Hydration structure and polarization of heavy alkali ions; A First principles molecular dynamics study of Rb and Cs

重アルカリイオンの水和構造と分極; RbとCsの第一原理分子動力学による研究

池田 隆司; Boero, M.*

Ikeda, Takashi; Boero, M.*

常温常圧下の水中でのRbとCsの水和構造と分極を第一原理分子動力学を用いて調べた。ワニエ関数に基づいた系統的な電子状態の解析からイオンの第一水和殻内の水分子のもつ双極子モーメントが原子番号とともにわずかに増大することがわかった。また、重アルカリイオン、特にCsの分極が非対称な水和構造を安定化させる傾向があることがわかった。

Hydration structure and polarization of Rb and Cs in liquid water at ambient conditions were studied by first principles molecular dynamics. Our systematic analysis of the relevant electronic structures, based on maximally localized Wannier functions, revealed that the dipole moment of HO molecules in the first solvation shell of the ions slightly increases with increasing the atomic number. We also found that the polarization of heavy alkali ions, particularly Cs, tends to stabilize a peculiar asymmetric hydration structure with relevant consequences in the extraction of the harmful Cs resulting from nuclear wastes.