Calculation of Surface-Enhanced Raman Spectra Including Orientational and Stokes Effects Using TDDFT/Mie Theory QM/ED Method

This chapter describes new models combining a quantum mechanical description of a molecular system and an electrodynamics (ED) description of a metal nanoparticle to determine surface-enhanced Raman spectra. The models considered involve inclusion of frequency dependence, Stokes shifts, and the effects of surface averaging into previously developed models. The chapter presents calculations with one of the models using a multi-nanoparticle system, and this is found to provide more experimentally realistic enhancements which slightly improve the spectra. New multiscale models have recently been developed for the combination of quantum mechanics (QM) and classical ED for describing surface-enhanced Raman and hyper-Raman spectra including chemical (CHEM) and electromagnetic (EM) enhancement mechanisms for both. In these models, TDDFT is used for the QM calculation, and Mie theory is used for the ED calculations.