Physical, Analytical, and Materials Chemistry

Laser Raman Spectroscopies

Our group's research focuses on using the inelastic laser light scattering technique known as resonance Raman spectroscopy to study the specific atomic-level motions that occur in a molecule or nanocrystal immediately after it absorbs light. This information is particularly relevant to the mechanisms of photochemistry, vision, photography, xerography, and natural and artificial  photosynthesis (solar energy conversion).  Our work involves close coupling between experimental measurements and computational simulations of the Raman spectra.  In addition to work on standard resonance Raman scattering, we have developed the two-photon analog, resonance hyper-Raman spectroscopy, as a tool to explore the structures and dynamics of two-photon allowed states of molecules and materials. The large enhancement of the scattering intensities observed for molecules adsorbed to the surfaces of silver and gold nanoparticles (surface enhanced Raman and hyper-Raman scattering) has been explored both theoretically and experimentally and has been applied to help understand the efficiency enhancement of organic polymer-based solar photovoltaic devices by metallic nanostructures.  A currently active and exciting area of our group’s research is the use of resonance Raman spectroscopy to probe how the vibrations (phonons) of semiconductor nanocrystals couple to the electronic states of these materials.