物理化学学报 >> 2008, Vol. 24 >> Issue (03): 497-501.doi: 10.3866/PKU.WHXB20080326

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高斯多峰拟合在径向分布函数中的应用

冯望生; 房艳; 徐继香; 房春晖; 贾全杰; 王焕华; 姜晓明   

  1. 中国科学院青海盐湖研究所, 西宁 810008; 中国科学院高能物理研究所, 北京 100049; 中国科学院研究生院, 北京 100049
  • 收稿日期:2007-09-25 修回日期:2007-12-03 发布日期:2008-03-10
  • 通讯作者: 房春晖 E-mail:fangch@isl.ac.cn

Application of Gaussian Multi-Peak Fitting to Radial Distribution Function

FENG Wang-Sheng; FANG Yan; XU Ji-Xiang; FANG Chun-Hui; JIA Quan-Jie; WANG Huan-Hua; JIANG Xiao-Ming   

  1. Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xining 810008, P. R. China; Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, P. R. China; Graduate School of the Chinese Academy of Sciences, Beijing 100049, P. R. China
  • Received:2007-09-25 Revised:2007-12-03 Published:2008-03-10
  • Contact: FANG Chun-Hui E-mail:fangch@isl.ac.cn

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摘要： 利用同步辐射X射线散射法测定了盐水摩尔比分别为1:30和1:14的Rb2SO4和Cs2SO4的水溶液结构. 通过对散射数据的处理, 获得了两种溶液的径向分布函数. 采用多峰拟合中的Gaussian法对径向分布函数中金属离子第一水合层附近的叠加峰进行了处理, 多峰拟合结果与实验结果吻合得很好. 通过将拟合数据与已报道的溶液结构和晶体结构对比分析, 确定了每个拟合峰的归属.多峰拟合结果分析表明, Rb+和Cs+第一水合层配位数为6, 为变形的八面体构型. 两种溶液中都存在着金属离子和硫酸根离子接触离子对: Rb—S 和Cs—S 的特征距离分别为0.407和0.427 nm. 研究证实, 多峰拟合有助于阐述溶液中离子的水合结构.

关键词: 同步辐射, X射线散射, 径向分布函数, 多峰拟合, 水合结构

Abstract: Aqueous structures with salt to water molar ratios of 1:30 (Rb2SO4) and 1:14 (Cs2SO4) were measured by X-ray scattering of synchrotron radiation. The radial distribution functions (RDF) of the two example solutions were obtained by analyzing the scattering data. RDF overlapped peaks near the first hydration shell were dealt with Gaussian multi-peak fitting. The fitting data were agreed well with the experimental data. The adscription of every fitting peak was determined by comparing the fitting data with hydrated ion and crystal structure data reported in literatures. The analysis of fitting result indicates that the coordination number of Rb+ and Cs+ is six in the first hydration shell, and the spatial structures are both distorted octahedrons. The contact ion pairs of metal ions with sulphate ion exist in two solutions where the characteristic distances of Rb—S and Cs—S were determined to be 0.407 and 0.427 nm, respectively. The study demonstrated that multi-peak fitting was useful for interpreting the hydrated structure of ions.

Key words: Synchrotron radiation, X-ray scattering, Radial distribution function, Multi-peak fitting, Hydrated structure

MSC2000: 

  • O645