Gas-Phase Electron Paramagnetic Resonance Absorption in a N 16O, N 17O, and N 18O Mixture

The X‐band EPR spectra of a gaseous mixture of ¹⁴N¹⁶O, ¹⁴N¹⁷O, and ¹⁴N¹⁸O are presented. Statistically significant differences in the spectra indicate that a unified theory of isotopic effects is derivable from the data. Further interpretation will be presented in a second paper. The oxygen‐17 hyperfine interaction was found to be $\text{≈ 57.4\hspace{0.17em}}\mathrm{G}$ and a large oxygen‐17 quadrupole interaction is indicated. The s character of the 2pπ electron on oxygen in nitric oxide is estimated to be 2.0%, in good agreement with that estimated for the isoelectronic molecule ${}^{17}{\mathrm{O}}_2^{-}$ .