Study of lattice dynamics via extended x-ray absorption fine structure

EXAFS (extended x-ray absorption fine structure), besides being a powerful structural probe, can also give original information on local dynamics in solids. EXAFS is peculiarly sensitive to the correlation of vibrational motion, both parallel and perpendicular to the bond direction, and to anharmonicity. This paper contains an introduction to the effects of thermal disorder on EXAFS of crystals and to the data analysis based on the cumulant expansion. Cumulants are easily connected to average local vibrational properties. Recently obtained experimental results concerning the mean square relative displacement and the thermal expansion in crystals confirm the potentialities of EXAFS as a dynamical probe.