| Abstract: | The direct reaction field (DRF ) method, developed to incorporate the effects of a (large) semiclassical environment into the Hamiltonian of a quantum mechanical system, is briefly reviewed. It is shown that the DRF method behaves—at least—like a supermolecule SCF calculation. With the water dimer as an example, the similarity with the SCF procedure is demonstrated, and an application to the interaction between the active site of papain and the remaining 3000 or so atoms of this protein shows the inadequacy of dielectric constant models and the necessity of including atomic polarizabilities in model force fields. |
