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The low-dimensional quantum-magnet, linarite, PbCuS(OH), has been investigated using terahertz (THz) spectroscopy coupled with detailed density functional theory (DFT) calculations in order to explore the effects of the temperature on its lattice vibrations. Linarite is characterized by largely isolated CuO chains propagating along the crystallographic -axis, which at very low temperatures are responsible for exotic, quasi-1D magnetism in this material. To better understand the synergy between the structural bonds and lattice oscillations that contribute to these chains, polarized THz spectroscopic measurements were performed. Consolidating these results with detailed DFT calculations has revealed that the anisotropic vibrational motion for the THz modes is correlated with extreme motion associated with the crystallographic -axis. An unexpected feature observed in the infrared spectrum is attributed to subtle lattice distortions which break the centro-symmetry in linarite at high temperatures. This phenomenon has not previously been observed in linarite and likely results from anharmonicity in lattice oscillations.
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http://dx.doi.org/10.1021/acs.jpca.3c06926 | DOI Listing |
J Phys Chem C Nanomater Interfaces
September 2025
Departamento de Física Aplicada - Instituto de Ciencia de Materiales, Matter at High Pressure (MALTA) Consolider Team, Universidad de Valencia, Edificio de Investigación, C/Dr Moliner 50, 46100 Burjassot, Valencia Spain.
The effects of pressure on the crystal structure of scheelite-type perrhenates were studied using synchrotron powder X-ray diffraction and density-functional theory. At ambient conditions, the studied materials AgReO, KReO, and RbReO, exhibit a tetragonal scheelite-type crystal structure described by space group 4/. Under compression, a transition from scheelite-to-M'-fergusonite (space group 2/) was observed at 1.
View Article and Find Full Text PDFJ Phys Chem C Nanomater Interfaces
September 2025
Department of Materials Science and Engineering, University of California, Berkeley, California 94720, United States.
Density functional theory (DFT) calculations are employed to investigate the formation energies, charge redistribution, and binding energies of iron-oxygen divacancies in magnetite (FeO) and hematite (FeO). For magnetite, we focus on the low-temperature phase to explore variations with local environments. Building on previous DFT calculations of the variations in formation energies for oxygen vacancies with local charge and spin order in magnetite, we extend this analysis to include octahedral iron vacancies before analyzing the iron-oxygen divacancies.
View Article and Find Full Text PDFRSC Adv
September 2025
Computational Biotechnology, RWTH Aachen University Worringerweg 3 52074 Aachen Germany
Recent advances in two-dimensional (2D) magnetic materials have promoted significant progress in low-dimensional magnetism and its technological applications. Among them, atomically thin chromium trihalides (CrX with X = Cl, Br, and I) are among the most studied 2D magnets due to their unique magnetic properties. In this work, we employ density functional theory calculations to investigate the mechanical and electronic properties of CrX monolayers in the presence of in-plane uniaxial strain.
View Article and Find Full Text PDFRSC Adv
September 2025
Process and Environmental Engineering Laboratory (LIPE), Faculty of Chemistry, University of Science and Technology of Oran Mohamed Boudiaf P. O. Box 1503, El Mnaouer 31000 Oran Algeria.
In this contribution, Molecular Electron Density Theory (MEDT) is employed to investigate the (3 + 2) cycloaddition reaction between ()--methyl--(2-furyl)-nitrone 1 and but-2-ynedioic acid 2. DFT calculations at the M06-2X-D3/6-311+G(d,p) level of theory under solvent-free conditions at room temperature show that this reaction proceeds CA3-Z diastereoselectivity, with the formation of the CA3-Z cycloadduct being both thermodynamically and kinetically more favoured than the CA4-Z one. Reactivity parameters obtained from CDFT calculations reveal that compound 1 predominantly behaves as a nucleophile with moderate electrophilic features, in contrast to compound 2, which demonstrates strong electrophilicity and limited nucleophilic ability.
View Article and Find Full Text PDFBeilstein J Org Chem
August 2025
A. N. Nesmeyanov Institute of Organoelement Compounds of Russian Academy of Sciences, INEOS, Vavilova St. 28, Moscow, 119334, Russia.
Reducing agents with phosphorus-hydrogen bond, such as sodium hypophosphite, phosphite, and hypophosphorous acid are commercially available in bulk amounts, however, their usage is understudied in organic processes. While NaHPO has proved to be an efficient four-electron reductant in the catalyst-free reductive amination, the influence of cation in hypophosphite salt has not been studied yet. This issue is a fundamentally important factor.
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