We note that the choice of a particular force field should depend on the system properties one is interested in.
Some applications require more refined force fields than others.
Moreover, there should be a balance between the levels of accuracy or refinement of different parts of a molecular model. Otherwise the computing effort put into a very detailed and accurate part of the calculations may easily be wasted due to the distorting effect of the cruder parts of the model. In other words, a force field which has a complicated potential form for representing bonds and angles and is very precise in terms of reproducing geometries and vibrational frequencies will not accurately model complex intermolecular interactions if the charge model is not also of high quality. The new charges which were developed for the 1994 force field are called RESP charges, for Restrained ElectroStatic Potential fit. This modification of the original ESP method was developed by Christopher Bayly, who was a postdoc in the group.