"Combined Quantum Mechanics and Classical Electrodynamics Multiscale Approach for Calculating of SERS Spectra" (A Brief Survey, October 2013)

Abstract

The challenge to build a theory for calculating SERS optical response that inclu-des both quantum mechanics (QM) and electrodynamics (ED) lies with the fact, that the length scales needed for the two calculations differ in order of magnitude. Purely chemical models of SERS based on QM methods are generally limited to ~1 nm in size, including the metal particle/cluster, while electromagnetic field evaluations are usually based on grids or finite elements, that have 1 nm dimensions at the minimum. For this reason, theoretical treatments of SERS often take one of two paths: One approach neglects the CHEM enhancement and focuses on the predominant EM enhancement, while other studies only determine the CHEM enhancement using a small ato-mic cluster model of the nanoparticle. Much of current research in this field focuses on novel multiscale methods for analysis and understanding SERS mechanisms by combination of quantum mechanics (RT-TDDFT, LR-TDDFT) and classical electrodynamics (f.i. FDTD). The RT-TDDFT/ FDTD model will be briefly discussed here.