Screening effects in surface infrared spectra of CO adsorbed on electrodes: application to isothermal desorption measurements

Infrared spectra of CO adsorbed on platinum electrodes were examined for ef fects of dielectric screening. Screening of the incident infrared radiation field by the adlayer polarization typically results in non-linear relation ships between adsorbed CO vibrational band intensities and CO surface cover ages. It is shown that the solvent in the electrochemical environment can r educe the strong Beer's law deviations observed for adsorbed CO in vacuum b y maintaining the adlayer polarizability more constant with changes in CO s urface coverage. The screening analysis was applied to correct adsorbed CO infrared peak absorbances in measurements of rate constants for CO desorpti on from electrodes. (C) 1999 Elsevier Science B.V. All rights reserved.