1. Quantum Chemistry Program Exchange, 1985 Catalog, QCPE, Indiana University, Bloomington, Indiana.
2. M.M. Goodgame and W.A. Goddard III, J. Phys. Chem., 85, 215 (1981)
3. Phys. Rev. Lett. 48, 135 (1982).
4. S.P. Walch, C.W. Bauschlicher, B.O. Roos and C.J. Nelin, Chem. Phys. Lett., 103, 175 (1983).
5. P. Hohenberg and W. Kohn, Phys. Rev., 136, B864 (1964).