Extended X-ray absorption fine structure spectroscopy measurements and ab initio molecular dynamics simulations reveal the hydration structure of the radium(II) ion
Akiko Yamaguchi, Kojiro Nagata, Keita Kobayashi, Kazuya Tanaka, T. Kobayashi, Hajime Tanida, Kojiro Shimojo, Tetsuhiro Sekiguchi, Yui Kaneta, Shohei Matsuda, Keiichi Yokoyama, Tsuyoshi Yaita, Takashi Yoshimura, Masahiko Okumura, Yoshio Takahashi
Abstract
molecular dynamics (AIMD) simulation. The EXAFS experiment showed that the coordination number and average distance between radium ion and the oxygen atoms in the first hydration shell are 9.2 ± 1.9 and 2.87 ± 0.06 Å, respectively. They are consistent with those obtained from the AIMD simulations, 8.4 and 2.88 Å. The AIMD simulations also revealed that the water molecules in the first hydration shell of radium are less structured and more mobile than those of barium, which is an analogous element of radium. Our results indicate that radium can be more labile than barium in terms of interactions with water.