1. Influence of Flipping Si Dimers on the Dissociation Pathways of Water Molecules on Si(001)
- Author
-
Yong-Sung Kim, Ja-Yong Koo, Hanchul Kim, and Sang-Yong Yu
- Subjects
Sticking coefficient ,education.field_of_study ,Molecular adsorption ,Chemistry ,Population ,Dissociative adsorption ,Dissociation (chemistry) ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,law.invention ,General Energy ,law ,Molecule ,Physical chemistry ,Physical and Theoretical Chemistry ,Atomic physics ,Scanning tunneling microscope ,education - Abstract
The dissociative adsorption of water molecules on Si(001) was studied up to 850 K by scanning tunneling microscopy. Water molecules dissociate into OH and H fragments to form on-dimer (OD) and interdimer (ID) configurations, and the population ratio nID/nOD is measured to change from ∼5 at room temperature to the saturation value of ∼0.6 above 500 K, contradicting to the prediction from the static transition-state theory. The sticking coefficient also shows an abnormal temperature dependence. The temperature dependence in the H dissociation and in the molecular adsorption can be elucidated only by taking into account the flip-flop motion of Si dimers.
- Published
- 2011