EFFECT OF POSITIVE-ENERGY ORBITALS ON THE CONFIGURATION-INTERACTION CALCULATION OF THE H- ATOM

We present the theoretical energy eigenvalues of the 1S ground state and the (pp)3Pe state of H- calculated in a simple configuration-interaction procedure, using a finite set of L2-basis functions constructed from one-electron hydrogenic orbitals. The energy corrections, due to the electron-electron interaction between configurations with various combinations of bound (negative-energy) and continuum (positive-energy) orbitals, are examined in detail. In particular, our calculation has shown that the continuum-continuum type of configurations contribute approximately 15% and 13%, respectively, to the electron affinity of the 1S ground state and the (pp)3Pe state of H-. In addition, our calculation has shown that the calculated oscillator strength for the transition from the 1S ground state of H- to the lowest 1P Feshbach resonance below the n = 2 threshold is significantly reduced (nearly 30%) by the presence of the continuum-continuum type of configurations in the ground-state wave function.