Abstract's Details

Comparison between Liquid Water, Simple Liquids and Alkali Halide Solutions Studied by Small Angle X-ray Scattering
Abstract ID	MAT-18
Presenter	Congcong Huang
Presentation Type	Poster
Full Author List	C. Huang (1), D. Nordlund (1), M. Niebuhr (1), T. Weiss (1), A. Nilsson (1)
Affiliations	(1) Synchrotron Radiation Laboratory, MS 69, 2575 Sand Hill Road, Menlo Park, CA, USA
Category	Materials Science
Abstract	Earlier x-ray absorption spectroscopy (XAS) and x-ray emission spectroscopy (XES) studies of liquid water observed that water can be understood as a two-state component system, i.e. symmetrical double donor configurations (ice-like) and asymmetrical single-donor configurations (ring or chain like). The further question is whether these two components are separated spatially on a nanometer length scale. One possibility, based on the mixture model, is that regions with near-symmetrical configurations are equilibrated in a homogeneous “sea” of asymmetrical configurations. Our recent small-angle x-ray scattering (SAXS) study supplies evidence favoring such a phase separation within liquid water. We observed an unanticipated increase of scattering intensity at very low momentum transfers Q, which disappears gradually as temperature increases from 5 to 80 degree C. Interestingly, the carbon tetrachloride solution doesn’t exhibit this abnormal low-Q enhancement within a similar temperature range. Moreover, it was found that the slope of SAXS curves at low Qs varies significantly in the presence of ions in alkali halide aqueous solutions.
Footnotes
Funding Acknowledgement	SSRL is supported by the DOE Office of Basic Energy Sciences. The SSRL Structural Molecular Biology Program is supported by the NIH National Center for Research Resources, Biomedical Technology Program and by the DOE Office of Biological and Environmental Research.