Abstract
Several mechanisms proposed and calculated for the sequential oxidation of tungsten suboxide clusters by H 2 O/ D 2 O [Mayhall, J. Chem. Phys. 131, 144302 (2009)] are evaluated using anion photoelectron spectroscopy of an apparent intermediate, W 2 O 6 D 2 -. The spectrum of W 2 O 6 D 2 -is consistent with the W 2 O 5 - + D 2 O→ W 2 O 6 - + D 2 intermediate in which the initial water addition involves the interaction of the oxygen from D 2 O with a tungsten atom, approaching from a direction with the least repulsion from the W 2 O 5 - oxygen atoms, coupled with the interaction between a deuterium with a tungsten-tungsten bridging oxygen on the cluster. The presence of W 2 O 6 H 2 - and W 2 O 6 D 2 - 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 H 2 or D 2 evolution, which was calculated to be energetically favorable. The quality of the calculations is verified by direct comparison between experimental photoelectron spectra of W 2 O 5 - and W 2 O 6 - and spectral simulations generated from the lowest energy structures calculated for W 2 O 5 -, W 2 O 6 - and their corresponding neutrals. The results shed light on the importance of repulsion on the pathway a reaction follows under room temperature conditions.
| Original language | English (US) |
|---|---|
| Article number | 144306 |
| Journal | Journal of Chemical Physics |
| Volume | 131 |
| Issue number | 14 |
| DOIs | |
| State | Published - 2009 |
| Externally published | Yes |
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ASJC Scopus subject areas
- Physics and Astronomy(all)
- Physical and Theoretical Chemistry
Cite this
Termination of the W 2 O y - + H 2 O/ D 2 O→ W 2 O y+1 - + H 2 / D 2 sequential oxidation reaction : An exploration of kinetic versus thermodynamic effects. / Rothgeb, David W.; Hossain, Ekram; Mayhall, Nicholas J.; Raghavachari, Krishnan; Jarrold, Caroline Chick.
In: Journal of Chemical Physics, Vol. 131, No. 14, 144306, 2009.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Termination of the W 2 O y - + H 2 O/ D 2 O→ W 2 O y+1 - + H 2 / D 2 sequential oxidation reaction
T2 - An exploration of kinetic versus thermodynamic effects
AU - Rothgeb, David W.
AU - Hossain, Ekram
AU - Mayhall, Nicholas J.
AU - Raghavachari, Krishnan
AU - Jarrold, Caroline Chick
PY - 2009
Y1 - 2009
N2 - Several mechanisms proposed and calculated for the sequential oxidation of tungsten suboxide clusters by H 2 O/ D 2 O [Mayhall, J. Chem. Phys. 131, 144302 (2009)] are evaluated using anion photoelectron spectroscopy of an apparent intermediate, W 2 O 6 D 2 -. The spectrum of W 2 O 6 D 2 -is consistent with the W 2 O 5 - + D 2 O→ W 2 O 6 - + D 2 intermediate in which the initial water addition involves the interaction of the oxygen from D 2 O with a tungsten atom, approaching from a direction with the least repulsion from the W 2 O 5 - oxygen atoms, coupled with the interaction between a deuterium with a tungsten-tungsten bridging oxygen on the cluster. The presence of W 2 O 6 H 2 - and W 2 O 6 D 2 - 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 H 2 or D 2 evolution, which was calculated to be energetically favorable. The quality of the calculations is verified by direct comparison between experimental photoelectron spectra of W 2 O 5 - and W 2 O 6 - and spectral simulations generated from the lowest energy structures calculated for W 2 O 5 -, W 2 O 6 - and their corresponding neutrals. The results shed light on the importance of repulsion on the pathway a reaction follows under room temperature conditions.
AB - Several mechanisms proposed and calculated for the sequential oxidation of tungsten suboxide clusters by H 2 O/ D 2 O [Mayhall, J. Chem. Phys. 131, 144302 (2009)] are evaluated using anion photoelectron spectroscopy of an apparent intermediate, W 2 O 6 D 2 -. The spectrum of W 2 O 6 D 2 -is consistent with the W 2 O 5 - + D 2 O→ W 2 O 6 - + D 2 intermediate in which the initial water addition involves the interaction of the oxygen from D 2 O with a tungsten atom, approaching from a direction with the least repulsion from the W 2 O 5 - oxygen atoms, coupled with the interaction between a deuterium with a tungsten-tungsten bridging oxygen on the cluster. The presence of W 2 O 6 H 2 - and W 2 O 6 D 2 - 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 H 2 or D 2 evolution, which was calculated to be energetically favorable. The quality of the calculations is verified by direct comparison between experimental photoelectron spectra of W 2 O 5 - and W 2 O 6 - and spectral simulations generated from the lowest energy structures calculated for W 2 O 5 -, W 2 O 6 - and their corresponding neutrals. The results shed light on the importance of repulsion on the pathway a reaction follows under room temperature conditions.
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U2 - 10.1063/1.3246833
DO - 10.1063/1.3246833
M3 - Article
VL - 131
JO - Journal of Chemical Physics
JF - Journal of Chemical Physics
SN - 0021-9606
IS - 14
M1 - 144306
ER -