|
|
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
|
|
|
Collisions of electrons with diatomic molecules
Matoušek, Mikuláš ; Houfek, Karel (advisor) ; Čížek, Martin (referee)
For succesfully carrying out R-matrix calculations, a good description of the excited states of the neutral molecule around the equilibrium is needed, obtained by an ab-initio method in a relatively small basis. It is also neccesary to have potential curves of the neutral molecule and the anion that are consistent with the experimentally obtained values for the molecule and are used to set up the initial parameters of these calculations. In this work we are trying to find a description of the excited states and to obtain reference curves in order to perform R-matrix calculations for two molecules, BeH and OH. For BeH we propose a description of the excited states by the SA-CASSCF method with an active space of 6,2,2,0 and in the aug-cc-pVDZ basis. Similarly for OH a description by the SA-CASSCF method with an active space of 6,2,2,0 or 7,3,3,0 and an in an aug-cc-pVDZ basis should be used, where we have also found a setting of the weights of the states in the SA-CAS-SCF method significantly improving the shape of the curves. We have not yet been able to perform the R-matrix calculations because of insufficient time. 1
|
guest ::
RSS feed.