Chemical Structure and Orientation of Ethylene on Si(114)-(2x1)/c(2x2)
NAVAL RESEARCH LAB WASHINGTON DC CHEMISTRY DIV
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The basic chemical structure and orientation of ethylene chemisorbed on Si114-2 1 at submonolayer coverage is characterized in ultrahigh vacuum using transmission Fourier transform infrared FTIR spectroscopy. The spectra are consistent with di-sigma bonding of ethylene to the surface with a preferential molecular orientation over macroscopic lengths. These results are supported by density functional theory DFT calculations of vibrational frequencies for optimized ethylene-Si114 structures occupying the dimer and rebonded atom surface sites. A detailed analysis of the strong angular and polarization dependence of the C-H stretching mode intensities is also consistent with the adsorption structures identified by DFT, indicating that ethylene chemisorbs with the C-C bond axis parallel to the structural rows oriented along the 1h10 direction on the Si114-2 1 surface. The results indicate that the unique structure of this surface makes it an excellent template for elucidating relationships between surface structure and organic reaction mechanisms on silicon.
- Organic Chemistry
- Numerical Mathematics