English
 
Help Privacy Policy Disclaimer
  Advanced SearchBrowse

Item

ITEM ACTIONSEXPORT

Released

Journal Article

Characterization of water dissociation on α-Al2O3(1̅102): theory and experiment

MPS-Authors
/persons/resource/persons21722

Kirsch,  Harald
Physical Chemistry, Fritz Haber Institute, Max Planck Society;

/persons/resource/persons127540

Wlosczyk,  Sebastian
Physical Chemistry, Fritz Haber Institute, Max Planck Society;

/persons/resource/persons45966

Tong,  Yujin
Physical Chemistry, Fritz Haber Institute, Max Planck Society;

/persons/resource/persons37877

Campen,  R. Kramer
Physical Chemistry, Fritz Haber Institute, Max Planck Society;

External Resource
No external resources are shared
Fulltext (restricted access)
There are currently no full texts shared for your IP range.
Fulltext (public)

c6cp01397j.pdf
(Publisher version), 4MB

Supplementary Material (public)
There is no public supplementary material available
Citation

Wirth, J., Kirsch, H., Wlosczyk, S., Tong, Y., Saalfrank, P., & Campen, R. K. (2016). Characterization of water dissociation on α-Al2O3(1̅102): theory and experiment. Physical Chemistry Chemical Physics, 18(22), 14822-14832. doi:10.1039/C6CP01397J.


Cite as: https://hdl.handle.net/11858/00-001M-0000-002A-513F-2
Abstract
The interaction of water with α-alumina (i.e. α-Al2O3) surfaces is important in a variety of applications and a useful model for the interaction of water with environmentally abundant aluminosilicate phases. Despite its significance, studies of water interaction with α-Al2O3 surfaces other than the (0001) are extremely limited. Here we characterize the interaction of water (D2O) with a well defined α-Al2O3(1̅102) surface in UHV both experimentally, using temperature programmed desorption and surface-specific vibrational spectroscopy, and theoretically, using periodic-slab density functional theory calculations. This combined approach makes it possible to demonstrate that water adsorption occurs only at a single well defined surface site (the so-called 1-4 configuration) and that at this site the barrier between the molecularly and dissociatively adsorbed forms is very low: 0.06 eV. A subset of OD stretch vibrations are parallel to this dissociation coordinate, and thus would be expected to be shifted to low frequencies relative to an uncoupled harmonic oscillator. To quantify this effect we solve the vibrational Schrödinger equation along the dissociation coordinate and find fundamental frequencies red-shifted by more than 1,500 cm-1. Within the context of this model, at moderate temperatures, we further find that some fraction of surface deuterons are likely delocalized: dissociatively and molecularly absorbed states are no longer distinguishable.