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The important stationary points on the potential energy surface of the reaction CH(3)O(2) + NO have been investigated using ab initio and density functional theory techniques. The optimizations were carried out at the B3LYP/6-311++G(d,p) and MP2/6-311++G(d,p) levels of theory while the energetics have been refined using the G2MP2, G3//B3LYP, and CCSD(T) methodologies. The calculations allow the proper characterization of the transition state barriers that determine the fate of the nascent association conformeric minima of methyl peroxynitrite. The main products, CH(3)O + NO(2), are formed through either rearrangement of the trans-conformer to methyl nitrate and its subsequent dissociation or via the breaking of the peroxy bond of the cis-conformer to CH(3)O + NO(2) radical pair. The important consequences of the proposed mechanism are (a) the allowance on energetic grounds for nitrate formation parallel to radical propagation under favorable external conditions and (b) the confirmation of the conformational preference of the homolytic cleavage of the peroxy bond, discussed in previous literature.

The gas-phase adsorption of 1,2,3-triazole, benzotriazole, and naphthotriazole-considered as corrosion inhibitors-on copper surfaces was studied and characterized using density functional theory (DFT) calculations. We find that the molecule-surface bond strength increases with increasing molecular size, thus following the sequence: triazole

The p(1×1) adsorption of atomic oxygen on the fcc and hcp three-fold hollow site of a Pt(111) surface has been investigated by a periodic slab model, varying the number of layers from two to four. The density functional method with local spin density approximation and with generalized gradient exchange−correlation functionals was employed using the CRYSTAL95 ab initio program. It was found that the three-layer slab model was a good compromise between accuracy and the computational time. The LDA/VWN calculations predict that the fcc-hollow site is energetically preferable by 0.29 eV compared to the hcp-hollow site. This preference is also supported by experimental data. Oxygen p(1×1) heat of adsorption of 0.61 eV calculated with the BPW91 method is in reasonable agreement with the experimentally estimated one. The corresponding equilibrium adsorbate−surface distance is 1.25 Å. Density-of-states analysis demonstrates that the formation of the Pt−O bond is mainly due to the interaction of Pt 5d xz and 5d yz orbitals of the surface platinum atom and 2p x and 2p y orbitals of the oxygen adatom. Three-dimensional difference electron density plots indicate a delocalized interaction of the oxygen adatoms to the surface.