ORCID Profile
0000-0002-1340-2186
Current Organisation
Utrecht University
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Publisher: American Chemical Society (ACS)
Date: 22-07-2006
DOI: 10.1021/JA061802I
Abstract: Distinct spectral features at the Fe L-edge of the two compounds K3[Fe(CN)6] and K4[Fe(CN)6] have been identified and characterized as arising from contributions of the ligand pi orbitals due to metal-to-ligand back-bonding. In addition, the L-edge energy shifts and total intensities allow changes in the ligand field and effective nuclear charge to be determined. It is found that the ligand field term dominates the edge energy shift. The results of the experimental analysis were compared to BP86 DFT calculations. The overall agreement between the calculations and experiment is good however, a larger difference in the amount of pi back-donation between Fe(II) and Fe(III) is found experimentally. The analysis of L-edge spectral shape, energy shift, and total intensity demonstrates that Fe L-edge X-ray absorption spectroscopy provides a direct probe of metal-to-ligand back-bonding.
Publisher: AIP
Date: 2007
DOI: 10.1063/1.2644448
Publisher: American Physical Society (APS)
Date: 10-11-2022
Publisher: American Physical Society (APS)
Date: 07-01-2020
Publisher: Stichting SciPost
Date: 04-08-2022
DOI: 10.21468/SCIPOSTPHYS.13.2.012
Abstract: We show that the recently introduced ModMax theory of electrodynamics and its Born-Infeld-like generalization are related by a flow equation driven by a quadratic combination of stress-energy tensors. The operator associated to this flow is a 4d 4 d analogue of the T\\overline{T} T T ¯ deformation in two dimensions. This result generalizes the observation that the ordinary Born-Infeld Lagrangian is related to the free Maxwell theory by a current-squared flow. As in that case, we show that no analogous relationship holds in any other dimension besides d=4 d = 4 . We also demonstrate that the \\mathcal{N}=1 𝒩 = 1 supersymmetric version of the ModMax-Born-Infeld theory obeys a related supercurrent-squared flow which is formulated directly in \\mathcal{N} = 1 𝒩 = 1 superspace.
Publisher: Springer Science and Business Media LLC
Date: 02-2020
Abstract: The $$ T\\overline{T} $$ T T ¯ deformation of a supersymmetric two-dimensional theory preserves the original supersymmetry. Moreover, in several interesting cases the deformed theory possesses additional non-linearly realized supersymmetries. We show this for certain $$ \\mathcal{N} $$ N = (2, 2) models in two dimensions, where we observe an intriguing similarity with known $$ \\mathcal{N} $$ N = 1 models in four dimensions. This suggests that higher-dimensional models with non-linearly realized supersymmetries might also be obtained from $$ T\\overline{T} $$ T T ¯ -like flow equations. We show that in four dimensions this is indeed the case for $$ \\mathcal{N} $$ N = 1 Born-Infeld theory, as well as for the Goldstino action for spontaneously broken $$ \\mathcal{N} $$ N = 1 supersymmetry.
No related grants have been discovered for Frank de Groot.