Removal of electron-electron poles from many electron hamiltonians

In many‐electron problems, the Hamiltonian has poles 1/rij which produce difficulties in the solution of the Schrodinger equation HΨ = EΨ. If Ψ is taken to be φχ where φ= ∏ i>j[1+12rijexp(−αrij)], it is found that χ satisfies the new Schrodinger equation H′χ=Eχ where the new Hamiltonian H′ has no electron—electron poles.