Analytical MP2 Energy Gradients Derived By Low-scaling Orbital-Specific Virtual (OSV) Ansaetz

Abstract

In recent years, efficient linear scaling gold-standard correlated electronic structure methods have been developed to greatly reduce the computational cost by orders of magnitude and applied to treat systems containing hundreds of atoms as well as condensed materials. The success of these methods opens up a new opportunity to make these high-level methods available for accelerating geometrical structure search and even molecular dynamics simulations with unprecedented gold-standard accuracy that was considered impossible previously. Along this line, we have developed a formulation and algorithm of the analytical energy gradients for the orbital-specific virtual-based second-order Moller–Plesset perturbation (MP2) scheme, which explicitly incorporates the relaxation of OSV orbitals due to a perturbation. In this presentation, we will have a general discussion on the algorithm and methodology in our recent implementation with an analysis of formal computing complexity, and access the numerical performance of OSV-MP2 for structure optimisation. As a proof-of-principle study, we have also explored the possibility to drive Born-Oppenheimer molecular dynamics (BOMD) simulations by our OSV-MP2 analytical energy gradient techniques.