TEMPERATURE-DEPENDENCE OF EXAFS FOR BROMIDE LONE IN SOLUTION

Extended X-ray absorption fine structure (EXAFS) spectra have been obt ained for bromide ions in water, 2,2,2-trifluoroethanol, ethylene glyc ol and n-butyl alcohol at various temperatures. Cumulant analysis was applied to the EXAFS data to determine the atomic distances of Br--O, the mean square relative displacements, sigma(2), and the third-order cumulants, C-3. The potential-energy curves for the Br--O interaction were obtained from the analysis of sigma(2)/T and C-3/T-2 by using the diatomic chain model with a first-principle calculation. A correlatio n was found between the anharmonicity in the Br--O interaction and the Mayer-Gutmann acceptor number of the solvent.