2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/190118We test the Salpeter formalism for the electron screening of the solar proton-proton fusion reaction by solving numerically the relevant Schrodinger equation. We evaluate exactly the square of the overlap integral of the two-proton wave function and the deuteron wave function and compare with the usual analytic approximation. The usual WKB solution agrees with the numerical result to $O(10^{-4})$. The WKB approximation should be even more precise for the other nuclear fusion reactions in the $pp$ chain and CNO cycles.8 pages, RevTeX, some modifications and extensions, to appear in Phys. Rev. CAstrophysicsHigh Energy Physics - PhenomenologyNuclear Theorytext