Temperature dependence of EXAFS for bromide ions in solution

Extended X-ray absorption fine structure (EXAFS) spectra have been obtained for bromide ions in water, 2,2,2-trifluoroethanol, ethylene glycol 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, σ2, and the third-order cumulants, C3. The potential-energy curves for the Br–—O interaction were obtained from the analysis of σ2/T and C3/T2 by using the diatomic chain model with a first-principle calculation. A correlation was found between the anharmonicity in the Br–—O interaction and the Mayer-Gutmann acceptor number of the solvent.