Fully self-consistent optimization of the Jastrow-Slater-type wave function using a similarity-transformed Hamiltonian

It has been well established that the Jastrow correlation factor can effectively capture the electron correlation effects, and thus, the efficient optimization of the many-body wave function including the Jastrow correlation factor is of great importance. For this purpose, the transcorrelated $+$ variational Monte Carlo (TC$+$VMC) method is one of the promising methods, where the one-electron orbitals in the Slater determinant and the Jastrow factor are self-consistently optimized in the TC and VMC methods, respectively. In particular, the TC method is based on similarity-transformation of the Hamitonian by the Jastrow factor, which enables the efficient optimization of the one-electron orbitals under the effective interaction. Through test calculations of some closed-shell atoms, He, Be, and Ne, we find that the total energy is in many cases systematically improved by using better Jastrow functions. We find that even a one-shot TC$+$VMC calculation, where the Jastrow parameters are optimized at the Hartree-Fock$+$VMC level, can yield partial benefits from orbital optimization. It is also suggested that one-shot TC$+$VMC can be a good alternative way for complex systems. Our study provides important insights for optimizing many-body wave function including the Jastrow correlation factor, which would be of great help for development of highly accurate electronic structure calculations.Comment: 19 pages, 8 figure

TC++: First-principles calculation code for solids using the transcorrelated method

TC++ is a free/libre open-source software of the transcorrelated (TC) method for first-principles calculation of solids. Here, the TC method is one of the promising wave-function theories that can be applied to periodic systems with reasonable computational cost and satisfactory accuracy. We present our implementation of TC++ including a detailed description of the divergence correction technique applied to the TC effective interactions. We also present the way to use TC++ and some results of application to simple periodic systems: bulk silicon and homogeneous electron gas.Comment: 56 pages, 2 figure