Cs+水合结构的密度泛函理论计算研究

Hydration Structure of Cs+ with Density Function Theory

中文关键词:  [Cs(H₂O)_n]⁺(n=1~15)水合团簇  配位数  水合离子  红外光谱

英文关键词:[Cs(H₂O)_n]⁺(n=1-15) hydrated clusters  Coordination number:Hydrated ions  IR spectra

中文摘要:

      基于密度泛函理论在ωB97XD/gen def2-tzvp基组水平上对 [Cs(H₂O) n]⁺(n=1~15)水合团簇结构的振动光谱进行了研究。研究表明,随着水分子数的增加,在气相和液相中,八配位的Cs⁺ 水合团簇是最稳定的；随着水分子数的增加,Cs-O键长增大,Cs⁺上的电荷密度减小。当水分子数大于11时,Cs-O键长和Cs⁺上的电荷密度变化很小。O(H₂O)-O(H₂O)距离、∠O(H₂O)-Cs-O(H₂O)°统计结果表明,15个水分子足以形成Cs⁺的近似饱和水合层。此外,红外光谱显示[Cs(H₂O)_n]⁺水合团簇中O-H伸缩振动随着水分子数的增加而发生变化,由此可以作为鉴别水合层位置的一种参考方法。

英文摘要:

      The density functional theory with ωB97XD/gen def2-tzvp was used to study the hydration structure of[Cs(H₂O)_n]⁺(n=1-15) clusters. The results show that with increasing of the water molecules,eight-coordinated water molecules for Cs⁺ clusters is the most stable structure in gas or aqueous phase. The distances of Cs-O increases while the charge density of Cs⁺ decline with increasing of water molecules. When there are more than eleven water molecules around Cs⁺,the distance of Cs-O and Cs⁺ charge density changes a little.The statistical results of the average distance O-O,the∠O-Cs-O° of [Cs(H₂O)_n]⁺(n=1-15) clusters illustrates that fifteen water molecules are enough to form an approximated complete hydration shell for Cs⁺. Furthermore,IR spectra of [Cs(H₂O)_n]⁺(n=1-15) clusters presents that O-H stretching vibration changing with increasing water molecules,thus it can be a reference to identify the position (hydration shell) of water molecules in hydration clusters.