CORE POLARIZATION IN ALUMINUM

Core polarization in atomic Al was analyzed by using core-valence correlation potentials with relativistic effective potentials in quantum Monte Carlo simulations. The core-valence correlation potential included dipole, quadrupole, and higher order corrections within the constraints of the 10-electron core (spdf) basis set. With core polarization included, relativistic effective potential quantum Monte Carlo (REP-QMC) simulations gave the first three Al ionization potentials to within 0.03 eV of the experimental values. Although the core polarization correction to the first ionization potential is negligible (due to cancellation), corrections to the second and third potentials are quite significant, 0.1 and 0.4 eV, respectively. We encountered no difficulty in carrying out Monte Carlo simulations, including branching, on the three-electron (Fermi) ground state. © 1990 American Chemical Society.