTIAL Harun Reşit YAZAR ( M.Sc. Thesis) 1997 ANKARA ABSTRACT In this study, The applicability of the Woodcock potential is considered for studying the crystalline properties of alkali halides. This potential form represents the composite form of the inverse power dependence and the exponential dependence of the repulsive energy. Woodcock potential is parametrized using Hildebrand equations of the state and the requirement the parameters are determined. The cohesive energy, pressure derivative of bulk modulus, thermal expansion coefficient, Griineisen and Anderson- Grüneisen parameters are calculated for sixteen NaCL -structure alkali halide crystals. The pressure effect is also considered and applied on some termoelastic properties such as Griineisen gama, thermal expansion coefficient and pressure- volume relation. The obtained results are good agreement with the available experimental data. Second order elastic constants(S.O.E.C) are calculated using Woodcock potential and compared with the experimental data and some other theoretical works. Some of the thermoelastic properties such as Griineisen gama, Anderson-Grüneisen parameters and thermal expansion coefficient are calculated in terms of S.O.E.C and T.O.E.C. Science Code - : 404.05.01 Key Words : Alkali halides,Elastic constants, Thermal expansion coefficient,Griineisen parameters, Anderson-Grüneisen parameters Page :100 Supervisor : Prof. Dr. Kemal ÇOLAKO?LU