Finite-element calculations for the three-body Coulomb problem with two equal masses

Abstract
An accurate numerical finite-element method (FEM) solution of the three-body Coulomb problem with two equal masses is presented. The application of the FEM to systems with mass ratios ranging from 1836 to 1/1836 yields upper bounds for energy eigenvalues to a precision in the range of 1011109 a.u. Expectation values for different operators are computed and discussed. © 1996 The American Physical Society.