The magnetic properties of a substance can be determined using spectroscopic methods and magnetic measurements, which provide detailed insight into the electronic structure. The electronic structure and the magnetic properties can be predicted with high accuracy using various quantum chemical methods. We are particularly interested in the magnetic properties of iron-containing substances and magnetic couplings. These topics are of great relevance to the SFB “Iron, upgraded!” Iron, upgraded!

Publications:

Diederich, Tim Marcel ; Wehland, Tim ; Schrodt, Maximilian ; Kochetov, Nikolai ; Schnegg, Alexander ; Jimenez-Muñoz, Carlos M. ; Krewald, Vera ; Ni, Lingmei ; Segura-Salas, Nicole ; Kramm, Ulrike I. ; Ballmann, Joachim ; Enders, Markus (2025) Electronic and magnetic properties of ferrous iron in a true square-planar molecular environment. In: Chemistry – A European Journal, 31 (39)

doi: 10.1002/chem.202501474 Artikel, Bibliographie

Mehmel, Jannik ; Jimenez-Muñoz, Carlos M. ; Rivic, Filip ; Krewald, Vera ; Schäfer, Rolf (2025) Magnetism of transition-metal-doped tetrel nanoclusters: multi-reference character and spin–orbit effects in Sn 12 TM (TM = Cr, Mn, Fe). In: Nanoscale

doi: 10.1039/D4NR03920C Artikel, Bibliographie

Stein, Christopher J. ; Pantazis, Dimitrios A. ; Krewald, Vera (2019) Orbital Entanglement Analysis of Exchange-Coupled Systems. In: The Journal of Physical Chemistry Letters, 10

doi: 10.1021/acs.jpclett.9b02417 Artikel, Bibliographie

Krewald, Vera ; Pantazis, Dimitrios A. Hrsg.: Broclawik, Ewa ; Borowski, Tomasz ; Radoń, Mariusz (2019) Applications of the Density Matrix Renormalization Group to Exchange-Coupled Transition Metal Systems. In: Transition Metals in Coordination Environments: Computational Chemistry and Catalysis Viewpoints

doi: 10.1007/978-3-030-11714-6_4 Buchkapitel, Bibliographie

Roemelt, Michael ; Krewald, Vera ; Pantazis, Dimitrios A. (2018) Exchange Coupling Interactions from the Density Matrix Renormalization Group and N-Electron Valence Perturbation Theory: Application to a Biomimetic Mixed-Valence Manganese Complex. In: Journal of Chemical Theory and Computation, 14 (1)

doi: 10.1021/acs.jctc.7b01035 Artikel, Bibliographie

The redox chemistry of iron compounds is one of our research topics in the SFB “Iron, upgraded!” Iron, upgraded!. While relative redox potentials can generally be described well using density functional theory, the solvation environment of the solute must be described adequately to accurately predict absolute redox potentials. With regard to reactions being studied experimentally under in situ or operando conditions, we are interested in the spectroscopic discernability of the involved redox partners.

Publications:

Gallenkamp, Charlotte ; Kramm, Ulrike I. ; Krewald, Vera (2024) FeN4 environments upon reduction: a computational analysis of spin states, spectroscopic properties, and active species. In: JACS Au – an open access journal of the American Chemical Society

doi: 10.1021/jacsau.3c00714 Artikel, Bibliographie

Krewald, Vera ; Pantazis, Dimitrios A. (2016) Understanding and tuning the properties of redox-accumulating manganese helicates. In: Dalton Transactions, 45 (47)

doi: 10.1039/C6DT02800D Artikel, Bibliographie

Mössbauer spectroscopy is an key method to investigate iron-containing compounds. While Mössbauer measurements can be performed at different temperatures, Mössbauer parameters are formally predicted at 0 K using quantum chemical methods. Since both the isomer shift and the quadrupole splitting show temperature dependencies, the comparison between experiment and theory is limited to low-temperature measurements (< 80 K). We have developed a method to study an important contributor to the temperature dependence of quadrupole splitting.

Publications:

Rhein, Niklas von ; Krewald, Vera (2025) The temperature dependence of Mössbauer quadrupole splitting values: a quantum chemical analysis. In: Chemical Communications, 61 (12)

doi: 10.1039/D4CC03943B Artikel, Bibliographie

Gallenkamp, Charlotte ; Kramm, Ulrike I. ; Proppe, Jonny ; Krewald, Vera (2020) Calibration of Computational Mössbauer Spectroscopy to Unravel Active Sites in FeNC-Catalysts for the Oxygen Reduction Reaction. In: International Journal of Quantum Chemistry

doi: 10.1002/qua.26394 Artikel, Bibliographie

The Angular Overlap Model is a model within ligand field theory that parameterizes the influence of individual ligands on the central metal ion. We have developed a method that determines the Angular Overlap Model parameters for a complex using ab initio ligand field theory analysis in the quantum chemistry program ORCA.

Publications:

Buchhorn, Moritz ; Krewald, Vera (2024) AOMadillo: a program for fitting angular overlap model parameters. In: Journal of Computational Chemistry, 45 (2)

doi: 10.1002/jcc.27224 Artikel, Bibliographie

Buchhorn, Moritz ; Krewald, Vera (2023) The π-interactions of ammonia ligands evaluated by ab initio ligand field theory. In: Dalton Transactions

doi: 10.1039/D3DT00511A Artikel, Bibliographie

Buchhorn, Moritz ; Deeth, Robert J. ; Krewald, Vera (2022) Revisiting the Fundamental Nature of Metal‐Ligand Bonding: An Impartial and Automated Fitting Procedure for Angular Overlap Model Parameters. In: Chemistry – A European Journal, 2022

doi: 10.1002/chem.202103775 Artikel, Bibliographie