Scramble for hydrogen bond between light and heavy water (Press Release)
- Release Date
- 09 Nov, 2013
- BL07LSU (University-of-Tokyo Synchrotron Radiation Outstation)
- BL17SU (RIKEN Coherent Soft X-ray Spectroscopy)
University of Tokyo
RIKEN
Japan Synchrotron Radiation Research Institute (JASRI)
Key findings
• Revealing the validity of the mixture (micro-heterogeneity) model of liquid water by selective observation of hydrogen-bond-broken water molecules
• Highly sensitive detection of the difference in the degree of hydrogen bond*1 strength between light and heavy water
• Integration of vibrational and electronic spectroscopy of water for the clarification of the role of water in biological organisms and chemical reactions
The unique property of water, such as high boiling and melting point compared to molecules like non-metal hydride, or less density in solid form than in liquid form, are explained by an attractive force between water molecules, called 'hydrogen bond'. There are many proposed local structural models that describe the water network. Among them, a continuum model, where hydrogen bonds in water are distorted, broken and reformed continuously, but water itself is composed of a single component, or a mixture (micro-heterogeneity) model, where the network is considered as a mixture of various hydrogen bond configurations, are well known. However, the model that describes better the hydrogen bond property of liquid water, is still under debate. Associate Professor Yoshihisa Harada from Institute for Solid State Physics and Synchrotron Radiation Research Organization, The University of Tokyo, and Dr. Takashi Tokushima, Engineer of RIKEN (President, Ryoji Noyori), in collabration with an international research team including scientists from Hiroshima University, Japan Synchrotron Radiation Research Institute (JASRI), University of Iceland, Stockholm University and SLAC National Accelarator Laboratory have succeeded in revealing validity of the mixture (micro-heterogeneity) model by selective observation of hydrogen-bond-broken water molecules and in detecting with high sensitivity the difference in the degree of hydrogen bond strength between light (normal) water and heavy water (in which both hydrogen atoms have been replaced with deuterium) using soft X-ray resonant inelastic scattering at University-of-Tokyo Synchrotron Radiation Outstation Beamline BL07LSU*3 and RIKEN Coherent Soft X-ray Spectroscopy beamline BL17SU*4 of SPring-8*2. The results of this research are expected to lead to the clarification of the role of water in various chemical and catalytic reactions as well as water in biological organisms where hydrogen bond plays an important role. The research result was published in Physical Review Letters (online published date: 8 Nov. 2013). This work was supported by the Japan Society for the Promotion of Science (JSPS) through its Funding Program for World-Leading Innovative R&D on Science and Technology (FIRST) Program and by the Icelandic Research Fund. Publication: |
<<Figures>>
the soft X-ray emission spectrum in the multiple vibrational excitation region
and D2O and (b) HDO spectrum fitted by the sum of H2O and D2O spectra
<<Glossary>>
*1 Hydrogen bond
Widom line
Kumar PNAS104 9579 (2007)
Xu PNAS 102 16558 (2005)
Science 339 1302 (2013) Real time observation
PRB85 235149 (2012) distance dependence of delocalization of the electronic structure of CO.
*2 SPring-8
A large synchrotron radiation facility that generates the highest-quality synchrotron radiation, located in Hyogo prefecture, Japan. Owned by Riken, and operated by JASRI. The nickname SPring-8 is short for Super Photon ring-8 GeV. Synchrotron radiation refers to the strong and highly oriented electron magnetic waves generated when the orbit of electrons, accelerated to a near-light speed, is bent by magnetic field. Applications of the synchrotron radiation produced by SPring-8 includes nanotechnology, biotechnology and industrial use.
*3 University-of-Tokyo Synchrotron Radiation Outstation Beamline BL07LSU
One of the highest brilliant soft X-ray undulator beamline installed at the long straight section of SPring-8, constructed by the material science division of Synchrotron Radiation Research Organization, The University of Tokyo in May 2006. Three regular endstations of advanced spectrscopies are equipped and one free port is prepared for outside users. The proposals of the joint researches are accepted biannually.
*4 RIKEN Coherent Soft X-ray Spectroscopy beamline BL17SU
Soft X-ray undulator beamline constructed by RIKEN, aiming at the most advanced spectroscopies for promoting materials science. One of the regular station used in this research is dedicated to the study on the electronic structure of liquids and solutions under atmospheric pressure.
For more information, please contact: Dr. Takashi Tokushima (RIKEN) |
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