Nitrogen oxides play a key role in the pollution of the troposphere. They participate in processes that involve the formation of the acid rain and tropospheric ozone and they directly impact the biota. An increment of their concentration has been observed through the years as a consequence of anthropogenic activity. Their accumulation in the troposphere is mostly attributed to the burning of fossil fuels, burning of biomasses and intense growing methods. Further the nitrogen oxides are a photoactive tropospheric species. They photodissociate after absorbing a photon with the appropriate wave length from the incoming solar radiation. One of the products of this reaction is atomic oxygen which instantelly reacts with the O2 molecule in the surroundings. This reaction leads to the formation of tropospheric ozone, one of the keycomponents of the photochemical smog. The photochemical processes occur in excited states and, beside various physical phenomena, some quantum phenomena, such as the collision of a photon and a molecule, are involved. Hence,there action rate depends on various parameters, primarily the solar zenith angle,the absorption cross-section and the quantum yield. With the use of the Gaussian software we did a basic thermodynamic analysis of the reaction which can be used as a beginning for further research of the reaction mechanism and reaction kinetics. We evaluated the obtained data from the acquired theoretical knowledge and through a comparison with the available experimental data.
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