In this talk we will present the results of DMRG calculations on Iron-Sulfur molecules. These molecules are ubiquitous in nature and catalyze for example electron-transport in photosynthesis and reduction of atmospheric nitrogen to ammonia in biological nitrogen fixation.Here we target two sets of molecules, one containing a planar Fe2S2 moiety and the other containing cubane Fe4S4 moiety. These molecules are strongly correlated quantum systems with many nearly degenerate molecular orbitals which present significant challenges for electronic structure calculation. They also contain many closely spaced spin states which give rise to interesting magnetic properties. To resolve these nearly degenerate spin states we have developed an efficient spin-adapted DMRG code. In addition, the molecule containing Fe4S4 moiety has nearly three fold degenerate ground state. Special perturbations are applied to Hamiltonian to break this degeneracy and guide DMRG towards the ground state of interest. The results of our calculations will be compared with previous DFT studies and experimental results.

Iron-sulfur chemistry using density matrix renormalization group (DMRG)

244th National Meeting (2012)

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