First Ionization Potential of Li atom from VQMC Calculation

Abstract

The total non-relativistic energies of the Lithium atom and its positive ion are calculated using the fixed-node VQMC method. Over 90% of the correlation energy is obtained for both the neutral atom and the cation. Subtracting these energies yields the ionization potential of 5.345 electron volts, in excellent agreement with the recommended experimental value 5.39 electron volt. Calculations were performed using Slater-Jastrow type trial wave function with Polynomial Pade Jastrow factor having one variational parameter.