An exciton approach to the excited states of two electron atoms. II Determination of spectroscopic parameters, polarizabilites and dispersion coefficients of H-, He, Li+, Be2+ and Ne8+

The exciton model is applied quantitatively to a description of the excited states of representative members of the helium isoelectronic series; viz. H+, He, Li+, Be2+ and Ne8+. The energies of the eight lowest excited states are in good agreement with experiment, for a relatively small (1s-4p) hydrogenic basis; the ground state is obtained with slightly less precision. Response properties including oscillator strengths, polarizabilites and dispersion interaction coefficients are also calculated. The method leads to particularly simple interpretations of the wave functions and the energies