Reactions of NO+ with H2O in a Photoionization Mass Spectrometer

The reactions of NO⁺ with H₂O have been studied in a photoionization mass spectrometer. Nitrosonium ions produced by Kr resonance radiation at 10.03 eV react with water in a field free region. Products observed are $\mathrm{NO}({\mathrm{H}}_2\mathrm{O}{)}_n^{+}\text{\hspace{0.17em}(n=1,\hspace{0.17em}2,\hspace{0.17em}3)}$ and $\mathrm{H}({\mathrm{H}}_2\mathrm{O}{)}_n^{+}\text{(n=1–5)}$ . Rate constants are calculated, heats of formation of hydrated NO⁺ are estimated and some evidence is presented which is consistent with a structure of $\mathrm{NO}({\mathrm{H}}_2\mathrm{O}{)}_n^{+}$ where the waters are hydrogen bonded in a linear fashion rather than forming a solvation sphere.