The research was the first to apply a technique called X-ray absorption spectroscopy to the local structure of water. The technique, developed by SSRL, among other laboratories, bombards a material with X-rays that are finely tuned to excite particular electrons in a molecule's structure. Careful measurement of the scattered radiation reveals the motions of the excited electrons, which, in turn, reveal what bonds molecules are forming. The experiments used intense X-ray sources at the Argonne National Laboratory and the Lawrence Berkeley National Laboratory, both of which are DOE facilities.

The team is now working on several projects to extend their results. ''We want to study water in a whole range of pressures and temperatures,'' Bergmann says. SPEAR3, SSRL's newly upgraded, state-of-the-art X-ray source that formally opened Jan. 29, would be the ideal place for that. ''We propose to build a new facility at SPEAR3 where the structure of water would be a large part of the scientific drive,'' he says.

''Water covers the majority of the Earth's surface, is present in all forms of life and is perhaps the most important natural resource for humanity. Despite its familiarity and years of rigorous study, water can still yield remarkable surprises,'' says Patricia Dehmer, director of the DOE Office of Basic Energy Sciences. ''This collaboration ... has given a new understanding of the molecular bonding in liquid water.''

In addition to Nilsson and Bergmann, the other SLAC scientists included in the five-year collaboration are Philippe Wernet (first author of the paper, now at the BESSY laboratory in Berlin), Hirohito Ogasawara and Lars Naslund.

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Contact: Neil Calder
Neil.Calder@slac.stanford.edu
650-926-8707
Stanford University
2-Apr-2004