Adsorption of hydrogen atoms on the Si(100)-2×1 surface: implications for the H2 desorption mechanism

Christine J. Wu, Emily A. Carter

Research output: Contribution to journalArticlepeer-review

136 Scopus citations


The adsorption of atomic hydrogen on the reconstructed Si(100)-2×1 surface is studied using embedded Si clusters as models of an extended Si surface. Analytic gradients of generalized valence bond (GVB) wavefunctions are used to predict equilibrium structures and harmonic vibrational frequencies; the correlation-consistent configuration interaction (CCCI) method is used to calculate heats of adsorption. We predict that the first SiH bond strength of a silicon dimer D0(SiSiH) is 86.1 kcal/mol, while the second SiH bond strength D0(HSiSiH) is 87.9 kcal/mol. Thus, no significant thermodynamic preference exists for either SiSiH or HSiSiH surface configurations, consistent with recent infrared and scanning tunneling microscopy experiments. The predicted adsorption energetics have important consequences for H2 desorption (ΔEdes=70.7 kcal/mol), with a new mechanism proposed involving H atom diffusion followed by pre-pairing desorption of two H atoms on adjacent silicon dimers in the same dimer row.

Original languageEnglish (US)
Pages (from-to)172-178
Number of pages7
JournalChemical Physics Letters
Issue number1-2
StatePublished - Oct 11 1991
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • General Physics and Astronomy
  • Physical and Theoretical Chemistry


Dive into the research topics of 'Adsorption of hydrogen atoms on the Si(100)-2×1 surface: implications for the H2 desorption mechanism'. Together they form a unique fingerprint.

Cite this