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Research was conducted to examine the trend in the activation energies of the recombination reactions with molecular oxygen. The third-order recombination reaction Sr(1S) + O2 + He -> SrO2 + He experiment was performed in a fast-flow reactor in the temperature and pressure range of 303-968 K and 6-12 Torr, respectively. Results show the occurrence of activation energies using ab initio calculations.

In this paper, we present a method for growing copper-based nanowires. The method is based on the unusual modification of a halogenated copper surface by exposure to a helium plasma. The nanowires have diameters ranging between 50 and 150 nm and lengths up to 50 microm. They are polycrystalline, and large parts of the wires have a pronounced core-shell structure with a dense shell and less material inside. The wires are grown in a plasma environment at room temperature, and large amounts can be grown in a matter of minutes. The critical process parameters for the growth process are the gas flow and pressure settings, and the impact thereof will be discussed in detail. In order to gain insight in a possible growth mechanism, our observations are compared with literature on the growth of silver whiskers from halogenated silver crystallites. Finally, photoluminescence spectra of the wires are discussed in view of the analytical data about the stoichiometry and structure of the nanowires.

The decomposition reaction mechanism of the anions generated by atmospheric pressure chemical ionization (APCI) mass spectrometry, in the negative mode, of nitroanilines and 2,4-dinitroanilines has been probed using quantum chemical calculations. The same process has been analyzed for the neutral counterparts and the simpler neutral and anionic nitrobenzenes. Our computations using density functional theory at the B3LYP/6-311++G(3df,2p) level demonstrate that the decomposition of the anion occurs in a two-stage process, involving an initial nitro-nitrite rearrangement followed by a NO-elimination leading to formation of a phenoxy radical anion derivative. The former is by far the rate-determining step. Calculations using the MP2 and CCSD(T)/6-311++G(d,p) levels also pointed out the same energy landscape. A similar mechanism has also been emphasized for the neutral counterparts. The effects of the amino and nitro groups as well as that of the negative charge on the nitro-nitrite interconversion are rather small and do not qualitatively modify the landscape of the pertinent energy surface and thereby the NO-loss mechanism.

The electronic structure aspects of the M (1S,3P) + N2O(X 1sigma+) (M = Be, Mg, Ca) reactions are investigated using the CASSCF/MRMP2 (complete active space SCF and the multireference Møller-Plesset perturbation theory of the second order) computational methodology. The lowest adiabatic 1 1A' and 1 3A' potential energy surfaces (PESs) favor the bending dissociation mechanism of N2O in all studied cases. The rate-limiting channels are determined by the classical barriers that decrease in the series Be (8.9) > Mg (7.0) > Ca (1.2) kcal/mol, whereas the spin-forbidden reaction channels are found to be less important. A comparison with elaborated kinetic results (Plane et al. J. Phys. Chem. 1990, 94, 5255; Gas-Phase Metal Reactions; Elsevier: Amsterdam, 1992; Vinckier et al. J. Phys. Chem. A 1999, 103, 5328) on the Ca (1S) + N2O(X 1sigma+) reaction is presented, and the differences in the kinetic behavior of the title reactions are discussed. Our results also indicate that the techniques based on the multiconfigurational wave functions are unavoidable if a correct topology of the PESs governing these reactions is needed.