The domain Green’s function method

An implementation of the domain Green’s function Monte Carlo algorithm is described. Unlike the short time approximation, the method is variational and exact within the limits of the fixed node approximation. The systems investigated include LiH, Be in the ground and first excited states, a study of the C2v insertion pathway of Be into H2, and H2O. We predict a barrier of 0.190 hartree for the insertion reaction with a statistical accuracy of ±2%. Better than 90% of the correlation energy is recovered in each case, which makes these some of the most accurate computations to date.