Pseudopotential variational quantum Monte Carlo approach to bcc lithium

The pseudopotential variational quantum Monte Carlo scheme is applied to bcc lithium. The pseudopotential is constructed from all-electron Hartree-Fock calculations. Atomic levels calculated using the pseudopotential show good agreement with experimental atomic spectroscopic data. Calculations for bcc lithium provide accurate equilibrium lattice constant and bulk modulus. Calculated cohesive energy is within 0.1 eV of the experimental value. Use of the pseudopotential enables accurate evaluation of the correlation energy among the conduction electrons. The results have demonstrated that the correlation energy is very important in determining bulk lithium properties.