Ground state of excitonic molecules by the Green's-function Monte Carlo method

The ground-state energy of excitonic molecules is evaluated as a function of the ratio of electron and hole masses, σ, with use of the Green's-function Monte Carlo method. For all σ, the Green's-function Monte Carlo energies are significantly lower than the variational estimates and in favorable agreement with experiments. In excitonic rydbergs, the binding energy of the positronium molecule (σ=1) is predicted to be - 0.06 and for σ1, the Green's-function Monte Carlo energies agree with the "exact" limiting behavior, E=-2.346+0.764σ. © 1983 The American Physical Society.