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Multi-guest clathrates exhibit lots of functional characteristics owing to their unique structures, which herald beautiful application prospects, but their fundamental information is still scarce. Herein, we explore a type of (helium, excess electrons/EEs)–C60F60 co-clathrates with quasi-Matryoshka-doll structures using ab initio molecular dynamics simulation and reveal the EEs-entangled He roaming dynamics in C60F60 and its effect on the characteristics of clathrates. Perfluorination ensures that C60F60 possesses an extremely electropositive interior cavity. Its unique confinement effect can stabilize He as an extremely inert entity by noticeably enlarging the 1s–2s orbital gap and can also trap 1–2 EEs in its s-type interior orbital with extremely large binding energies. Co-inclusion of He and EEs in C60F60 exhibits inter-repulsive He⋯EEs entangling dynamics featuring quasi-Matryoshka-doll structures (He@EEs@C60F60). In this structure, EEs screen the attraction of cage-shell Cδ+ to He 1s2 electrons, thus inhibiting their stabilization and orbital expansion, while He conversely decreases the stability of EEs and redshifts their transition absorption. He can roam in the cavity, but its trajectory is impacted by EEs serving as a medium, and thus, the structures exhibit anormal dynamic variation of internuclear He⋯C spin coupling JHeC, which is manipulated by the EEs-entangled He roaming dynamics. JHeC and JHeC′ present opposite distance dependences for the colinearly aligned C⋅⋅⋅He⋅⋅⊗⋅⋅⋅⋅⋅C′ (⊗, the cage center). This work provides insights into the Matryoshka-doll structured He@EEs@C60F60 with He–EEs entangling dynamics and its modulation on EEs absorption and reveals the dynamic role of EEs in manipulating He-roaming and JHeC coupling properties for promising applications. [ABSTRACT FROM AUTHOR]

In the conventional GW method, the three-point vertex function (Γ) is approximated to unity (Γ ∼ 1). Here, we developed an all-electron first-principles GWΓ method beyond a conventional GW method by considering a first-order three-point vertex function (Γ(1) = 1 + iGGW) in a one-electron self-energy operator. We applied the GWΓ method to simulate the binding energies (BEs) of B1s, C1s, N1s, O1s, and F1s for 19 small-sized molecules. Contrary to the one-shot GW method [or G0W0(LDA)], which underestimates the experimentally determined absolute BEs by about 3.7 eV for B1s, 5.1 eV for C1s, 6.9 eV for N1s, 7.8 eV for O1s, and 5.8 eV for F1s, the GWΓ method successfully reduces these errors by approximately 1–2 eV for all the elements studied here. Notably, the first-order three-point vertex corrections are more significant for heavier elements, following the order of F > O > N > C > B1s. Finally, the computational cost analysis revealed that one term in the GWΓ one-electron self-energy operator, despite being computationally intensive, contributes negligibly (< 0.1 eV) to the C1s, N1s, O1s, and F1s. [ABSTRACT FROM AUTHOR]

Ab initio molecular dynamics simulations of negatively charged clusters of 2–48 ammonia molecules were performed to elucidate the electronic stability of the excess electron as a function of cluster size. We show that while the electronic stability of finite temperature clusters increases with cluster size, as few as 5–7 ammonia molecules can bind an excess electron, reaching a vertical binding energy slightly less than half of the bulk value for the largest system studied. These results, which are in agreement with previous studies wherever available, allowed us to analyze the excess electron binding patterns in terms of its radius of gyration and shape anisotropy and provide a qualitative interpretation based on a particle-in-a-spherical-well model. [ABSTRACT FROM AUTHOR]

We introduce an individually fitted screened-exchange interaction for the time-dependent Hartree–Fock (TDHF) method and show that it resolves the missing binding energies in polymethine organic dye molecules compared to time-dependent density functional theory (TDDFT). The interaction kernel, which can be thought of as a dielectric function, is generated by stochastic fitting to the screened-Coulomb interaction of many-body perturbation theory (MBPT), specific to each system. We test our method on the flavylium and indocyanine green dye families with a modifiable length of the polymethine bridge, leading to excitations ranging from visible to short-wave infrared. Our approach validates earlier observations on the importance of inclusion of medium range exchange for the exciton binding energy. Our resulting method, TDHF@vW, also achieves a mean absolute error on a par with MBPT at a computational cost on a par with local-functional TDDFT. [ABSTRACT FROM AUTHOR]

The fragmentation of ion clusters within the accelerating fields of ionic liquid ion sources (ILISs) is well documented and degrades ILIS performance and lifetime. Some of the most popular ILIS liquids, such as EMI-BF4 (1-Ethyl-3-methylimidazolium tetrafluoroborate) and EMI-Im (1-Ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide), emit clusters with lifetimes as low as ∼1 ns. Studies of fragmentation within the accelerating field typically rely on measuring the plume energy distribution averaged over all plume species and comparing those measurements with numerical simulations to estimate ion cluster lifetimes. Here, for the first time, we estimate EMI-BF4 cluster lifetimes by analyzing the energy distributions of individual plume species. We use this novel analysis method to estimate mean lifetimes of positive EMI-BF4 ion clusters from previously published experimental data. We find that the mean lifetime ranges from τ = 3.7 ns to τ = 124 ns for [ EM I + ] [ EMI - B F 4 ] dimers and ranges from τ = 1.5 ns to τ = 23 ns for [ EM I + ] [ EMI - B F 4 ] 2 trimers. Fitting those data to an analytical fragmentation model, we estimate the binding energy and temperature as Δ G S 0 = 0.49 eV and T = 394 K for dimers and Δ G S 0 = 0.40 eV and T = 365 K for trimers. Comparing our results with previous studies supports the conclusion that clusters are emitted with a wide distribution of internal energies, contrary to the common assumption of single internal energy for each species. [ABSTRACT FROM AUTHOR]

A series of Mg doped p-type multi-layered hBN films were prepared by atmospheric pressure chemical vapor deposition. Temperature dependent conductivity measurements were performed from 0.1 Hz to 10 MHz to analyze the characteristics of tail states close to the valence band edge. Jonscher's power law (A ω s ) is successfully applied to understand charge carrier transport through these states. In this work, exponent S increases from 0.6 → 0.8, 0.8 → 0.995, and 1.4 → 1.6 for samples B (precursor temperature, 750 °C), D (850 °C), and E (900 °C), indicating that non-overlapping small polaron tunneling dominates to 548 K. Polaron binding energies of 0.2–0.40 eV and tunneling distances <4.9 Å are calculated, confirming transport through localized states. The density of states near the Fermi level N(EF) was extracted from a fit to the AC conductivity data, yielding values of 10 15 and 10 17 e V − 1 c m − 3 as the precursor temperature increases. Singular Mg acceptor levels of 74, 30, and 17 meV are identified for each sample. A hole concentration from 6.5 × 1017 to 1 × 1018 cm−3 and carrier mobility from 18 to 25 cm2/V s is measured at 300 K. From RC fitting, carrier recombination lifetimes of 1.2, 0.4, and 0.35 μs are determined. Fermi's golden rule is used to determine an optical joint density of states of 1.1 × 1021 eV−1 cm−3 at a band edge. Overall, we show that AC conductivity is an effective method to evaluate midgap states in 2D (two-dimensional) materials at EF and p-type hBN possesses sufficient electrical properties to be integrated into a wide range of semiconductor applications. [ABSTRACT FROM AUTHOR]

The Hf/Ti ratio was precisely controlled at monolayer thickness using atomic partial layer deposition (APLD). HfxTi1−xO2 films with varying Hf concentrations were deposited by adjusting the pulse time of Hf precursors within a single atomic layer. Characterization using x-ray reflectivity, x-ray photoelectron spectroscopy, and spectroscopic ellipsometry confirmed the presence of Hf, Ti, and O in the films. Increasing the Hf content caused the binding energies of the O 1s peak to shift to higher values, indicating a chemical environment change from TiO2-like to HfO2-like. A higher Hf content also increased the relative atomic percentages of Hf, Ti, and O, altering the film properties. The mass density and optical properties were notably sensitive to changes in the Hf/Ti ratio at monolayer thickness. The potential of APLD to reduce dimensionality through precise control of both thickness and composition renders it especially appropriate for applications requiring highly specific material properties. [ABSTRACT FROM AUTHOR]

We have done comprehensive first-principles calculations of He-vacancy-interstitial clusters in FCC nickel. The calculated total binding energy of V n (Ni vacancy cluster), I n (Ni interstitial cluster), He n (helium interstitial cluster), He n V (helium interstitials in one vacancy), and He n V 2 (helium interstitials in one divacancy) cluster is reported. The total binding energy of a two Ni interstitial cluster is relatively large (1.07 eV), and the binding energy between a monovacancy and a vacancy cluster containing < 20 vacancies is relatively small (< 0.8 eV). The dissociation/emission energy barrier of a Ni interstitial from a He 3 interstitial cluster (three helium interstitial clusters) and a He 8 V cluster (eight helium interstitials in one vacancy) is ≤ 1.06 and ≤ 1.32 eV, respectively. The diffusion activation energy of helium is 1.36 eV via a dissociative mechanism. Comparisons with reported experimental results of helium diffusion and helium desorption have been done to verify the calculation results. The relative stability of stacking fault tetrahedron and void has been investigated further based on quasi-harmonic phonon calculations directly to consider the temperature effects. The reported binding energy results can be used to build molecular simulation potentials or provide input parameters for the cluster dynamics or lattice Monte Carlo simulations of helium-defect cluster evolution. [ABSTRACT FROM AUTHOR]

In this paper, we investigate the Feshbach resonances of high partial waves and the influence of spin–spin (S–S) interaction on ultracold scattering processes. Taking the N a 23 - R b 87 system as an example, we plot the variations of weakly bound state energy and elastic scattering cross section with magnetic field and with collision energy. We find that the number of splittings in high partial wave Feshbach resonances does not strictly conform to the expected l + 1 (l is rotational angular momentum), and the deviation is attributed to the influence of bound states in other channels coupled by S–S interaction. For different ml (the projection of l on the external magnetic field direction), the effects of S–S interaction lead to different scattering patterns in the incident channels. These results reveal the complex features of ultracold scattering processes in high partial waves caused by S–S interaction. [ABSTRACT FROM AUTHOR]

Recently, high entropy alloy (HEA) has become a research hotspot as a new candidate structural material in nuclear reactors due to its good irradiation resistance in swelling and hardening. Focusing on the temperature effect of irradiation damage, this work investigated the influence of irradiation temperature on dislocation evolution and irradiation hardening of HEAs. CoCrFeMnNi HEA was irradiated by high-energy Fe ions at room temperature and 500 °C. It was found that dense small dislocations were produced in the damage attenuation region (i.e., the tail of the ion range) of HEAs after irradiation at room temperature, whereas the irradiation-induced dislocations could not be observed in the damage attenuation region when the irradiation temperature was increased to 500 °C. For the small-sized dislocations, dissociation may occur more easily than long-range migration in HEAs (such as CoCrFeNi systems) due to the inhibition of defect migration and the decrease in defect binding energy, and this order is reversed in pure metals (such as Ni, W). Therefore, at 500 °C irradiation, small dislocations in the damage attenuation region of CoCrFeMnNi HEAs were dissociated before migrating to deeper regions, thereby resulting in the depth of dislocation distribution smaller than the stopping and range of ions in matter-calculated damage stopping depth, unlike the phenomenon in pure metals where dislocations migrated to regions exceeding the calculated depth. In addition, the dislocation density of CoCrFeMnNi HEAs decreased significantly due to the promotion of dissociation and merging of dislocations by elevated temperatures, and the hardening after 500 °C irradiation was less than that after room temperature irradiation. [ABSTRACT FROM AUTHOR]

Water freezing, initiated by ice nucleation, occurs widely in nature, ranging from cellular to global phenomena. Ice nucleation has been experimentally proven to require the formation of a critical ice nucleus, consistent with classical nucleation theory (CNT). However, the accuracy of CNT quantitative predictions of critical cluster sizes and nucleation rates has never been verified experimentally. In this study, we circumvent this difficulty by using molecular dynamics (MD) simulation. The physical properties of water/ice for CNT predictions, including density, chemical potential difference, and diffusion coefficient, are independently obtained using MD simulation, whereas the calculation of interfacial free energy is based on thermodynamic assumptions of CNT, including capillarity approximation among others. The CNT predictions are compared to the MD evaluations of brute-force simulations and forward flux sampling methods. We find that the CNT and MD predicted critical cluster sizes are consistent, and the CNT predicted nucleation rates are higher than the MD predicted values within three orders of magnitude. We also find that the ice crystallized from supercooled water is stacking-disordered ice with a stacking of cubic and hexagonal ices in four representative types of stacking. The prediction discrepancies in nucleation rate mainly arise from the stacking-disordered ice structure, the asphericity of ice cluster, the uncertainty of ice–water interfacial free energy, and the kinetic attachment rate. Our study establishes a relation between CNT and MD to predict homogeneous ice nucleation. [ABSTRACT FROM AUTHOR]

The binding energy between hydrogen (H) and defects in solid phase materials has been widely studied, which is of vital importance to understand the H retention effects and defect growth mechanisms. However, present studies of binding energy through density functional theory (DFT) or the molecular statics (MS) method were usually performed at 0 K, which could not take the influence of entropy into consideration. In this work, a thermodynamic method has been proposed to obtain the trapping energy between H and defects at finite temperatures. The method is based on the rate theory, which uses trapping energy (V) and trapping range (δ) to describe the trapping properties of defects. Ultimately, a parameterized H spatial cumulative distribution function at thermodynamic equilibrium state could be given. The trapping energy and trapping range parameters in the function can be determined by contrast with the results obtained from molecular dynamics or other methods. This method has been applied to calculate the trapping energies and trapping ranges of H to helium bubble and grain boundary, respectively. Further discussion has been made on the discrepancy between trapping energies obtained by this method and the conventional DFT/MS method. [ABSTRACT FROM AUTHOR]

Organic–inorganic hybrid perovskite quantum wells exhibit electronic structures with properties intermediate between those of inorganic semiconductors and molecular crystals. In these systems, periodic layers of organic spacer molecules occupy the interstitial spaces between perovskite sheets, thereby confining electronic excitations to two dimensions. Here, we investigate spectroscopic line broadening mechanisms for phonons coupled to excitons in lead-iodide layered perovskites with phenyl ethyl ammonium (PEA) and azobenzene ethyl ammonium (AzoEA) spacer cations. Using a modified Elliot line shape analysis for the absorbance and photoluminescence spectra, polaron binding energies of 11.2 and 17.5 meV are calculated for (PEA)2PbI4 and (AzoEA)2PbI4, respectively. To determine whether the polaron stabilization processes influence the dephasing mechanisms of coupled phonons, five-pulse coherent Raman spectroscopies are applied to the two systems under electronically resonant conditions. The prominence of inhomogeneous line broadening mechanisms detected in (AzoEA)2PbI4 suggests that thermal fluctuations involving the deformable organic phase broaden the distributions of phonon frequencies within the quantum wells. In addition, our data indicate that polaron stabilization primarily involves photoinduced reorganization of the organic phases for both systems, whereas the impulsively excited phonons represent less than 10% of the total polaron binding energy. The signal generation mechanisms associated with our fifth-order coherent Raman experiments are explored with a perturbative model in which cumulant expansions are used to account for time-coincident vibrational dephasing and polaron stabilization processes. [ABSTRACT FROM AUTHOR]

In the pursuit of reliable energy storage solutions, the significance of engineering electrodes cannot be overstated. Previous research has explored the use of surface modifiers (SMs), such as single-side fluorinated graphene, to enhance the thermodynamic stability of ion intercalation when applied atop few-layer graphene (FLG). As we seek alternatives to lithium-ion batteries (LIBs), earth-abundant elements like sodium and potassium have emerged as promising candidates. However, a comprehensive investigation into staging intercalation has been lacking thus far. By delving into staging assemblies, we have uncovered a previously unknown intercalation site that offers the most energetically favorable binding. Here, we study the first three elements in both alkali (Li, Na, K) and alkaline (Be, Mg, Ca) earth metals. Furthermore, the precise mechanism underlying this intercalation system has remained elusive in prior studies. In our work, we employed density functional theory calculations with advanced hybrid functionals to determine the electrical properties at various stages of intercalation. This approach has been proven to yield more accurate and reliable electrical information. Through the analysis of projecting density of states and Mulliken population, we have gained valuable insights into the intricate interactions among the SM, ions, and FLG as the ions progressively insert into the structures. Notably, we expanded our investigation beyond lithium and explored the effectiveness of the SM on ions with varying radii and valence, encompassing six alkali and alkaline earth metals. Additionally, we discovered that the number of graphene layers significantly influences the binding energy. Our findings present groundbreaking concepts for material design, offering diverse and economically viable alternatives to LIBs. Furthermore, they serve as a valuable reference for fine-tuning electrical properties through staging intercalation and the application of SMs. [ABSTRACT FROM AUTHOR]

This work aims to validate the feasibility of device-level analysis to reflect the effects of fabrication processes and operations, as contrasted with the conventional method of x-ray photoelectron spectroscopy (XPS), which is widely employed in amorphous oxide semiconductor thin-film transistors (TFTs) but analyzes film-level specimens. First, an analysis setup was introduced to determine the optimal x-ray target position for device-level XPS, where the intensity of channel components is maximized, through imaging XPS. Then, to demonstrate the effectiveness of this approach, the impact of channel composition and bias-stress was investigated through the implementation of device-level XPS on bottom-gate InGaZnO TFTs. The cationic composition ratios of the fabricated TFTs varied from 0.27:1:1.33 (In:Ga:Zn) and 0.28:1:2.21 when the subcycle of the Zn precursor increased by a factor of 1.5 in the atomic-layer deposition process. The device with a higher Zn ratio exhibited a more negative turn-on voltage and a twice larger subthreshold swing. These characteristics were validated from the comparisons in the relative amount of oxygen vacancies in O 1s of the channel and interface regions by 8.4%p and 5.6%p, respectively, between the devices. Furthermore, the electron trapping effect was verified for the devices subjected to a positive gate bias-stress of 3 MV/cm, as evidenced by the changes in the binding energy difference (0.35 eV) between the channel and gate insulator layers, in comparison to the non-stressed device. Consequently, this work demonstrates that device-level XPS can be an effective tool for understanding TFTs' characteristics in various ways beyond film-level analysis. [ABSTRACT FROM AUTHOR]

We consider the electron stimulated desorption, via dissociative electron attachment, of anionic species from thin condensed CD4 films deposited on a Pt substrate and compare experimentally observed desorption yields with density functional theory calculations of the binding energies of various anionic and neutral moieties to Pt(111). Certain species (which can be considered chemisorbed) exhibit very high binding energies and large charge transfer with the substrate. Other "physisorbed" species have much lower binding energies. Species that chemisorb have lower desorption yields than those that physisorb, especially at 1–2 monolayer coverage of the Pt substrate. The binding energy of D− to Pt is the weakest, and experimentally, the desorption yield is the highest regardless of the thickness of CD4. The calculations show that the formation and desorption of anionic species at a distance of 16 Å from the substrate, which is equivalent to the thickness of CD4 films of four monolayers, are not influenced by the short-range interactions between the substrate and the molecule and DEA products. [ABSTRACT FROM AUTHOR]

Using the density-functional theory approach, including Hubbard U correction, we investigate the defect structures consisting of vanadium (V) atoms embedded in a monolayer silicene. Specifically, we consider V–V atom pairs in antiferromagnetic (AFM), ferromagnetic (FM), and non-magnetic states, which are embedded in substitutional and interstitial sites. We determine the ground-state structures, formation and binding energies, electronic structures, induced magnetization, as well as the spin-exchange coupling between the V–V pair. For the substitutional vanadium atom pair, the stability of the AFM and FM spin configurations depends on the sublattice sites in which the V atoms are sited. When the V pair is located on a similar sublattice site type, the AFM spin alignment is more energetically favored, whereas when the pair is located in a different sublattice site, the FM interactions are more stable. However, the relative stability of the AFM or FM configurations changes rapidly as the separation between the V pair increases. Regarding the interstitial-hole V–V pair configurations, the most stable structure is when the pair is at the nearest-neighbor hole sites and is in an FM alignment. Also, at larger separations, the AFM or FM hole configurations are approximately degenerate in energy. Furthermore, we elucidate on the Ruderman–Kittel–Kasuya–Yosida, direct-exchange, and the superexchange interaction mechanisms in the vanadium-embedded silicene. In addition, we estimate a Curie temperature (Tc) of up to ∼500 K for a silicene structure containing a V pair in the FM spin alignment. Such a high Tc, in addition to the stability of the material, suggests that vanadium-embedded silicene is a potential candidate material for spintronic device applications. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) Sn-based perovskites exhibit significant potential in diverse optoelectronic applications, such as on-chip lasers and photodetectors. Yet, the underlying mechanism behind the frequently observed dual-peak emission in 2D Sn-based perovskites remains a subject of intense debate, and there is a lack of research on the carrier dynamics in these materials. In this study, we investigate these issues in a representative 2D Sn-based perovskite, namely, PEA2SnI4, through temperature-, excitation intensity-, angle-, and time-dependent photoluminescence studies. The results indicate that the high- and low-energy peaks originate from in-face and out-of-face dipole transitions, respectively. In addition, we observe an anomalous increase in the non-radiative recombination rate as temperature decreases. After ruling out enhanced electron–phonon coupling and Auger recombination as potential causes of the anomalous carrier dynamics, we propose that the significantly increased exciton binding energy (Eb) plays a decisive role. The increased Eb arises from enhanced electronic localization, a consequence of weakened lattice distortion at low temperatures, as confirmed by first-principles calculations and temperature-dependent x-ray diffraction measurements. These findings offer valuable insights into the electronic processes in the unique 2D Sn-based perovskites. [ABSTRACT FROM AUTHOR]

The random-phase approximation (RPA) includes a subset of higher than second-order correlation-energy contributions, but stays in the same complexity class as the second-order Møller–Plesset perturbation theory (MP2) in both Gaussian-orbital and plane-wave codes. This makes RPA a promising ab initio electronic structure approach for the binding energies of molecular crystals. Still, some issues stand out in practical applications of RPA. Notably, compact clusters of nonpolar molecules are poorly described, and the interaction energies strongly depend on the reference single-determinant state. Using the many-body expansion of the binding energy of a crystal, we investigate those issues and the effect of beyond-RPA corrections. We find the beneficial effect of quartic-scaling exchange and non-ring coupled-cluster doubles corrections. The nonadditive interactions in compact trimers of molecules are improved by using the self-consistent Hartree–Fock orbitals instead of the usual Kohn–Sham states, but this kind of orbital input also leads to underestimated dimer energies. Overall, a substantial improvement over the RPA with a renormalized singles approach is possible at a modest quartic-scaling cost, which encourages further research into additional RPA corrections. [ABSTRACT FROM AUTHOR]

We use molecular dynamics simulations to examine the homogeneous nucleation of ice VII from metastable liquid water. An unsupervised machine learning classification identifies two distinct local structures composing Ice VII nuclei. The seeding method, combined with the classical nucleation theory (CNT), predicts the solid–liquid interfacial free energy, consistent with the value from the mold integration method. Meanwhile, the nucleation rates estimated from the CNT framework and brute force spontaneous nucleations are inconsistent, and we discuss the reasons for this discrepancy. Structural and dynamical heterogeneities suggest that the potential birthplace for an ice VII embryo is relatively ordered, although not necessarily relatively immobile. Moreover, we demonstrate that without the formation of hydrogen-bond links, ice VII embryos do not grow. [ABSTRACT FROM AUTHOR]

The isotope shifts in electron affinities of Pb were measured by Walter et al. [Phys. Rev. A 106, L010801 (2022)] to be −0.002(4) meV for 207–208Pb and −0.003(4) meV for 206–208Pb by scanning the threshold of the photodetachment channel Pb− ( S 3 / 2 ◦ 4 ) − Pb (3P0), while Chen and Ning reported 0.015(25) and −0.050(22) meV for the isotope shifts on the binding energies measured relative to 3P2 using the SEVI method [J. Chem. Phys. 145, 084303 (2016)]. Here we revisited these isotope shifts by using our second-generation SEVI spectrometer and obtained −0.001(15) meV for 207–208Pb and −0.001(14) meV for 206–208Pb, respectively. In order to aid the experiment by theory, we performed the first ab initio theoretical calculations of isotope shifts in electron affinities and binding energies of Pb, as well as the hyperfine structure of 207Pb−, by using the MCDHF and RCI methods. The isotope shifts in electron affinities of 207–208Pb and 206–208Pb are −0.0023(8) and −0.0037(13) meV for the 3P0 channel, respectively, in good agreement with Walter et al.'s measurements. The isotope shifts in binding energies relative to 3P1,2, −0.0015(8) and −0.0026(13) meV for 207–208Pb and 206–208Pb, respectively, are compatible with the present measurements. The hyperfine constant for the ground state of 207Pb− obtained by the present calculations, A ( S 3 / 2 ◦ 4 ) = − 1118 MHz, differs by a factor of 3 from the previous estimation by Bresteau et al. [J. Phys. B: At., Mol. Opt. Phys. 52, 065001 (2019)]. The reliability is supported by the good agreement between the theoretical and experimental hyperfine parameters of 209Bi. [ABSTRACT FROM AUTHOR]

CNDOL is an a priori, approximate Fockian for molecular wave functions. In this study, we employ several modes of singly excited configuration interaction (CIS) to model molecular excitation properties by using four combinations of the one electron operator terms. Those options are compared to the experimental and theoretical data for a carefully selected set of molecules. The resulting excitons are represented by CIS wave functions that encompass all valence electrons in the system for each excited state energy. The Coulomb–exchange term associated to the calculated excitation energies is rationalized to evaluate theoretical exciton binding energies. This property is shown to be useful for discriminating the charge donation ability of molecular and supermolecular systems. Multielectronic 3D maps of exciton formal charges are showcased, demonstrating the applicability of these approximate wave functions for modeling properties of large molecules and clusters at nanoscales. This modeling proves useful in designing molecular photovoltaic devices. Our methodology holds potential applications in systematic evaluations of such systems and the development of fundamental artificial intelligence databases for predicting related properties. [ABSTRACT FROM AUTHOR]

The isotope shifts in electron affinities of Pb were measured by Walter et al. [Phys. Rev. A 106, L010801 (2022)] to be −0.002(4) meV for 207–208Pb and −0.003(4) meV for 206–208Pb by scanning the threshold of the photodetachment channel Pb− ( S 3 / 2 ◦ 4 ) − Pb (3P0), while Chen and Ning reported 0.015(25) and −0.050(22) meV for the isotope shifts on the binding energies measured relative to 3P2 using the SEVI method [J. Chem. Phys. 145, 084303 (2016)]. Here we revisited these isotope shifts by using our second-generation SEVI spectrometer and obtained −0.001(15) meV for 207–208Pb and −0.001(14) meV for 206–208Pb, respectively. In order to aid the experiment by theory, we performed the first ab initio theoretical calculations of isotope shifts in electron affinities and binding energies of Pb, as well as the hyperfine structure of 207Pb−, by using the MCDHF and RCI methods. The isotope shifts in electron affinities of 207–208Pb and 206–208Pb are −0.0023(8) and −0.0037(13) meV for the 3P0 channel, respectively, in good agreement with Walter et al.'s measurements. The isotope shifts in binding energies relative to 3P1,2, −0.0015(8) and −0.0026(13) meV for 207–208Pb and 206–208Pb, respectively, are compatible with the present measurements. The hyperfine constant for the ground state of 207Pb− obtained by the present calculations, A ( S 3 / 2 ◦ 4 ) = − 1118 MHz, differs by a factor of 3 from the previous estimation by Bresteau et al. [J. Phys. B: At., Mol. Opt. Phys. 52, 065001 (2019)]. The reliability is supported by the good agreement between the theoretical and experimental hyperfine parameters of 209Bi. [ABSTRACT FROM AUTHOR]

Layered superatomic semiconductors, whose building blocks are atomically precise molecular clusters, exhibit interesting electronic and vibrational properties. In recent work [Tulyagankhodjaev et al., Science 382, 438 (2023)], transient reflection microscopy revealed quasi-ballistic exciton dynamics in Re6Se8Cl2, which was attributed to the formation of polarons due to coupling with acoustic phonons. Here, we characterize the electronic, excitonic, and phononic properties with periodic density functional theory. We further parameterize a polaron Hamiltonian with nonlocal (Su–Schrieffer–Heeger) coupling to an acoustic phonon to study the polaron ground state binding energy and dispersion relation with variational wavefunctions. We calculate a polaron binding energy of about 10 meV at room temperature, and the maximum group velocity of our polaron dispersion relation is 1.5 km/s, which is similar to the experimentally observed exciton transport velocity. [ABSTRACT FROM AUTHOR]

Loading of WS2 can greatly improve water splitting H2 generation efficiency of CdS in experiments. Here, we constructed WS2/CdS(100) and WS2/CdS(110) heterostructures with smaller mismatches and explored their interaction energy and band offset by first-principles calculations. Our calculation suggests that the WS2/CdS(100) interface with a stronger binding energy is more active in experiments, while the WS2/CdS(110) interface is metastable. The band alignment between CdS and WS2 is highly dependent on the orientation of the interfaces, and WS2/CdS(100) and WS2/CdS(110) belong to type-I and type-II band alignments, respectively. Therefore, a metal electrode and hole scavenger may be essential in experiments to help WS2/CdS(100) efficiently trap electrons, and a suitable substrate and an appropriate growth temperature are also needed to composite the CdS(110) surface to achieve a higher photocatalytic efficiency. In addition, we performed a detailed analysis of the macroscopic average potential and found that the calculated accuracy of potential difference across the heterostructures due to slab thickness is less than 80 meV at WS2/CdS interfaces. In total, our calculations not only explain the physical reasons for the increased efficiency of WS2/CdS, but also provide a detailed guideline for the design of a more efficient synergistic catalyst. [ABSTRACT FROM AUTHOR]

Layered superatomic semiconductors, whose building blocks are atomically precise molecular clusters, exhibit interesting electronic and vibrational properties. In recent work [Tulyagankhodjaev et al., Science 382, 438 (2023)], transient reflection microscopy revealed quasi-ballistic exciton dynamics in Re6Se8Cl2, which was attributed to the formation of polarons due to coupling with acoustic phonons. Here, we characterize the electronic, excitonic, and phononic properties with periodic density functional theory. We further parameterize a polaron Hamiltonian with nonlocal (Su–Schrieffer–Heeger) coupling to an acoustic phonon to study the polaron ground state binding energy and dispersion relation with variational wavefunctions. We calculate a polaron binding energy of about 10 meV at room temperature, and the maximum group velocity of our polaron dispersion relation is 1.5 km/s, which is similar to the experimentally observed exciton transport velocity. [ABSTRACT FROM AUTHOR]

3,4-bis(3-nitrofurazan-4-yl) furoxan (DNTF) is one of the third-generation energetic compounds with excellent comprehensive properties, which can be added to polymer bonded explosive (PBX) to improve energy levels and regulate sensitivity, so the compatibility of DNTF with other components in PBX, especially the binder, is the first question. Herein, two typical hydrocarbon polymers commonly used in PBX, which are hydroxyl-terminated polybutadiene (HTPB) and polyisobutylene (PIB), were selected as the binder, and the compatibility of HTPB and PIB with DNTF was investigated by differential scanning calorimetry (DSC), the vacuum stability test (VST), and in situ infrared spectroscopy (in situ IR). The results of compatibility experiments were verified by using the binding energy and solubility parameter criteria in molecular dynamics (MD). Experimental and MD simulation results showed that DNTF could be compatible with PIB but incompatible with HTPB. The frontier molecular orbital theory in quantum chemistry (QC) was adopted to explore the frontier orbital electron distribution and energy levels of DNTF/HTPB and DNTF/PIB composite systems to better understand the microscopic compatibility mechanism. The compatibility results of the two composite systems were explained from the perspective of electron transfer. All these can deduce that a hydrocarbon polymer binder with a saturated carbon–hydrogen bond at the end of the molecular chain has good compatibility with DNTF, compared with a hydroxyl group, which has bad compatibility with DNTF. [ABSTRACT FROM AUTHOR]

We present fully coupled, full-dimensional quantum calculations of the inter- and intra-molecular vibrational states of HCl trimer, a paradigmatic hydrogen-bonded molecular trimer. They are performed utilizing the recently developed methodology for the rigorous 12D quantum treatment of the vibrations of the noncovalently bound trimers of flexible diatomic molecules [Felker and Bačić, J. Chem. Phys. 158, 234109 (2023)], which was previously applied to the HF trimer by us. In this work, the many-body 12D potential energy surface (PES) of (HCl)3 [Mancini and Bowman, J. Phys. Chem. A 118, 7367 (2014)] is employed. The calculations extend to the intramolecular HCl-stretch excited vibrational states of the trimer with one- and two-quanta, together with the low-energy intermolecular vibrational states in the two excited v = 1 intramolecular vibrational manifolds. They reveal significant coupling between the intra- and inter-molecular vibrational modes. The 12D calculations also show that the frequencies of the v = 1 HCl stretching states of the HCl trimer are significantly redshifted relative to those of the isolated HCl monomer. Detailed comparison is made between the results of the 12D calculations on the two-body PES, obtained by removing the three-body term from the original 2 + 3-body PES, and those computed on the 2 + 3-body PES. It demonstrates that the three-body interactions have a strong effect on the trimer binding energy as well as on its intra- and inter-molecular vibrational energy levels. Comparison with the available spectroscopic data shows that good agreement with the experiment is achieved only if the three-body interactions are included. Some low-energy vibrational states localized in a secondary minimum of the PES are characterized as well. [ABSTRACT FROM AUTHOR]

Density functional approximations to the exchange–correlation energy can often identify strongly correlated systems and estimate their energetics through energy-minimizing symmetry-breaking. In particular, the binding energy curve of the strongly correlated chromium dimer is described qualitatively by the local spin density approximation (LSDA) and almost quantitatively by the Perdew–Burke–Ernzerhof generalized gradient approximation (PBE-GGA), where the symmetry breaking is antiferromagnetic for both. Here, we show that a full Perdew–Zunger self-interaction-correction (SIC) to LSDA seems to go too far by creating an unphysical symmetry-broken state, with effectively zero magnetic moment but non-zero spin density on each atom, which lies ∼4 eV below the antiferromagnetic solution. A similar symmetry-breaking, observed in the atom, better corresponds to the 3d↑↑4s↑3d↓↓4s↓ configuration than to the standard 3d↑↑↑↑↑4s↑. For this new solution, the total energy of the dimer at its observed bond length is higher than that of the separated atoms. These results can be regarded as qualitative evidence that the SIC needs to be scaled down in many-electron regions. [ABSTRACT FROM AUTHOR]

This study focuses on the recognition and isolation of fullerenes, which are crucial for further exploration of their physical and chemical properties. Our goal is to investigate the potential recognition of the D5h–C70 fullerene using crown-shaped metal compositions through density functional theory calculations. We assess the effectiveness of fullerene C70 recognition by studying the binding energy. Additionally, various analyses were conducted, including natural bond order charge analysis and reduced density gradient analysis, to understand the interaction mechanism between the host and guest molecules. These investigations provide valuable insights into the nature of the interaction and the stability of the host–guest system. To facilitate the release of the fullerene guest molecule, the vis–NIR spectra were simulated for the host–guest structures. This analysis offers guidance on the specific wavelengths that can be utilized to release the fullerene guest from the host–guest structures. Overall, this work proposes a new strategy for the effective recognition of various fullerene molecules and their subsequent release from host–guest systems. These findings could potentially be applied in assemblies involving fullerenes, advancing their practical applications. [ABSTRACT FROM AUTHOR]

This study focuses on the recognition and isolation of fullerenes, which are crucial for further exploration of their physical and chemical properties. Our goal is to investigate the potential recognition of the D5h–C70 fullerene using crown-shaped metal compositions through density functional theory calculations. We assess the effectiveness of fullerene C70 recognition by studying the binding energy. Additionally, various analyses were conducted, including natural bond order charge analysis and reduced density gradient analysis, to understand the interaction mechanism between the host and guest molecules. These investigations provide valuable insights into the nature of the interaction and the stability of the host–guest system. To facilitate the release of the fullerene guest molecule, the vis–NIR spectra were simulated for the host–guest structures. This analysis offers guidance on the specific wavelengths that can be utilized to release the fullerene guest from the host–guest structures. Overall, this work proposes a new strategy for the effective recognition of various fullerene molecules and their subsequent release from host–guest systems. These findings could potentially be applied in assemblies involving fullerenes, advancing their practical applications. [ABSTRACT FROM AUTHOR]

We modify the reweighting factor of the projector used in diffusion Monte Carlo to reduce the time-step error of the total energy. Furthermore, we present a reweighting scheme that has the desirable feature that it is exactly size-consistent, i.e., the energy of a system containing widely separated fragments is the same as the sum of the energies of the individual fragments. The practical utility of the latter improvement is that it reduces the time-step error of the binding energies of some weakly interacting systems. [ABSTRACT FROM AUTHOR]

We examine the optical and electronic properties of a GaAs spherical quantum dot with a hydrogenic impurity in its center. We study two different confining potentials: (1) a modified Gaussian potential and (2) a power-exponential potential. Using the finite difference method, we solve the radial Schrodinger equation for the 1s and 1p energy levels and their probability densities and subsequently compute the optical absorption coefficient (OAC) for each confining potential using Fermis golden rule. We discuss the role of different physical quantities influencing the behavior of the OAC, such as the structural parameters of each potential, the dipole matrix elements, and their energy separation. Our results show that modification of the structural physical parameters of each potential can enable new optoelectronic devices that can leverage inter-sub-band optical transitions.

An in‐depth investigation of transition metal impurities (Hf, Zr, Nb, and W) is presented as shallow donors in monoclinic Ga2O3 using first‐principles calculations within the framework of density functional theory. A combination of semilocal and hybrid functionals is used to predict their binding energies and hyperfine parameters. The generalized gradient approximation (GGA) allows performing calculations for supercells of up to 2500 atoms, enabling an extrapolation to the dilute limit. The shortcoming of GGA in correctly describing the electron localization is then overcome by the use of the hybrid functional. Results are presented and discussed in light of the application of these transition‐metal elements as shallow donors in Ga2O3 and their identification in the experiment. The methodology applied here can be used in calculations for shallow donors in other systems.

This study examines the structures, energies, and IR vibrational spectra of the sulfur dioxide–water SO2(H2O) complexes by employing coupled cluster theory CCSD(T) with Dunning style correlation consistent type basis sets aug-cc-pV(n+d)Z (n = D, T, Q, 5). Complete basis set (CBS) extrapolations have been carried out to predict binding energies for two isomers of the SO2(H2O) complex: a stacked global minimum (1A) structure and a hydrogen-bonded local minimum (1B) structure. The CCSD(T)/CBS extrapolation predicts an intermolecular S–O distance rS⋯O = 2.827 Å for the stacked isomer, which is in excellent agreement with an experimental measurement of 2.824 Å [K. Matsumura et al., J. Chem. Phys., 91, 5887 (1989)]. The CCSD(T)/CBS binding energy for the stacked dimer 1A and hydrogen-bonded form 1B is De = −4.37 kcal/mol and De = −2.40 kcal/mol, respectively. This study also employs anharmonic VPT2 MP2/aug-cc-pV(n+d)Z level corrections to CCSD(T)/aug-cc-pV(n+d)Z vibrational frequencies in both forms of SO2(H2O). The anharmonic CCSD(T)/aug-cc-pV(Q+d)Z OH stretching frequencies in the stacked structure 1A are 3743 cm−1 (ν3) and 3647 cm−1 (ν1), and these align well with the recorded IR spectroscopic values of 3745 and 3643 cm−1, respectively [C. Wang et al., J. Phys. Chem. Lett., 13, 5654 (2022)]. If we combine CCSD(T)/aug-cc-pV(n+d)Z De values with VPT2 vibrational frequencies, we obtain a new CCSD(T)/aug-cc-pV(Q+d)Z anharmonic dissociation energy D0 = −3.48 kcal/mol for 1A and D0 = −1.74 kcal/mol for 1B. In summary, the results presented here demonstrate that the application of CCSD(T) calculations with aug-cc-pV(n+d)Z basis sets and CBS extrapolations is critical in probing the structure and IR spectroscopic properties of the sulfur dioxide–water complex. [ABSTRACT FROM AUTHOR]

The role of strain in material properties is well-established, serving as a tool for altering atomic positions and defect formation, adjusting electronic structures and lattice vibrations, and influencing phase transitions, physical characteristics, and chemical properties. In this study, we conducted theoretical calculations of the binding energy and photoionization cross section (PCS) within a spherical core/shell quantum dot (CSQD) for the different transitions between the ground state of a donor impurity and the four low-lying conduction band states. During our study, we employed the finite element method to determine the energy levels and wave functions of the system within the effective mass approximation. Subsequently, we investigated the changes in PCS and binding energy while varying shell width under the influence of an applied electric field, considering both cases with and without the effect of strain. The strain effect was incorporated based on Hooke's law, and we developed specific expressions and utilized the continuum linear elasticity mechanical model for a single spherically symmetric shell. The results demonstrate that the strain correction enhances the binding energy of the four low-lying energy levels, leading to a shift of the PCS peaks toward higher energies. Conversely, the application of an external electric field has varying effects depending on the specific transition being considered. We compared our theoretical results with available experimental data and found them to be in good agreement. The pronounced blue-shift and substantial enhancement in magnitude of PCS spectra concerning shell width, electric field, and strain make CSQDs highly promising candidates for applications in adjustable nano-optoelectronic devices. [ABSTRACT FROM AUTHOR]

The electronic properties of SO2 at the surface of a water cluster were investigated by employing a combination of Born–Oppenheimer molecular dynamics and electron propagator theory (EPT). In our work, we utilized a revised version of the Perdew–Burke–Ernzerhof (PBE) exchange-correlation functional, which incorporates empirical corrections for dispersion interactions in line with a recent study of the air–water interface conducted by Ohto et al. [J. Phys. Chem. Lett. 10(17), 4914–4919 (2019)]. Polarization effects induce a significant broadening of the electron binding energy distribution, as predicted by EPT. This broadening can result in a substantial increase in electron affinity, impacting the chemical reactivity of SO2 at the air–water interface, a topic of significant and recent research interest. We discuss the relationship between electron binding energies (EBEs) and the specific connections of SO2 to water. The results indicate that configurations involving an OS⋯H bond tend to yield higher electron affinities compared to complex formation through S⋯OW bonds. Surprisingly, SO2 molecules not bound to water molecules according to a specific criterion may also exhibit higher electron affinities. This feature can be explained by the role played by the polarization field from water molecules. Our best estimate for the HOMO–LUMO (H–L) gap of SO2 at the surface of a water cluster is 11.6 eV. Very similar H–L gaps are predicted for isolated and micro-solvated SO2. Fukui functions for the gas phase, and the micro-solvated SO2–H2O complex supports the view that the LUMO is predominantly localized on the SO2 moiety. [ABSTRACT FROM AUTHOR]

The GW electron–hole interaction kernel, which includes two second-order exchange terms in addition to the first-order direct and exchange terms considered in the conventional GW + Bethe–Salpeter method, is applied to 10 two-molecular systems and six thermally activated delayed fluorescence (TADF) molecules in which inter- and intramolecular charge transfer excitations are expected to occur. The contributions of the two second-order exchange terms are almost zero for intermolecular charge transfer excitations and ∼0.75 eV for intramolecular charge transfer excitations according to our exciton analysis method with exciton wave functions. For TADF molecules, we found that the second-order exchange terms are more significant than the first-order exchange terms, and the contributions—even for local-type and delocalized-type excitations—are not negligibly small. We revealed that the two second-order exchange terms are proportional to the molecular size, the exciton binding energy, and the electron–hole overlap strength for intramolecular charge-transfer excitations. We believe that our findings are indispensable for further considerations of the GW method in the future. [ABSTRACT FROM AUTHOR]

A practical ab initio composite method for modeling x-ray absorption and non-resonant x-ray emission is presented. Vertical K-edge excitation and emission energies are obtained from core-electron binding energies calculated with spin-projected ΔHF/ΔMP and outer-core ionization potentials/electron affinities calculated with electron propagator theory. An assessment of the combined methodologies against experiment is performed for a set of small molecules containing second-row elements. [ABSTRACT FROM AUTHOR]

In the present work, two quasi-molecular compounds each involving one antiproton and one electron ( p ̄) , H e + − p ̄ and H − p ̄ , are investigated. Using completely relativistic calculations within the finite-basis method adapted to systems with axial symmetry, the adiabatic potential curves are constructed by numerically solving the two-center Dirac equation. The binding energies of electron are obtained as a function of the inter-nuclear distance and compared with the corresponding nonrelativistic values and relativistic leading-order corrections calculated in the framework of other approaches. A semantic analysis of antiproton quasi-molecular ions with compounds containing a proton (p) instead of an antiproton is given. The advantages of the A-DKB method are demonstrated. [ABSTRACT FROM AUTHOR]

The free energy cost of forming a cavity in a solvent is a fundamental concept in rationalizing the solvation of molecules and ions. A detailed understanding of the factors governing cavity formation in bulk solutions has inter alia enabled the formulation of models that account for this contribution in coarse-grained implicit solvation methods. Here, we employ classical molecular dynamics simulations and multistate Bennett acceptance ratio free energy sampling to systematically study cavity formation at a wide range of metal–water interfaces. We demonstrate that the obtained size- and position-dependence of cavitation energies can be fully rationalized by a geometric Gibbs model, which considers that the creation of the metal–cavity interface necessarily involves the removal of interfacial solvent. This so-called competitive adsorption effect introduces a substrate dependence to the interfacial cavity formation energy that is missed in existing bulk cavitation models. Using expressions from scaled particle theory, this substrate dependence is quantitatively reproduced by the Gibbs model through simple linear relations with the adsorption energy of a single water molecule. Besides providing a better general understanding of interfacial solvation, this paves the way for the derivation and efficient parametrization of more accurate interface-aware implicit solvation models needed for reliable high-throughput calculations toward improved electrocatalysts. [ABSTRACT FROM AUTHOR]

X-ray photoelectron spectroscopy (XPS) is generally used for chemical analysis of surfaces and interfaces. This method involves the analysis of changes in binding energies and peak shapes of elements under consideration. It is also possible to use XPS to study the effect of x-ray radiation on the electrical properties of thin films. We measured the Si 2p peak using x-ray powers of 300 and 150 W on ∼135 nm silicon dioxide (SiO2) thin films grown on both n- and p-type substrates while applying DC or AC external biases. Using the shifts in the binding energy of the Si 2p peak, we calculated the resistances and the capacitances of the SiO2 thin film. The way that the binding energies of the Si 2p peak and the capacitance of the thin film change as a function of the type of Si substrate and the power of the x-ray are explained using band bending. [ABSTRACT FROM AUTHOR]

By employing a recently proposed Hubbard U density-corrected scheme within density functional theory, we provide design principles towards the design of materials exhibiting a spin crossover-assisted gas release. Small molecular fragments are used as case study to identify two main mechanisms behind the change in binding energy upon spin transitions. The feasibility of the proposed mechanism in porous crystals is assessed by correlating the change in binding energy of CO2, CO, N2, and H2, upon spin crossover, with the adiabatic energy difference associated with the spin state change of the square-planar metal in Hofmann-type clathrates (M = Fe, Mn, Ni). A few promising cases are identified for the adsorption of intermediate ligand field strength molecules such as N2 and H2. The latter stands out as the most original result as the strong interaction in low spin, as expected from a Kubas mechanism, results in a large change in binding energy. This work provides a general perspective towards the engineering of open-metal site frameworks exhibiting local environments designed to have a spin crossover upon adsorption of specific gas molecules. [ABSTRACT FROM AUTHOR]

A new approach for obtaining interacting quantum atoms-defined components of binding energy of intermolecular interactions, which bypasses the use of standard six-dimensional integrals and two-particle reduced density matrix (2-RDM) reconstruction, is proposed. To examine this approach, three datasets calculated within the density functional theory framework using the def2-TZVP basis have been explored. The first two, containing 53 weakly bound bimolecular associates and 13 molecular clusters taken from the crystal, were used in protocol refinement, and the third one containing other 20 bimolecular and three cluster systems served as a validation reference. In addition, to verify the performance of the proposed approach on an exact 2-RDM, calculations within the coupled cluster formalism were performed for part of the first set systems using the cc-pVTZ basis set. The process of optimization of the proposed parametric model is considered, and the role of various energy contributions in the formation of non-covalent interactions is discussed with regard to the obtained trends. [ABSTRACT FROM AUTHOR]

The fragmentation of fulminic acid, HCNO, after excitation and ionization of core electrons was investigated using Auger-electron–photoion coincidence spectroscopy. A considerable degree of site-selectivity is observed. Ionization of the carbon and oxygen 1s electron leads to around 70% CH+ + NO+, while ionization at the central N-atom produces only 37% CH+ + NO+, but preferentially forms O+ + HCN+ and O+ + CN+. The mass-selected Auger-electron spectra show that these fragments are associated with higher binding energy final states. Furthermore, ionization of the C 1s electron leads to a higher propensity for C–H bond fission compared to O 1s ionization. Following resonant Auger–Meitner decay after 1s → 3π excitation, 12 different ionic products are formed. At the C 1s edge, the parent ion HCNO+ is significantly more stable compared to the other two edges, which we also attribute to the higher contribution of final states with low binding energies in the C 1s resonant Auger electron spectra. [ABSTRACT FROM AUTHOR]

To improve the performance of Cu(In,Ga)Se2 thin-film photovoltaic devices, a robust understanding of the dominant diffusion pathways of the alloy species In and Ga is needed. Here, the most probable defect complexes and mechanisms for In and Ga diffusion are identified with the aid of density functional theory. The binding energies and migration barriers for these complexes are calculated in bulk CuInSe2 and CuGaSe2. Analytic models and kinetic lattice Monte Carlo simulations are employed to predict the diffusivity of In and Ga under variations in composition and temperature. We find that a model based on coulombic interactions between group III antisites and vacancies on the Cu-sublattice produces results that match well with experiment. [ABSTRACT FROM AUTHOR]

To improve the performance of Cu(In,Ga)Se2 thin-film photovoltaic devices, a robust understanding of the dominant diffusion pathways of the alloy species In and Ga is needed. Here, the most probable defect complexes and mechanisms for In and Ga diffusion are identified with the aid of density functional theory. The binding energies and migration barriers for these complexes are calculated in bulk CuInSe2 and CuGaSe2. Analytic models and kinetic lattice Monte Carlo simulations are employed to predict the diffusivity of In and Ga under variations in composition and temperature. We find that a model based on coulombic interactions between group III antisites and vacancies on the Cu-sublattice produces results that match well with experiment. [ABSTRACT FROM AUTHOR]

Lignin can affect the enzymatic hydrolysis efficiency of lignocellulose. In this study, the lignin isolated from sugarcane bagasse (SCB) pretreated with p-toluenesulfonic acid (PL) was firstly aminated, and then the effects of PL and aminated PL (APL) on the bagasse enzymatic hydrolysis efficiency (EHE) were investigated. The results showed that the addition of PL and APL promoted the EHE, and EHE with APL (73.82 %) was higher than PL (51.39 %). To explore the reason, the data were further analyzed including cellulase adsorption capacity, enzyme activity, cellulase-lignin interaction, and molecular docking. It was found that APL adsorbed more cellulase (27.83 mg protein/g lignin) than PL (4.96 mg protein/g lignin), resulting from the greater interaction force and lower binding free energy between APL and cellulase. The addition of APL more remarkably enhanced the cellobiohydrolase and endoglucanase activities than PL due to more effectively inducing cellulase conformation optimization. [Display omitted] • Enzymatic hydrolysis of cellulosic substrate was enhanced from 45.83 % to 73.82 % by aminated lignin. • Aminated lignin adsorbed more cellulase molecules. • Activities of cellobiohydrolase (CBH) and endoglucosidase (EG) were promoted by aminated lignin. • Aminated lignin owned lower binding energy with cellulase. [ABSTRACT FROM AUTHOR]

The LiFe 0.6 Mn 0.4 PO 4 /C composite has become a cost-effective and reliable material for lithium battery storage in commercial applications, due to its significant safety benefits. However, its industrial application is limited by its suboptimal high-rate capacity and unsatisfactory cycling performance. To address this issue, Li(Fe 0.6 Mn 0.4) 1-x Sb x PO 4 (x = 0, 0.01, 0.03, 0.04, 0.05) materials were synthesized using a one-step solvothermal method in this study, aiming to modulate the microstructure and achieve Sb doping, thereby enhancing the electrochemical performance. The electrochemical test results indicate that LFMP/C doped with Sb (designated as LFMP/C-Sb0.04) displays exceptional electrochemical performance, with remarkable capacities of 166.6 mAh·g−1 and 146.8 mAh·g−1 at 0.2C and 1C, respectively. Notably, it achieves a capacity of 126.1 mAh·g−1 at a high rate (5C) and maintains an impressive capacity retention rate of 93.6 % after 300 cycles, outperforming the original LMFP/C (109.5 mAh·g−1), which retains only 61.5 % of its initial capacity. Further characterization of the samples reveals that in situ Sb doping promotes the growth of the [001] crystal orientation, enhancing the lithium-ion diffusion rate and effectively reducing electrode polarization and charge transfer resistance, thereby contributing to its exceptional rate performance. Moreover, Sb doping increases the M − O binding energy, strengthens the metal-oxygen framework, mitigates the Jahn-Teller effect caused by Mn3+ dissolution, and enhances its cycling stability. [Display omitted] [ABSTRACT FROM AUTHOR]

The pyrazine-based Fe-MOFs with modulated O-Fe-N coordination were developed by ligand substitution strategy, which exhibited enhanced catalytic hydroxyl radical (OH) generation in Fenton-like process via degreasing H 2 O 2 activation barrier and triggering OH involved Fe(III) reduction. [Display omitted] Rational design of coordination environment of Fe-based metal-organic frameworks (Fe-MOFs) is still a challenge in achieving enhanced catalytic activity for Fenten-like advanced oxidation process. Here in, novel porous Fe-MOFs with modulated O-Fe-N coordination was developed by configurating amino terephthalic acid (H 2 ATA) and pyrazine-dicarboxylic acid (PzDC) (Fe-ATA/PzDC-7:3). PzDC ligands introduce pyridine-N sites to form O-Fe-N coordination with lower binding energy, which affect the local electronic environment of Fe-clusters in Fe-ATA, thus decreased its interfacial H 2 O 2 activation barrier. O-Fe-N coordination also accelerate Fe(II)/Fe(III) cycling of Fe-clusters by triggering the reactive oxidant species mediated Fe(III) reduction. As such, Fe-ATA/PzDC-7:3/H 2 O 2 system exhibited excellent degradation performance for typical antibiotic sulfamethoxazole (SMX), in which the steady-state concentration of hydroxyl radical (OH) was 1.6 times higher than that of unregulated Fe-ATA. Overall, this study highlights the role of O-Fe-N coordination and the electronic environment of Fe-clusters on regulating Fenton-like catalytic performance, and provides a platform for precise engineering of Fe-MOFs. [ABSTRACT FROM AUTHOR]