𝑆 𝑇 0 One should note that the resulting N spectra yield a broadened NMR signal with a non-Lorentzian lineshape. This is a result of exchange of deuterons in the ortho-positions of Py with dihydrogen protons, which leads to the formation of three isotopomers of free pyridine, with D-D, H-D and H-H nuclei in the ortho-positions. Since each isotopomer has its own spin system, the spectral pattern becomes more complex and contains several components. However, the signal of fully deuterated pyridine dominates over any other signal in the resulting N spectra, The improvement of the enhancement by a factor of 7 allows 𝜀 one to calculate the populations of the spin states of H 2 . Here we do so assuming that (i) is proportional to and (ii) 𝜀 𝛿𝑃 𝑃 𝑇 ± (this corresponds to 85% of pH 2 enrichment). Hence, if = 0.05 we set before the pulse is applied, we obtain that 𝑃 𝑆 = 𝑥 𝑃 𝑇 0 . After application of the pulse we obtain = 0.9 -𝑥 𝑃 ′ 𝑆 = 𝑃 𝑆 = 𝑥 and . Consequently,