Collision strength
= Collision strength
{title2=$\Omega_{ji}$}
A dimensionless atomic collision measure used to parameterize electron-impact transition coefficients. In the Maxwellian approximation used here, $q_{ji}=8.6\times10^{-12}\Omega_{ji}/(g_j\sqrt{T_e})$ in $\mathrm{m^3\,s^{-1}}$, and <detailed balance> fixes the excitation coefficient. Its value and <temperature> dependence encode atomic scattering physics beyond the elementary <Boltzmann factor>.