A RAPID CALCULATION OF THE COULOMB FIELD IN LARGE MOLECULES

RECENTLY THERE HAS BEEN A RAPIDLY GROWING INTEREST IN DENSITY FUNCTIONAL THEORY (DFT) AS A GENERAL PROCEDURE FOR PREDICTING PHYSICAL PROPERTIES OF MOLECULES. THIS IS RELATIVELY INEXPENSIVE COMPARED TO TRADITIONAL CORRELATED METHODS. FOR THE LARGEST MOLECULAR SYSTEMS WHOSE STUDY IS FEASIBLE BY THE CURRENT DFT PROGRAM (SEVERAL HUNDRED ATOMS), THE TREATMENT OF THE COULOMB INTERACTIONS, WITH ITS QUADRATIC COST IN SYSTEM SIZE, IS COMPUTATIONALLY DOMINANT. IN ORDER TO BE ABLE TO PERFORM CALCULATIONS ON TRULY LARGE MOLECULES, A BREAKTHROUGH IN THE SCALING OF THE COULOMB CONTRIBUTION IS REQUIRED. IN PHASE I AN ALTERNATE APPROACH TO THE COULOMB PROBLEM WHICH WILL REDUCE THE INTRINSIC ORDER OF THE COMPUTATIONAL COST DEPENDENCE ON SYSTEM SIZE WILL BE INVESTIGATED. DURING PHASE I AN INITIAL IMPLEMENTATION OF THIS METHOD WILL BE DEVELOPED AND TESTED, AND, SINCE THE APPROACH IS PARTICULARLY WELL-SUITED FOR MASSIVELY PARALLEL ARCHITECTURES, SUBSEQUENT EXTENSION TO SUCH PLATFORMS DURING PHASE II IS NOT EXPECTED TO BE DIFFICULT.