Vibrationally resolved sum-frequency generation with broad-bandwidth infrared pulses

We present a novel procedure for vibrationally resolved sum-frequency generation (SFG) in which a broad-bandwidth IR pulse is mixed with a narrow-bandwidth visible pulse. The resultant SFG spectrum is dispersed with a spectrograph and detected in parallel with a scientific-grade CCD detector, permitting rapid and high signal-to-noise ratio data acquisition over a 400-cm(-1) spectral region without scanning the IR frequency. Application to the study of a self-assembled monolayer of octadecanethiol is discussed.     

Nonlinear optics of chiral surface systems

Differential SHG signals from chiral surfaces are recorded using right and left circularly polarized incident light. We show that chiral information from the surface is conveyed through this SHG process. This study focuses on the model protein system, cytochrome c, adsorbed on various self-assembled mono- and bi-layers at the solid/liquid interface. SHG-CD signals are shown to be related to the oxidation state of the protein and are utilized to observe changes in this feature of the protein in situ at surfaces of varying chemical properties. Received: 20 September 1998 / Revised version: 9 December 1998