Using the acetic acid/Si(001) system as an illustrative example, we discuss the limits and opportunities of “chemical analogy” as a paradigm to rationalize chemisorption processes on surfaces. Recent proposals that acetic acid chemisorption results in a bidentate, single-dehydrogenated product are based on earlier findings for the acetic acid/Ge(001) system. In contrast, the well-characterized reaction of acetone with Si(001) suggests that acetic acid chemisorption leads to the loss of two hydrogen atoms from the molecule. Density-functional calculations resolve this ambiguity, finding the latter structure model to be thermodynamically preferred and kinetically viable.

• Received 22 July 2011

DOI:https://doi.org/10.1103/PhysRevB.84.153302