A review for DFT in chemical mechanism of SERS studies.

This review presents the state of the art in using density functional theory (DFT) to investigate the mechanism of chemical enhancement in surface enhanced Raman scattering (SERS). Computational DFT models have been shown to align well with experimental data and to be useful in their interpretation. In this context, the combined use of theoretical data and experimental SERS results can help explore the mechanisms contributing to chemical amplification. This review examines the application of DFT to estimate chemical enhancement of SERS under the following conditions: the presence of silver ions on the surface, the size and stability of metal clusters, the energy characteristics of the investigated molecule in the system from the cluster size in molecule-nanoparticle models, changes in the spatial orientation of the molecule on the nanoparticle surface depending on the concentration of molecules. Additionally, the review analyses the influence of the metal cluster shape and size in DFT calculations in simplified cluster systems. This information will be useful for researchers working with experimental SERS aspects.