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Magnetic circular dichroism and aromatic compounds
Štěpánek, Petr ; Bouř, Petr (advisor) ; Matějka, Pavel (referee) ; Srnec, Martin (referee)
Title: Magnetic circular dichroism and aromatic compounds Author: Petr Štěpánek Department/Institute: Institute of Organic Chemistry and Biochemistry AS CR, v.v.i. Supervisor: prof. RNDr. Petr Bouř, DSc., Institute of Organic Chemistry and Biochemistry AS CR, v.v.i. Abstract: The thesis presents a series of studies concerning magnetic circular dichroism (MCD), a spectroscopic method, which experienced an intense theo- retical development in the recent years. New computational codes opened possi- bilities to calculate MCD spectra of larger and more varied molecules than was possible in the past. In the presented studies, we took the advantage of the new computational codes to broaden the possible span of applications of the MCD technique. As an example, we present MCD as a method useful for obtaining information about the structure of fullerenes. We also studied the influence of the molecular conformation and the explicit and implicit solvent models on the MCD spectra of aromatic amino acids using the newly implemented alterna- tive computational protocol based on sum-over-states calculations. We have also theoretically predicted spectra of the nuclear spin circular dichroism (NSCD), a potential new high-resolution spectroscopy. Keywords: magnetic circular dichroism, quantum-chemical calculations, density...
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Electronic structure calculations of biologically relevant transition metal complexes
Matoušek, Mikuláš ; Veis, Libor (advisor) ; Mančal, Tomáš (referee)
Porphyrins are an important class of biomolecules, which are heavily studied, both ex- perimentally and computationally. But, despite the intensive efforts, for many questions we still aren't able to consistently find an agreement between theory and experiment. One of the still unresolved issues is the character of the ground state of the Fe(II)-porphyrin molecule. We used a model of the Fe(II)-porphyrin molecule to study the effects of geometrical changes on the spin states. By carrying out extensive DMRG-CASSCF cal- culations topped with TCCSD correlation treatment we are able to link the effects of these geometrical changes to the experimental results, and predict a quintet ground state for the isolated Fe(II)-porphyrin molecule. Also, using a ligated porphyrin belonging to the iron porphyrin carbene class of molecules, we demonstrate by combining the CASSCF and AC0 methods that geometrical changes outside the porphyrin core cannot be over- looked. 1
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Magnetic circular dichroism and aromatic compounds
Štěpánek, Petr ; Bouř, Petr (advisor) ; Matějka, Pavel (referee) ; Srnec, Martin (referee)
Title: Magnetic circular dichroism and aromatic compounds Author: Petr Štěpánek Department/Institute: Institute of Organic Chemistry and Biochemistry AS CR, v.v.i. Supervisor: prof. RNDr. Petr Bouř, DSc., Institute of Organic Chemistry and Biochemistry AS CR, v.v.i. Abstract: The thesis presents a series of studies concerning magnetic circular dichroism (MCD), a spectroscopic method, which experienced an intense theo- retical development in the recent years. New computational codes opened possi- bilities to calculate MCD spectra of larger and more varied molecules than was possible in the past. In the presented studies, we took the advantage of the new computational codes to broaden the possible span of applications of the MCD technique. As an example, we present MCD as a method useful for obtaining information about the structure of fullerenes. We also studied the influence of the molecular conformation and the explicit and implicit solvent models on the MCD spectra of aromatic amino acids using the newly implemented alterna- tive computational protocol based on sum-over-states calculations. We have also theoretically predicted spectra of the nuclear spin circular dichroism (NSCD), a potential new high-resolution spectroscopy. Keywords: magnetic circular dichroism, quantum-chemical calculations, density...
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