DFT Study on the Intermolecular Substrate-mediated Interaction Energy in the Self-assembly of Alkanethiols on Silver

The B3LYP/LanL1 MB and B3LYP/LanL2DZ methods for Ag atom in conjunction with the 6-31G(d) basis set for S, C and H atoms were used to optimize the geometries and calculate the energies for (SCH3)mAg20 (m=1-4), resvectively. A single molecular adsorption energy of (SCH3)m (m=1-4) on Ag20 and the intermolecular substrate-mediated interaction energy were evaluated. The results revealed that there is a proportional relation between the single molecular adsorption energy and the substrate-mediated intermolecular interaction energy. The results qualitatively demonstrated the semi-empirical expression for the substratemediated interaction energy proposed previously by us is consistent with the results of the density functional theory.