Reactive scattering of sodium clusters with molecular oxygen.

Autor: Goerke, Alexander, Leipelt, Gregor, Palm, Hartmut, Schulz, C., Hertel, I.
Zdroj: Zeitschrift für Physik D Atoms, Molecules & Clusters; 1995, Vol. 32 Issue 4, p311-320, 10p
Abstrakt: The first reactive differential scattering study for atomic clusters is reported. Oxidation of Na ( x≦8) with O is investigated in a crossed beam apparatus. Sodium oxide (NaO, n≦4) and sodium dioxide (NaO, n≦6) are produced with a total reactive cross section from 50 to 80 Å, depending on the cluster size. The excess energies for these reactions are estimated by an SCF type ab initio calculation and range from 0.5 to 5 eV. The large cross section may then be understood quantitatively in terms of a harpooning mechanism as a first step in the reaction path. Angular distributions have been determined for the most abundant products, showing strong forward scattering. Two different schemes are discussed for the reaction: while the dioxides NaO may be formed by an evaporative cooling process from a highly excited collision complex, formation of NaO appears to originate from a direct process. In both cases the experimental data suggest that most of the exothermicity remains in the reaction products. [ABSTRACT FROM AUTHOR]
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