A Variational Wave Function for 2p2-Orbitals in Atomic Negative Ions

A variational wave function is used to describe the binding energy of atomic negative ions using a two-electron system in the 2p²-state. Each electron is described by a modified screened hydrogenic wave function involving two free screening parameters denoted by c and a. The model is applied to hydrogen, helium, lithium, and boron anions, where the optimum values of the screening parameters are deduced through fitting the optimized energy to available experimental and theoretical values. The behavior of the optimum wave function for each anion is also investigated as a function of electronic radial distance and compared with its counterpart in the screened hydrogenic model and the Hartree–Fock method.