Spin-population rates for 14N-, 15N-nitroxides with cross relaxation & m_I$m_I$-dependent T_1e$T_{1e}$.

m_I$m_I$-independent saturation recovery rates arise naturally from population differences.

Saturation recovery gives mean $T_{1e}^{-1}$ & cross-relaxation rates, independent of pump & observer positions.

Cross relaxation exceeds $T_{1e}^{-1}$ electron-nuclear dipolar contribution to recovery rates.

Cross relaxation & m_I$m_I$-dependent T_1e$T_{1e}$ contribute less than nuclear relaxation to $T_1^{\mathit{eff}}$ in CW-EPR.