The nitrogen (N) isotope exchange between nitric oxide (NO) and nitrogen dioxide (NO2) has been previously suggested to influence N stable isotope compositions (δ15N) of these molecules. However, there is disagreement in the magnitude of the N isotopic fractionation ( αNO2true/NO) resulting from this exchange process between previous experimental and theoretical studies. To this end, we measured αNO2true/NO associated with this exchange reaction at various temperatures. Our results indicate αNO2true/NO to be 1.0403 ± 0.0015, 1.0356 ± 0.0015, and 1.0336 ± 0.0014 at 278 K, 297 K, and 310 K, respectively. These measured values are within experimental error of the values we calculated using a modified version of the Bigeleisen‐Mayer equation corrected for accurate zero‐point energies, indicating an agreement between experiment and theory. Modeling of this exchange reaction demonstrates that δ15N‐NO2 may exhibit a diurnal and seasonal profile if N isotopic equilibrium is achieved.

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