Anharmonic Thermal Vibrations in CdSe

EXAFS measurements have been done at the K edge of Se in bulk CdSe, in the temperature range 20 to 300 K, and analyzed by the cumulant method. The anharmonicity of the effective pair potential is monitored by the regular growth with temperature of 3rd and 4th cumulants. The first order anharmonic contribution to the MSRD has been calculated. An estimate of the sensitivity of EXAFS so thermal expansion has been attempted taking into account the effect of thermal vibrations normal to the bond direction.