46: Overcoming fluorescence in time-resolved sum frequency generation spectroscopy of organic pollutants using a spatial filter

Abstract: Despite the known environmental impact of organic pollutants, their interactions and photo-induced reaction mechanisms at aqueous interfaces remain poorly understood. Femtosecond time-resolved sum frequency generation (TR-SFG) spectroscopy with ultraviolet excitation is a powerful technique for studying these ultrafast dynamics. However, competitive fluorescence from certain molecules often overwhelms the desired SFG signal. Here, we demonstrate the use of a spatial filter to successfully suppress fluorescence scattering from phenol at the air-water interface. This approach enables the characterization of adsorption behaviors and the unraveling of photo-induced reaction mechanisms for atmospherically relevant organic pollutants at aqueous interfaces.