= Atomic and nuclear beta-decay energy conventions
{title2=$Q_{\beta^-}=[M_{\rm nuc}(i)-M_{\rm nuc}(f)-m_e]c^2$}
For ground-to-ground beta-minus decay of bare <nuclei>, the nuclear <mass> difference supplies the <electron> rest <energy> as well as the <kinetic energy> shared among products. Neglecting recoil and <neutrino> <mass>, $T_{\max}=Q_{\beta^-}$. For neutral atomic <masses> the additional final atomic <electron> cancels the emitted <electron> rest-mass subtraction, giving $Q\simeq[M_{\rm atom}(i)-M_{\rm atom}(f)]c^2$ up to electron-binding corrections. A daughter excitation reduces the endpoint by its <excitation energy>.
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