Neutron and X-ray diffraction studies of aqueous rubidium bromide solutions

A systematic study, combining neutron (Budapest Research Reactor, Hungary) and X-ray (Hasylab, Germany) diffraction, has been conducted on aqueous solutions of RbBr at two concentrations. Total structure factors (neutron and X-ray) have then been modeled by applying the Reverse Monte Carlo technique. Partial pair correlation functions, numbers of nearest neighbours and angle distributions characterizing the first coordination spheres have been evaluated from sets of particle coordinates obtained from the computer modeling. Based on these quantities, the network of water molecules appears to be increasingly distorted with increasing salt concentration. Generally, the hydration shells of the ions, particularly of the cation, are found to be rather diffuse.