Tuning Vibrational Lifetimes by Chemical Substitution and Impact on Plasmon-Assisted Catalysis.

Recent experiments indicate that the NO stretch of 4-nitrobenzenethiol (NBT) attached to gold can be selectively excited via plasmonic excitation, catalyzing the decomposition of NBT. However, the effectiveness of catalysis is limited by intramolecular vibrational redistribution, which depletes the population of the excited NO stretch in a few picoseconds. In this study, vibrational lifetimes of the NO stretch are computed quantum mechanically for 20 substituted NBTs, including 10 chemical groups in the meta and ortho positions, attached to plasmonic nanoparticles.