Computational Methods for Ensemble Averaged Surface-Enhanced Raman Scattering

With support from the Chemical Theory, Models and Computational Methods program in the Division of Chemistry, Professor Lasse Jensen of Pennsylvania State University will develop new theoretical methods to describe ensemble averaged surface-enhanced Raman scattering (SERS). SERS is a powerful technique that can be used to obtain detailed information about chemical reactions and the orientation of molecules on surfaces. Modeling is important to obtain this information but remains difficult due to the complicated interface and the need to average over many different molecular orientations. Professor Lasse Jensen and his team will develop new computational tools to describe this spectroscopy that will be disseminated to the broad scientific community through incorporation into available computational chemistry software packages. Using interactive simulators, Dr. Jensen will educate students on nano-concepts, machine learning and fundamental theory; and emphasize the interplay between theory and experiments. In this project, the Jensen team at Pennsylvania State University will develop a multiscale model that goes beyond the harmonic approximation and allows for sampling over molecular configurations such that ensemble averaged surface-enhanced Raman scattering (SERS) can be modeled. The proposed research will provide new theoretical tools for fundamental understanding of dynamics and orientation of molecules on nanoparticle surfaces for characterizing of interfaces of relevance for heterogeneous catalysis, photovoltaics, and molecular sensing. The combination of a machine-learning approach with an efficient multiscale model is expected to enable simulations of ensemble-averaged SERS spectra that include both electromagnetic and chemical enhancement mechanisms. The developed computational tools will be disseminated to a broad scientific community through incorporation into software packages. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.