title: Polarizable density embedding: a new QM/QM/MM-based computational strategy.
abstract: We present a new QM/QM/MM-based model for calculating molecular properties and excited states of solute-solvent systems. We denote this new approach the polarizable density embedding (PDE) model, and it represents an extension of our previously developed polarizable embedding (PE) strategy. The PDE model is a focused computational approach in which a core region of the system studied is represented by a quantum-chemical method, whereas the environment is divided into two other regions: an inner and an outer region. Molecules belonging to the inner region are described by their exact densities, whereas molecules in the outer region are treated using a multipole expansion. In addition, all molecules in the environment are assigned distributed polarizabilities in order to account for induction effects. The joint effects of the inner and outer regions on the quantum-mechanical core part of the system is formulated using an embedding potential. The PDE model is illustrated for a set of dimers (interaction energy calculations) as well as for the calculation of electronic excitation energies, showing promising results.
authors.affiliation: †Laboratory of Computational Chemistry and Biochemistry, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland.|‡Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, DK-5230 Odense M, Denmark.
authors.forename: Jógvan Magnus Haugaard
authors.initials: JM
authors.lastname: Olsen
authors.affiliation: ‡Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, DK-5230 Odense M, Denmark.
authors.forename: Casper
authors.initials: C
authors.lastname: Steinmann
authors.affiliation: §Centre for Theoretical and Computational Chemistry, Department of Chemistry, University of Tromsø-The Arctic University of Norway, N-9037 Tromsø, Norway.
authors.forename: Kenneth
authors.initials: K
authors.lastname: Ruud
authors.affiliation: ‡Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, DK-5230 Odense M, Denmark.
authors.forename: Jacob
authors.initials: J
authors.lastname: Kongsted