AN EXTENDED X-RAY-ABSORPTION FINE-STRUCTURE STUDY OF AQUEOUS-SOLUTIONS BY EMPLOYING MOLECULAR-DYNAMICS SIMULATIONS

Bromine-oxygen radial distribution functions [g(r)] have been calculat ed by means of molecular dynamics simulations for aqueous solutions of rubidium bromide, 2-bromopropane and bromoethane. X-ray absorption sp ectra at the bromine Kedge have been recorded for these solutions. The water contribution to the extended x-ray absorption fine structure sp ectra has been calculated starting from the g(Br,O)(r) distribution fu nction. Fits of the x-ray absorption spectra have been performed direc tly on the raw experimental data, allowing the reliability of the g(r) distribution;functions to be verified. The agreement between theoreti cal and experimental spectra is satisfactory. A procedure to improve m odel g(r) functions on the basis of the short-range structural informa tion provided by extended x-ray absorption fine structure data is prop osed.