Dimer Preparation That Mimics the Transition State for the Adsorption of H2 on the Si(100)-2 × 1 Surface
Emily J. Buehler,
John J. Boland*
A chemically induced dimer configuration was prepared on the
silicon (Si) (100) surface and was characterized by scanning tunneling
microscopy (STM) and spectroscopy (STS). These prepared dimers, which
are essentially untilted and differ both electronically and
structurally from the dynamically tilting dimers normally found on this
surface, are more reactive than normal dimers. For molecular hydrogen
(H2) adsorption, the enhancement is about
109 at room temperature. There is no appreciable barrier
for the H2 reaction at prepared sites, indicating the
prepared configuration closely approximates the actual dimer structure
in the transition state. This previously unknown ability to prepare
specific surface configurations has important implications for
understanding and controlling reaction dynamics on semiconductor
surfaces.
Venable and Kenan Laboratories, Department of Chemistry,
University of North Carolina at Chapel Hill, Chapel Hill, NC
27599-3290, USA.
*
To whom correspondence should be addressed. E-mail:
boland{at}unc.edu
