Enhancement of molecular circular dichroism with silver nanoparticles

Plasmon resonances in metal nanoparticles provide a powerful way to amplify molecular circular dichroism (CD). In this paper, we use time-dependent density-functional theory to systematically investigate the CD enhancement of a molecule on a silver nanoparticle or sandwiched between two silver nanoparticles. We find that in both systems the enhancement increases roughly as the square root of the number of Ag atoms up to the considered 923-atom Ag particle. The enhancement in dimers is more significant. In addition, we analyze the influences of the molecular orientation, molecule-nanoparticle distance, and the molecular coverage on the CD enhancement.