Nitric electronically excited, from

Banded optical emission results from electronically excited nitric oxide. The y and /S bands are often observed. Furthermore, chemiluminescence results from the well-studied step... 

Nitric oxide is also present in the upper atmosphere its role has been reviewed by Nicolet.326-328 Because of solar radiation, important processes are photoionization, photodissociation, and the formation of electronically excited levels. The continuum seen in the night airglow has often been ascribed to reaction (4). However, both the y and / bands of NO are absent in the night airglow. Since the / and y emissions arise from... 

Visible chemiluminescence was observed from the electronically excited HNO product of the crossed-molecular beam reaction of H + (NO)2 [277]. Variation of the nitric oxide beam source conditions confirmed that the reaction was with dimers, (NO)2, rather than with NO. The cross section for chemiluminescence was estimated to be in the range 3.5—9A2. Emission was seen from the (010), (020), (001) and (100) levels of HNO ( A"). 

Electronically excited NO has been observed as a product of the reaction of ground state oxygen atoms with nitric oxide. In the first [447], the emission results from the two-body radiative recombination reaction... 

As mentioned above, the nonequilibrium radiation code NEQAIR is employed for prediction of ultraviolet emission from the DSMC flow field solutions. The modeling of ultraviolet emission with this code is discussed for nitric oxide in Ref. 84 and for atomic oxygen in Ref. 87. A common assumption made in using the NEQAIR code is that a quasisteady state (QSS) exists for the number densities of the electronically excited species. The assumption requires that the time scale of chemical processes is much smaller than the time scales for diffusion and for changes in overall properties. Under these conditions, the local values of temperatures and ground state species number densities obtained from the DSMC computation may be used to compute the populations of the electronically excited states. 

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. 

Clyne, Thrush, and Wayne107 reexamined the chemiluminescence from the nitric oxide-ozone reaction and found its spectrum to be similar to that of the thermal emission of N02 at 1200°K. They concluded that the spectra represented transitions from similar low-lying vibration levels of the same excited electronic state of NOa to the ground state. By measuring the decay in chemiluminescence down a flow tube, they obtained the value of the rate constant between 216 and 322°K. The partial pressures of ozone and nitric oxide were 5 x 10-3 and 2 x 10 2 torr, respectively, in an argon carrier at a total pressure of 2 torr. In the presence of excess nitric oxide, they assumed the logarithmic disappearance of ozone proportional to [NO], so that... 

This wide development is observed in the study of the participation of ARs in various photochemical reactions, and the phototransfer of electrons and electronic energy. For some radicals the basic process is dissociation with the detachment of nitric oxide, whereas other types of ARs mainly abstract hydrogen atoms from solvents. The quantum yield of such process is very high (-0.5) [42]. Di- -alkylaminoxyls are poorly stable under exposure to UV light. The photolysis of radical IV (Rj = OH) by light with A, = 350 nm in toluene completely converts them into equal quantities of hydroxylamine and benzyl ether of hydroxylamine [43]. Thus, the capability of some excited ARs to abstract a hydrogen atom with the subsequent recombination of formed radicals and ARs provides a method of the functionalisation of macromolecules. 

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