Precise chemical, electronic, and magnetic structure of binuclear complexes studied by means of X-ray spectroscopies and theoretical methods

Kuepper, Karsten; Benoit, David M.; Wiedwald, Ulf; Mögele, Florian; Meyering, Andreas; Neumann, Manfred; Kappler, Jean-Paul; Joly, Loïc; Weidle, Stefan; Rieger, Bernhard; Ziemann, Paul

Abstract

We investigate two planar complexes MnNi and CoNi (see Scheme 1) by X-ray photoelec- tron spectroscopy (XPS) and ultralow-temperature X-ray magnetic circular dichroism (XMCD). In this way the valence states as well as the presence of uncompensated magnetic moments are obtained. The magnetism has been probed at a temperature of 0.6 K in order to reveal the magnetic ground state properties. We find that divalent Ni ions are in a diamagnetic low spin ground state in both complexes; however, in MnNi a small fraction of divalent nickel high-spin ions leads to a residual XMCD signal, indicating parallel spin alignment with the Mn spins. Mn and Co are found to be in a divalent high-spin configuration in both compounds. Theoretically, we address the energetic ordering of the different possible spin states of the binuclear complexes using (zeroth-order) relativistic approximation density functional calculations and a triple-ζ quality basis set. These results show that intermediate-spin states are often favored over low-spin states for most both metal combinations, in qualitative agreement with our experimental observations.

Citation

Kuepper, K., Benoit, D. M., Wiedwald, U., Mögele, F., Meyering, A., Neumann, M., …Ziemann, P. (2011). Precise chemical, electronic, and magnetic structure of binuclear complexes studied by means of X-ray spectroscopies and theoretical methods. Journal of physical chemistry. C, 115(50), 25030-25039. https://doi.org/10.1021/jp2069804

• Journal Article Type: Article
• Acceptance Date: Oct 26, 2011
• Online Publication Date: Nov 28, 2011
• Publication Date: Dec 22, 2011
• Journal: Journal of Physical Chemistry C
• Print ISSN: 1932-7447
• Electronic ISSN: 1932-7455
• Publisher: American Chemical Society
• Peer Reviewed: Peer Reviewed
• Volume: 115
• Issue: 50
• Pages: 25030-25039
• DOI: https://doi.org/10.1021/jp2069804
• Keywords: General Energy; Physical and Theoretical Chemistry; Electronic, Optical and Magnetic Materials; Surfaces, Coatings and Films
• Public URL: https://hull-repository.worktribe.com/output/424098