I describe several techniques for characterizing molecules based on the
shapes of their fields. The minimal distance between two molecular fields
is used as a shape-based metric, independent of the underlying chemical
structure, and a high-dimensional shape space description of the
molecules is generated. I then show how these attributes can be used in
creating, characterizing, and searching databases of molecules based on
field similarity. In particular, they allow searches of a database in
sublinear time. Next, I extend the utility of this approach by describing
a way to automatically break molecules into a series of fragments by
using an ellipsoidal Gaussian decomposition. Not only can these fragments
then be analyzed by the shape metric technique described above, but the
parameters of the decomposition themselves can also be used to further
organize and search databases. The most immediate application of these
techniques is to pharmaceutical drug discovery and design.