Optical Investigations of Film Formation and Removal on Gold Anodes in Acidic Oxalate Solutions
RECENT investigations of the oxidation of oxalate ions in acidic solutions using gold anodes have provided electrochemical evidence for the formation of a film on this anode during steady-state electrolysis at potentials well below that for Au2O3 formation, 1.36 V normal hydrogen electrode1. The determination of the nature of the film on gold at potentials below 1.36 V using electrochemical techniques has introduced uncertainties as to whether the film is a ‘three dimensional’ oxide film or a ‘two dimensional’ chemisorbed oxygen film. Some investigators2–5 using charging curves as their basis conclude that the formation of an oxide occurs only above 1.36 V, the formation of a chemisorbed oxygen film being the process occurring below this potential. The formation of this chemisorbed oxygen film begins at potentials as low as 1 15 V (ref. 6). Other work, however, also based on electrochemical evidence, indicates that the formation of an oxide film does occur below 1.36 V (ref. 7).
Application of Auger and Photoelectron Spectroscopy to Electrochemical Problems
Auger electron spectroscopy (AES) and X-ray photoelectron spectroscopy (XPS), known also as electron spectroscopy for chemical analysis (ESCA), were used originally in surface physics and theoretical chemistry but their range of application has expanded rapidly.
Glass Dewars for Optical Studies at Low Temperatures
All glass or predominantly glass vessels are well suited to spectroscopic or photochemical studies down to temperatures as low as 1.2°K. The choice of glass offers advantages of economy and simplicity in addition to allowing for a large degree of flexibility to be incorporated into a given design. A number of such Dewars are described and their relative merits discussed. It is shown that the heat leak arising from the optical arrangement is, in general, not serious.