Influence of the Au-S bond in the self-assembled monolayer of the helical peptides on gold

We numerically investigate molecular arrangement and orientation in the sel f-assembled peptide monolayer adsorbed on Sold considering dipoles of each amide group in peptides and a dipole due to the Au-S bond at the chemisorpt ion site. We investigate a single peptide adsorbed on gold and SAM of two d imensional crystal. Comparing their results with that of ignoring Au-S dipo le, we show that molecules can take an orientation standing normal to the s urface by Au-S dipole.