J. Phys. IV France 7 (1997) C2-1173-C2-1174
Anharmonic Effective Pair Potentials of KBr and CsBr Determined by EXAFSA. Yoshiasa1, O. Kamishima2, A. Nakatsuka1, T. Ishii3 and H. Maeda2
1 Graduate School of Science, Osaka University, Toyonaka 560, Japan
2 Faculty of Science, Okayama University, Okayama 700, Japan
3 Faculty of Engineering, Okayama University, Okayama 700, Japan
The anharmonic effective pair potentials V(u)=αu2+βu3/3!+γu4/4! in KBr and CsBr have been investigated at room temperature by the EXAFS technique. In the parameter fitting, we have directly carried out the numerical integration of EXAFS function and evaluated the anharmonic effective pair potential. The Grüneisen parameters γGwere calculated from the obtained values of α and β as 1.65 for KBr and 1.37 for CsBr, respectively. Contribution of the van der Waals term to the total energy has been determined by comparing with the calculated curve obtained by the empirical estimation, and rises from 1.8 % for KBr to 3.0 % for CsBr.
© EDP Sciences 1997