Acta Phys. -Chim. Sin. ›› 2016, Vol. 32 ›› Issue (3): 647-655.doi: 10.3866/PKU.WHXB201601042

• ARTICLE • Previous Articles     Next Articles

Molecular Dynamics Simulation on the Structure and Thermodynamics of Molten LiCl-KCl-CeCl3

Tao JIANG1,Ning WANG1,Chang-Ming CHENG1,Shu-Ming PENG1,*(),Liu-Ming YAN2   

  1. 1 Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang 621999, Sichuan Province, P. R. China
    2 Department of Chemistry, College of Sciences, Shanghai University, Shanghai 200444, P. R. China
  • Received:2015-10-28 Published:2016-03-04
  • Contact: Shu-Ming PENG E-mail:pengshuming@caep.cn
  • Supported by:
    the Major Research Plan of the National Natural Science Foundation of China(91426302);National Natural Science Foundation of China(21301163)

Abstract:

The structure and thermodynamics of CeCl3 in molten LiCl-KCl-CeCl3 mixtures were studied by molecular dynamics simulation. The relationship formulas of temperature and density, and composition and density were obtained. The first peak for the gCe-Cl(r) radial distribution function was located at 0.259 nm and the corresponding first coordination number of Ce3+ was ~6.9. This inconsistency between molecular dynamics and experimental data could be attributed to the fact that our values were obtained for molten LiCl-KCl-CeCl3 mixtures, in which the interaction between Ce3+ and Cl- was more powerful than that in pure molten CeCl3. Regarding self-diffusion coefficients, the activation energy of Ce3+ was 22.5 kJ·mol-1, which is smaller than that of U3+ (25.8 kJ·mol-1). Furthermore, the pre-exponential factors for Ce3+ decreased from 31.9×10-5 to 21.8×10-5 cm2·s-1 as the molar fraction of Ce3+ increased from 0.005 to 0.05. This means that in the unit volume (ignoring the change of total volume), the diffusion resistance of Ce3+ increased, and the self-diffusion ability decreased, which resulted in a decrease of pre-exponential factors.

Key words: LiCl-KCl-CeCl3, Structure, Thermodynamics, Molecular dynamics, Diffusion coefficient

MSC2000: 

  • O641