First Principle Study on the Adsorption of Styrene on Si(100)2 x 1

The chemisorption of styrene on Si(100)2 x 1 is modeled by density functional theory using a slab model, providing the adsorption structures, intermediates, adsorption energies, and reaction barriers. From the pi complex, the vinyl group can react with one Si dimer and also with two adjacent dimers. The [4 + 2] addition involving both the vinyl and the phenyl double bonds is barrierless, although it requires the proper alignment of styrene with the silicon dimer. Full coverage of the Si(100)2 x 1 surface through vinyl group adsorption can produce chiral structures due to the repulsion among neighboring styrene molecules. Simulated images provide new assignment for the experimental STM images, and vibrational frequencies are also calculated for comparison with experiment.