Improved Prediction of Mössbauer Quadrupole Splitting at High and Low Temperatures with a Quantum Chemical Ensemble Approach
Abstract
Mössbauer spectroscopy is a key method for characterizing the electronic structures of iron compounds. The resulting Mössbauer parameters show a well-established temperature dependence. For quantum chemical calculations that are often used to aid in the interpretation of Mössbauer spectra, this poses a major challenge: they commonly employ a single, rigid equilibrium structure that is assumed to deliver good results for low temperatures up to ca. 80 K. In this work, we reveal this approach to be a rather severe approximation. We use a structural sampling approach that captures the effect of temperature dependent molecular vibrations on the quadrupole splitting. Even for low temperatures, this approach delivers a significantly improved agreement with experimental data. In addition, the T-dependence of the quadrupole splitting can be qualitatively reproduced for four iron(II) high spin complexes. The results are analyzed in terms of the individual EFG tensor contributions, which shows the origin of the temperature dependence being rooted in different electronic structures with varying contributions at different temperatures. Limitations in the sampling approach and electronic structure method are discussed. The approach presented herein may provide better agreement with experiment in future in situ and operando studies at low, ambient and elevated temperatures.
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BibTeX
@misc{rhein2026improved,
title = {{Improved Prediction of Mössbauer Quadrupole Splitting at High and Low Temperatures with a Quantum Chemical Ensemble Approach}},
author = {Niklas von Rhein and Lennart Jennes and Carlos M. Jimenez-Muñoz and Vera Krewald},
howpublished = {ChemRxiv},
year = {2026},
month = oct,
doi = {10.26434/chemrxiv.15010877/v1},
url = {https://chemrxiv.org/doi/full/10.26434/chemrxiv.15010877/v1},
note = {CC BY},
}
RIS
TY - UNPB
TI - Improved Prediction of Mössbauer Quadrupole Splitting at High and Low Temperatures with a Quantum Chemical Ensemble Approach
AU - Niklas von Rhein
AU - Lennart Jennes
AU - Carlos M. Jimenez-Muñoz
AU - Vera Krewald
PY - 2026
DA - 2026/10/22
PB - ChemRxiv
DO - 10.26434/chemrxiv.15010877/v1
UR - https://chemrxiv.org/doi/full/10.26434/chemrxiv.15010877/v1
AB - Mössbauer spectroscopy is a key method for characterizing the electronic structures of iron compounds. The resulting Mössbauer parameters show a well-established temperature dependence. For quantum chemical calculations that are often used to aid in the interpretation of Mössbauer spectra, this poses a major challenge: they commonly employ a single, rigid equilibrium structure that is assumed to deliver good results for low temperatures up to ca. 80 K. In this work, we reveal this approach to be a rather severe approximation. We use a structural sampling approach that captures the effect of temperature dependent molecular vibrations on the quadrupole splitting. Even for low temperatures, this approach delivers a significantly improved agreement with experimental data. In addition, the T-dependence of the quadrupole splitting can be qualitatively reproduced for four iron(II) high spin complexes. The results are analyzed in terms of the individual EFG tensor contributions, which shows the origin of the temperature dependence being rooted in different electronic structures with varying contributions at different temperatures. Limitations in the sampling approach and electronic structure method are discussed. The approach presented herein may provide better agreement with experiment in future in situ and operando studies at low, ambient and elevated temperatures.
ER -