The structure of the surface formate chemisorbed on Si(100) at 300 K was st
udied by near edge X-ray absorption fine structure (NEXAFS) at the carbon K
-edge. By probing the incidence-angle-dependent NEXAFS spectra, it was dete
rmined that the CDO group bond of the surface formate is tilted away from t
he surface normal by an average angle of 21 +/- 2 degrees. This geometry is
analogous to the dihedral angle (21 degrees) of the O=C-O-Si group of sily
l formate in the gas phase. This finding indicates that the surface formate
and the gas-phase silyl formate have similar steric structures. It could b
e expected that the electronic structure of the chemisorbed formate is also
similar to that of the gas-phase silyl formate, (C) 1999 Elsevier Science
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