Relativity and magnetic properties: a density functional study

dc.contributor.advisorZiegler, Tom
dc.contributor.authorSchreckenbach, Hans Georg
dc.descriptionBibliography: p. 153-165.en
dc.description.abstractThis thesis has two major, related subjects, relativity and magnetic properties. All the investigations are based on density functional theory (DFf). An algorithm has been developed and implemented that allows the determination of relativistic energy gradients. This implementation enables automated geometry optimization at the relativistic level. The scheme has been applied to the calculation of M-CO bond lengths and first bond dissociation energies in binary transition metal carbonyls. A unique program system has been developed that allows the calculation of NMR shieldings and EPR g-tensors. The program is based on the use of "gauge including atomic orbitals" (GIAO). Expressions have been derived for the extension of the program to include the frozen core approximation, a scheme in which only the valence electrons are treated explicitly, and scalar relativistic effects. These expressions have been implemented into the DFf-GIAO program. The program has been applied to the chemical shift in systems ranging from small first row compounds to the metal chemical shift in transition metal carbonyls M(CO)6. This represents the first calculation of heavy element shifts that is based on a relativistic first principle quantum mechanical method. The calculated metal shifts of M( CO)6, taken relative to [MO4] 2-, are -1,846, -1804, and -3615 ppm for M = Cr, Mo, W, respectively. The corresponding experimental values are -1,795, -1,857, and -3,505 ppm. The inclusion of relativity is crucial for a proper description of ligand and metal shifts in 5 d complexes. Various aspects of NMR shielding calculations are discussed in this thesis. They comprise basis set requirements, exchange-correlation functionals, the importance of core orbitals, relativistic effects, the relation of the GIAO method to the common-gauge scheme, among others. Certain limitations of the method and possible future directions have been considered as well. The DFf-GIAO NMR program has been extended to include the calculation of the EPR g-tensor. This extension is the first GIAO and the only first principle DFT program for the g-tensor. The program is validated by calculations of g-tensors for a comprehensive set of small radicals.
dc.format.extentxix, 191 leaves ; 30 cm.en
dc.identifier.citationSchreckenbach, H. G. (1996). Relativity and magnetic properties: a density functional study (Doctoral thesis, University of Calgary, Calgary, Canada). Retrieved from doi:10.11575/PRISM/15922en_US
dc.identifier.lccQD 462.6 D45 S37 1996en
dc.publisher.institutionUniversity of Calgaryen
dc.rightsUniversity of Calgary graduate students retain copyright ownership and moral rights for their thesis. You may use this material in any way that is permitted by the Copyright Act or through licensing that has been assigned to the document. For uses that are not allowable under copyright legislation or licensing, you are required to seek permission.
dc.subject.lccQD 462.6 D45 S37 1996en
dc.subject.lcshDensity functionals
dc.subject.lcshQuantum chemistry
dc.titleRelativity and magnetic properties: a density functional study
dc.typedoctoral thesis of Calgary of Philosophy (PhD)
ucalgary.thesis.accessionTheses Collection 58.002:Box 1058 520538430
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