Chemical and electromagnetic mechanisms of tip-enhanced Raman scattering
In this paper, we attempt to reveal the nature of the chemical and electromagnetic mechanisms of tip-enhanced Raman scattering (TERS). Direct visual evidence regarding the chemical mechanism via charge transfer was obtained with charge difference density. It is found that there are several kinds of charge transfer: (1) tip to molecule, (2) surface to molecule, (3) tip and surface to molecule simul
