Local Structures of RbBr_xCl_1-x and CuBr_xCl_1-x Solid Solutions Studied by Temperature-Dependent Br K-Edge Extended X-Ray-Absorption Fine-Structure Spectroscopy

Abstract

Local structures of RbBr x Cl 1- x and CuBr x Cl 1- x (0.1≦ x ≦1.0) solid solutions were investigated by means of temperature-dependent extended X-ray-absorption fine-structure (EXAFS) spectroscopy and compared with the results of AgBr x Cl 1- x (0.05≦ x ≦1.0) and AgBr x I 1- x (0.6≦ x 1.0). The mixing ratio, x , and temperature dependences of the bromine-cation distance R ( x ) show significant differences among these solid solutions. In AgBr x Cl 1- x and AgBr x I 1- x , d R ( x )/dx i s s t r o n g l y t e m p e r a t u r e - d e p e n d e n t ; dR(x)/dx i s l a r g e a t l o w t e m p e r a t u r e a n d i t b e c o m e s s m a l l e r a s t h e t e m p e r a u t r e i n c r e a s e s . I n c o n t r a s t , dR(x)/dx i n R b B r _x C l _1-x s h o w s l i t t l e t e m p e r a t u r e d e p e n d e n c e a n d m a i n t a i n s a n e a r l y c o n s t a n t v a l u e <jat