Optical parameters of spun on films of Calix-4-resorcinarene molecules by attenuated total reflection technique

Surface plasmon resonance (SPR) measurements under attenuated total reflection (ATR) were taken in air as well as in pure water, for an overlayer containing Calix-4-resorcinarene (Azol) molecules spun on Au coated slides. SPR data for both media used throughout this work were fitted to Fresnel reflection theory for a four layered (glass-Au-Azol-air or water) system. By varying the Azol film thickness during the fitting procedure, different solutions have been obtained for the film dielectric constant and hence its refractive index. The refractive index versus thickness for both media were plotted and from the intersecting point of the two curves an exact solution was found which gives film optical parameters of organic overlays.