X-RAY-FLUORESCENCE CORRELATION SPECTROSCOPY - A METHOD FOR STUDYING PARTICLE DYNAMICS IN CONDENSED MATTER

We have demonstrated that x-ray fluorescence correlation spectroscopy, in conjunction with microfocused synchrotron x-ray beams, can be used for elucidating particle dynamics. The dynamics of gold and ferromagn etic colloidal panicles and aggregates undergoing both diffusion and s edimentation in water has been studied by measuring the time autocorre lation of the x-ray fluorescence intensity from a small illuminated vo lume, The dynamical parameters obtained are in excellent agreement wit h theoretical estimates and other measurements, Potential applications of the technique are discussed. [S0031-9007(97)05208-3].