Abstract
In this presentation we review some theoretical aspects of the combined Density Functional Theory/Molecular Mechanics (DFT/MM) approach designed to describe large molecular systems in an effective and efficient manner. We will introduce the concept of (polarizable) DFT/MM response theory thereby enabling calculation of a variety of molecular properties. Here we will focus on spectroscopic properties described by linear response with respect to the applied magnetic or electric field. Of special interest will be UV and NMR properties since these are ideal probes for extracting important information concerning the nature of the intermolecular interactions between a solute and the solvent. The methods developed will be applied to acetone and pyridine in aqueous solution. In all cases we find, upon comparison to experimental data, the DFT/MM scheme to be accurate and at the same time cost-effective.