Electron-electron Interaction Research Articles

Surface Plasmon Polariton Photoluminescence Enhancement of Single InP Nanowires with InAsP Quantum Wells

A significant (up to 4 times) photoluminescence enhancement of single InP/InAsP/InP nanowires transferred onto a silicon oxide‐covered silver layer on silicon substrate with a metal surface roughness level of less than 1 nm and a dielectric thickness of 5 nm has been demonstrated. This phenomenon is explained by the interaction of electron–hole pairs in the semiconductor with surface plasmon polaritons. The photoluminescence kinetics and results of modeling confirm the indicated enhancement mechanism.

Carrier localization induced by electron-electron interaction and its impact on the electrical transport and magnetic properties of nonstoichiometric IrMnSn

Carrier localization induced by electron-electron interaction and its impact on the electrical transport and magnetic properties of nonstoichiometric IrMnSn

Dual Modulation of Hydroxyl Action on Ruthenium Surface by Single‐Atom Supports for Alkaline H2 Evolution

AbstractRuthenium (Ru)‐based catalysts are known to accelerate the slow kinetics of the alkaline hydrogen evolution reaction (HER). However, enhancing the transfer kinetics of adsorbed hydroxyl (OHad) remains challenging. Herein, a dual‐regulation strategy is presented to alleviate OH blockage on the catalyst surface, using a cluster‐level Ru electrocatalyst supported by single‐atom CoN4 generated in situ on carbon nanotubes (CNTs). Experimental and theoretical studies demonstrate that introducing oxophilic single‐atom CoN4 can mitigate the strong interaction between Ru and OHad by directly competing for OHad on the Ru surface, thereby preventing Ru site poisoning. Meanwhile, single‐atom CoN4 effectively modifies the electronic structure of Ru atomic clusters (ACs), indirectly optimizing the energy barriers for OH desorption at the Ru interface and promoting OHad release. The electronic interaction between Ru ACs and CoN4 also inhibits Ru atom migration, significantly enhancing catalytic stability. The resulting catalyst shows excellent HER activity at 10 mA cm−2 with a low overpotential of 15 mV in alkaline solution and remains stable at 200 mA cm−2 for over 1000 h. An alkaline anion‐exchange membrane water electrolyzer (AEMWE) using this catalyst can exhibit an ultralow potential (1.785 V at 1 A·cm−2) and high stability at 500 mA·cm−2.

Synergistic Electronic Interaction in PdCu Alloy/TiO2‐NSs for Ambient Efficient Dehydrogenation of Formic Acid

AbstractPalladium‐based catalysts are remarkable in endorsing hydrogen (H2) generation through formic acid (HCOOH, FA) dehydrogenation under near‐ambient conditions. Hydrogen energy efficiency depends on high‐performance catalyst design. In this study, Pd‐Cu nanoalloy catalysts with mutable atomic ratios are successfully fabricated on TiO2 nanosheets (TiO2‐NSs).The synergistic electronic interactions between Palladium (Pd) and copper (Cu) are revealed through a density of states (DOS) analysis of alloy supported over a mixed valence state of Ti linked to oxygen vacancies (Vo) in TiO2‐NSs, Enhanced adsorption of target molecules reveals novel active sites for Formic acid dehydrogenation (FAD), with O─H bond cleavage via HCOO formate intermediate preceding C─H and C─O bond cleavage. Experimental and theoretical research demonstrates that the Pd‐Cu/TiO2‐NSs (3:7) catalyst d electron redistribution and d‐band center shift lower the activation energy for O─H bond cleavage, exhibit superior H2 production than pure Pd and Cu, increasing Pd electron density due to synergistic effects from reactive crystal facets, defects, and strong metal support interactions (SMSI), lowering the activation energy for HCOOH dissociation step, generating carbon dioxide (CO2) and H2 with a unprecedented high turnover frequency (TOF) of 6268 molH2.h−1.molPd−1 at 303K with activation energy (Ea) of 15 KJ mol−1. This attempt models an efficient HCOOH‐to‐hydrogen catalyst.

Tropone Hydrazides in [10+2]‐Hetero‐Higher‐Order Cycloaddition for the Synthesis of Tetrahydropyridazine Derivatives

Abstract[10+2]‐Hetero‐higher‐order cycloaddition between tropone hydrazides (acting as 10π‐components) and 3‐alkylidene oxindoles (acting as 2π‐components) has been established. Under Brønsted base catalysis the reaction proceeded in a fully peri‐ and diastereoselective manner with the stereochemical outcome governed mainly by electronic interactions. Following such a strategy, a series of structurally diverse tetrahydropyridazines were prepared in 30–70% yields. Furthermore, the potential of the obtained cycloadducts has been confirmed in selected chemoselective transformations.

Electron scattering study on acetic acid and methyl formate

Abstract In this work we report the results of a theoretical calculation of the elastic, differential scattering, and excitation cross-sections on electron interactions with the C2H4O2 isomers (methyl formate and acetic acid) using the ab initio R-matrix method in the energy range of 0.1-20 eV. The computations were performed using static exchange (SE), static exchange plus polarization (SEP) and Close-Coupling (CC) models with electronic structure calculation for these molecules performed using GAMESS. In the electron scattering cross section we have identified π* type resonance in both the isomers. Ionization cross-sections for both the molecules from ionization threshold to 500 eV using BEB method are also presented here. We endeavoured to explore the isomeric effect on various cross sections among these two isomers and included the third isomer, namely glycolaldehyde, as reported in our previous publication.

Bayesian Learning Aided Theoretical Optimization of IrPdPtRhRu High Entropy Alloy Catalysts for the Hydrogen Evolution Reaction

AbstractThe complex compositional space of high entropy alloys (HEAs) has shown a great potential to reduce the cost and further increase the catalytic activity for hydrogen evolution reaction (HER) by compositional optimization. Without uncovering the specifics of the HER mechanism on a given HEA surface, it is unfeasible to apply compositional modifications to enhance the performance and save costs. In this work, a combination of density functional theory and Bayesian machine learning is used to demonstrate the unique catalytic mechanism of IrPdPtRhRu HEA catalysts for HER. At high coverage of underpotential‐deposited hydrogen, a d‐band investigation of the active sites of the HEA surface is conducted to elucidate the superior catalytic performance through electronic interactions between elements. At low coverage, a novel Bayesian learning with oversampling approach is then outlined to optimize the HEA composition for performance improvement and cost reduction. This approach proves more efficacious and efficient and yields higher‐quality structures with less training set bias compared with neural‐network optimization. The proposed HEA optimization theoretically outperforms benchmark Pt catalysts’ overpotential by ≈40% at a 15% reduced synthesis cost comparing to the equiatomic ratio HEA.

Electron‐Penetrating in Heterointerface Engineering for Oxygen Evolution Reaction in Seawater Splitting

AbstractThe interfacial electric field (IEF) between heterogeneous units plays an important role in the electronic modulation of active centers during oxygen evolution reaction (OER). However, the weak electronic coupling between spatially separated IEFs limits the deep activation of metal sites on the surface of the catalyst. Herein, a proof‐of‐concept strategy is provided that imbed MS2 (M = Ni3Fe) species with high spin Fe orbits into heterogeneous units to promote the electron penetrating between IEFs. By designing a Fe2O3@MS/MS2@MOy model catalyst, the electronic interaction between adjacent IEFs is effectively enhanced for the deep oxidation of bimetals on the surface, breaking the competing relationship between adsorbed evolution mechanism (AEM) and lattice oxygen mechanism (LOM) of catalysts during OER. As a result, the onset overpotential of the synthesized electrode is only 171 mV, and it maintains excellent stability for more than 2300 h at a current density of 10 mA cm−2 in 1 M KOH + 0.5 M NaCl electrolyte.

Spontaneous photon emission by shaped quantum electron wavepackets and the QED origin of bunched electron beam superradiance.

It has been shown that the spontaneous emission rate of photons by free electrons, unlike stimulated emission, is independent of the shape or modulation of the quantum electron wavefunction (QEW). Nevertheless, here we show that the quantum state of the emitted photons is non-classical and does depend on the QEW shape. This non-classicality originates from the shape dependent off-diagonal terms of the photon density matrix. This is manifested in the Wigner distribution function and would be observable experimentally through homodyne detection techniques as a squeezing effect. Considering a scheme of electrons interaction with a single microcavity mode, we present a QED formulation of spontaneous emission by multiple modulated QEWs through a build-up process. Our findings indicate that in the case of a density modulated QEWs beam, the phase of the off-diagonal terms of the photon state emitted by the modulated QEWs is the harbinger of bunched beam superradiance, where the spontaneous emission is proportional to N_e^2 . This observation offers a potential for enhancement of other quantum electron interactions with quantum systems by a modulated QEWs beam carrying coherence and quantum properties of the modulation.

Simulation Study of High-Precision Characterization of MeV Electron Interactions for Advanced Nano-Imaging of Thick Biological Samples and Microchips

The resolution of a mega-electron-volt scanning transmission electron microscope (MeV-STEM) is primarily governed by the properties of the incident electron beam and angular broadening effects that occur within thick biological samples and microchips. A precise understanding and mitigation of these constraints require detailed knowledge of beam emittance, aberrations in the STEM column optics, and energy-dependent elastic and inelastic critical angles of the materials being examined. This simulation study proposes a standardized experimental framework for comprehensively assessing beam intensity, divergence, and size at the sample exit. This framework aims to characterize electron-sample interactions, reconcile discrepancies among analytical models, and validate Monte Carlo (MC) simulations for enhanced predictive accuracy. Our numerical findings demonstrate that precise measurements of these parameters, especially angular broadening, are not only feasible but also essential for optimizing imaging resolution in thick biological samples and microchips. By utilizing an electron source with minimal emittance and tailored beam characteristics, along with amorphous ice and silicon samples as biological proxies and microchip materials, this research seeks to optimize electron beam energy by focusing on parameters to improve the resolution in MeV-STEM/TEM. This optimization is particularly crucial for in situ imaging of thick biological samples and for examining microchip defects with nanometer resolutions. Our ultimate goal is to develop a comprehensive mapping of the minimum electron energy required to achieve a nanoscale resolution, taking into account variations in sample thickness, composition, and imaging mode.

Visualizing the Structure and Dynamics of Transition Metal-Based Electrocatalysts Using Synchrotron X-Ray Absorption Spectroscopy.

As the global energy structure evolves and clean energy technologies advance, electrocatalysis has become a focal point as a critical conversion pathway in the new energy sector. Transitional metal electrocatalysts (TMEs) with their distinctive electronic structures and redox properties show great potential in electrocatalytic reactions. However, complex reaction mechanisms and kinetic limitations hinder the improvement of energy conversion efficiency, highlighting the necessity for comprehensive studies on structure and performance of electrocatalysts. X-ray Absorption Fine Structure (XAFS) spectra stand out as a robust tool for examining the electrocatalyst's structures and performance due to its atomic selectivity and sensitivity to local environments. This review delves into the application of XAFS technology in characterizing TMEs, providing in-depth analyses of X-ray Absorption Near-Edge Structure (XANES) spectra, and Extended XAFS (EXAFS) spectra in both R-space and k-space. These analyses reveal intrinsic structural information, electronic interactions, catalyst stability, and aggregation morphology. Furthermore, the paper examines advancements in in-situ XAFS techniques for real-time monitoring of active site changes, capturing critical intermediate and transitional states, and elucidating the evolution of active species during electrocatalytic reactions. These insights deepen our understanding on structure-activity relationship of electrocatalysts and offer valuable guidance for designing and developing highly active and stable electrocatalysts.

Low-Energy Magnetic States of Tb Adatom on Graphene.

Electronic structure and magnetic interactions of a Tb adatom on graphene are investigated from first principles using combination of density functional theory and multiconfigurational quantum chemistry techniques including spin-orbit coupling. We determine that the six-fold symmetry hollow site is the preferred adsorption site and we investigate electronic spectrum for different adatom oxidation states including Tb3+, Tb2+,Tb1+, and Tb0. For all charge states, the Tb 4f8configuration is retained with other adatom valence electrons being distributed over 5dxy, 5dx2+y2, and 6s/5d0single-electron orbitals. We find strong intra-site adatom exchange coupling that ensures that the 5d6sspins are parallel to the 4fspin. For Tb3+, the energy levels can be described by theJ= 6 multiplet split by the graphene crystal field. For other oxidation states, the interaction of 4felectrons with spin and orbital degrees of freedom of 6s5delectrons in the presence of spin-orbit coupling results in the low-energy spectrum composed closely lying effective multiplets that are split by the graphene crystal field. Stable magnetic moment is predicted for Tb3+and Tb2+adatoms due to uniaxial magnetic anisotropy and effective anisotropy barrier around 440 cm-1controlled by the temperature assisted quantum tunneling of magnetization through the third excited doublet. On the other hand, in-plane magnetic anisotropy is found for Tb1+and Tb0adatoms. Our results indicate that the occupation of the 6s5dorbitals can dramatically affect the magnetic anisotropy and magnetic moment stability of rare earth adatoms.

Interatomic and intermolecular decay processes in quantum fluid clusters.

In this comprehensive review, we explore interatomic and intermolecular correlated electronic decay phenomena observed in superfluid helium nanodroplets subjected to extreme ultraviolet (XUV) radiation. Helium nanodroplets, known for their distinctive electronic and quantum fluid properties, provide an ideal environment for examining a variety of non-local electronic decay processes involving the transfer of energy, charge, or both between neighboring sites and resulting in ionization and the emission of low-kinetic energy electrons. Key processes include interatomic or intermolecular Coulombic decay (ICD) and its variants, such as electron transfer-mediated decay (ETMD). Insights gained from studying these light-matter interactions in helium nanodroplets enhance our understanding of the effects of ionizing radiation on other condensed-phase systems, including biological matter. We also emphasize the advanced experimental and computational techniques that make it possible to resolve electronic decay processes with high spectral and temporal precision. Utilizing ultrashort pulses from free-electron lasers, the temporal evolution of these processes can be
followed, significantly advancing our comprehension of the dynamics within quantum fluid clusters and non-local electronic interactions in nanoscale systems.

Polyoxometalates‐Mediated Selectivity in Pt Single‐Atoms on Ceria for Environmental Catalysis

AbstractOptimizing the reactivity and selectivity of single‐atom catalysts (SACs) remains a crucial yet challenging issue in heterogeneous catalysis. This study demonstrates selective catalysis facilitated by a polyoxometalates‐mediated electronic interaction (PMEI) in a Pt single‐atom catalyst supported on CeO2 modified with Keggin‐type phosphotungstate acid (HPW), labeled as Pt1/CeO2‐HPW. The PMEI effect originates from the unique arrangement of isolated Pt atoms and HPW clusters on the CeO2 support. Electrons are transferred from the ceria support to the electrophilic tungsten in HPW clusters, and subsequently, Pt atoms donate electrons to the now electron‐deficient ceria. This phenomenon enhances the positive charge of Pt atoms, moderating O2 activation and limiting lattice oxygen mobility compared to the conventional Pt1/CeO2 catalyst. The resulting electronic structure of Pt combined with the strong and local acidic environment of HPW on Pt1/CeO2‐HPW leads to improved efficiency and N2 selectivity in the degradation of NH3 and NO, as well as increased CO2 yield when inputting volatile organic compounds. This study sheds the light on the design of SACs with balanced reactivity and selectivity for environmental catalysis.

Ultrasensitive In2O3-Based Nanoflakes for Lung Cancer Diagnosis and the Sensing Mechanism Investigated by Operando Spectroscopy.

Rapid gas sensing with high sensitivity and selectivity is pivotal in advanced production, in smart living, and increasingly in medical health applications. This study presents a novel Pt@InNiOx nanoflake isoprene sensor that achieves an exceptionally low limit of detection (LOD) at 2 ppb, the lowest reported for isoprene sensors to date. Notably, it exhibits high selectivity and remarkable antihumidity capacity, thus meeting the stringent requirements for lung cancer screening. To unravel the sensing mechanism, we fabricate an operando DRIFTS-Raman cell coupled to online electrical measurements. It reveals that the ultrasensitive performance of Pt@InNiOx nanoflakes stems from the activated conjugated structure of isoprene by Pt nanoclusters and from the enhanced isoprene adsorption and electron interaction due to the nanoflake morphology. The p-n junction constructed by doping Ni maintains Fermi level equilibrium, shielding it from humidity interference. Practically, we integrate these ultrasensitive Pt@InNiOx nanoflakes into a miniaturized portable electronic device that successfully distinguishes lung cancer patients with expiratory isoprene below 40 ppb, from the healthy population with isoprene above 60 ppb, enabling an accurate diagnosis in clinics. Our work not only provides a breakthrough in low-cost, noninvasive cancer screening through breath analysis but also advances the rational design of cutting-edge gas sensing materials.

Информационная гигиена как фактор успешной профессиональной деятельности сотрудников уголовно-исполнительной системы

The article examines the issues of information hygiene as a factor of successful professional activity of employees of the penal correction system in the context of digital transformation. The insufficiency of research on information hygiene in the psychology of professional activity of specialists is emphasized. Information (digital) hygiene is a certain set of norms and rules that ensure optimal interaction with information of various kinds, which, in turn, ensures the preservation of professional health, personal resources, professional and personal identity and is one of the factors of success of professional activity in the context of digital transformation. Recommendations on the observance of information hygiene in the official activities of employees of the penitentiary system are given. The directions of the official activity of employees of the penal enforcement system in which the use of information hygiene is significant are highlighted: interaction with various information tools and software service products; organization of interdepartmental electronic interaction with law enforcement agencies and other federal executive authorities; information support for the activities of the Federal Penitentiary Service of Russia; information security and protection of information resources of the Federal Penitentiary Service of Russia; implementation of various projects of digital transformation of the Federal Penitentiary Service of Russia. Two approaches are proposed in training to improve the level of development of digital hygiene by employees of the penitentiary system: within the framework of higher and additional professional education. Considering information hygiene as a complex professionally important quality and a factor of successful performance of employees of the penal enforcement system, it is quite natural that these aspects can serve as the basis for taking into account and developing criteria for the success of professional activity in the future, an expanded description and characterization of generalized labor functions of professional standards by position, clarification of occupational and psychograms, optimization of procedures for professional selection and professional certification of employees of the penitentiary system in the dynamics of the professional path.

Band gap effect of TiO2 on supported Ru single-atom catalysts for CO2 methanation by DFT calculations

The influence of TiO2 band gap on structure and reactivity of the supported single ruthenium (Ru1) atom was studied by density functional theory calculations, utilizing Ru1/2L-TiO2 and Ru1/3L-TiO2 as model catalysts for CO2 methanation. The supports have band gaps of 2.39 eV and 1.48 eV, respectively. The band gap plays a significant role in electronic metal-support interactions (EMSIs) and the position of the d-band center of the Ru1 on the TiO2. The Ru1/3L-TiO2, the Ru1 catalyst supported on the 3L-TiO2 with a narrower band gap, shows enhanced EMSIs and a d-band center that is positioned farther from Fermi level, leading to lower charge density on the Ru1 and weaker adsorption of H2, CO2, and CO compared to the Ru1/2L-TiO2. CO2 methanation followed CO pathway, with the hydrogenation of CO* to HCO* identified as the rate-determining step on the Ru1/nL-TiO2. The Ru1 catalyst supported on TiO2 with a narrower band gap is more favorable kinetically and thermodynamically for CO2 methanation, despite the band gap not altering the reaction pathway. Enhanced hydrogen mobility and a pronounced promotional effect of hydrogen on CO adsorption, due to the narrower band gap support, are key factors facilitating the easier hydrogenation of CO* on the Ru1/3L-TiO2.

Low-energy (0–9 eV) electron interaction with gas phase 1,3-dichlorobenzene: an experimental and theoretical study

Abstract Dichlorobenzene used widely in industry for the synthesis of complex products, such as polymers. The processes using this compound require, as the initial step, the breakage of the C–Cl bond. In this work, we study the interaction of electrons with 1,3 dichlorobenzene molecules not only below 2 eV [M Mahmoodi-Darian et al 2001 J. Phys. Chem. A 113 11923–14929] but also at higher energies, i.e., up to 10 eV. In this investigated energy range, the electron induces the cleavage of the C–Cl bond producing essentially a Cl− anion and the chlorobenzene radical via dissociative electron attachment. The experimental measurements are completed with quantum scattering treatments providing the resonant states and also the integral scattering cross sections. These outcomes may potentially contribute to elaborate synthesis strategies using electrons (i.e., cold plasma, surface plasmon resonance, …).

Improved gas sensing properties of copper-doped MoSe2 monolayers: a first-principles study on CO2 and NO2 adsorption

Abstract This paper investigates the impact of copper (Cu)-doped MoSe2 monolayer (ML) on gas sensing properties. The adsorption behaviour of CO2 and NO2 gas molecules on Cu-doped MoSe2 ML is reported and various sensing and electronic parameters such as adsorption energy, charge transfer and recovery time, are computed to delineate the adsorption characteristics and gas sensitivity. In our study, the doped Cu-atom in Se vacant MoSe2 ML shows the adsorption energies to be −1.32 eV (O-orient) and −1.72 eV (C-orient), for CO2, while for NO2, they are −0.879 eV (O-orient) and −1.06 eV (N-orient), respectively. The negative formation energy of −6.62 eV shows the electronic stability of Cu-doped MoSe2 ML and thermal stability, demonstrated by the molecular dynamics study through the Nose-Vervlet Thermostat (NVT) algorithm. Also, significant changes are observed in electronic conductivity and work function upon adsorbed Cu-MoSe2 ML. Lastly, these outcomes illustrate that Cu doping amplifies the capture ability of MoSe2 ML towards gas molecules, fostering improved electron interaction between the substrate surface and gas molecules, consequently enhancing its gas sensing ability.

3d-orbital overlap modulated d-band center of high-entropy oxyhydroxide for efficient oxygen evolution reaction

As an emerging high entropy material, recently, a few studies have shown that high-entropy oxyhydroxides possess higher catalytic performance due to their multiple active sites and more excellent stability for the oxygen evolution reaction (OER). Although the high-entropy effect, cocktail effects etc. have been proposed for the catalytic mechanism, the electronic interaction mechanisms among multiple metal elements still require further in-depth investigation. Herein, a high-entropy oxyhydroxide (FeCoNiZnOOH) was synthesized. Experimental results and density functional theory (DFT) calculation demonstrate that there are electronic interactions and strong 3d orbital overlap among the four metals. This overlapping effect of the Fe/Co/Ni/Zn 3d orbitals shifts the d-band center downward, thereby reducing the adsorption barrier for oxygen intermediates during the reaction and accelerating the reaction kinetics. The FeCoNiZnOOH shows excellent electrocatalytic performance with a low overpotential of 206 mV at a current density of 20 mA cm−2, and a Tafel slope of 54.3 mV dec–1, which is better than the synthesized monometallic oxyhydroxide, bimetallic oxyhydroxide, medium entropy oxyhydroxides and commercial Ir/C catalyst. This work offers new insight into designing efficient OER catalysts through regulate the electronic structure and optimize electrochemical performance for high-entropy electrocatalysts.