Parametrically Temperature-Dependent Potential for Molecular Dynamics Simulation of Uranium Dioxide Properties
Nagornov Yuri,
Katz Andrey
Issue:
Volume 1, Issue 3, November 2013
Pages:
18-26
Received:
5 December 2013
Published:
20 December 2013
Abstract: The present paper justifies the application of the temperature-dependent potential to the molecular dynamics method through the example of uranium dioxide. Substantiation of the temperature dependence of interatomic potential is carried out based on the Newton quantum equation. Mean force can be represented as a sum of derivative of potential at the average atomic coordinate and the summand that depends on square dispersion of the coordinate depending on the temperature of the crystal. Temperature dependence of potential is introduced as linear slightly varying functions of the Coulomb plus Buckingham potential. The selection of parameters of potential was done at three temperature values: the initial temperature and temperatures of phase transitions – 2670 and 3120K, parameters of potentials for all other temperatures were found by approximation. We calculated temperature dependencies for the lattice constant, enthalpy, heat capacity under constant pressure and volume. Application of the temperature-dependent potential well complies with experimental data; the difference did not exceed 0.5% in the entire temperature range of 300-3120K.
Abstract: The present paper justifies the application of the temperature-dependent potential to the molecular dynamics method through the example of uranium dioxide. Substantiation of the temperature dependence of interatomic potential is carried out based on the Newton quantum equation. Mean force can be represented as a sum of derivative of potential at th...
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