2-DIMENSIONAL BASIS FOR THE INVESTIGATION OF ANGULAR-CORRELATIONS IN HELIUM-LIKE SYSTEMS

In the method of hyperspherical coordinates, a basis of two independen t variables is proposed for the study of the contribution of angular c orrelations to the spectroscopic parameters of helium-like systems. Qu antum-mechanical calculations of six lowest adiabatic potentials and c hannel functions for a negative hydrogen ion and a helium atom were pe rformed by means of solution of a two-dimensional boundary-value probl em by the method of sweep in conjugation conditions. It is demonstrate d that the solution of the radial equation in the single-channel appro ximation allows one to determine the energy with an accuracy that can be achieved in the standard approach only when a two-channel problem i s solved. A classification of quantum states with the help of node lin es corresponding to the angular part of the wave function of the syste m is proposed. The crossing points of adiabatic potentials are reveale d. Nonadiabatic transitions occur in the neighborhood of these points.