Acta Phys. -Chim. Sin. ›› 2011, Vol. 27 ›› Issue (02): 379-387.doi: 10.3866/PKU.WHXB20110233

• THEORETICAL AND COMPUTATIONAL CHEMISTRY • Previous Articles     Next Articles

Structures and Binding Energies of Sr2+/Ba2+-Water Systems by Ab initio and ABEEM/MM Method

LIU Yan1, WANG Fang-Fang1,2, YU Chun-Yang1, LIU Cui1, Gong Li-Dong1, YANG Zhong-Zhi1   

  1. 1. School of Chemistry and Chemical Engineering, Liaoning Normal University, Dalian 116029, Liaoning Province, P. R. China;
    2. School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022, P. R. China
  • Received:2010-10-07 Revised:2010-12-02 Published:2011-01-25
  • Contact: Gong Li-Dong E-mail:gongjw@lnnu.edu.cn
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (20633050, 20703022, 21011120087) and Foundation of Education Bureau of Liaoning Province, China (2009T057).

Abstract:

Hydrated clusters of Sr2+/Ba2+(H2O)n (n=1-6) were investigated by the ab initio method and the ABEEM/MM fluctuating charge molecular force field. ABEEM/MM potential functions of cation-water interactions were constructed based on the stable structures and binding energies of the hydrated clusters were obtained. The results from ABEEM/MM are consistent with those from the ab initio method. Furthermore, Sr2+ and Ba2+ aqueous solutions were studied by ABEEM/MM molecular dynamic simulations. Results show that for the Sr2+ aqueous solution the first and second peaks of the SrO radial distribution function (RDF) are located at 0.257 and 0.464 nm, respectively. The coordination numbers of the water molecules for the first and second hydration shells are 9.2 and 11.4, respectively. For the Ba2+ aqueous solution, the first and second peaks of the BaO RDF are located at 0.269 and 0.467 nm, respectively. The coordination numbers of water molecules for the first and second hydration shells are 9.9 and 12.4, respectively. These results also show good consistency with experimental observations and other theoretical simulations. Compared with the external water molecules, the water molecules in the first hydration shell are evidently polarized by the cation and their O―H bond lengths are stretched while the HOH bond angles are found to be reduced.

Key words: Hydrated metal cation cluster, Ion solvation, Ab initio method, ABEEM/MM fluctuating charge molecular force field, Interaction energy

MSC2000: 

  • O641