Nonlinear optical response of molecule in inhomogeneous solvation environment: A response theory formalism

We present a method for determining quadratic response molecular properties of heterogeneously solvated molecules. The method enables the calculation of frequency-dependent hyperpolarizabilities and two-photon transition matr ix elements of molecules that are (i) located at the surface of a metal or (ii) solvated alongside the surface of a metal. The metal is represented as a perfect conductor and the solvent is described by a dielectric medium. T he method is able to describe the electronic structure of the molecular sys tems both at the uncorrelated and correlated electronic structure levels. T he latter is given by the multiconfigurational self-consistent field method . We have completed sample calculations of the frequency-dependent first-or der hyperpolarizability tensor and two-photon matrix elements for heterogen eously solvated CO. We find that the molecular properties depend strongly o n the heterogeneous solvent configuration. (C) 2001 American Institute of P hysics.