Electrochemical impedance spectroscopy (EIS) is a powerful technique to study electrochemical processes and to perform screening tasks. Recently an integrated measuring and modeling methodology for EIS based on a multisine excitation signal was developed. A key issue in this methodology is the data analysis, allowing us to rapidly quantify the reliability of the measured data. In this paper, a comparison is made between classical single-sine and the proposed multisine measurements on the same system. The fitting of the impedance data obtained by single-or multisine excitation and using different weighting factors is also discussed. In addition to the advantages reported in earlier work, it is concluded that, of all investigated frequencies, the odd random phase multisine excitation yields the highest quality data in the shortest measurement time.

No abstract

Experimental results for the adsorption frequencies of SCNon a silver electrode obtained with the surfaceenhanced Raman spectrometry (SERS) method are presented and discussed. These results were confronted with a quantum chemical DFT-based study. Different clusters were used from the simple monoatomic case to a much more realistic representation of the silver electrode by means of a Ag 23 cluster simulating the (100) surface. The calculations were performed at the B3PW91/LanL2DZ and the BP86/TZP level. The interaction energies indicate the importance of the cluster size and calculation level. The cluster size was increased until the results were converged. Calculated vibrational frequencies for the different possible adsorption geometries on a (100) surface are compared with experiment. Together with the interaction energy results, they indicate that the preferred interaction via the sulfur atom on a hollow site of the silver electrode is in agreement with the hard and soft acids and bases principle.

No abstract