Adsorption of a Methylthio Radical on Silver Nanoparticles: Size Dependence

A systematic study of the adsorption of a methylthio on different sites of silver nanoparticles of 13, 55, 147, and 309 atoms with icosahedral symmetry as well as on the (111) surface is performed using density functional theory. Ab initio molecular dynamics were used to obtain the adsorption energies, atomic positions, and electronic properties of the lowest-energy configurations. Different adsorption sites and orientations of the molecule were tested. The electronic density of states also shows a size dependence, in which a transition from discrete to more band-like structure is found. Adsorption of a second methylthio is also studied. It was observed that final structures, adsorption energies, and electronic density of states strongly depended on the nanoparticle size and thus on the atomic coordination number, where bridge configurations had the lowest total energy and the highest adsorption energy for all sizes except Ag<sub>13