Density functional theory fragmentation model

In recent years researchers have begun to use density functional theory to model supported metal complexes, representing the support as a cluster (fragment of the bulk support). Examples of supported complexes characterized by both theory and spectroscopy are presented below. 

Two limiting-case surface structures, Re(CO)3 OMg 3 and Re(CO)3 HOMg 3, represented here as structures A and B, have been modeled with density functional theory, with the MgO being represented as a fragment of its surface, shown in the structures below (Hu etaL, 1999). Consistent with the experimental results, the most stable species (structure A) was found to exist... 

Abstract We review and further develop the excited state structural analysis (ESSA) which was proposed many years ago [Luzanov AV (1980) Russ Chem Rev 49 1033] for semiempirical models of r r -transitions and which was extended quite recently to the time-dependent density functional theory. Herein we discuss ESSA with some new features (generalized bond orders, similarity measures etc.) and provide additional applications of the ESSA to various topics of spectrochemistry and photochemistry. The illustrations focus primarily on the visualization of electronic transitions by portraying the excitation localization on atoms and molecular fragments and by detaiUng excited state structure using specialized charge transfer numbers. An extension of ESSA to general-type wave functions is briefly considered. 

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