2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/197187Elaborating on a previous letter, we use a new approach to compute energy levels of a non-relativistic bound-state of two constituents, with masses m and M, by systematic expansions - one in powers of m/M and another in powers of (1-m/M). Technical aspects of the calculations are described in detail. Theoretical predictions are given for O(alpha(Z*alpha)^5) radiative recoil and O((Z*alpha)^6) pure recoil corrections to the average energy shift and hyperfine splitting relevant for hydrogen, muonic hydrogen, and muonium.9 pages, revtexHigh Energy Physics - PhenomenologyExpansion of bound state energies in powers of m/M and (1-m/M)text