CI Calculations of the Ground State Ionization Potential and Electron Affinity of Aluminum

Nonrelativistic configuration interaction study for Al⁺, Al and Al¯ are presented, included calculations of ionization potential and electron affinity of the ²P° ground state of Al. CI calculations up to double, triple and quadrupole excitations for Al⁺, Al and Al¯, respectively, where neon fixed core is considered. Appropriate Slater type basis functions were developed suitable to recover both of core-valence and core-core correlation effect. The relativistic effect on both ionization potential and electron affinity are taken into account at the relativistic Hartree-Fock level. The calculated electron affinity is 432.811 meV which is in excellent agreement with experimental value of Sheer et al. 432.83(5) meV, whereas the calculated ionization potential is 5985.764 meV, the latter is in perfect agreement with experimental value of 5985.768 meV.