For the 1 L a state with λ 2 1 = 0.977, Γ NTO ≈ d CD1 to within 0.004 Å but the difference is more substantial for the 1 L b state where λ 2 1 = 0.555. In the latter case, Γ NTO = 0.28 Å but d CD1 = 0.06 Å.