The possibility of observing light absorption on the SERS-active silver electrode

The intensity of light reflected from the SERS-active electrode was measured as a function of the potential and time. The different possible reasons for the observed changes of reflected light intensity are discussed. The investigations lead to the conclusion that the observed irreversible increase in intensity of reflected light is caused by an irreversible decrease in light absorption. It is well known that the decrease in potential and ageing of the electrode cause also irreversible changes of the SERS signal. It seems that the origin of observed irreversible variations of both the SERS signal and the light absorption in a SERS-active system is the same, viz. the irreversible decay of 'active sites.'