A REPRESENTATION OF THE EXCHANGE OPERATOR USEFUL FOR LARGE MOLECULES

A simple and efficient way of representing the kernel of an exchange operator that still maintains its non-local character, is presented here. Such an approach seems particularly effective in the case of large molecules constituted by separate, well-defined chemical fragments whose contributions to the kernel of the total exchange operator can be prepared through separate calculations on each fragment. The performance of the method is illustrated through calculations on a specific molecular example.