Cluster-in-solid Embedding for Strongly Correlated Ionic Systems.

Uwe Birkenheuer

Max Planck Institute for Chemical Physics of Solids, Dresden, Germanny

Many complex solids, such as Ca2Li6[Mn2N6], which contain transition metals or even rare earth metals exhibit interesting but quite unusual chemical bondings. To investigate such bonding situations, wave-function-based quantum chemical investigations are necessary to obtain the correlated 2-particle density matrix of these compounds. Electron  localization indices (like ELI or ELI-D) can then be applied to identify the various kinds of chemical bondings in space. Standard wave function-based quantum chemical calculations are sill not possible for solids. In order to make such calculations accessible for non-metallic solids, an embedding scheme has been set up which is based on freezing the, preferentially ionic, environment of an active cluster. In order to avoid approximations like in the AIEMP (ab initio effective embedding potentials) approach, the frozen orbitals in the direct vicinity of the active cluster are explicitly included in the quantum chemical calculations.