Electronic Structure Of Ions Research Articles

The Role of Carrier Ion‐Ligand Interaction on Intercalation Potentials and Phase Evolution of Berlin Green Cathodes in Rechargeable Batteries

AbstractIntercalation and deintercalation are fundamental processes in battery electrodes that involve the reversible addition and extraction of carrier ions such as lithium (Li) and sodium (Na) into a host framework made of transition metal (TM) ions and ligands. Although TM–ligand interactions are known to primarily determine intercalation potentials, a comprehensive understanding of their interactions involving the carrier ions still remains elusive. This study investigates the complex interactions between carrier ions (Li and Na) and the ligand in Berlin green (BG, Fe3+[Fe3+(CN)6]) cathodes to elucidate their effects on intercalation potentials and phase evolution. Comprehensive X‐ray characterizations and electrochemical analyses reveal that the strong carrier ion–ligand interaction, influenced by the type and concentration of carrier ions, can modify the electronic structure of Fe ions and affect the intercalated structure of BG cathodes, thereby tuning the intercalation potentials. Specifically, the enhanced covalent interaction of the Na–CN units compared with that of the Li–CN units induces rhombohedral distortion in the fully sodiated state and increases the working potential of high‐spin Fe ions. The findings highlight the critical role of carrier ion–ligand interactions in tuning the electrochemical properties of battery electrodes for the design of advanced battery systems.

Two-Dimensional NiCo2S4 Nanosheets Deliver Efficient Oxygen Evolution Reaction

Introduction: The development of cost-effective and efficient catalysts plays a pivotal role in the realization of hydrogen production through electrochemical water splitting. Method: In this study, two-dimensional NiCo2S4 nanosheets weresynthesized usinga hydrothermal method followed by a sulfidation process. Results: The resulting materials were thoroughly characterized to understand their morphology and structure. The findings indicate that the NiCo2S4 nanosheets exhibit exceptional electrical conductivity and a high density of pores, which facilitate electrolyte infiltration and interfacial charge transfer during electrochemical reactions. Furthermore, the incorporation of S2− modulates the electronic structure of metal ions, reducing the oxidation potential of metal sites and promoting the surface reconstruction of the electrode to form active species. Electrochemical tests conducted in a 1 M KOH solution using the synthesized catalyst as the working electrode demonstrate an overpotential of merely 280 mV and 300 mV at a current density of 20 mA cm−2 and 40 mA cm−2 , respectively, which are much lower than those of NiCo-LDH electrodes (360 mV and 410 mV). Conclusion: Furthermore, the NiCo2S4 electrode delivers a remarkably low Tafel slope of 47.9 mV dec−1 . This investigation presents a novel approach to the development of efficient transition metal-based electrocatalysts.

Metal (Mn2+, Co2+ and Cd2+) ions induced differentiation in mixed-ligands MOFs constructed from H3btb and H2bdc: Highly porous Structures, new topology nets and two-step gate-opening behaviors

Mix-ligands strategy is highly efficient for the rational construction of MOFs with particular structure motifs and high porosity, yet challenging and requiring matching in hierarchical coordination assembly and synergetic crystallization. The solvothermal reactions of 1,3,5-tris[4-carboxyphenyl]benzene (H3btb) and 1,4-benzenedicarboxylic acid (H2bdc) with different 3d metal ions, generated highly porous mixed-ligands MOFs of [(CH3)2NH2]2[Mn3(btb)2 (bdc)]·12DMF·3MeOH (Mn-btb-bdc) having anionic 3D frameworks constructed from linear [Mn3(COO)8] nodes, [Co4(btb)2(bdc)(H2O)3]·15DMF·7H2O (Co-btb-bdc) processing neutral frameworks constituted by linear [Co3(COO)6(H2O)4] and paddle-wheel [Co2(COO)4(H2O)2] nodes, as well as one single-ligand MOFs of [(CH3)2NH2][Cd(btb)(H2O)]·8DMF (Cd-btb-2fold) exhibiting 2-fold interpenetrated ths net frameworks due to the unsuccessful introduce of the coexisted bdc ligand. Two new topology net of 2,3,8-connected net with point symbol of (42·6)2(44·66·812·105·12)(6) and 2,3,4,6-connected net with Point Symbol of (4·82)4(42·811·102)2(84·122)(82) were found for Mn-btb-bdc and Co-btb-bdc. All these three MOFs are highly porous with void fractions of 60.9%, 52.2% and 61.4%, stemming from 3D-penetrated, 3D-penetrated and 1D channels, respectively. Such structural differentiations are attributed to the diversified electronic structure and coordination preference of different 3d metal ions, as well as the solvent template and temperature effects. Two-steps gate-opening behaviour in gas sorption isotherms was found in the flexible Mn-btb-bdc MOFs.

Merits of atomic cascade computations

Atomic cascades refer—first and foremost—to the stepwise de-excitation of excited atoms owing to the emission of electrons or photons. Apart from dedicated experiments at storage rings and synchrotrons, such cascades frequently occur in astro and plasma physics, material research, surface science and at various places elsewhere. In addition, moreover, “atomic cascades” have been found a useful concept for modeling atomic behavior under different conditions, for instance, when dealing with the photoabsorption of matter, the generation of synthesized spectra, or for determining a rather wide class of (plasma) rate coefficients. We here compile and discuss several atomic cascades (schemes) that help predict cross sections, rate coefficients, electron and photon spectra, or ion distributions. We also demonstrate how readily these schemes have been implemented within JAC, the Jena Atomic Calculator. Emphasis is placed on the classification of atomic cascades and their (quite) natural breakdown into cascade computations, to deal with the electronic structure and transition amplitudes of atoms and ions, as well as the cascade simulation of those properties and spectra, that are experimentally accessible. As an example, we show and discuss the computation of dielectronic recombination plasma rate coefficients for beryllium-like gold ions. The concept of atomic cascades and its implementation into JAC can be applied for most ions across the periodic table and will facilitate the modeling and interpretation of many forthcoming observations.Graphical abstract

Composition-tunable Co3-xFexSe4 as efficient electrocatalysts for the oxygen evolution reaction

In the oxygen evolution reaction (OER), the selection of highly active catalysts is fundamental to curtail overpotentials and to enhance the typically sluggish kinetics characteristic of the reaction. Cobalt selenide (Co3Se4), with its optimally configured electronic structure of cobalt ions, is consistently hailed as a prospective electrocatalyst for the OER, making it highly efficient in facilitating the reaction.Despite the persistent challenges of the exposure of catalytic active sites and the limited electronic conductivity, our study unveils a breakthrough solution. We introduce a highly efficient Fe-doped Co3Se4 electrocatalyst for the OER, addressing these long-standing issues, and it has desirable compositional flexibility, formed Co3-xFexSe4 (0 ≤ x ≤ 3) selenides, by introducing Fe doping, the electronic structure of Co3Se4 is effectively regulated, resulting in a remarkable reduction in the overpotential of the OER under alkaline conditions.Simultaneously, the introduction of Fe induces the formation of highly active Co–O sites, ultimately establishing a highly active and stable catalytic surface for oxygen evolution. Consequently, this leads to a significant improvement in the activity of the oxygen evolution reaction (OER). The synthesized Co2.5Fe0.5Se4 catalyst exhibits lower overpotential (η10 = 220 mV) and Tafel slope (41.2 mV dec−1), which is superior to the general commercial RuO2 benchmark. In addition, Co2.5Fe0.5Se4 also exhibits exceptional structural integrity and sustained operational longevity, with a durability of up to 280 h at 100 mA cmgeo−2. Impressively, the Pt/C∥Co2.5Fe0.5Se4 water electrolysis cell only requires a battery voltage of 1.67 V to provide a current density of 100 mA cmgeo−2 and has excellent long-term stability.

Gas-Phase Electronic Structure of Phthalocyanine Ions: A Study of Symmetry and Solvation Effects.

Research into and applications of phthalocyanines (Pc) are mostly connected to their intriguing electronic properties. Here, messenger-type UV-vis spectroscopy of two metal-free ions from the phthalocyanine family, cationic H2Pc+ and H2PcD+, along with their hydrates is performed. They show that the electronic properties of both ions can be traced to those in the conjugate base, Pc2-, however, they are affected by state splitting due to the reduced symmetry; in the H2Pc+ radical cation, a new band appears due to excitations into the singly-occupied molecular orbital. Quantum chemical spectra modeling reproduces all important features of the measured spectra and provides insight into the nature of electronic transitions. Hydration of the ions has only a mild effect on the electronic spectra, showing the stability of the electronic structure with respect to solvation effects.

Enhanced Oxygen Evolution Reaction Activity of Fe-Doped Lithium Nickel-Based Metal Oxide through Modification of Nickel Oxidation State

The oxygen evolution reaction (OER) involves the four-electron transfer process of water oxidation to produce oxygen gas and protons. However, this reaction is kinetically sluggish and requires high overpotential compared to hydrogen evolution reaction (HER). Herein, we have fabricated Fe-doped LiNiO2 using electrospray deposition (ESD) technique. With this technique, we can modify the electronic structure of LiNiO2 by controlling amounts of Fe, and the morphology can be controlled with various parameters such as applied voltage, spray rate, and substrate temperature. The synergistic effect of iron doping can modify the electronic structure of the surface Ni ions and increase oxidation state of Ni2+ to Ni3+. Through this oxidation state change, Ni becomes more electrophilic and then adsorbed oxygen in the M – O step, which is considered as rate-determining step in OER, easily reacts with OH ions. In electrochemical analysis, the optimized Fe-doped LiNiO2 showed improved OER performance compared to LiNiO2. The surface chemical compositions of the Fe-doped LiNiO2 electrode were characterized by X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD). From our result, we can improve OER performance and stability with simple control of ESD technique parameters and electronic structure modification by Fe doping.

Single-particle-exact density functional theory

We introduce ‘single-particle-exact density functional theory’ (1pEx-DFT), a novel density functional approach that represents all single-particle contributions to the energy with exact functionals. Here, we parameterize interaction energy functionals by utilizing two new schemes for constructing density matrices from ‘participation numbers’ of the single-particle states of quantum many-body systems. These participation numbers play the role of the variational variables akin to the particle densities in standard orbital-free density functional theory. We minimize the total energies with the help of evolutionary algorithms and obtain ground-state energies that are typically accurate at the one-percent level for our proof-of-principle simulations that comprise interacting Fermi gases as well as the electronic structure of atoms and ions, with and without relativistic corrections. We thereby illustrate the ingredients and practical features of 1pEx-DFT and reveal its potential of becoming an accurate, scalable, and transferable technology for simulating mesoscopic quantum many-body systems.

Variational atomic model of plasma accounting for ion radial correlations and electronic structure of ions.

We propose a model of ion-electron plasma (or nucleus-electron plasma) that accounts for the electronic structure around nuclei (i.e., ion structure) as well as for ion-ion correlations. The model equationsare obtained through the minimization of an approximate free-energy functional, and it is shown that the model fulfills the virial theorem. The main hypotheses of this model are (1) nuclei are treated as classical indistinguishable particles, (2) electronic density is seen as a superposition of a uniform background and spherically symmetric distributions around each nucleus (system of ions in a plasma), (3) free energy is approached using a cluster expansion (nonoverlapping ions), and (4) resulting ion fluid is modeled through an approximate integral equation. In the present paper, the model is described only in its average-atom version.

Electronic stopping power of magnesium including inner-electron excitation

The electronic stopping power of magnesium for protons and He ions is studied by a nonequilibrium approach based on real-time time-dependent density-functional theory combined with Ehrenfest molecular-dynamics simulation. The electronic stopping power of Mg for energetic protons and He ions is calculated, and the microscopic excitation mechanism for the inner $2p$ electron of Mg and its contribution to electronic stopping power is revealed. In the low-energy range, the velocity proportionality of the electronic stopping power of Mg for protons is displayed. The low-energy stopping power of Mg for He ions displays deviations from the velocity proportionality, which is ascribed to the electronic structure of He ions that enables an additional energy-loss channel due to charge exchange. Our calculated stopping power is in a quantitative agreement with the experimental data up to the stopping maximum, and the stopping power including also $2p$-electron excitation is considerably improved compared to that with only the valence electron taken into account. Our results showed that the contribution of $p$-electron excitation to the electronic stopping is remarkable in the high-velocity regime. The scaling relationship $\sqrt{{S}_{\ensuremath{\alpha}}/{S}_{H}}$ = ${\overline{q}}_{\ensuremath{\alpha}}/{\overline{q}}_{H}$ can be extended to low velocities provided that the mean steady-state charge is employed instead of assuming fully ionized charges and considering also $2p$-electron excitation of Mg.

Heterostructured Mo and Co-based phosphides as high-performance bifunctional electrocatalysts for overall water splitting.

Transitional metal phosphides are efficient and durable electrocatalysts for water splitting. In this work, Mo-CoP/Co2P/NF heterostructures are reported to exhibit bifunctional electrocatalyst properties in various electrolytes. The Co phosphides were found to be possessing a hydrogenase-like structure in these heterostructures with P as the proton-acceptor site and Co as the hydride-acceptor site, making them highly active during the HER process. Moreover, the electronic structure of Co ions could be modified, or the transfer of electrons could be accelerated due to the different valence states of Mo. Additionally, the Mo centers possessed superior adsorption properties toward hydrogen. Consequently, excellent performance for the electrocatalytic HER was exhibited by the Mo-CoP/Co2P/NF-300 heterostructure with small overpotentials of 86.6 mV and 48 mV at a current density of 10 mA cm-2 in 1.0 M KOH and 0.5 M H2SO4 solutions, respectively. Furthermore, it also exhibited efficient OER activity in an alkaline solution with a low overpotential of 245 mV at 30 mA cm-2. Post-analysis revealed the changes in the surface and the formation of Co oxyhydroxide during the OER process, and the formation of Co-P-O during the HER process. The high HER and OER performances are attributed to these transformations of morphologies and compositions. Consequently, a two-electrode electrolyzer based on Mo-CoP/Co2P/NF-300 required voltages of 1.59 V and 1.703 V at 20 mA cm-2 and 100 mA cm-2, respectively, and maintained long-term stability.

Novel Insight into Rechargeable Aluminum Batteries with Promising Selenium Sulfide@Carbon Nanofibers Cathode.

Due to the unique electronic structure of Al3+ with strong Coulombic interaction and complex bonding situation (simultaneously covalent/ionic bonds), traditional electrodes, mismatching with the bonding orbital of Al3+ , usually exhibit slow kinetic process with inferior rechargeable aluminum batteries (RABs) performance. Herein, to break the confinement of the interaction mismatch between Al3+ and electrode, we potentially develop a previously unexplored Se2.9 S5.1 -based cathode with sufficient valence electronic energy overlap with Al3+ and easily accessible structure. Through this new strategy, Se2.9 S5.1 encapsulated in multichannel carbon nanofibers with free-standing structure exhibits a high capacity of 606 mAh g-1 at 50mA g-1 , fast kinetics (211 mAh g-1 at 2.0 A g-1 ), robust stability (187 mAh g-1 at 0.5 A g-1 after 3,000 cycles), and enhanced flexibility. Simultaneously, in/ex-situ characterizations also reveal the unexplored mechanism of Sex Sy in RABs. This article is protected by copyright. All rights reserved.

Air Instability of Ni‐Rich Layered Oxides–A Roadblock to Large Scale Application

AbstractBenefiting from the excellent lithium ions diffusion kinetics and considerable discharge specific capacity, Ni‐rich layered oxides have become the preferred selection cathode active materials (CAMs) for high energy density Li‐ion batteries. However, due to the distinctive electronic structure of nickel ions (Ni2+/3+/4+) and the strict criteria for sintering conditions, the Ni‐rich CAMs inherently suffer from notorious deterioration when in contact with the ambient air. This review provides a comprehensive and critical overview of air instability for Ni‐rich CAMs, a neglected but critical issue for large‐scale application. The fundamental understanding of derivation of air instability and characterizations is first given, followed by a discussion of evolution behaviors and the corresponding negative influence on fabricating properties of electrodes and electrochemical/safety performance of batteries. Afterward, various material modification strategies for improving air storage stability including pre‐treatment by doping and coating and post‐treatment by gas, wash, and heat are overviewed. Finally, some perspectives for further exploration to address the air instability issue and pave ways toward Ni‐rich CAMs’ practical applications are also proposed.

Plasma environmental effects in the atomic structure for simulating x-ray free-electron-laser-heated solid-density matter.

High energy density (HED) matter exists extensively in the Universe, and it can be created with extreme conditions in laboratory facilities such as x-ray free-electron lasers (XFEL). In HED matter, the electronic structure of individual atomic ions is influenced by a dense plasma environment, and one of the most significant phenomena is the ionization potential depression (IPD). Incorporation of the IPD effects is of great importance in accurate modeling of dense plasmas. All theoretical treatments of IPD so far have been based on the assumption of local thermodynamic equilibrium, but its validity is questionable in ultrafast formation dynamics of dense plasmas, particularly when interacting with intense XFEL pulses. A treatment of transient IPD, based on an electronic-structure calculation of an atom in the presence of a plasma environment described by classical particles, has recently been proposed [Phys. Rev. E 103, 023203 (2021)2470-004510.1103/PhysRevE.103.023203], but its application to and impact on plasma dynamics simulations have not been investigated yet. In this work, we extend XMDYN, a hybrid quantum-classical approach combining Monte Carlo and molecular dynamics, by incorporating the proposed IPD treatment into plasma dynamics simulations. We demonstrate the importance of the IPD effects in theoretical modeling of aluminum dense plasmas by comparing two XMDYN simulations: one with electronic-structure calculations of isolated atoms (without IPD) and the other with those of atoms embedded in a plasma (with IPD). At equilibrium, the mean charge obtained in the plasma simulation with IPD is in good agreement with the full quantum-mechanical average-atom model. The present approach promises to be a reliable tool to simulate the creation and nonequilibrium evolution of dense plasmas induced by ultraintense and ultrashort XFEL pulses.

Composite nanoarchitectonics of ZIF-67 derived CoSe2/rGO with superior charge transfer for oxygen evolution reaction

The poor conductivity and electronic structure of transition metal chalcogenide electrocatalysts turn to be the hurdles as the appropriate successors of noble metal electrocatalysts for oxygen evolution reaction (OER). The conductivity can be adjusted by introducing graphene to construct hetero interface, in which the stacking of graphene remains a challenge. Herein, CoSe2 anchored on reduced graphene oxide (rGO) composites were prepared using zeolitic imidazolate frameworks-67 (ZIF-67) and graphene oxide (GO) as precursors. Without iR-correction, CoSe2 anchored on rGO composites with a superior OER performance just demands a low potential of 296 mV to reach the current density of 10 mA cm−2, which is lower than that of pure CoSe2 (348 mV). The interfacial interaction between CoSe2 and rGO adjusts the electronic structure of cobalt ions and optimizes the filling of eg orbital as well as the bonding strength between cobalt ions and oxygen intermediate species, ameliorating the intrinsic OER activity. Meanwhile, the employment of ZIF-67 with a three-dimensional structure alleviates the coverage of active sites caused by the accumulation of graphene, which is also responsible for the excellent OER activity.

Metal-insulator transition and local-moment collapse in negative charge transfer CaFeO3 under pressure

We compute the electronic structure, spin and charge state of Fe ions, and the structural phase stability of paramagnetic ${\mathrm{CaFeO}}_{3}$ under pressure using a fully self-consistent in charge density $\mathrm{DFT}+$ dynamical mean-field theory method. We show that at ambient pressure ${\mathrm{CaFeO}}_{3}$ is a negative charge transfer insulator characterized by strong localization of the Fe $3d$ electrons. It crystallizes in the monoclinic $P{2}_{1}/n$ crystal structure with a cooperative breathing mode distortion of the lattice. While the Fe $3d$ Wannier occupations and local moments are consistent with robust charge disproportionation of Fe ions in the insulating $P{2}_{1}/n$ phase, the physical charge density difference around the structurally distinct Fe $A$ and Fe $B$ ions with the ``contracted'' and ``expanded'' oxygen octahedra, respectively, is rather weak, of $\ensuremath{\sim}0.04$. This implies the importance of the Fe $3d$ and O $2p$ negative charge transfer and supports the formation of a bond-disproportionated state characterized by the Fe $A 3{d}^{5\ensuremath{-}\ensuremath{\delta}}{\underline{L}}^{2\ensuremath{-}\ensuremath{\delta}}$ and Fe $B 3{d}^{5}$ valence configurations with $\ensuremath{\delta}\ensuremath{\ll}1$, in agreement with strong hybridization between the Fe $3d$ and O $2p$ states. This complex interplay between electronic correlations, strong covalency, and lattice effects, resulting in bond disproportionation, is in many ways reminiscent of the behavior of rare-earth nickelates, $R{\mathrm{NiO}}_{3}$ $(R=\text{rare earth})$. Upon compression, ${\mathrm{CaFeO}}_{3}$ undergoes the metal-to-insulator phase transition (MIT) which is accompanied by a structural transformation into the orthorhombic $Pbnm$ phase. The phase transition is accompanied by suppression of the cooperative breathing mode distortion of the lattice and, hence, results in the melting of bond disproportionation of the Fe ions. Our analysis suggests that the MIT transition is associated with orbital-dependent delocalization of the Fe $3d$ electrons and leads to a remarkable collapse of the local magnetic moments. Our results imply the crucial importance of the interplay of electronic correlations and structural effects to explain the properties of ${\mathrm{CaFeO}}_{3}$.

Tunable exchange bias in La1.5Sr0.5CoMnO6 double perovskite doped with nonmagnetic Ga ions

The crystal structure, electronic structure, and magnetic behaviors of nonmagnetic Ga ions doped double perovskite La1.5Sr0.5CoMnO6 single phase crystals have been investigated. Different from the traditional magnetic dilution effect of nonmagnetic doping, Ga doping in La1.5Sr0.5CoMnO6 enhances the ferromagnetic (FM) exchange interaction of Co3+-O-Mn3+. Moreover, both conventional and spontaneous exchange bias (EB) effects can be tuned by modulating the Ga doping content, which is accompanied by the variation of the Co3+/4+ and Mn3+/4+ and the effective magnetic moment. The EB field and magnetization can be improved by nonmagnetic Ga3+ doping with content lower than 0.2. The evolution of conventional and spontaneous EB effects in La1.5Sr0.5Co1-xGaxMnO6 can be understood in terms of the unidirectional interface anisotropic coupling between FM/anti-FM, and/or FM/spin glass, which is affected by antisite disorder, spin glass, and the uncompensated coupling between Co and Mn.

Effects of surface spatial structures and electronic properties of chalcopyrite and pyrite on Z-200 selectivity

Chalcopyrite (CuFeS2) is one of the main copper minerals, and is always found associated with pyrite (FeS2). To obtain a satisfactory Cu concentration, the undesirable pyrite component must be discharged into tailings. O-isopropyl-N-ethyl thionocarbamate (Z-200) has been proven to be a collector with good selectivity for chalcopyrite flotation. However, the fundamental mechanism for the much greater selectivity of Z-200 for chalcopyrite than for pyrite is still not clear. In the present study, density functional theory (DFT) calculations have been performed to investigate the interaction mechanism of Z-200 with chalcopyrite (112) and pyrite (100) surfaces, and to understand the better selectivity of Z-200 for chalcopyrite during Cu–S flotation separation. Calculated parameter tests suggest that, for the calculation of chalcopyrite, using antiferromagnetism and the Hubbard U correction is very important to obtain its reasonable structural and electronic properties. Moreover, antiferromagnetism determines the activity of copper ions on the chalcopyrite surface. The Z-200 adsorption results suggest that the structures of the mineral surfaces and Z-200 molecules as well as the electronic structures of the Cu and Fe ions are critical for the selectivity of Z-200. The (112) surface of chalcopyrite obviously relaxes after cleavage, leaving iron, copper, and sulphur ions almost on the same plane. The adsorption of Z-200 on the chalcopyrite (112) surface has an energy barrier of 78.7 kJ/mol and is exoenergetic by 101.5 kJ/mol, whereas the adsorption of Z-200 on the pyrite surface is very weak, with an adsorption energy of –32.0 kJ/mol. Copper atoms can be pulled up from the surface by the adsorption of Z-200 to restore the tetrahedral structure of Cu, but the pyrite surface Fe atoms cannot be pulled up. Considering these results, the surface structure of pyrite is determined to be non-conducive to the adsorption of Z-200, and the possible influences of the electronic structure of Cu and Fe ions on the adsorption of Z-200 are discussed.

Paramagnetic phases of two-dimensional magnetic materials

The magnetic long-range ordering states of van der Waals magnets at low temperatures have gained much interest, yet their high-temperature paramagnetic states remain largely unexplored. In this paper, we apply the disordered local moment picture for describing the paramagnetic states of two-dimensional magnetic semiconductors. We calculate the electronic structure of paramagnetic phases of ${\mathrm{CrI}}_{3},\phantom{\rule{0.28em}{0ex}}{\mathrm{CrSiTe}}_{3}$, and ${\mathrm{NiPS}}_{3}$ using the density functional theory with static Hubbard corrections. The semiconducting electronic structures are successfully reproduced without any inclusion of dynamical correlation effects. The local electronic structure of magnetic ions in the paramagnetic phase resembles those in the magnetically ordered phase. The band structures of the paramagnetic phases are also analyzed. The itinerant ferromagnet ${\mathrm{Fe}}_{3}{\mathrm{GeTe}}_{2}$ is also briefly discussed where the disordered local moment picture is not applicable due to the coexistence of itinerant and local magnetism.

Comment on an article by Gonzaga et al. J Am Ceram Soc. 2020;103:6280‐6288

AbstractI argue that the authors’ interpretation of X‐ray photoelectron spectroscopy (XPS) Ce3d spectra of their materials is untenable because it largely neglects the electronic structure of cerium ions and spin‐orbit interaction of the Ce3d subshell. I conclude that at %Ce3+ values the authors derived from their Ce3d spectra offer an inaccurate account of the cerium chemistry of their materials.