Nitrogen atom recombination

It seems inappropriate to review here the immense literature on active nitrogen. We will simply mention some of the recent work on the recombination process itself and the work cited will provide an introduction and access to the main body of the literature on the afterglow. The subject has recently been reviewed157,332. 

Recently Campbell and Thrush164 have pointed out the importance to the afterglow mechanism of quenching of the B state by N2. Including this, they estimate that roughly half the N+N recombinations go into the B state, though at 

Clearly we have not yet at hand a rigorously convincing interpretation of the complex behavior of nitrogen afterglows as a function of pressure, temperature, and diluents. In particular, the importance of a third body in the recombination, and the competition between quenching, spontaneous radiation, and vibrational relaxation must be worked out in detail. It is likely that studies using apparatus with resolution sufficient to resolve the rotational structure would be informative. 

Carroll and Mulliken167 have discussed radiative recombination into the C3nu and C 3nu states, observed in active nitrogen at high pressure and low temperature. These states correlate with N(45)+N(2D) at 12.1 eV above the N2 ground state. 

The decay of first positive emission from a pulsed nitrogen afterglow has been observed over an intensity range of almost 106 and it has been postulated in this connection that recombination into the B state involves N atoms complexed in some sense with impurity molecules168. 

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Lowered Nitrogen Atom Recombination Activation Energy and Preexponential... 

R. P. Thorman, D. Anderson, and S. L. Bernasek, Internal energy of heterogeneous reaction products Nitrogen atom recombination on iron, Phys. Rev. Lett. 44 743 (1980). 

No element is ever destroyed by use. The radioactive ones decay, but stable elements may be used over and over. The nitrogen cycle shows how the nitrogen atoms in your body and the ones in the air have been combining and recombining for millions of years. 

The most rapid reaction is N—N-dimerization (the rates of reactions A, B, C are related as 1 0.15 0.02 [94], Naphthylaminyl radicals recombine with the formation of N—C-dimers only [95], probably because voluminous naphthalene rings sterically hinder N—N-dimerization. A correlation between the rate constant of hyperfine splitting on the nitrogen atom of the aminyl radical and the rate constant of recombination of substituted ( (YC6H4)2N ) diphenyl-aminyl radicals was observed [95],... 

The mechanism for the photoreaction between 133 and cyclohexene can be summarized as in Scheme 8. The initiating electron transfer fluorescence quenching of 133 by cyclohexene resulted in the formation of an w-amino radical-radical cation pair 136. Proton transfer from the 2-position of the cyclohexene radical cation to the nitrogen atom of the a-amino radical leads to another radical cation-radical pair 137. Recombination of 137 at the radical site affords the adduct 134, while nucleophilic attack at the cation radical of 136 leads to another radical pair 138 which is the precursor for the adduct 135. 

Two aminyl radicals combine to form the N—N-dimer with the rate constant proportional to the spin density on the nitrogen atom [96]. This recombination also depends on the steric factor. Thus, diethylaminyl radicals recombine with a rate constant of 109 L mol 1 s 1, while diisopropylaminyl radicals are only able to disproportionate with a rate constant of... 

In atomic flames, where one might expect direct excitation of a metal atom as third body, an intermediate is often involved instead. For example, in studies of excitation of iron by nitrogen atoms in CO it has been postulated that Fe is excited by collision with excited N2 or CO produced as third bodies in the atom recombination process178. Brennen and Kistiakowsky55 studied the excitation of nickel, iron and other metals in active nitrogen and concluded that the metal atom is not excited as third body in the recombination process, but by interaction with the metastable N2 (A3XI ). 

Recombination of the nitrogen atoms to N2 is a slow process since it requires a three-body collision of the nitrogen atoms with the walls of the container or a termolecular, homogeneous second-order association of the nitrogen atoms. This can result in excited dinitrogen molecules that are responsible for the yellow glow. 

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