Ab initio molecular dynamics (AIMD): A new approach for development of accurate potentials

In this study a new approach is presented for the development of accurate potential energy hypersurfaces based on ab initio calculations that can be utilized to conduct molecular dynamics and Monte Carlo simulations to study chemical and mechanical properties at the atomistic level. The method integrates ab initio electronic structure calculations with the interpolation capability of multilayer neural networks. A sampling technique based on novelty detection is also developed to ensure that the neural network fitting for the potential energy spans the entire configuration space involved during the simulation. The procedure can be initiated using an empirical potential or direct dynamics simulation. The procedure is applied for developing the potential energy hypersurface for 5-atom clusters within a silicon workpiece. Ab initio calculations were performed using Gaussian 98 electronic structure program. Results for 5-atom silicon clusters representing the bulk and the surface structure are presented.