Practical considerations of the ir attenuated-total-reflection (ir-ATR) technique for electrochemical investigations

✍ Scribed by Brian W. Johnson; Jörg Bauhofer; Karl Doblhofer; Bruno Pettinger

• Publisher: Elsevier Science
• Year: 1992
• Tongue: English
• Weight: 860 KB
• Volume: 37
• Category: Article
• ISSN: 0013-4686
• DOI: 10.1016/0013-4686(92)85128-8

✦ Synopsis

Abstract4old or platinum thin metal electrodes have been sputtered onto germanium or galliumarsenide i transparent crystals for use in attenuated-total-reflection (ATR) spectroelectrochemistry. These different crystal/metal combinations have been used to obtain i spectra of a third medium (water or air) and the results compared with theoretical responses calculated via the well-known Fresnel fomulae. It is shown that widely different spectra are obtained for the different systems. very good in some cases and very poor in others. Agreement with theory is obtained in the cases where no metal layer is present, and in the case of 2Onm Pt upon Ge. In all other cases significant discrepancies between the calculated and measured optical behaviour are apparent. These differences arise because tire optical properties of the thin metal layers are not the same as the bulk, either due to non-ideal geometric arrangement of the atoms (eg island structures) or through compositional changes caused by interdiffusion of the phases in the process of film formation.