Theoretical modeling of chemical and biological processes is a key to understand nature and to predict experiments. Unfortunately, this is very data and computation extensive. However, the worldwide computing grid can now provide the necessary resources. Here, we present a coupling of the GAMESS quantum chemical code to the Nimrod/G grid distribution tool, which is applied to the parameter scan of a group difference pseudopotential (GDP). This represents the initial step in parameterization of a capping atom for hybrid quantum mechanics-molecular mechanics (QM/MM) calculations. The results give hints to the physical forces of functional group distinctions and starting points for later parameter optimizations. The demonstrated technology significantly extends the manageability of accurate, but costly quantum chemical calculations and is valuable for many applications involving thousands of independent runs.