Collective Mid-Infrared Vibrations in Surface-Enhanced Raman Scattering
Niclas S. Mueller, Rakesh Arul, Lukas A. Jakob, Matthew O. Blunt, Tamás Földes, Edina Rosta, Jeremy J. Baumberg
Abstract
, tuning with the mixing fraction and IR dipole strength, in excellent agreement with microscopic models and density functional theory. These cooperative frequency shifts can be used as a ruler to measure intermolecular distance and disorder with angstrom resolution. We demonstrate this for photochemical reactions of 4-nitrothiophenol, which depletes the number of neighboring IR-active molecules and breaks the collective vibration, enabling direct tracking of the reaction. Collective molecular vibrations reshape SERS spectra and need to be considered in the analysis of vibrational spectra throughout analytical chemistry and sensing.