Endre søk
RefereraExporteraLink to record
Permanent link

Direct link
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annet format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annet språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf
Systematic theoretical investigation of the zero-field splitting in Gd(III) complexes: Wave function and density functional approaches
Stockholms universitet, Naturvetenskapliga fakulteten, Fysikum.
Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
Vise andre og tillknytning
2015 (engelsk)Inngår i: Journal of Chemical Physics, ISSN 0021-9606, E-ISSN 1089-7690, Vol. 142, nr 3, artikkel-id 034304Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

The zero-field splitting (ZFS) of the electronic ground state in paramagnetic ions is a sensitive probe of the variations in the electronic and molecular structure with an impact on fields ranging from fundamental physical chemistry to medical applications. A detailed analysis of the ZFS in a series of symmetric Gd(III) complexes is presented in order to establish the applicability and accuracy of computational methods using multiconfigurational complete-active-space self-consistent field wave functions and of density functional theory calculations. The various computational schemes are then applied to larger complexes Gd(III)DOTA(H2O)(-), Gd(III)DTPA(H2O)(2-), and Gd(III)(H2O)(8)(3+) in order to analyze how the theoretical results compare to experimentally derived parameters. In contrast to approximations based on density functional theory, the multiconfigurational methods produce results for the ZFS of Gd(III) complexes on the correct order of magnitude.

sted, utgiver, år, opplag, sider
2015. Vol. 142, nr 3, artikkel-id 034304
HSV kategori
Forskningsprogram
kemisk fysik
Identifikatorer
URN: urn:nbn:se:su:diva-114354DOI: 10.1063/1.4905559ISI: 000348302900024PubMedID: 25612706OAI: oai:DiVA.org:su-114354DiVA, id: diva2:793670
Merknad

AuthorCount:5;

Tilgjengelig fra: 2015-03-09 Laget: 2015-03-02 Sist oppdatert: 2019-12-17bibliografisk kontrollert
Inngår i avhandling
1. Combined Quantum Mechanical and Molecular Dynamics study of paramagnetic complexes: Towards an understanding of electronic spin relaxation
Åpne denne publikasjonen i ny fane eller vindu >>Combined Quantum Mechanical and Molecular Dynamics study of paramagnetic complexes: Towards an understanding of electronic spin relaxation
2018 (engelsk)Doktoravhandling, med artikler (Annet vitenskapelig)
Abstract [en]

The prime objectives of contrast agents in Magnetic Resonance Imaging (MRI) is to accelerate the relaxation rate of the solvent water protons in the surrounding tissue. Paramagnetic relaxation originates from dipole-dipole interactions between the nuclear spins and the fluctuating magnetic field induced by unpaired electrons. Currently Gadolinium(III) chelates are the most widely used contrast agents in MRI, and therefore it is incumbent to extend the fundamental theoretical understanding of parameters that drive the relaxation mechanism in these complexes. In compounds such as Gadolinium(III) complexes with total electron spins higher than 1 (in this case S=7/2) the Zero-Field Splitting (ZFS) plays a significant role in influencing the electron spin dynamics and nuclear spin dynamics. For this purpose, the current research delves into an understanding of the relaxation process, focusing on ZFS in various complexes of interest, using multi-scale modelling by combining quantum, semi-quantum and newtonian methods.

We compare and contrast Density Function Theory (DFT) with multi-configurational quantum chemical calculation and find that DFT is highly functional dependent and unreliable in accurately reproducing experimental data for the static ZFS. It was found that long-range corrected functionals (in particular LC-BLYP) perform significantly better as compared to other functionals in predicting the magnitude of the static ZFS. We study hydrated Gd(III) and Eu(II) systems to compare and contrast these isoelectronic complexes (both contain 7 unpaired electrons in their valence shell) and through ab-initio molecular dynamics (AIMD) sampling followed by multi-reference quantum chemical calculations, it was established that inclusion of the first shell has a dominant influence (over 90%) on the ZFS. We also studied the complex [Gd(III)(HPDO3A)(H2O)], which is of clinical relevance as a contrast agent for MRI, through post-Hartree-Fock and DFT calculations by utilizing configurations derived from AIMD trajectories. From the fluctuations in the ZFS tensor, we extract a correlation time of the transient ZFS which is on the sub-picosecond time scale, showing a faster decay than experimental data.

sted, utgiver, år, opplag, sider
Stockholm: Department of Physics, Stockholm University, 2018. s. 58
Emneord
molecular dynamics, quantum chemistry, zero-field splitting
HSV kategori
Forskningsprogram
kemisk fysik
Identifikatorer
urn:nbn:se:su:diva-155519 (URN)978-91-7797-320-1 (ISBN)978-91-7797-321-8 (ISBN)
Disputas
2018-06-12, FB53, AlbaNova Universitetscentrum, Roslagstullsbacken 21, Stockholm, 13:00 (engelsk)
Opponent
Veileder
Merknad

At the time of the doctoral defense, the following paper was unpublished and had a status as follows: Paper 4: Manuscript.

Tilgjengelig fra: 2018-05-18 Laget: 2018-04-23 Sist oppdatert: 2018-05-09bibliografisk kontrollert

Open Access i DiVA

Fulltekst mangler i DiVA

Andre lenker

Forlagets fulltekstPubMed

Søk i DiVA

Av forfatter/redaktør
Khan, ShehryarKowalewski, JozefOdelius, Michael
Av organisasjonen
I samme tidsskrift
Journal of Chemical Physics

Søk utenfor DiVA

GoogleGoogle Scholar

doi
pubmed
urn-nbn

Altmetric

doi
pubmed
urn-nbn
Totalt: 78 treff
RefereraExporteraLink to record
Permanent link

Direct link
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annet format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annet språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf