Coverage Dependence of the Structure of Acrolein

R.M. FERULLO; M. M. BRANDA; F. ILLAS

J. of Phys. Chem. Lett.

American Chemical Society

Año: 2010 vol. 1 p. 2546 - 2549

1948-7185

The structure of adsorbed acrolein is crucial to the chemoselective hydrogenation of the CdO bond. Density functional calculations show that at low coverage the molecule is parallel to the surface, in agreement with experiments. At high coverage, two stable superstructures are obtained. In one of these, the acrolein molecules are oriented head-to-tail and almost parallel to the surface. In the other one, the adsorbed molecules, oriented head-to-head, lead to a complex network with different orientations with respect to the surface. This is in contrast with the geometric structure obtained by the models used to interpret NEXAFS spectra, which show a change in the orientation of the CdC bond at high coverage. Therefore, the calculated structures may provide an alternative interpretation of recent NEXAFS experiments.