Gross atomic structure
= Gross atomic structure
{title2=$E_n\sim-\alpha^2\mu c^2/(2n^2)$}
<Gross atomic structure> denotes the leading nonrelativistic Coulomb binding levels, before fine and hyperfine splittings. For a hydrogenic two-body system, the <reduced mass> controls the binding <energy> and characteristic separation. <Fine structure> is smaller by roughly $\alpha^2$; nuclear magnetic hyperfine effects have an additional electron-to-nuclear <mass> suppression.