An extended x-ray absorption fine structure study of aqueous solutions by employing molecular dynamics simulations

P. D'Angelo and A. Di Nola
Dipartimento di Chimica, Università degli Studi di Roma ``La Sapienza,'' P.le Aldo Moro 5, 00185 Roma, Italy
A. Filipponi
Dipartimento di Fisica, Università degli Studi dell'Aquila, Via Vetoio, 67010 Coppito-L'Aquila, Italy
N. V. Pavel and D. Roccatano
Dipartimento di Chimica, Università degli Studi di Roma ``La Sapienza,'' P.le Aldo Moro 5, 00185 Roma, Italy

FULL TEXT

Abstract

Bromine-oxygen radial distribution functions [g(r)] have been calculated by means of molecular dynamics simulations for aqueous solutions of rubidium bromide, 2-bromopropane and bromoethane. X-ray absorption spectra at the bromine K edge have been recorded for these solutions. The water contribution to the extended x-ray absorption fine structure spectra has been calculated starting from the gBr,O(r) distribution function. Fits of the x-ray absorption spectra have been performed directly on the raw experimental data, allowing the reliability of the g(r) distribution functions to be verified. The agreement between theoretical and experimental spectra is satisfactory. A procedure to improve model g(r) functions on the basis of the short-range structural information provided by extended x-ray absorption fine structure data is proposed.