Nitrogen dioxide, excited, emission oxide

Here a chemical reaction produces a molecule with electrons in an excited state. Upon decay to the ground state the liberated radiation is detected. One such example is the reaction between ozone and nitric oxide to form nitrogen dioxide emitting radiation in the near infra-red in the 0.5-3/t region. The technique flnds use for measuring nitric oxide in ambient air or stack emissions. 

The oldest chemiluminescent detector was the thermal energy analyzer (TEA), which was specific for N-nitroso compounds. N-nitroso compounds such as nitrosamines are catalytically pyrolyzed and produce nitric oxide which reacts with ozone to produce nitrogen dioxide in the excited ] state, which decays to the ground state with the emission of a photon. A photomultiplier in the reaction chamber measures the emission. Nitrosodi-methylamines have been detected to about 30-40 pg [108]. 

Nitric oxide gives a chemiluminescence emission when reacted with ozone to yield electronically excited nitrogen dioxide (reaction [I]) ... 

The reaction between oxygen atoms and nitric oxide produces a continuum between 400 and 1400 nm from excited nitrogen dioxide. These are significantly lower wavelengths than those of the previously discussed reaction between nitric oxide and ozone. This reaction has been used to determine oxygen atoms in kinetic experiments. As with the oxidation of sulfur monoxide with ozone, oxidation with oxygen atoms produces sulfur dioxide in electronically excited states. In this case, the emission is distributed from 240 to 400 nm with a maximum at 270 nm. 

Nitrosamines can be detected after thermal cleavage and nitrogen-containing compounds after oxidation to nitric oxide, which reacts with ozone to form nitrogen dioxide in an excited state with photon emission in the near-infrared around 1200 nm. 

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