| Autor: |
Rothgeb, David W., Hossain, Ekram, Mayhall, Nicholas J., Raghavachari, Krishnan, Jarrold, Caroline Chick |
| Předmět: |
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| Zdroj: |
Journal of Chemical Physics; 10/14/2009, Vol. 131 Issue 14, p144306, 8p, 2 Diagrams, 2 Graphs |
| Abstrakt: |
Several mechanisms proposed and calculated for the sequential oxidation of tungsten suboxide clusters by H2O/D2O [Mayhall et al., J. Chem. Phys. 131, 144302 (2009)] are evaluated using anion photoelectron spectroscopy of an apparent intermediate, W2O6D2-. The spectrum of W2O6D2- is consistent with the W2O5-+D2O→W2O6-+D2 intermediate in which the initial water addition involves the interaction of the oxygen from D2O with a tungsten atom, approaching from a direction with the least repulsion from the W2O5- oxygen atoms, coupled with the interaction between a deuterium with a tungsten-tungsten bridging oxygen on the cluster. The presence of W2O6H2- and W2O6D2- suggests that there is insufficient internal energy in the complex to surmount the barrier for rearrangement required for tungsten hydride and hydroxide formation necessary for H2 or D2 evolution, which was calculated to be energetically favorable. The quality of the calculations is verified by direct comparison between experimental photoelectron spectra of W2O5- and W2O6- and spectral simulations generated from the lowest energy structures calculated for W2O5-, W2O6- and their corresponding neutrals. The results shed light on the importance of repulsion on the pathway a reaction follows under room temperature conditions. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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