Implementation and refinement of the modified-conductorlike screening quantum mechanical solvation model at the MP2 level

A modified conductorlike screening continuum solvation model, implemented in the quantum chemistry program GAMESS, has been extended to second order perturbation theory (MP2). Two possible schemes have been considered: (a) the calculation of the MP2 energy using the solvated Hartree-Fock (HF) orbitals, and (b) the implementation of a double-iterative procedure where the HF density is updated with respect to the MP2 surface charges. The influence of the self-consistency of the surface charge distribution with respect to the MP2 density has been analyzed for a small dataset of 21 neutral molecules and 13 ions. In addition, the details of the distribution of surface charge density (sigma profiles) and the effects of electron correlation on the accuracy of such distributions is analyzed in terms of the overall concept of deviation of continuum models from dielectric theory, leading to insights into higher order models. (C) 2000 American Institute of Physics. [S0021-9606(00)52741-X].