Stretched hyperfine Zeeman state
= Stretched hyperfine Zeeman state
{title2=$m_F=\pm(I+1/2)$}
For electronic $J=1/2$, an extremal total projection has only one product state rather than a two-dimensional <spin> block. With dimensionless angular-momentum operators and nuclear Zeeman coefficient $g_I$ in Bohr-magneton units, its <energy> is $AI/2\pm\mu_BB(g_J/2+g_I I)$. Extending both signs of a two-state <Breit-Rabi formula> square root to each stretched projection would invent an extra state.