Comparison of IR and SERS spectroscopy for investigation of catalytic reactions on cold-deposited Cu

Infrared (IR) and surface-enhanced Raman spectroscopy (SERS) of similarly prepared samples show different results that cannot be explained by different selection rules. One main difference is the missing of a signal of NO in the SERS spectra, only reaction products like N/sub 2/ and N/sub 2/O could be seen, whereas in IR clearly NO vibrations were detected. IR spectra were taken to investigate the influence of additional heat and additional photons during the measurement. Besides desorption, no influence like increase of the reaction products N/sub 2/ or N/sub 2/O could be found. It seems to us that a disturbance of the investigated system due to laser irradiation during SERS is not the explanation for the different findings.