Peptide monolayers on metal study by FELIX using surface electromagnetic waves

摘要

Infrared (IR) spectroscopy is successfully used in the vibrational study of surfaces to identify molecular structures on these surfaces. One of the techniques improving the sensitivity of IR surface analysis is the spectroscopy of surface electromagnetic waves (SEW) . The SEW is a sensitive probe for diagnostics of the surface as far as its amplitude is maximal on the surface and exponentially decays above the surface. Collimated and polarized laser radiation can be effectively converted into SEW. Free-electron lasers covering a broad spectral range are excellent sources for SEW spectroscopy and had just been used to study very thin films on metals. The measurements of propagation parameters of the SEW for different frequencies allow to obtain optical constants of the media of interest from experimentally measured parameters. The SEW propagation can be described by the absorption index (characterizing SEW attenuation along the surface) and by the SEW effective refractive index (related to the SEW phase velocity).