A DIFFERENTIAL ANOMALOUS X-RAY-SCATTERING STUDY AND REVERSE MONTE-CARLO SIMULATION OF A HIGHLY CONCENTRATED-SOLUTION OF ZINC BROMIDE IN WATER

A differential anomalous X-ray scattering (DAS) study of the structure of a highly concentrated aqueous solution of zinc bromide (19.5 molal ) is presented Synchrotron radiation was used for four diffraction exp eriments at photon energies of 12500 eV, 13462 eV (Br-K-edge) and 9000 eV, 9650 eV (Zn-K-edge) The dispersion corrections were calculated fr om the photoabsorption coefficients determined by absorption experimen ts. The differential structure factor and its Fourier transform, the d ifferential atom pair correlation function, were obtained after an int ricate data evaluation procedure The technique of the Reverse Monte Ca rlo simulation, which requires no intermolecular potential as input, w as used to elucidate the microscopic structure of zinc bromide solutio n, which resembles the crystal structure of ZnBr2 . H2O, in which the zinc ion is coordinated tetrahedrally with two bromine ions and two wa ter molecules.