TRANSFORMATION OF THE HELIUM ATOM SCHRODINGER-EQUATION INTO INTEGRAL FORM

We define the Green's function for two identical particles moving in a Coulomb field. We use this Green's function as a basis for deriving a n integral equation of the helium atom Schrodinger equation by treatin g the electron repulsion term as a perturbation. The two-particle Gree n's function is further simplified by means of a contour integration. An additional transformation does not lead to further simplification o f the result. (C) 1998 Elsevier Science B.V.