Two-stage strategy for high-precision variational calculations

The problem of high-precision, variational, bound-state calculations in few-body systems is discussed. The simple and very effective variational procedure developed below makes possible numerical, bound-state computations in few-body systems with extremely high accuracy. This procedure is based on the proposed two-stage strategy, which is used to construct the approximate wave function. The highly accurate numerical results, which include both energetical and geometrical properties, for various three-body systems $[{\mathrm{Ps}}^{-}{,}^{\infty }{\mathrm{H}}^{-}{,}^{\infty }\mathrm{He}$, and ${\mathrm{}\left(\mathrm{ppe}\right)\mathrm{}}^{+}$] are presented.