A method and apparatus for analysis of molecular combinations featuring two or more molecular subsets is described. The computational method estimates the electrostatic affinity of the system via utilization of a basis expansion representing charge density and electrostatic potential functions associated with the first and second molecular subsets in a coordinate system. An electrostatic affinity, representing a correlation of the charge density and electrostatic potential functions of the first and second molecular subsets, is computed via suitable application of translation and rotation operators to the basis expansion coefficients over a sequence of different sampled configurations for the molecular combination. The method may also be combined with other methods for computation of shape complementarity in determining a composite or augmented score reflecting both electrostatic affinity and shape complementarity for configurations of a molecular combination.