  State-of-the-art first principles calculations based on density functional
theory were performed on CH_3(CH_2)_{n-1}S-Au(111) systems. We show that the
adsorption site of methylthiolate at low coverage on the Au(111) surface is the
fcc site, not the hcp site as has been recently reported. Further, we report
results for chain length dependency and the electronic structure of the system.
