Nonorthogonal configuration interaction to study electron and excitation energy transfer

R K Kathir


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A theoretical study of electron transfer (ET) and excitation energy transfer (EET) processes can yield a more nuanced understanding of the underlying physics that is not always accessible through experiments. The focus of this thesis is the development of nonorthogonal configuration interaction (NOCI) - Fragments, an electronic structure method that has shown promise for the study of ET and EET phenomena. The main aspects of NOCI fragments are: the ability to maintain the diabatic nature of the molecular states involved, a compact extension of the NOCI wave function in terms of many electron base functions (MEBFs) that spin-adapted antisymmetric products of molecular (multiconfiguration) wave functions, direct accessibility of electronic coupling between diabatic states and the inclusion of static correlation effects. NOCI is therefore a viable option to provide an unbiased description of the ground and excited state wavefunctions in a molecular cluster. Singlet fission (SF) is a widely studied EET process for its promise to improve organic photovoltaic efficiency and was chosen as a suitable application to investigate using NOCI fragments. The work done in the thesis enables NOCI-Fragments to: study large molecular systems relevant to ET and EET processes, using multiconfiguration wavefunctions with moderately large active spaces as the initial molecular wavefunctions, dynamic correlation effects within each molecule, and environmental effects. The advances made in this thesis will be helpful to get a clearer and more realistic picture of some photophysical phenomena.
Originele taal-2English
KwalificatieDoctor of Philosophy
Toekennende instantie
  • Rijksuniversiteit Groningen
  • de Graaf, Coen, Supervisor
  • Braam, Ria, Supervisor
  • Havenith, Remco, Co-supervisor
Datum van toekenning18-jan-2022
Plaats van publicatie[Groningen]
StatusPublished - 2022

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