A GAUSSIAN DESCRIPTION OF MOLECULAR SHAPE

A simple description of molecular shape is presented in which overlapping atom-centered Gaussians replace the more conventional intersecting hard spheres. Expressions for the volume and surface area of this Gaussian model are obtained, as are the gradient and Hessian of the nuclear coordinate derivatives. The quantities calculated using the Gaussian model are compared to their hard-sphere analogues, for simple model systems, small molecules, and some macromolecules (proteins).