Relativistic recoil corrections of order \boldmath$m(Zα)^6(m/M)$: Hydrogen-like atom and hydrogen molecular ion

Abstract: The finite operators are derived for the recoil $m\alpha^6(m/M)$ order relativistic corrections (to spin-averaged energy levels) in hydrogen-like atoms and ions in the two- and three-body formalism beyond the adiabatic approximation. Results are presented in a form suitable for numerical evaluation.