Trapping-mediated chemisorption of ethylene on Si(001)-c(4 x 2)

Adsorption of ethylene molecules on Si(001)-c(4 x 2) was studied using scanning tunneling microscopy at low temperatures. Ethylene molecules trapped at the surface at 50 K were imaged only after decay to chemisorption, each bonding to a Si dimer. Atomic-scale observations of temperature-dependent ki...

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Bibliographic Details
Published inPhysical review letters Vol. 97; no. 11; p. 116102
Main Authors Chung, Chun-Hyung, Jung, Woo-Jin, Lyo, In-Whan
Format Journal Article
LanguageEnglish
Published United States 15.09.2006
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Summary:Adsorption of ethylene molecules on Si(001)-c(4 x 2) was studied using scanning tunneling microscopy at low temperatures. Ethylene molecules trapped at the surface at 50 K were imaged only after decay to chemisorption, each bonding to a Si dimer. Atomic-scale observations of temperature-dependent kinetics show that the decay exhibited Arrhenius behavior with the reaction barrier of 128 meV in clear evidence of the trapping-mediated chemisorption, however, with an anomalously small preexponential factor of 300 Hz. Such a small prefactor is attributed to the entropic bottleneck at the transition state caused by the free-molecule-like trap state.
ISSN:0031-9007
DOI:10.1103/PhysRevLett.97.116102