A Building For AMOEBA Polarization Force Fields Of Metals Pt And Pd

The article first gives a brief introduction of the molecular field and molecular dynamics method. The efficiency of the molecular dynamics simulation is mainly determined by the quality of the force field. Traditional force field in the charge processing does not take into account the impact of the charge polarization and charge transfer, just treats it as a fixed charge. However, in many systems the polarization phenomenon is widespread. For example there are a large number of polar groups and the hydrogen bond network in a protein molecule. Mutual polarization also exists between the water molecules and proteins in solution. So the development of polarized force field is necessary. In recent years, the polarization force field has developed rapidly. Especially Ren and Ponder founded AMOEBA polarization force field. Compared to traditional force field it takes into account the polarization effect of the charge, dipole moment and the quadrupole moment to describe the electrostatic interactions. In this article we have discussed the current status of polarization force field, and focused on AMOEBA polarization force field and its application. In the field of catalysis, transition metal having good catalytic properties and stability Pt, Ni and Pd are the most important in them. They have a very significant value in industry. There is no Pt and Pd AMOEBA force field. In order to study their catalytic properties, we constructed the AMOEBA polarization force fields about metals Pt, Pd and common small organic molecules. In the specific study, through compared calculation results between AMOEBA force field and QM (Quantum Chemistry Method), one can discover the results are quite different. It reminded the effect of charge‐transfer energy correct is considered in the force field, and then the force field parameters obtained by comparison with results of QM. The calculated results were in good agreement with those of QM. In the paper, we obtain the parameters of the Pt, Pd, and several small organic molecules by the means of calculations and parameter fitting, and it means the new force fields are constructed. Next, In order to test the new force field parameters, we carried out molecular dynamics simulations for two systems, combined with RDF, adsorption capacity and the diffusion coefficient of polarization force field inspection. The first system is Pt and methane, the other one is Pt and ethane. During the dynamics simulations, we have tested the two force fields. One considered the charge transfer energy correction and the other does not. The result shows not too much differences. Staying have the relevant experimental data can better compare and verify the new field.