@article{Engels1993, author = {Engels, Bernd}, title = {Study of influences of various excitation classes on ab initio calculated isotropic hyperfine coupling constants}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-58973}, year = {1993}, abstract = {Reliable prediction of the isotropic hyperfine coupling constant A\(_{iso}\) is still a difficult task for ab initio calculations. Strang dependence on the method employed for its ca1culation has been found. Within a CI ansatz A\(_{iso}\) is considerably affected by the excitation classes taken into account within the CI calculation. In the present work the influence of various excitation classes on A\(_{iso}\) is examined. Calculations including all single, double, triple and a large part of the quadruple excitations are performed and the individual effects of the excitation classes are studied. It is found that the surprisingly good agreement found for S-CI treatments is due to large error cancellations. The importance of higher than double excitations arises from their indirect influence on the single excitations.}, subject = {Organische Chemie}, language = {en} } @phdthesis{Remenyi2006, author = {Remenyi, Christian}, title = {Density Functional Studies on EPR Parameters and Spin-Density Distributions of Transition Metal Complexes}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-19848}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2006}, abstract = {In dieser Arbeit wurden EPR-Parameter und Spindichteverteilungen von {\"U}bergangsmetallkomplexen mit Hilfe der Dichtefunktionaltheorie (DFT) berechnet. Um das Potential der DFT bei der Beschreibung solcher Systeme zu zeigen, wurden mehrere Validierungsstudien durchgef{\"u}hrt, die in den Kapiteln 3-5 vorgestellt werden. Die Kapitel 6-8 besch{\"a}ftigen sich dagegen eher mit konkreten chemischen Fragestellungen, die einige biologisch relevante {\"U}bergangsmetallkomplexe betreffen.}, subject = {Dichtefunktionalformalismus}, language = {en} }