Charge transfer of alkanethiolate adsorbed on Au(111) surface : First-principles calculations

The electronic structures of the self-assembled monolayers (SAMs) of n-alkanethiolate [CH₃(CH₂)_nS, n=1-5] on Au(111) surface have been investigated using the state-of-the-art first-principles calculations. The adsorption energy, the tile angle, and the partial charge of n-alkanethiolate were presented. The charge transfer at the metal-molecule interface was calculated by the Mulliken population analysis. It was found that a net charge transfer of 0.11 e~0.15 e from gold surface to n-alkanethiolate molecules. Most of the charge transfer is accumulated in the carbon atom which is nearest to the sulfur atom. The result shows that the charge transfer is independent of chain length of n-alkanethiolate.