Abstract

Quantum Monte Carlo methods are first-principle approaches that provide a stochastic solution to the interacting many-electron Schroedinger equation. While the methods are routinely employed to predict accurate total energies of relatively large systems, a major limitation has been the lack of efficient and reliable schemes to obtain energy derivatives. Here, we present a simple and general formalism we have recently developed to overcome this limitation and compute interatomic forces and other derivatives in quantum Monte Carlo with the same numerical scaling as computing the energy alone in the sampling process. We demonstrate the computational gain on linear polyenes up to C60H62 and further discuss the combination of our optimization scheme with different choices of many-body wave functions for the fast and accurate computation of structural properties in quantum Monte Carlo.