Methanol adsorption on the Si(100)-2 × 1 surface: a first-principles calculation

Abstract

The process of adsorption of methanol on a Si(100)-2 × 1 surface has been investigated theoretically, using density functional theory and a periodic boundary condition.The methanol adsorption on Si(100)-2 × 1 is known to be dissociative, resulting in hydrogen (methanol) -oxygen (surface) and oxygen (methanol) -silicon (surface) bond formation. Adsorption energies have been calculated here for five different surface sites for the methoxy fragment (top, bridge, cave, valley-bridge and pedestal). The top site was found to be energetically most favourable. Surface sites bridging Si atoms from the first and second atomic layers were found to be energetically equivalent to the top site. The effects of the position of the hydrogen fragment on the methoxy adsorption energy for the various adsorption sites were also investigated. These various hydrogen positions only influenced the adsorption energies marginally.

DIPEPTIDE ADSORPTION ON Si(100)-2 × 1 ASYMMETRIC SURFACE BY FIRST PRINCIPLES

“…In another study dealing with the adsorption of methanol molecule on Si(100)-2 × 1 surface, the calculated Si-O bond is 1.76Å. 10 These results are also in good agreement with our values. The second energetically favorable state is the groove-180 • which is obtained by rotating around the CH 3 axis by 180 • [shown in Fig.…”

“…This gave rise to investigation of methanol, cyclopentene and ethanol adsorption on silicon. [10][11][12] Those studies give a wider picture of the adsorption process, for instance, the energetics of the process as a function of the reaction coordinates. 13,14 The simple amino acid glycine adsorption was investigated on several surfaces Cu, TiO 2 , Si, NiAl, Au, Pt and single-walled carbon nanotubes.…”

Coverage effects on phenol adsorption on Si(100)2×1 as: A first principle calculation

“…The large vacuum region allows the geometry optimization both when the phenol molecule lies perpendicular as well as parallel to the surface, hence avoiding interference of other images. We performed our calculations at the C-point similarly to the cases of ethanol [16], methanol [17], toluene [18] and stilbene [19] on Si(1 0 0). A monolayer of hydrogen is used to saturate the dangling bonds on the lower side of the slab.…”

Dissociative versus molecular adsorption of phenol onSi(100)2×1: A first-principles calculation

“…The large vacuum region allows the geometry optimization both when the phenol molecule lies perpendicular to the surface, hence avoiding interference of other images. We adopted a sampling of the Brillouin zone at the ⌫ point, similarly to the cases of ethanol, 18 methanol, 21 toluene, 24 and stilbene 34 on Si͑100͒. A monolayer of hydrogen is used to saturate the dangling bonds on the lower side of the slab.…”

“…[11][12][13][14][15][16][17][18][19][20][21] A recent development in the adsorbate-silicon systems was the investigation of multifunctional molecules which may be employed in stepwise reactions, where in the first step the molecule anchors to the surface with one functional group and in a following step it may interact with an incoming reactant.…”