A new variational Monte Carlo trial wavefunction with directional Jastrow functions

The addition of a directional term to standard Jastrow functions was investigated in variational quantum Monte Carlo calculations for the LiH molecule using wavefunctions composed of Slater determinants combined with Padé and with Schmidt–Moskowitz functions. The recovery of correlation energy was improved significantly by the added term: from 52% to 71% for the Padé function and from 61% to 78% for the Schmidt–Moskowitz function.