Electron affinity of fluorine: A quantum Monte Carlo study

Abstract

The total nonrelativistic energies of the fluorine atom and its negative ion are calculated using the fixed-node quantum Monte Carlo (QMC) method. Over 90% of the correlation energy is obtained for both the neutral and the anion. Subtracting these energies yields an electron affinity of 3.45±0.11 eV, in excellent agreement with the recommended experimental value of 3.40 eV. The observed dependence of our Monte Carlo energies on the time step is discussed within the short-time QMC formalism. As in previous QMC studies in this series, only a single determinant, constructed with a small (double-zeta) basis set, multiplied by simple functions of electron–electron and electron–nuclear separation, is required as an importance function.