On the other hand, it also demonstrates that for a given surface composition the variation in binding energies and thus in catalytic activity induced by different configurations outside the adsorption ensemble may be small and can in many cases be neglected. This is even when considering that the binding energy enters the rate exponentially, leading to a weighting preference for the optimum binding energy. Finally, while focusing here on smooth bimetallic surfaces, a similar approach as described in the above papers is of course also possible for other surfaces and even catalyst nanoparticles with a variety of different active sites. In a more general sense, this also leads to the conclusion that the often used picture of 'the active site' is in most cases incorrect. Instead, the reaction is likely to proceed on a variety of different active sites, all of which contribute to the overall reaction rates, though by different amounts. Only in cases where the difference in activity between the most active site and other, less active sites is rather large the reaction will be dominated by a single type of active site. On the other hand, this also means that the reaction may not necessarily be dominated by the most active site. This would be the case, e.g., if the relative number of less active sites is so much larger than that of the most active site that the contribution from the most active site is small compared to the contributions from the other site(s).