We all know that water is a complex and vital component on earth. Yet in spite of its familiarity and simple structure, water exhibits many unusual features. For more than a century, scientists have focused on the study of water, trying to better explain its composition. An international team of researchers, led by an expert from the University of Hiroshima, has developed a process that allows them to reproduce a high-density x-ray emission spectroscopy (XES) in liquid water.
A study that helps improve the understanding of water structure, led by Osamu Takahashi, associate professor at Hiroshima University’s Graduate School of Advanced Science and Engineering, was published February 25 in Physical Review Letters.
Over the years, as scientists have worked to better understand the structure of liquids, some have studied water using a two-dimensional model. Some scientists, in many different fields, have used a similar, continuous liquid model. XES has proven to be a useful tool for researchers studying materials whose features are unique.
For more than a decade, scientists have debated how to interpret the XES spectra of liquid water. To solve this problem a team of researchers performed molecular dynamics to model the structure of liquids. Their next step was to measure the XES spectra of liquid water, using the basic principles of quantum mechanical calculations.
The team was able to reproduce the dual element 1b1, which is present in the x-ray spectroscopy of the liquid fluid x-ray. They examined different effects, such as geometry and strength, to determine the XES spectra shape.
Embracing the imitation of ancient molecular dynamics, the team was able to build a water structure in the liquid phase. In these simulations, the researchers worked at different temperatures with bond lengths and suspended water molecule angles. In the exhibition they cited, the researchers were able to reproduce features, such as double the peaks of the 1b1 region, that earlier scientists had previously observed in XES experiments.
To better understand the features they observed, the team of researchers separated the XES exhibition into a number of different hydrogen bonds. They saw a double point in the XES spectra on all the different types of hydrogen bonds they had studied.
After examining the spectra associated with hydrogen bonds, the team studied the effect of vibration modes with an exciting effect on the XES view. They found nine independent vibrations and studied their effects on spectra.
Researchers have been able to successfully reproduce the XES spectrum of liquids by examining the effects of saturated vibrations, O-H stretching, bending, and rotating mechanisms. They define both temperature and isotope dependence by examining the hydrogen-bond configuration next to the excited water molecule and the dynamic energy generated by the core-hole. “Our process is standard and can work in a variety of systems related to conditions including liquid water,” Takahashi said.
The team hopes that its research could help resolve some of the long-standing debates regarding the definition of a liquid body. Looking to the future, researchers see a variety of potential applications for their process. “The development of new materials such as battery-operated electrodes, organic matter such as artificial blood vessels, and functional polymers such as water treatment membranes may be interesting projects, related to the structure of liquid fluids,” Takahashi said.
The research team, led by Osamu Takahashi, included Ryosuke Yamamura from the Department of Chemistry, University of Hiroshima, Japan; Takashi Tokushima from MAX IV Laboratory, Lund University, Sweden; and Yoshihisa Harada from the Institute for Solid State Physics and Synchrotron Radiation Research Organization, University of Tokyo, Japan. The Japan Society for the Promotion of Science sponsored this study.
