The estimation of Schwinger variational principle efficiency by means of two-center problem terms calculations

The application of Schwinger variational principle (SVP) efficiency to three body problem is studied. Two-center problem in adiabatic approximation was considered. The dependence of ground state energy for such system on the distance between centers is investigated. It was shown that SVP even with a few number of terms in the approximations is sufficiently effective and gives better consent with the exact solution than the strong coupling channel method. (author). 8 refs.; 1 fig