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Electron Spectroscopy and Density-Functional Study of "Ferric Wheel" Molecules

A. V. Postnikov·S. G. Chiuzbaian·M. Neumann·S. Bluegel
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Abstract

The Li-centered "ferric wheel" molecules with six oxo-bridged iron atoms form molecular crystals. We probed their electronic structure by X-ray photoelectron (XPS) and soft X-ray emission spectroscopy (XES), having calculated in parallel the electronic structure of a single "ferric wheel" molecule from first-principles by tools of the density-functional theory, using, specifically, the Siesta method. The Fe local moments were found to be 4 mu_B, irrespective of their mutual orientation. Neighbouring atoms, primarily oxygen, exhibit a noticeable magnetic polarization, yielding effective spin S=5/2 per iron atom, that can get inverted as a "rigid" one in magnetic transitions. Corresponding energy preferences can be mapped onto the Heisenberg model with effective exchange parameter J of about -80 K.

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A. V. Postnikov, S. G. Chiuzbaian, M. Neumann, S. Bluegel. 2003-06-17. Electron Spectroscopy and Density-Functional Study of "Ferric Wheel" Molecules. https://doi.org/10.1016/j.jpcs.2003.11.025

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