= Electron spin g-factor
{title2=$g_s$}
The dimensionless coefficient in the <spin> part of the <electron magnetic moment>. It is distinct from a <gyromagnetic ratio>, which has units: in the angular convention, $\gamma_e=-g_se/(2m_e)$. It is also distinct from the <Landé g-factor> $g_J$ of a combined atomic <angular momentum> and from a nuclear or hyperfine <g-factor>.
For <spin one-half>, the largest magnitude of a spin-component <magnetic dipole moment> is $g_s\mu_B/2$, not $g_s\mu_B$. Thus the ideal value $g_s=2$ gives one <Bohr magneton>. This follows directly from the <spin angular momentum> projections $S_z=\pm\hbar/2$.
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