On spectroscopic structure of two interacting electrons in a quantum dot

The shifted 1/N expansion technique, used by El-Said (Phys. Rev. B 61, 13026 (2000)), to study the relative Hamiltonian of two interacting electrons confined in a quantum dot, is investigated. El-Said's results from SLNT are revised and results from an alternative method are also reported. The distinctive role of the central spike term, $(m^2-1/4)/q^2$, in determinig the spectral properties of the above problem is shown, moreover.