Orbital Distribution Research Articles

Pristine and Alkaline Earth Metal‐Decorated C24N24 Fullerenes as Potential Sensors for Halomethanes: A Comparative DFT Investigation

AbstractIn this paper, attempts were made to investigate the adsorption potential of pristine and alkaline earth metal (AEM)‐decorated C24N24 fullerenes toward the halomethanes (XCH3, where X═F, Cl, and Br). By means of DFT calculations, the XCH3⋯C24N24 and ⋯AEM@C24N24 complexes (AEM═Be and Mg) were adequately examined. Upon energetic features, the FCH3⋯Mg@C24N24 complex exhibited the most negative adsorption and interaction energies with values of −21.01 and −22.61 kcal/mol, respectively. From thermodynamic analysis, spontaneous and exothermic natures of XCH3⋯Mg@C24N24 interactions were affirmed, unveiling favorable role of Mg decoration in enhancing the adsorption process. From SAPT analysis, the electrostatic forces dominated the interactions within the XCH3⋯C24N24 and ⋯Be/Mg@C24N24 complexes. Upon FMOs analysis, notable alterations in the distribution of molecular orbitals of studied fullerenes were noticed, indicating the effect of XCH3 adsorption on the electronic features of the studied fullerenes. Further, the Egap values were decreased after the adsorption process which enhanced electrical conductivity of studied fullerens. From DOS plots, the capacity of the C24N24 and Be/Mg@C24N24 to adsorb the XCH3 molecules was affirmed. Solvation energies demonstrated the favorability of the studied adsorption process in the water phase. The present findings established C24N24 and AEM@C24N24 fullerenes as potential effective candidates for detecting halomethanes.

Studying the main characteristics of the Geminid meteor shower from baseline video observations in 2021

The Geminid meteor shower has been studied using data obtained by the method of baseline video observations during the period from December 01, 2021 to December 17, 2021. The meteors were examined in the brightness range from –3m to 2m and with an angular track length of at least 2°; the sample size was 327 events. The behavior of the shower is considered in terms of the interacting DRG (December ρ-Geminids) and GEM (Geminids) branches, which are closely related to each other and share a common origin. The shower activity was ZHR=127, Flux=19 at the general maximum of DRG+GEM (λsol~261.8°) and ZHR=32, Flux=4 at the putative local maximum of DRG (λsol~258.8°). Daily drift values were obtained for GEM (Δα=0.84°, Δδ=–0.27°, Δλec=0.75°, Δβ=–1.17°) and DRG (Δα=1.29°, Δδ=0.09°, Δλec=1.09°, Δβ=0.23°) in the equatorial and ecliptic coordinate systems; the intrinsic drift in the λec–λsol system was 0.09° and –0.26° for the DRG and GEM components respectively. We have found the opposite nature of the drift of both branches with a tendency for them to intersect at the point α=112.1°, δ=32.5°, λsol=259.8°. We have determined the kinematic and orbital parameters of meteoroids and have identified differences between the most probable geocentric velocities for the DRG (vg=35 km/s) and GEM (vg=34 km/s) branches. The morphology of the distribution of orbits within the plume has been studied. We give recommendations for reliably determining whether the meteors belong to one or another branch.

Исследование основных характеристик метеорного потока Геминиды по данным базисных видеонаблюдений 2021 г.

The Geminid meteor shower has been studied using data obtained by the method of baseline video observations during the period from December 01, 2021 to December 17, 2021. The meteors were examined in the brightness range from –3m to 2m and with an angular track length of at least 2°; the sample size was 327 events. The behavior of the shower is considered in terms of the interacting DRG (December ρ-Geminids) and GEM (Geminids) branches, which are closely related to each other and share a common origin. The shower activity was ZHR=127, Flux=19 at the general maximum of DRG+GEM (λsol~261.8°) and ZHR=32, Flux=4 at the putative local maximum of DRG (λsol~258.8°). Daily drift values were obtained for GEM (Δα=0.84°, Δδ=–0.27°, Δλec=0.75°, Δβ=–1.17°) and DRG (Δα=1.29°, Δδ=0.09°, Δλec=1.09°, Δβ=0.23°) in the equatorial and ecliptic coordinate systems; the intrinsic drift in the λec–λsol system was 0.09° and –0.26° for the DRG and GEM components respectively. We have found the opposite nature of the drift of both branches with a tendency for them to intersect at the point α=112.1°, δ=32.5°, λsol=259.8°. We have determined the kinematic and orbital parameters of meteoroids and have identified differences between the most probable geocentric velocities for the DRG (vg=35 km/s) and GEM (vg=34 km/s) branches. The morphology of the distribution of orbits within the plume has been studied. We give recommendations for reliably determining whether the meteors belong to one or another branch.

Platinum Compound on Gold-Magnesia Hybrid Structure: A Theoretical Investigation on Adsorption, Hydrolysis, and Interaction with DNA Purine Bases.

Cisplatin-based platinum compounds are important clinical chemotherapeutic agents that participate in most tumor chemotherapy regimens. Through density-functional theory calculations, the formation and stability of the inorganic oxide carrier, the mechanisms of the hydrolysis reaction of the activated platinum compound, and its binding mechanism with DNA bases can be studied. The higher the oxidation state of Pt (II to IV), the more electrons transfer from the magnesia-gold composite material to the platinum compound. After adsorption on the composite carrier, 5d←2p coordination bonds of Pt-N are strengthened. For flat and oblique adsorption modes of cisplatin, there is no significant difference in the density of states of the gold and magnesium oxide film, indicating the maintenance of the heterojunction structural framework. However, there are significant changes in the electronic states of cisplatin itself with different adsorption configurations. In the flat configuration, the band gap width of cisplatin is larger than that of the oblique configuration. The Cl-Pt bond range in the Pt(III) compound shows a clear charge reduction on the magnesia film, indicating the Cl-Pt bond is an active site with the potential for decomposition and hydrolysis. The substitution of chloride ions by water can lead to hydrolysis products, enhancing the polarization of the composite and showing strong charge separation. The hydrolysis of the free platinum compound is endothermic by 0.309 eV, exceeding the small activation energy barrier of 0.399 eV, indicating that hydrolysis of this platinum compound is easily achievable. ADME (absorption, distribution, metabolism, and excretion) prediction parameters indicate that hydrolysis products have good ESOL (Estimated SOLubility) solubility and high gastrointestinal absorption, consistent with Lipinski's rule. During the coordination reaction process, there are significant changes in the distribution of frontier molecular orbitals, with the HOMO (highest occupied molecular orbital) of the initial state primarily located on the purine base, providing the possibility for electron transfer to the empty orbitals of the platinum compound in the LUMO (lowest unoccupied molecular orbital). The HOMO and HOMO-1 of the transition state and product are mainly distributed on the platinum compound, indicating clear electron transfer and orbital rearrangement. The activation energy barrier for the purine coordination reaction with the hydrolysis products is reduced to 0.61 eV, and the dipole moment gradually decreases to 6.77 Debye during the reaction, indicating a reduction in the system's charge separation and polarization. This contribution is anticipated to provide a new theoretical clue for developing inorganic oxide carriers of platinum compounds.

Enhancing Reverse Intersystem Crossing with Extended Inverted Singlet–Triplet (X−INVEST) Systems

AbstractThe discovery of triangular‐shaped molecules displaying an inverted singlet–triplet (INVEST) energy gap between their lowest singlet (S1) and triplet (T1) states opened the way for a new strategy to increase the internal quantum efficiency (IQE) of organic light‐emitting diodes (OLEDs), enhancing the reverse intersystem crossing (RISC) thanks to a downhill process. However, the compounds showing a negative ΔEST suffer from both a vanishing spin–orbit coupling (SOC) between these excited states and high energy differences with higher‐lying singlets and triplets, therefore limiting their involvement in the spin conversion process. Here, we proposed a new design strategy entailing the extension of the triangulene cores by connecting two INVEST triangulene units to form Uthrene‐ and Zethrene‐like systems, doped with N and B. The inspection of the resulting molecular orbitals (MOs) distribution allowed rationalizing the electronic structure properties obtained from wavefunction‐based methods, showing how the Uthrene‐like architecture can lead to the quasi‐resonance between S1 and T1, in some cases provoking their inversion. By feeding a kinetic model with the non‐radiative rate constants, calculated from first principles, we showed how the extended INVEST (X−INVEST) design strategy can open new pathways to boost the spin conversion process and the population of the emissive S1.

Multipath Mitigation in Single-Frequency Multi-GNSS Tightly Combined Positioning via a Modified Multipath Hemispherical Map Method

Multipath is a source of error that limits the Global Navigation Satellite System (GNSS) positioning precision in short baselines. The tightly combined model between systems increases the number of observations and enhances the strength of the mathematical model owing to the continuous improvement in GNSS. Multipath mitigation of the multi-GNSS tightly combined model can improve the positioning precision in complex environments. Interoperability of the multipath hemispherical map (MHM) models of different systems can enhance the performance of the MHM model due to the small multipath differences in single overlapping frequencies. The adoption of advanced sidereal filtering (ASF) to model the multipath for each satellite brings computational challenges owing to the characteristics of the multi-constellation heterogeneity of different systems; the balance efficiency and precision become the key issues affecting the performance of the MHM model owing to the sparse characteristics of the satellite distribution. Therefore, we propose a modified MHM method to mitigate the multipath for single-frequency multi-GNSS tightly combined positioning. The method divides the hemispherical map into 36 × 9 grids at 10° × 10° resolution and then searches with the elevation angle and azimuth angle as independent variables to obtain the multipath value of the nearest point. We used the k-d tree to improve the search efficiency without affecting precision. Experiments show that the proposed method improves the mean precision over ASF by 10.20%, 10.77%, and 9.29% for GPS, BDS, and Galileo satellite single-difference residuals, respectively. The precision improvements of the modified MHM in the E, N, and U directions were 32.82%, 40.65%, and 31.97%, respectively. The modified MHM exhibits greater performance and behaves more consistently.

Investigation of lunar ejecta dynamics: particles reaching the near-Earth space and their effect on Earth-based observation

Aims. Particles ejected from the lunar surface via hypervelocity impacts form a torus between the Earth and the Moon. According to our previous study, about 2.3 × 10−4 kg/s particles impact the Earth after long-term orbital evolution. We mainly focus on these Earth impactors, analyze their orbital element distribution, and estimate their influence on Earth-based observations. Methods. In previous work we simulated the long-term orbital evolution of particles ejected from the lunar surface, and obtained their steady-state spatial distribution in the Earth–Moon system. For this work we analyzed the simulation results for the Earth impactors, including the fraction of impactors with different initial parameters among all impactors, the orbital element distribution, and the projection of particles onto several Earth-based observatories. Results. Particles ejected from the lunar surface are more likely to impact the Earth within a certain range of initial parameters. Most of these lunar-ejected impactors (~70%) reach the Earth within one year, while most of the small ones (87.2% of 0.2 μm particles and 64.6% of 0.5 μm particles) reach the Earth within one week. A large proportion of lunar-ejected Earth impactors can be distinguished from interplanetary dust particles according to the differences in their orbital distributions. In addition, lunar-ejected particles may exhibit distinct configurations and orientations from the perspectives of different Earth-based observatories.

Possible origin of Mars-crossing asteroids and related dynamical properties of inner main-belt asteroids

Context. The orbital element distribution of the inner main belt (IMB) provides clues to the origin of the main-belt asteroids. Mars-crossing asteroids (MCAs) and near-Earth objects (NEOs) can provide some references to validate and improve theoretical models of the IMB evolution. Aims. With the updated Asteroid Families Portal database, we analyzed the distribution of orbital elements and the dynamic completeness limit of IMB asteroids. By incorporating larger and more diverse datasets, the study seeks to provide a more comprehensive understanding of the IMB and MCAs origin and evolution. Methods. We fitted the completeness-limit magnitude for the IMB. The size frequency and albedo distribution were used to analyze the family characteristics. The role of chaotic effects in the dynamic evolution of IMB and MCAs is further quantified by simulations. Results. An albedo analysis showed that some halo asteroids may have originated from family asteroids, whereas the remaining non-family asteroids (14%) are likely to be members of a potential ghost family. We estimated the chaotic diffusion of asteroid orbits considering 1M/2A mean motion resonance. The eccentricity diffusion rate is estimated to be 0.45 and the inclination diffusion rate is 0.4 for resonant asteroids. The loss rate of MCAs IIMC(17.6) = 24.13 Myr−1, while the loss rate of the IMB asteroids due to the chaotic diffusion is 0.2648 Myr−1, which represents only 1.1% of MCAs. This indicates that chaotic diffusion has a limited capacity to replenish MCAs. However, for the large MCAs, a loss rate of IIMC(12) = 0.2646 Myr−1 was observed. This suggests that the large MCAs (H < 12) are in the dynamic equilibrium, primarily evolving through chaotic diffusion.

A New Rarity Assessment of the “Disk of Satellites”: The Milky Way System Is the Exception Rather Than the Rule in the ΛCDM Cosmology

The majority of satellite galaxies around the Milky Way (MW) show disk-like distributions (the disk of satellites; DoS), which is a small-scale problem of the lambda cold dark matter cosmology. The conventional definition of the MW-like DoS is a satellite system with a minor-to-major axis ratio (c/a) lower than the MW’s c/a value of 0.181. Here, we question the validity of the c/a-based DoS rarity assessment and propose an alternative approach. How satellites are placed around a galaxy is dictated mainly by two factors: the distributions of the satellites’ orbital poles and their distances from the host. Based on this premise, we construct the “satellite distribution generator” code and generate 105 spatially and kinematically analogous systems (SKASs) sharing these two factors. The SKAS can disclose the intrinsic, underlying c/a probability distribution function (PDF), from which a present-day c/a value is fortuitously determined. We find that the c/a PDF of the MW DoS defined by 11 classical satellites is quite broad (σ c/a ∼ 0.105), implying that a simple present-day c/a value, combined with its highly time-variable nature, cannot fully represent the degree of flatness. Moreover, based on the intrinsic c/a PDF, we reevaluate the rarity of the MW DoS by comparing it with Illustris TNG50-1 host–satellite systems and find that even with the new measure, the MW DoS remains rare (0.00%–3.40%). We show that the reason behind the rareness is that both orbital poles and distances of the 11 MW satellites are far more plane-friendly than those of simulated host–satellite systems, challenging the current structure and galaxy formation model.

Ultra-high rate and long cycle life sodium-based dual-ion batteries enabled by Li2TiO3-modified cathode-electrolyte-interphase

Sodium-based dual-ion batteries (SDIBs) have received widespread attention due to their high voltage, low cost, safety, and eco-friendliness. Nevertheless, the irregular spherical graphite cathodes are limited by the mass transfer non-uniformity and sluggish reaction kinetics due to uneven anion migration through the highly tortuous pathways and the inductive anisotropic electric fields. Herein, we report a facile dissolution-precipitation-carbonation optimized modification strategy to synthesize a series of nano-Li2TiO3/C-modified graphite flake (GF-LTx, x = 1, 2.5, and 5) as cathode for SDIBs. The Li2TiO3-C-Cathode Electrolyte Interphase (Li2TiO3-C-CEI) trinity layer by in situ reactions shows good cycling performance. The intrinsic mechanism of Li2TiO3-C-CEI was further explored by DFT molecular orbital theory and distribution relaxation time (DRT) analysis. Notably, the GF-LT2.5 achieves 10,000 stable cycles at 3–5.2 V (vs. Na/Na+) with a initial capacity of 91.1 mAh g−1 and a decay rate of only 0.00217 % per cycle. Furthermore, GF-LT2.5 demonstrates an ultra-high rate performance of 100C with only 30 s for a single charge and 86 % capacity for low current density. Infrared thermography confirms the good thermal stability and safety of the gel-based flexible pouch cells. This work provides new insights into the design of high-rate performance, long-cycle stability, and high-safety energy storage systems.

Sensitivity of pure and Ni-decorated boron nitride B12N12 nanocages toward CH4, H2S, and N2 biogases: A DFT study

The sensitivity of pure and Ni-decorated boron nitride (B12N12) nanocages toward CH4, H2S, and N2 biogases was adequately unveiled by employing versatile density functional theory (DFT) calculations. In this regard, the Gas∙∙∙B12N12 and ∙∙∙Ni@B12N12 complexes were studied within all possible configurations. Based on the energetic quantities, the Ni@B12N12 nanocage exhibited higher sensitivity than the pure one toward the investigated gases. Among all studied complexes, the H2S∙∙∙Ni@B12N12 complex exhibited the most favorable adsorption (Eads) and interaction (Eint) energies with values of –29.25 and –29.46 kcal/mol, respectively. According to the outlines of the quantum theory of atoms in molecules (QTAIM) and noncovalent interaction (NCI) index analyses, the closed-shell nature of the interactions within the investigated complexes was ensured. Substantial alterations in the molecular orbitals distribution patterns of pure and Ni-decorated B12N12 nanocages were observed, announcing the occurrence of the adsorption process within the investigated complexes. The obtained negative values of thermodynamic parameters ensured the spontaneous exothermic nature of the investigated Ni-decorated complexes. Upon density of states (DOS) analysis, the influence of adsorbed gases on the electronic characteristics of the pure and Ni-decorated B12N12 nanocages was highlighted. According to the emerging findings, the pure and Ni-decorated B12N12 nanocages are promising sensing materials for biogas components, especially CH4, H2S, and N2 gases.

Prograde and retrograde stars in nuclear cluster merger. Evolution of the supermassive black hole binary and the host galactic nucleus

Nuclear star cluster (NSC) mergers, involving the fusion of dense stellar clusters near the centres of galaxies, play a pivotal role in shaping galactic structures. The distribution of stellar orbits has significant effects on the formation and characteristics of extreme mass ratio inspirals (EMRIs). In this study, we address the orbital distribution of stars in merging NSCs and the subsequent effects on supermassive black hole binary (SMBHB) evolution. We ran dedicated direct-summation $N$-body simulations with different initial conditions to do a detailed study of the resulting NSC after their progenitors had merged. Our findings reveal that prograde stars form a flattened structure, while retrograde stars have a more spherical distribution. The axial ratios of the prograde component vary based on the presence and mass ratio of the SMBHs. The fraction of prograde and retrograde stars depends on the merger orbital properties and the SMBH mass ratio. The interactions of retrograde stars with the SMBHB affect the eccentricity and separation evolution of the binary. Our analysis reveals a strong correlation between the angular momentum and eccentricity of the SMBH binary. This relationship could serve as a means to infer information about the stellar dynamics surrounding the binary. We find that prograde orbits are particularly close to the binary of SMBHs, a promising fact regarding EMRI production. Moreover, prograde and retrograde stars have different kinematic structures, with the prograde stars typically rotating faster than the retrograde ones. The line-of-sight velocity and velocity dispersion, as well as the velocity anisotropy of each NSC, depend on the initial merger orbital properties and SMBH mass ratios. The prograde and retrograde stars always show different behaviours. The distribution of stellar orbits and the dynamical properties of each kinematic population can potentially be used as a way to tell the properties of the parent nuclei apart, and has an important impact on expected rates of EMRIs, which will be detected by future gravitational wave observatories such as the Laser Interferometer Space Antenna (LISA).

β-to-β Singly Linked Subphthalocyanine Dimers with Effective π-Conjugation.

In this work, a series of π-conjugated Subphthalocyanine dimers assembled by simple π-bridges were efficiently synthesized through metal-catalyzed reactions. Despite being singly linked, these readily accessible arrays exhibit excellent π-electron communication, significantly perturbing the orbital distribution of conventional SubPcs and inducing notable alterations in their optical properties. The findings presented here demonstrate the potential of SubPcs for constructing curved porphyrin arrays with well-conjugated skeletons and intriguing functionalities.

Improving Optoelectronic Properties of Acceptor–Donor–Acceptor‐Type Non‐Fullerene Acceptors Containing Extended Fused Ring Donor Units for Efficient Organic Semiconductors

Developing efficient small molecule‐based non‐fullerene acceptors (NFAs) has gained huge attention in fabricating high‐efficiency and stable organic solar cells (OSCs). Herein, we designed and characterized eight new NFAs for OSCs. To investigate the potential of these newly designed NFAs series (IBH1–IBH8) for OSCs, various advanced quantum chemical simulation approaches are used and compared with the synthetic reference molecule IBH–R. Due to the extended donor cores, the IBH1–IBH8 molecules possess strong intramolecular and intermolecular interactions, which helps improve the thin‐film surface crystallinity. Moreover, the designed IBH1–IBH8 molecules present improved UV–visible absorption, narrower bandgaps, lower excitation, and binding energies, and improved photovoltaic characteristics. Furthermore, the impact on the intrinsic properties such as transition density matrix, density of state, electrostatic potential, distribution of frontier molecular orbitals, and reorganizational energies of holes and electrons are estimated. Additionally, the charge‐transfer phenomenon by establishing a donor:acceptor blend (PTB7–Th:IBH4) is analyzed, their geometric analyses are studied, and a good charge‐shifting process is found at the donor:acceptor interface. With these results, we demonstrated the enhancements in the optoelectronic and photovoltaic characteristics of OSCs by performing a simple end‐capped modulation. Hence, these molecules are recommended for the development of efficient and cost‐effective OSCs.

Investigating the Kinematics of Central and Satellite Galaxies Using Normalizing Flows

Galaxy clustering contains information on cosmology, galaxy evolution, and the relationship between galaxies and their dark matter hosts. On small scales, the detailed kinematics of galaxies within their host halos determines the galaxy clustering. In this paper, we investigate the dependence of the central and satellite galaxy kinematics on θ , the intrinsic host halo properties (mass, spin, concentration), cosmology (Ωm, σ 8), and baryonic feedback from active galactic nuclei and supernovae (A AGN1, A AGN2, A SN1, A SN2). We utilize 2000 hydrodynamic simulations in CAMELS run using IllustrisTNG and SIMBA galaxy formation models. Focusing on central and satellite galaxies with M * > 109 M ⊙, we apply neural density estimation (NDE) with normalizing flows to estimate their p(Δr ∣ θ ) and p(Δv ∣ θ ), where Δr and Δv are the magnitudes of the halocentric spatial and velocity offsets. With NDE, we accurately capture the dependence of galaxy kinematics on each component of θ . For central galaxies, we identify significant spatial and velocity biases dependent on halo mass, concentration, and spin. For satellite distributions, we find significant deviations from a Navarro–Frenk–White profile and evidence that they consist of distinct orbiting and infalling populations. However, we find no strong dependence on θ besides a weak dependence on host halo spin. For both central and satellite galaxies, there is no notable dependence on cosmological parameters and baryonic feedback. These results provide key insights for improving the current halo occupation distribution (HOD) models. This work is the first in a series that will reexamine and develop HOD frameworks for improved modeling of galaxy clustering at smaller scales.

IN SILICO AND DFT ANALYSIS OF A NEW MESO-SUBSTITUTED PORPHYRIN DERIVATIVE

In this study, we synthesized and characterized a novel unsymmetrical meso-aryl substituted porphyrin derivative. Comprehensive structural elucidation was achieved using a suite of spectroscopic techniques, including 1H and 13C Nuclear Magnetic Resonance (NMR), Fourier-Transform Infrared (FT-IR) spectroscopy, and Ultraviolet-Visible (UV-Vis) spectroscopy. To further investigate the compound's potential therapeutic applications, in silico studies were performed, focusing on its interactions with breast cancer-associated target receptors, specifically the epidermal growth factor receptor (EGFR) and insulin-like growth factor receptor (IGFR), through molecular docking simulations. Additionally, bioactivity properties were evaluated via absorption, distribution, metabolism, and excretion (ADME) analysis. Complementary to the experimental work, Density Functional Theory (DFT) calculations at the B3LYP/6-311G+(d,p) level were conducted to optimize the molecular structure and determine key quantum chemical parameters, such as the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) distributions. These computational insights provide a deeper understanding of the electronic characteristics and reactivity of the synthesized compound, highlighting its potential for further development as a cancer therapeutic agent.

On the Corotation of Milky Way Satellites: LMC-mass Satellites Induce Apparent Motions in Outer Halo Tracers

Abstract Understanding the physical mechanism behind the formation of a corotating thin plane of satellite galaxies, like the one observed around the Milky Way (MW), has been challenging. The perturbations induced by a massive satellite galaxy, like the Large Magellanic Cloud (LMC), provide valuable insight into this problem. The LMC induces an apparent corotating motion in the outer halo by displacing the inner regions of the halo with respect to the outer halo. Using the Latte suite of Feedback In Realistic Environments cosmological simulations of MW-mass galaxies, we confirm that the apparent motion of the outer halo induced by the infall of a massive satellite changes the observed distribution of orbital poles of outer-halo tracers, including satellites. We quantify the changes in the distribution of orbital poles using the two-point angular correlation function and find that all satellites induce changes. However, the most massive satellites with pericentric passages between ≈30 and 100 kpc induce the largest changes. The best LMC-like satellite analog shows the largest change in orbital pole distribution. The dispersion of orbital poles decreases by 20° during the first two pericentric passages. Even when excluding the satellites brought in with the LMC-like satellite, there is clustering of orbital poles. These results suggest that in the MW, the recent pericentric passage of the LMC should have changed the observed distribution of orbital poles of all other satellites. Therefore, studies of kinematically coherent planes of satellites that seek to place the MW in a cosmological context should account for the existence of a massive satellite like the LMC.

Induced magnetic effects on intrinsic properties of edge-passivated triangular zigzag phosphorene quantum dots using spin-polarized density functional theory

The electrical and magnetic characteristics of edge-passivated triangular zigzag phosphorene quantum dots, saturated with hydrogen and oxygen atoms, have been investigated using spin-polarized density functional theory. The findings indicate that oxygen passivation alters the bond lengths, cohesive energies, and bandgaps of the quantum dots, leading to increased stability and magnetism due to unbonded single electrons in the oxygen atoms. The study also explored the impact of an external electric field on the energy gap, molecular orbital distribution, and local spin density of selected quantum dots. Our results show significant changes in the energy spectra and magnetic moments of the magnetized structures. The tunability of the magnetic and electronic attributes of triangular phosphorene quantum dots can be exploited in designing electronic and spintronic devices.

Advancing Two-Photon Photodynamic Therapy Over NIR-II Excitable Conjugated Microporous Polymer with NIR-I Emission.

The availability of second near-infrared (NIR-II) excitable two-photon photosensitizers with NIR-I emission for efficient photodynamic therapy (PDT) is limited by challenges in molecular design. In this study, a NIR-II light-excitable two-photon conjugated microporous polymer (Tph-Dbd) with emission in the NIR-I region is developed. The large conjugated system and delocalized electronic structures endow Tph-Dbd with a large two-photon absorption cross-section under NIR-II light excitation. Moreover, the efficient electron acceptor and donor units within the π-conjugated backbones result in NIR-I emission for high signal-to-background ratio imaging, as well as separated highest occupied molecular orbitaland lowest unoccupied molecular orbital distributions for excellent singlet oxygen generation ability. The excellent NIR-II excitable two-photon absorption activity, NIR-I emission, good biocompatibility, and high photostability allow Tph-Dbd to be used for efficient in vitro fluorescence imaging guided PDT. Moreover, the impressive photothermal effect of Tph-Dbd can overcome the limitations of PDT in the treatment of hypoxic tumors. This study highlights a strategy for designing NIR-II excitable two-photon photosensitizers for advanced PDT.

σ Interference: Through-Space and Through-Bond Dichotomy.

Dividing orbital interactions into through-space (TS) and through-bond (TB) modes is valuable for understanding various molecular properties. In this paper, we elucidate how the quantum interference phenomenon known as σ interference in electron transport through σ systems arises from TS and TB interactions. We performed electron transport calculations using a combination of density functional theory and nonequilibrium Green's function methods, focusing on ethylenediamine, a classical molecule that effectively highlights the contrast between TS and TB interactions. Our results confirm that destructive σ interference occurs in the syn and gauche conformers of this molecule. To further investigate both TS and TB interactions, we employed two analytical methods: the fragment molecular orbital (FMO) method, which captures the effects of both TS and TB interactions, and the chemical graph theory method, which specializes in TB interactions. The FMO analysis demonstrated that TB interactions lead to the characteristic distribution and energy level alignment of the frontier orbitals. Additionally, it was clarified that a change in TS interaction, due to a variation in the dihedral angle of the molecule, alters the energy gap between these orbitals, resulting in the manifestation of σ interference in the syn and gauche conformers, but not in the trans conformer. The chemical graph theory analysis based on the ladder C model, aimed at exploring the topological origin of σ interference from the network of TB interactions, revealed that σ interference is caused by the cancellation between the walk associated with geminal interactions (σ-conjugation) and the one related to vicinal interaction (σ-hyperconjugation). Notably, it was found that the vicinal interaction, which changes sign with the dihedral angle, has a decisive influence on whether this cancellation occurs. These findings clarify that σ interference arises from the interplay between TS and TB interactions. This insight will be valuable for designing molecular systems that utilize σ interference.