A general approximation method for accurate evaluation of the intermolecular potential parameters by using density functional theory

Abstract

In this work, a new approach is developed and presented for determining the intermolecular potential parameters from intermolecular interaction energy data obtained using the Density Functional Theory (DFT) method over a different basis set. The proposed method in this work is especially useful for the evaluation of all intermolecular potential parameters of arbitrary atoms and molecules. The method developed in this study can be used for evaluating some thermodynamic properties of molecules. In general, this approach has great advantages for the determination of all types of potential parameters of atoms and molecules. As an application, the Lennard-Jones (12-6) and Morse potential parameters of the Ga(CH3)3 molecule have been determined first by using the basis set with density functional method (DFT/B3LYP) method over the 6-31G basis set. The speed of sound, heat capacities, and second virial coefficient over the Lennard-Jones (L-J) (12-6) potential of Ga(CH3)3 have been calculated. The results obtained for the speed of sound and heat capacities of Ga(CH3)3 are compared with theoretical and experimental data. The results indicate that our data are in good agreement with data from the literature.