Advanced Methods of Theory-Experiment Comparison

As in DC voltammetry, theory and experiment comparisons of AC voltammetric data have usually been undertaken heuristically, where the experimenter decides empirically whether a satisfactory agreement between the experiment data and the model has been achieved. However, an estimation of the quality of the fit between experimental and simulated data can be gained by examining the residual sum of squares (RSS) or by the mean percentage error (MPE) [34]. 

Nimrod/G, as used in FT AC voltammetric studies, forms part of the Nimrod tool kit which performs a parameter sweep [35,40,41], where each parameter of interest is assigned a set of values. The Nimrod/G tool can generate all possible combinations of these values and executes the simulation outcome corresponding to each combination using the model provided. Normally, the results of the sweep are presented in the form of a contour map for the objective metric where x (horizontal axis) and y (vertical axis) are used as floating parameters and the others are fixed. The objective metric is defined as the normalized differences between values predicted by a model and the values actually observed. As the experimental and model sinusoids are not necessarily in phase, when the experimental and model outputs are filtered to produce the various harmonics, the data points with the same 

The Nimrod tools referred to above do not provide statistical analysis, but rather a comparison of simulated data based on a model and experimental data. However, it is planned to introduce to the Nimrod computer grid a statistical form of analysis based on Bayesian probabilities which will be applied to each FT AC experimental data set. In time, major improvements in the reporting of parameters such as EP, IP, a, R and CpL should emerge when the full power of e-science is routinely introduced into the analysis of voltammetric experiments. 

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