Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Structure and dynamics in solution – the core electron perspective
Stockholm University, Faculty of Science, Department of Physics.ORCID iD: 0000-0002-8621-4282
2015 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

This thesis is based on theoretical studies of the molecular and electronic structure of solvated ions and molecules. Very detailed information of the system can be obtained from theoretical calculations, but a realistic model is dependent on an accurate computational method. Accurate calculations of core level electronic spectra, and evaluation of the modeling against experiments, are central parts of this work. The main tools used for characterization of the systems are high-level quantum chemistry and molecular dynamics simulations. 

Molecular components in solutions are involved in many key processes converting sunlight into chemical or electrical energy. Transition metal complexes, with their pronounced absorption in the visible light region of the electromagnetic spectrum, are core components in various energy conversion applications, and the iodide/triiodide redox couple is a commonly used electrolyte. The local structure of the electronic valence in transition metal complexes and the details of the solvation mechanisms of electrolyte solutions are investigated through the combination of computational modeling and core level spectroscopy. The studies of model systems show that interactions between the solute and solvent are important for the electronic structure, and knowledge of the details in model systems studied can be relevant for energy conversion applications. Furthermore, high-level quantum chemistry has been applied for interpreting time-resolved spectra, where the electronic structure of a metal complex is followed during a photoinduced chemical reaction in solution.

With advanced modeling in combination with recent experimental developments, more complex problems than previously addressed can be dissected.

Place, publisher, year, edition, pages
Stockholm: Department of Physics, Stockholm University , 2015. , 64 p.
Keyword [en]
quantum chemistry, RASSCF, molecular dynamics, x-ray spectroscopy, electrolyte solutions
National Category
Natural Sciences
Research subject
Physics
Identifiers
URN: urn:nbn:se:su:diva-119838ISBN: 978-91-7649-258-1 (print)OAI: oai:DiVA.org:su-119838DiVA: diva2:848776
Public defence
2015-10-15, sal FB42, AlbaNova universitetscentrum, Roslagstullsbacken 21, Stockholm, 10:00 (English)
Opponent
Supervisors
Note

At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 3: Submitted. Paper 8: Manuscript.

Available from: 2015-09-23 Created: 2015-08-26 Last updated: 2015-09-11Bibliographically approved
List of papers
1. Orbital-specific mapping of the ligand exchange dynamics of Fe(CO)5 in solution
Open this publication in new window or tab >>Orbital-specific mapping of the ligand exchange dynamics of Fe(CO)5 in solution
Show others...
2015 (English)In: Nature, ISSN 0028-0836, E-ISSN 1476-4687, Vol. 520, no 7545, 78-81 p.Article in journal (Refereed) Published
Abstract [en]

Transition-metal complexes have long attracted interest for fundamental chemical reactivity studies and possible use in solar energy conversion. Electronic excitation, ligand loss from the metal centre, or a combination of both, creates changes in charge and spin density at the metal site that need to be controlled to optimize complexes for photocatalytic hydrogen production and selective carbon-hydrogen bond activation. An understanding at the molecular level of how transition-metal complexes catalyse reactions, and in particular of the role of the short-lived and reactive intermediate states involved, will be critical for such optimization. However, suitable methods for detailed characterization of electronic excited states have been lacking. Here we show, with the use of X-ray laser-based femtosecond resolution spectroscopy and advanced quantum chemical theory to probe the reaction dynamics of the benchmark transition-metal complex Fe(CO)5 insolution, that the photoinduced removal of CO generates the 16-electron Fe(CO)4 species, a homogeneous catalyst with an electron deficiency at the Fe centre, in a hitherto unreported excited singlet state that either converts to the triplet ground state or combines with a CO or solvent molecule to regenerate a penta-coordinated Fe species on a sub-picosecond timescale. This finding, which resolves the debate about the relative importance of different spin channels in the photochemistry of Fe(CO)5 (refs 4, 16,17,18,19 and 20), was made possible by the ability of femtosecond X-ray spectroscopy to probe frontier-orbital interactions with atom specificity. We expect the method to be broadly applicable in the chemical sciences, and to complement approaches that probe structural dynamics in ultrafast processes.

National Category
Physical Sciences
Research subject
Physics
Identifiers
urn:nbn:se:su:diva-119834 (URN)10.1038/nature14296 (DOI)000352027700040 ()
Available from: 2015-08-26 Created: 2015-08-26 Last updated: 2017-12-04Bibliographically approved
2. From Ligand Fields to Molecular Orbitals: Probing the Local Valence Electronic Structure of Ni2+ in Aqueous Solutions with Resonant Inelastic X-ray Scattering
Open this publication in new window or tab >>From Ligand Fields to Molecular Orbitals: Probing the Local Valence Electronic Structure of Ni2+ in Aqueous Solutions with Resonant Inelastic X-ray Scattering
Show others...
2013 (English)In: Journal of Physical Chemistry B, ISSN 1520-6106, E-ISSN 1520-5207, Vol. 117, 16512-16521 p.Article in journal (Refereed) Published
Abstract [en]

Bonding of the Ni2+(aq) complex is investigated with an unprecedented combination of resonant inelastic X-ray scattering (RIXS) measurements and ab initio calculations at the Ni L absorption edge. The spectra directly reflect the relative energies of the ligand-field and charge-transfer valence-excited states. They give element-specific access with atomic resolution to the ground-state electronic structure of the complex and allow quantification of ligand-field strength and 3d–3d electron correlation interactions in the Ni2+(aq) complex. The experimentally determined ligand-field strength is 10Dq = 1.1 eV. This and the Racah parameters characterizing 3d–3d Coulomb interactions B = 0.13 eV and C = 0.42 eV as readily derived from the measured energies match very well with the results from UV–vis spectroscopy. Our results demonstrate how L-edge RIXS can be used to complement existing spectroscopic tools for the investigation of bonding in 3d transition-metal coordination compounds in solution. The ab initio RASPT2 calculation is successfully used to simulate the L-edge RIXS spectra.

National Category
Physical Sciences
Research subject
Physics
Identifiers
urn:nbn:se:su:diva-119836 (URN)10.1021/jp4100813 (DOI)000329331800016 ()
Available from: 2015-08-26 Created: 2015-08-26 Last updated: 2017-12-04Bibliographically approved
3. Mechanistic insight into the ultrafast ligand addition and spin crossover reactions following Fe(CO)5 photodissociation in ethanol
Open this publication in new window or tab >>Mechanistic insight into the ultrafast ligand addition and spin crossover reactions following Fe(CO)5 photodissociation in ethanol
Show others...
(English)Article in journal (Refereed) Submitted
National Category
Physical Sciences
Research subject
Physics
Identifiers
urn:nbn:se:su:diva-119833 (URN)
Available from: 2015-08-26 Created: 2015-08-26 Last updated: 2015-08-26
4. Ab Initio Calculations of X-ray Spectra: Atomic Multiplet and Molecular Orbital Effects in a Multiconfigurational SCF Approach to the L-Edge Spectra of Transition Metal Complexes
Open this publication in new window or tab >>Ab Initio Calculations of X-ray Spectra: Atomic Multiplet and Molecular Orbital Effects in a Multiconfigurational SCF Approach to the L-Edge Spectra of Transition Metal Complexes
Show others...
2012 (English)In: Journal of Physical Chemistry Letters, ISSN 1948-7185, E-ISSN 1948-7185, Vol. 3, no 23, 3565-3570 p.Article in journal (Refereed) Published
Abstract [en]

A new ab initio approach to the calculation of X-ray spectra is demonstrated. It combines a high-level quantum chemical description of the chemical interactions and local atomic multiplet effects. We show here calculated L-edge X-ray absorption (XA) and resonant inelastic X-ray scattering spectra for aqueous Ni2+ and XA spectra for a polypyridyl iron complex. Our quantum chemical calculations on a high level of accuracy in a post-Hartree–Fock framework give excellent agreement with experiment. This opens the door to reliable and detailed information on chemical interactions and the valence electronic structure in 3d transition-metal complexes also in transient excited electronic states. As we combine a molecular-orbital description with a proper treatment of local atomic electron correlation effects, our calculations uniquely allow, in particular, identifying the influence of interatomic chemical interactions versus intra-atomic correlations in the L-edge X-ray spectra.

Keyword
X-ray spectroscopy, spectrum simulations, resonant inelastic X-ray scattering, RASSCF calculations, transition metal ions
National Category
Physical Sciences
Research subject
Physics
Identifiers
urn:nbn:se:su:diva-85227 (URN)10.1021/jz301479j (DOI)000312170600029 ()
Funder
Swedish Research Council
Available from: 2013-01-07 Created: 2013-01-07 Last updated: 2017-12-06Bibliographically approved
5. Collective hydrogen-bond dynamics dictates the electronic structure of aqueous I-3(-)
Open this publication in new window or tab >>Collective hydrogen-bond dynamics dictates the electronic structure of aqueous I-3(-)
Show others...
2013 (English)In: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 15, no 46, 20189-20196 p.Article in journal (Refereed) Published
Abstract [en]

The molecular and electronic structures of aqueous I-3 and I ions have been investigated through ab initio molecular dynamics (MD) simulations and photoelectron (PE) spectroscopy of the iodine 4d core levels. Against the background of the theoretical simulations, data from our I4d PE measurements are shown to contain evidence of coupled solute-solvent dynamics. The MD simulations reveal large amplitude fluctuations in the I-I distances, which couple to the collective rearrangement of the hydrogen bonding network around the I-3(-) ion. Due to the high polarizability of the I-3(-) ion, the asymmetric I-I vibration reaches partially dissociated configurations, for which the electronic structure resembles that of I-2 + I-. The charge localization in the I-3(-) ion is found to be moderated by hydrogen-bonding. As seen in the PE spectrum, these soft molecular vibrations are important for the electronic properties of the I-3(-) ion in solution and may play an important role in its electrochemical function.

National Category
Physical Sciences
Research subject
Physics
Identifiers
urn:nbn:se:su:diva-97406 (URN)10.1039/c3cp52866a (DOI)000326747200028 ()
Note

AuthorCount:9;

Available from: 2013-12-11 Created: 2013-12-09 Last updated: 2017-12-06Bibliographically approved
6. Solvent-Dependent Structure of the I-3(-) Ion Derived from Photoelectron Spectroscopy and Ab Initio Molecular Dynamics Simulations
Open this publication in new window or tab >>Solvent-Dependent Structure of the I-3(-) Ion Derived from Photoelectron Spectroscopy and Ab Initio Molecular Dynamics Simulations
Show others...
2015 (English)In: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 21, no 10, 4049-4055 p.Article in journal (Refereed) Published
Abstract [en]

Ab initio molecular dynamics (MD) simulations of the solvation of LiI3 in four different solvents (water, methanol, ethanol, and acetonitrile) are employed to investigate the molecular and electronic structure of the I-3(-) ion in relation to X-ray photoelectron spectroscopy (XPS). Simulations show that hydrogen-bond rearrangement in the solvation shell is coupled to intramolecular bond-length asymmetry in the I-3(-) ion. By a combination of charge analysis and I 4d core-level XPS measurements, the mechanism of the solvent-induced distortions has been studied, and it has been concluded that charge localization mediates intermolecular interactions and intramolecular distortion. The approach involving a synergistic combination of theory and experiment probes the solvent-dependent structure of the I-3(-) ion, and the geometric structure has been correlated with the electronic structure.

Keyword
ab initio calculations, hydrogen bonds, molecular dynamics, photoelectron spectroscopy, solvent effects
National Category
Physical Sciences Chemical Sciences
Research subject
Physics
Identifiers
urn:nbn:se:su:diva-116632 (URN)10.1002/chem.201405549 (DOI)000350762400027 ()25631177 (PubMedID)
Note

AuthorCount:8;

Available from: 2015-04-24 Created: 2015-04-22 Last updated: 2017-12-04Bibliographically approved
7. Solvent Dependence of the Electronic Structure of I- and I-3(-)
Open this publication in new window or tab >>Solvent Dependence of the Electronic Structure of I- and I-3(-)
Show others...
2014 (English)In: Journal of Physical Chemistry B, ISSN 1520-6106, E-ISSN 1520-5207, Vol. 118, no 11, 3164-3174 p.Article in journal (Refereed) Published
Abstract [en]

We present synchrotron-based I4d photoelectron spectroscopy experiments of solutions from LiI and LiI3 in water, ethanol, and acetonitrile. The experimentally determined solvent-induced binding energy shifts (SIBES) for the monatomic I- anion are compared to predictions from simple Born theory, PCM calculations, as well as multiconfigurational quantum chemical spectral calculations from geometries obtained through molecular dynamics of solvated clusters. We show that the SIBES for I- explicitly depend on the details of the hydrogen bonding configurations of the solvent to the I- and that static continuum models such as the Born model cannot capture the trends in the SIBES observed both in experiments and in higher-level calculations. To extend the discussion to more complex polyatomic anions, we also performed experiments on I-3(-) and I-/I-3(-) mixtures in different solvents and the results are analyzed in the perspective of SIBES. The experimental SIBES values indicate that the solvation effects even for such similar anions as I- and I-3(-) can be rather different in nature.

National Category
Physical Sciences
Research subject
Physics
Identifiers
urn:nbn:se:su:diva-102957 (URN)10.1021/jp500533n (DOI)000333381800039 ()
Note

AuthorCount:9;

Available from: 2014-04-29 Created: 2014-04-25 Last updated: 2017-12-05Bibliographically approved
8. Solvation Structure Around Ruthenium(II) Tris(bipyridine) in Lithium Halide Solutions
Open this publication in new window or tab >>Solvation Structure Around Ruthenium(II) Tris(bipyridine) in Lithium Halide Solutions
(English)Manuscript (preprint) (Other academic)
National Category
Physical Sciences
Research subject
Physics
Identifiers
urn:nbn:se:su:diva-119840 (URN)
Available from: 2015-08-26 Created: 2015-08-26 Last updated: 2016-01-29Bibliographically approved

Open Access in DiVA

fulltext(5362 kB)257 downloads
File information
File name FULLTEXT01.pdfFile size 5362 kBChecksum SHA-512
c0c1b2857f09765c08c1d64b4dec3cf90e4fef5703c8a05771397477c95db8e8516804df65326bc3ea08fc0eb643e070dde6de2b92c03bb160f8460194656c53
Type fulltextMimetype application/pdf

Search in DiVA

By author/editor
Josefsson, Ida
By organisation
Department of Physics
Natural Sciences

Search outside of DiVA

GoogleGoogle Scholar
Total: 257 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

isbn
urn-nbn

Altmetric score

isbn
urn-nbn
Total: 1124 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf