Chem. J. Chinese Universities ›› 2021, Vol. 42 ›› Issue (6): 1855.doi: 10.7503/cjcu20200866

• Physical Chemistry • Previous Articles     Next Articles

Vibrational Density of States Analysis of Proton Hydration Structure

ZENG Yonghui, YAN Tianying()   

  1. Institute of New Energy Material Chemistry,School of Materials Science and Engineering,Nankai University,Tianjin 300350,China
  • Received:2020-12-15 Online:2021-06-10 Published:2021-06-08
  • Contact: YAN Tianying E-mail:tyan@nankai.edu.cn
  • Supported by:
    the National Natural Science Foundation of China(21573112)

Abstract:

Proton transfer(PT) is a very important basic reaction process in chemical reactions. It is important for understanding the dynamic process of biology and the development of proton fuel cells. In the work, the hydration structure of proton and the dynamic response of the hydration structure involved in the PT process in aqueous solution were studied in detail by the molecular dynamics simulation using multistate empirical valence bond(MS-EVB) model. Based on the theoretical framework of MS-EVB model, the proton hydration structure mainly exists in the form of H9O4+(Eigen) or the intermediate of H5O2+(Zundel), and the Eigen is do-minant in these two structures. Density of state(DOS) spectra of different hydration structures in PT process show continuous broad absorption band in the range of 2000―3000 cm-1, which is mainly attributed to the Eigen contribution because there are no obvious characteristic peaks for a Zundel structure at the above frequency. The characteristic peak is closely related to the strong hydrogen bonding in the first hydration shell of hydronium ions in Eigen structure. Moreover, for Zundel structure, a relatively obvious shoulder appears at 1760 cm-1, which is attributed to the characteristic of PT mode, in agreement with previous study. Through the analysis of DOS spectrum associated with PT, we hope to improve the understanding on the continuous broad absorption band in the infrared spectrum of the dilute acid solution, and the microscopic dynamical characte-ristic of PT in the aqueous solution.

Key words: Proton transfer, Hydration structure, Multistate empirical valence bond(MS-EVB) model, Molecular dynamics simulation, Vibrational density of state

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