Sum frequency generation studies of surfaces of high-surface-area powdered materials.

Abstract

We report the first observation of sum frequency generation (SFG) photons on high-surface-area powders, critically important materials in heterogeneous catalysis. We utilize SFG in total internal reflection (TIR) geometry and show that the TIR-SFG approach markedly reduces the destructive interference associated with nonlinear optical spectroscopy of small particle surfaces, making SFG studies of high-surface-area powders possible. The index of refraction of materials and their distance from the TIR-SFG prism are key parameters in generating and detecting the sum frequency signal. We find that TIR-SFG is highly sensitive to capillary condensation. To demonstrate the capability of the TIR-SFG technique, we measure the thermodynamics of methanol adsorption and desorption on high-surface-area SiO2.

Cite this paper

@article{Yeganeh2006SumFG, title={Sum frequency generation studies of surfaces of high-surface-area powdered materials.}, author={Mohsen S. Yeganeh and Shawn M Dougal and Bernard G Silbernagel}, journal={Langmuir : the ACS journal of surfaces and colloids}, year={2006}, volume={22 2}, pages={637-41} }