The Grassian group is involved in several research areas including surface chemistry of environmental interfaces, heterogeneous atmospheric chemistry, climate impact of atmospheric aerosols, and environmental and health aspects of nanoscience and nanotechnology.
The Grassian Group has in recent years begun to apply Raman microspectroscopy to a number of types of aerosols present in the atmosphere: including mineral dust and marine sea spray aerosols. Raman microspectroscopy combines the molecular identification capabilities of vibrational spectroscopy with the spatial resolution of microscopy-based techniques. Raman spectra and maps are used to go beyond aerosol mixing state to identify and quantify of both different species present, while also observing how these species are distributed spatially throughout individual aerosol particles (internal structure). Overall, single-particle Raman microspectroscopy is a powerful method for chemical imaging and the non-destructive physicochemical characterization of aerosol particles. To extend the capabilities of the Raman instrument, a flow system was developed to investigate the effects of specified environmental conditions on the samples. In this newly designed flow system aerosol can be equilibrated at different relative humidities to study hygroscopicity and phase transitions or exposed to reactive gases to study reactions and their effect on particle morphology and heterogeneity.