QUANTUM MONTE CARLO FOR NONCOVALENT INTERACTIONS: A TUTORIAL REVIEW

Theoretical predictions of noncovalent interaction energies, important e.g. in drug-design or design of hydrogen-storage materials, belong to grand-challenges of contemporary quantum chemistry. In this respect, quantum Monte Carlo (QMC) approaches based on the fixed-node diffusion Monte Carlo (FN-DMC), provide a promising alternative to the commonly used coupled-cluster (CC) methods for their benchmark accuracy, massive parallelism, and favorable scaling. The current tutorial review provides a brief state-of-the-art overview of QMC in ab initio quantum chemical calculations of noncovalent interaction energies, covering recent advances in this field: computational protocols based on FN-DMC with single Slater determinant guiding functions, range of their applicability, tradeoffs, analysis of the success of this simple approach in weakly bound molecular complexes and other related topics. The review is supplemented by an easy-to-grasp practical and detailed tutorial on calculation of molecular interaction energies using a free quantum chemical software (GAMESS, QWalk). This part thus provides an accessible starting point for the readers interested in practical calculations.