How the Charge Transfer (CT) Contributions Influence the SERS Spectra of Molecules? A Retrospective from the View of Albrecht's “A” and Herzberg-Teller Contributions

The role of charge transfer (CT) contribution to the surface-enhanced Raman scattering (SERS) effect from the view of Albrecht's “A” and Herzberg-Teller (HT) contributions is presented. The basic understanding of Albrecht's “A,” “B,” and “C” terms and the HT selection rule are explained to understand the SERS-CT mechanism. The Albrecht's “A” and HT selection rule are then applied to wide varieties of organic molecules to test their relevance.