dc.contributor.advisor | Ruud, Kenneth | |
dc.contributor.author | Solheim, Harald | |
dc.date.accessioned | 2011-09-08T11:39:28Z | |
dc.date.available | 2011-09-08T11:39:28Z | |
dc.date.issued | 2011-06-23 | |
dc.description.abstract | This dissertation presents theoretical studies mainly of natural and magnetic circular dichroism spectra. For magnetic circular dichroism, the importance of electron correlation effects, here included at the density-functional functional level of theory, and solvent effects are discussed, both being shown to have significant impact on the final spectra. In addition, a unified approach for calculating the temperate-independent contribution to MCD spectra are presented based on damped response theory. This approach is applicable also in energy regions with a high density of electronic states, where the calculation of MCD B terms based on residues of quadratic response functions may give unphysical results. It is argued for an abandonment of the conventional separation of the temperature-independent contribution into A and B terms since this separation may lead to incorrect analysis of the excited states.
For natural circular dichroism spectra, calculations have been performed both at the electronic level, as part of a study on Vitamin B12 including calculations of absorption and magnetic circular dichroism spectra, and at the vibronic level, in both cases employing density-functional theory. The study of vibrationally resolved circular dichroism was performed for a system where the observed spectrum is solely due to isotopic substitution. The model system, 2(R)-deutoriocyclopentanone, exists in two distinct, but near isoenergetic conformations with circular dichroism signals that nearly cancel each other, emphasizing a high requirement for computational accuracy.
The dissertation is concluded with a discussion on the construction of accurate model Hamiltonians for the simulation of vibronic spectra beyond the adiabatic approximation, using pyrazine as an example. Here, multireference wave-function based methods were employed in order to accurately describe potential energy surfaces over a large region of nuclear configuration space. | en |
dc.description.doctoraltype | ph.d. | en |
dc.description.popularabstract | Denne avhandlingen presenterer teoretiske studier av naturlig og magnetisk sirkulær dikroisme. Sirkulær dikroisme er en form for spektroskopi der forskjellen i absorbsjon mellom høyre- og venstre-sirkulært polarisert lys måles. I utgangspunktet vil denne forskjellen bare kunne observeres for kirale systemer, men hvis en legger til et statisk magnetisk felt kan en få synlige spektre for alle molekyler.
Disse formene for spektroskopi kan gi mye informasjon om de eksiterte tilstandene til molekyler, noe som blant annet er viktig for å forstå hva slags kjemiske reaksjoner de vil inngå i. Men ofte er det være vanskelig å tolke eksperimentelle spektra, og da vil være teoretiske beregninger være et nyttig supplement. I denne avhandlingen presenteres forskjellige metoder for å gjøre slike beregninger, og styrkene og svakhetene til de forskjellige approksimasjonene diskuteres. | en |
dc.description.sponsorship | YFF grant to Kenneth Ruud (Grant No. 162746/V00)
Computer time from the Norwegian Supercomputing Program | en |
dc.description | The papers of this thesis are not available in Munin: <br/>1. H. Solheim, L. Frediani, K. Ruud, and S. Coriani: 'An IEF-PCM study of solvent effects on the Faraday B term of MCD', Theor. Chem. Account (2008) 119, 231. Available at <a href=http://dx.doi.org/10.1007/s00214-006-0235-9>http://dx.doi.org/10.1007/s00214-006-0235-9</a> <br/>2. H. Solheim, K. Ruud, S. Coriani, and P. Norman: 'Complex polarization propagator calculations of magnetic circular dichroism spectra', J. Chem. Phys. (2008) 128, 094103. Available at <a href=http://dx.doi.org/10.1063/1.2834924>http://dx.doi.org/10.1063/1.2834924</a> <br/>3. H. Solheim, K. Ruud, S. Coriani, and P. Norman: 'The A and B terms of magnetic circular dichroism revisited', J. Phys. Chem A. (2008) 112, 9615. Available at <a href=http://dx.doi.org/10.1021/jp803135x>http://dx.doi.org/10.1021/jp803135x</a> <br/>4. H. Solheim, K. Kornobis, K. Ruud, and P. M. Kozlowski: 'Electronically excited states of Vitamin B12 and methylcobalamin: Theoretical analysis of absorption, CD and MCD data', J. Phys. Chem B. (2011) 115, 737. Available at <a href=http://dx.doi.org/10.1021/jp109793r>http://dx.doi.org/10.1021/jp109793r</a> <br/>5. Na Lin, Harald Solheim, Kenneth Ruud, Marcel Nooijen, Fabrizio Santoro, Xian Zhao, Marcin Kwit and Pawel Skowronek : 'Vibrationally resolved circular dichroism spectra of a molecule with isotopically
engendered chirality', manuscript, later published in Physical Chemistry Chemical Physics, 2012, 14, 3669-3680. Published version available at <a href= http://dx.doi.org/10.1039/C2CP23584F>http://dx.doi.org/10.1039/C2CP23584F</a><br/>
6. H. Solheim, A. Papp, C. Woywod, and K. Ruud: 'On the systematic construction of vibronic coupling Hamiltonians: the interaction between the 11B3u and 11B2u states of pyrazine as an example' (manuscript) | en |
dc.identifier.uri | https://hdl.handle.net/10037/3591 | |
dc.identifier.urn | URN:NBN:no-uit_munin_3307 | |
dc.language.iso | eng | en |
dc.publisher | Universitetet i Tromsø | en |
dc.publisher | University of Tromsø | en |
dc.rights.accessRights | openAccess | |
dc.rights.holder | Copyright 2011 The Author(s) | |
dc.rights.uri | https://creativecommons.org/licenses/by-nc-sa/3.0 | en_US |
dc.rights | Attribution-NonCommercial-ShareAlike 3.0 Unported (CC BY-NC-SA 3.0) | en_US |
dc.subject | VDP::Matematikk og Naturvitenskap: 400::Kjemi: 440::Teoretisk kjemi, kvantekjemi: 444 | en |
dc.subject | VDP::Mathematics and natural science: 400::Chemistry: 440::Theoretical chemistry, quantum chemistry: 444 | en |
dc.title | Theoretical studies of natural and magnetic circular dichroism | en |
dc.type | Doctoral thesis | en |
dc.type | Doktorgradsavhandling | en |