Emission from Long-Lived States in Ion Beams. New Band Systems of NO+

A method for investigating radiation from long‐lived, excited states of ions is described. Emission spectra, apparent lifetimes of the excited states, and electron impact cross sections for producing the radiation can be studied. The spectrum of emission from long‐lived states of NO⁺ in an ion beam has been obtained for wavelengths between 1250 and 2200 Å, but no NO⁺ emissions have been observed in spectral scans of the 2200–3400‐Å region. Some of the spectral features are produced by transitions to the $X^1{\Sigma }^{+}$ state of NO⁺ from the $\text{υ′\hspace{0.17em}=\hspace{0.17em}0}$ and 1 levels of a single electronic state having an internuclear distance 1.157_−0.01^+0.02 Å and an apparent lifetime 135 ± 35 μsec. These two vibrational levels are 7.301 ± 0.006 and 7.511 ± 0.01 eV above the ground state of NO⁺. The other emissions observed can be characterized by two apparent lifetimes, 10.8 ± 2 and 160 ± 50 μsec, and appear to be produced by transitions to the $X^1{\Sigma }^{+}$ state from several upper states. Tentatively, the energies of the upper states are set at 9.639 ± 0.006, 9.437 ± 0.009, and 9.232 ± 0.006 eV above the ground state of NO⁺. Other radiating levels may be at 9.34, 9.07, and/or 8.79 eV. Some of the observed radiation may be produced by the previously reported $A^1{\mathrm{\pi \hspace{0.17em}\to \hspace{0.17em}X}}^1{\Sigma }^{+}$ transitions, where the $A^1\pi$ state would have to be populated by a slow cascade.