Let There Be Light, Let There Be Surfaces, Let the Two Interact--Probing Surface Chemistry Using Nonlinear Spectroscopy

Abstract: With the advent of lasers producing light beams of high peak power, and thereafter the first demonstration of frequency doubling of optical light by Franken et.al. in 1961, the new branch of physics known as nonlinear optics emerged. The generation of optical harmonics from materials that lack inversion symmetry was most appealing due its potential application to selectively investigate the structures of surfaces and interfaces where centrosymmetry is broken. It was in the 1980s that nonlinear spectroscopy (NLS), namely, second harmonic (SHG) and sum frequency generation (SFG), of surfaces became a reality. In this presentation I will discuss the nature of nonlinear spectroscopy in relation to the traditional “linear” spectroscopy and highlight the significance of surface chemistry and the role of NLS in surface science. Selected research involving the equilibrium and kinetic processes at the planar and colloidal interfaces will also be presented.

Professor Mahamud Subir
Department of Chemistry, Ball State University