1. For references seeP. A. Fraser:Advances in Atomic and Molecular Physics, edited byD. R. Bates andI. Estermann, vol.4 (New York, 1968), p. 63.
2. H. S. W. Massey, J. Lawson andD. G. Thompson:Quantum Theory of Atoms, Molecules and Solid State (a tribute toJ. C. Slater), edited byP. O. Löwdin (New York, 1966), p. 203.
3. P. A. Fraser andM. Kraidy:Proc. Phys. Soc.,89, 533 (1966).
4. P. A. Fraser:Journ. Phys. B (Proc. Phys. Soc.),1, 1006 (1968).
5. M. I. Barker andB. H. Bransden:Journ. Phys. B (Proc. Phys. Soc.),1, 1109 (1968).