Carlson, Rebecca2017-10-092017-10-092017-07https://hdl.handle.net/11299/190460University of Minnesota Ph.D. dissertation. July 2017. Major: Chemistry. Advisor: Laura Gagliardi. 1 computer file (PDF); xii, 382 pages.The electronic structure and properties of various homo- and hetero-bimetallic complexes, which are relevant for small molecule activation, are discussed based on experimental and computational methods, including wave function theory and density functional theory. Due to their multiconfigurational nature, the theoretical challenges associated with transition metal complexes are also analyzed. A new method, Multiconfiguration Pair-Density Functional Theory (MC-PDFT), that is able to combine a multiconfigurational wave function with a density functional is introduced as a new way to treat these multiconfigurational systems and results on a wide variety of systems show, in general, good agreement with CASPT2. One of the fundamental quantities in MC-PDFT is the on-top pair density. An analytic solution of the on-top pair density is presented for H2 and as well as its relevance in understanding bond breaking.enbimetallicdensity functional theorymulticonfigurationaltransition metalswave function theoryThesis or Dissertation