Author/Authors :
Tokushima، نويسنده , , T. and Harada، نويسنده , , Y. and Takahashi، نويسنده , , O. and Senba، نويسنده , , Y. and Ohashi، نويسنده , , H. and Pettersson، نويسنده , , L.G.M. and Nilsson، نويسنده , , A. and Shin، نويسنده , , S.، نويسنده ,
Abstract :
The structure of liquid water is presently under intense debate. We summarize the historical development of the present description of water and the controversy surrounding the X-ray absorption spectroscopy (XAS) study of Wernet et al. [Ph. Wernet et al., Science 304 (2004) 995]. In order to provide further insight into the connection between X-ray spectroscopy and the structure of the hydrogen bonding network, we report new data comprising high resolution oxygen K-edge X-ray emission spectra (XES) of liquid water. We observe two distinct narrow lone-pair derived peaks, assigned, respectively, to tetrahedral and strongly distorted hydrogen-bonded species; the assignment is based on comparison with ice and gas phase spectra, temperature dependent measurements, excitation energy dependence and theoretical simulations. We estimate a 2:1 ratio between distorted and tetrahedral species at room temperature and discuss what this implies in connection to the previous XAS study and in terms of liquid water structure.
