Effective Pair Potentials of NaCl- and CsCl-type KBr Determined by X-Ray Absorption Fine Structure under Pressure

A difference in effective pair potentials between the NaCl- and CsCl-type KBr has been investigated using the X-ray absorption fine structure (EXAFS) technique under pressure. In the potential parameter fitting, we have directly carried out the numerical integration of the EXAFS function and evaluated the precise effective pair potential. The effective pair potential is influenced not only by pressure but also by coordination numbers. The high pressure CsCl-type phase has broader effective pair potentials than the NaCl-type phase.