Based on Quantum Chemistry Method to Calculate Intermolecular Interactions and Molecular Dynamics Simulations of Carbon Tetrachloride Fluids
Date Issued
2008
Date
2008
Author(s)
Huang, Shou-Cheng
Abstract
We have calculated the interaction potentials of Carbon Tetrachloride dimers using the Hatree-Fock (HF) Self-Consistent theory, the correlation-corrected second-order Møller-Plesset (MP2) perturbation theory and the density functional theory (DFT). The main of HF calculations yield repulsive potentials, the MP2 calculations yield totally van der Waals interactions. The basis set number will occur to large influence to the HF calculations but the opposite results to MP2 calculations. Also compare the basis set superposition error (BSSE) corrected and uncorrected results. At last, we use eighty species of exchange-correlation functional to perform DFT calculations and the compare the results of MP2.fter complete the quantum chemistry calculations, we use 4 Sites Lennard-Jones potential Model to curve fitting with ab initio calculations. By the 4 Sites Model, we can get the parameters and construct a force field to pave a way for the next step of molecular dynamics simulations. To simulate the structure properties, the dynamics properties and the diffusion coefficient of liquid carbon tetrachloride, we perform NVT ensemble of molecular dynamics simulations. We compare the results with experiments from several references and the results are acceptable for us. These results demonstrate that quantum chemistry calculated intermolecular interaction is very well which can reproduce the molecular dynamics simulation results with good accurately. Besides, we also simulate the diffusion coefficient of liquid methane to understanding the effect of the number of atoms of diffusion coefficient. Finally, we discuss the relationship of parameter between two different potentials. For the most part, the fitting results control the key point of molecular dynamics simulation results, so we can improve the fitting results by using the way of parameters transformation.
Subjects
Carbon Tetrachloride
Hatree-Fock (HF) approximation
Møller-Plesset (MP) perturbation theory
Density Function Theory (DFT)
Radial distribution function (RDF)
Velocity autocorrelation function (VAF)
Diffusion coefficient
Molecular Dynamics Simulations
Gaussian 03 package
Type
thesis
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