Molecular dynamics of polarizable point dipole models for molten NaI. Comparison with first principles simulations

Vicente Bitrián ,Olga Alcaraz ,Joaquim Trullàs

doi:10.1051/epjconf/20111502009

Abstract

Molecular dynamics simulations of molten NaI at 995 K have been carried out using polarizable ion models based on rigid ion pair potentials to which the anion induced dipole polarization is added. The polarization is added in such a way that point dipoles are induced on the anions by both local electric field and deformation short-range damping interactions that oppose the electrically induced dipole moments. The structure and self-diffusion results are compared with those obtained by Galamba and Costa Cabral using first principles Hellmann-Feynman molecular dynamics simulations and using classical molecular dynamics of a shell model which allows only the iodide polarization

Highlights

Polarization effects are of great interest in understanding the structure and dynamics of ionic systems
Galamba and Costa Cabral [7] have carried out first principle HellmanFeynman molecular dynamics (HFMD) of molten NaI at temperature close to the melting point, and compared the structure and self diffusion results with those obtained using classical molecular dynamics of the shell models (SM) proposed by Dixon and Sangster [1]
The main differences between the structures predicted by the rigidion models (RIM), polarizable point dipole models (PPDM), SM and HFMD for molten NaI concern the cation-cation correlations

Summary

Introduction

Polarization effects are of great interest in understanding the structure and dynamics of ionic systems. Galamba and Costa Cabral [7] have carried out first principle HellmanFeynman molecular dynamics (HFMD) of molten NaI at temperature close to the melting point, and compared the structure and self diffusion results with those obtained using classical molecular dynamics of the SM proposed by Dixon and Sangster [1]. This SM allows only the iodide polarization, and the parameter values of the rigid ion pair potential are those given in Table 2-I of reference [1]. In this paper we compare the structure and self-diffusion results for the PPDM, as well as for the RIM on which the former is constructed, with those for HFMD and SM obtained by Galamba and Costa Cabral

Simulated models

Results

Ionic transport properties