COMBINED MULTI-RANGE INTERPOLATED POTENTIAL FOR MD SIMULATIONS

摘要

The description of loosely bound systems is often a difficulty for quantum interaction models used in Molecular Dynamics (MD) simulations. On the other hand, a wide range of semi-classical or classical potentials (like polarization, Van Der Waals and Coulomb potentials) exists to model the interaction of atoms at large distances, outside the chemical bonding range. The method of Combined Multi-Range Interpolation (CMRI), proposed in the current work, allows to effectively interpolate the total energy as a function of atomic positions {R_i} between the cases of validity of bonded (f.e. quantum-chemical) description at small interatomic distances and classical description at large interatomic distances. The interpolation algorithm is a separability scheme which is automatic for any set of {R_i} and produces smooth total energy function and analytic forces. The method can be used to simulate the evolution of large systems consisting of bound and non-bound parts with breaking and forming of chemical bonds in the course of the simulation. Examples are: reactions in gaseous phase, injection of clusters onto surfaces, etc. The method can also be applied to smoothly switching between different quantum descriptions, e.g. different basis sets in case of highly heterogeneous system.