Calculation The Molecular Electrostatic Potential On Molecular Face Contour By ABEEM Model

Most of physical and chemical properties of molecules are closely related with the electrostatic potential. Molecular electrostatic potential refers to the potential energy of electrostatic interaction when the molecules are somewhere in space. The interaction between molecules can be expressed by the electrostatic potential.This paper used ABEEMσπ model calculation the charges which was regressed to atomic. The low energy structures of dimer water molecular were optimized by MP2/aug-cc-PVDZ and the structures of imidazole、pyrazole、thiophene、thiazole and isothiazole were optimized by MP2/6-311++G(3df,3pd). Calculation the molecular electrostatic potential by ABEEM model with the in-home program of Fortran, then compared with the ab initio method to calculate the electrostatic potential, and discussed the results of calculation. Projecting the results onto the electronic density isosurface and the molecular face contour. The software MATLAB was used to draw the distribution map of electrostatic potential of two method and compared them. By the comparison, the ABEEM model method not only can calculate the molecular electrostatic potential fast, but also the results well with the ab initio results. These coincides can demonstrate the ABEEM method in this paper is visual and intuitive.From the distribution map of electrostatic potential, we can obviously find that using isosurface of electronic density which is0.001a.u. or0.002a.u. in isovalue scale to describe the distribution of electrostatic potential, the shape of molecular was slightly larger, and the distribution of electrostatic potential charge clearly. While using molecular face contour to describe the distribution of electrostatic potential is better, and we can obtained the distribution of electrostatic potential characteristics, which is based to discuss some relevant properties. These conclusions support Yang et al, who proposed the molecular face contour was intrinsic and unique. This lays the foundation for the calculation of macro molecular electrostatic potential.