Reducing costs while maintaining efficiency in photocatalytic systems remains a major pursuit in the field of solar photocatalysis. Herein, we explore a universal strategy for regulating electronic transfer by employing earth‐abundant polyoxometalates (POMs) as electron sponges, dramatically promoting electron shuttling between photosensitizers (PSs) and substrates. This approach enables highly efficient photooxidative hydroxylation of arylboronic acids while significantly reducing the usage of noble‐metal PSs. Typically, replacing 90% PS [Ir(bpy)(coumarin6) 2 ] + ( Ir‐2 ) with an earth‐abundant Co 7 POM ([{(B‐α‐PW 9 O 34 )Co 3 (OH)(H 2 O) 2 (O 3 PC(O)(C 3 H 6 NH 3 )PO 3 )} 2 Co] 14− ) can efficiently boost photo‐oxidation efficiency, achieving complete substrate conversion within 3 h in air, ∼3.2 or 5.6 times higher than the system with 100% or 10% Ir‐2 , respectively. Notably, this strategy exhibits excellent compatibility with a wide range of substrates and POMs. Systematic kinetic studies and unique “heteropoly blue” characteristic of POMs clearly demonstrated their excellent capabilities for electron accepting, storing, and releasing in these photo‐oxidation systems. These properties can significantly promote electron transfer and stabilize reduced PSs, resulting in over five‐fold increase in O 2 •− generation under weak visible‐light irradiation ( λ > 420 nm, 50 mW cm −2 ) compared to POM‐free systems. This work not only opens an avenue for efficient photochemical synthesis but also highlights a promising new direction for POM application.

The photocatalytic degradation of plastic waste represents a pivotal strategy for mitigating the global plastic pollution and fostering resource-efficient utilization. Herein, a facile impregnation method was used to uniformly load various Ni-substituted polyoxometalates (Ni-POMs) onto CdS nanospheres and thus obtain a series of single-cluster Ni-POM@CdS photocatalysts. During visible-light irradiation for 10 h, the catalyst with the highest synergistic photoredox performance (Ni-9@CdS-10) achieved an exceptional extent of polylactic acid degradation and H-2 productivity (22.29 mmol center dot g(cat)(-1)) exceeding that of pristine CdS similar to 160-fold. The generation of pyruvate-a versatile and valuable chemical-as a degradation product (19.01 mmol center dot g(cat)(-1)) rendered the process highly economically viable. Systematic control experiments and comprehensive characterization analyses indicate that the photocatalytic degradation of plastic waste by Ni-9@CdS-10 proceeds via a charge transfer-mediated mechanism, with the Ni-9 clusters acting as electron sponges and efficiently extracting photogenerated electrons from CdS to promote H-2 evolution while facilitating hole-dominated plastic oxidation. This work provides valuable insights into the development of plastic waste degradation processes promoted by Ni-POM photocatalysts and establishes a practical strategy for converting plastic waste into fuels and chemicals.

低能高电荷态离子与H原子电荷交换X射线的实验和理论研究为天体环境中非平衡态等离子体的诊断和建模提供了重要原子数据。本工作利用半经典多通道Landau-Zener（MCLZ）方法计算了全裸和类氢的C、N、O离子与H原子电荷交换截面并与已报道实验结果进行了比较。我们发现，对于C 5+ +H碰撞体系，理论计算的总截面和实验测量相差较大。同时，也对比了太阳风离子速度（或能量）区间MCLZ方法和全量子分子轨道紧耦合（QMOCC）方法计算的态选择截面。发现，对于俘获到n=3壳层，MCLZ方法计算的态选择截面随碰撞能量升高而增加；对于俘获到n=4壳层，MCLZ方法计算的态选择截面随碰撞能量升高而减小；在低能端比QMOCC方法计算的截面小两个量级之多。最后，采用天文领域发展的Kronos程序包，通过Janev推荐的截面数据[Atomic Data and Nuclear Data Tables, 1999, 55（2）:201]计算了1 keV·u -1 O 8+ +H电荷交换X射线谱、线强比及硬度比，并与MCLZ计算结果比较。我们认为，MCLZ计算方法结合l分布模型具有较大的不确定性，会影响天体环境建模的准确性。亟需发展更加准确的全量子理论。

Intermolecular Coulombic decay (ICD) is considered a general phenomenon that plays a key role in many fundamental and applied fields related to biological environments. In many cases, however, the mechanisms and efficiency of ICD have yet to be uncovered. A prominent example is heavy-ion cancer therapy. Here, we report the first detection of a damaging intermolecular relaxation cascade initiated by heavy-ion bombardment of hydrated pyrimidine clusters. The process can significantly contribute to the high biological effectiveness of heavy-ion irradiation and thus might play an essential role in many radiotherapy techniques. Inner-valence ionization of the cluster initiates ICD and triggers proton transfer between water molecules, producing destructive low-energy electrons, HO^{•} radicals, and hydrated protons. Notably, the efficiency of ICD was found to increase dramatically with the number of water molecules, making ICD the dominant decay mechanism after inner-valence ionization. These findings indicate that the biological damage, caused by ICD in aqueous environments, is much more severe than was previously recognized.

Photocatalytic hydrogen evolution efficiency is critically dependent on electron transfer between photosensitizers (PSs) and catalysts. Herein, covalent assembly of Ir‐PSs with Co 7 polyoxometalate was achieved via Schiff‐base condensation to adjust electron transfer pathways, the resulting Ir‐2@Co 7 assembly exhibits a turnover number of 2280 for H 2 evolution, ∼18 and ∼253 times higher than that of its physically mixture and Ir‐1@Co 7 , respectively. Moreover, the generated H 2 can drive tandem styrene hydrogenation under ambient conditions, achieving 99.9% ethylbenzene yield. Spectroscopic and thermodynamic analyses reveal that covalent linkage switches dominant quenching mechanism from reductive to oxidative, and dramatically enhances electron quenching rate constant by over two orders of magnitude from 2.54 × 10 9 M −1 s −1 in physical‐mixed system to 5.87 × 10 11 M −1 s −1 in the assembly. This work highlights the key role of covalent integration in promoting electron transfer, providing a general design principle for developing high‐performance H 2 evolution and tandem hydrogenation systems.

Solar-driven CO 2 reduction and water oxidation to liquid fuels represents a promising solution to alleviate energy crisis and climate issue, but it remains a great challenge for generating CH 3 OH and CH 3 CH 2 OH dominated by multi-electron transfer. Single-cluster catalysts with super electron acceptance, accurate molecular structure, customizable electronic structure and multiple adsorption sites, have led to greater potential in catalyzing various challenging reactions. However, accurately controlling the number and arrangement of clusters on functional supports still faces great challenge. Herein, we develop a facile electrosynthesis method to uniformly disperse Wells-Dawson- and Keggin-type polyoxometalates on TiO 2 nanotube arrays, resulting in a series of single-cluster functionalized catalysts P 2 M 18 O 62 @TiO 2 and PM 12 O 40 @TiO 2 (M=Mo or W). The single polyoxometalate cluster can be distinctly identified and serves as electronic sponge to accept electrons from excited TiO 2 for enhancing surface-hole concentration and promote water oxidation. Among these samples, P 2 Mo 18 O 62 @TiO 2 -1 exhibits the highest electron consumption rate of 1260 μmol g −1 for CO 2 -to-CH 3 OH conversion with H 2 O as the electron source, which is 11 times higher than that of isolated TiO 2 nanotube arrays. This work supplied a simple synthesis method to realize the single-dispersion of molecular cluster to enrich surface-reaching holes on TiO 2 , thereby facilitating water oxidation and CO 2 reduction.

Rapidly stripping off multiple electrons from the target and triggering complete fragmentation with each constituent atom being charged up are ideal prerequisites for Coulomb explosion imaging. Here, we demonstrate that highly charged ion beam with energy in the Bragg peak region is a powerful tool capable of meeting these requirements. Using the 112.5 keV/u C 5 + beam, we successfully imaged the structures of pyridazine, pyrimidine, and pyrazine, three isomers of C4H4N2, by detecting ionic fragments H+, C2+, C+, and N+ in quadruple coincidence. The three isomers are unambiguously distinguished in the spectra of angular correlation between different fragments, and their structures are clearly visualized in momentum images. More importantly, taking the advantage of fast colliding interaction that creates high charge states on a subfemtosecond timescale, our approach effectively suppresses the distortion of molecular configuration during explosion, ensuring the high accuracy in structural imaging. This is confirmed by the quantitative agreement of momentum magnitudes between the point-charge model and the experiment for all fragments including hydrogen. Our work demonstrates that highly charged ion induced Coulomb explosion is a powerful tool for precisely imaging the initial structures of complex molecules.

This paper presents a novel reaction microscope designed for ion–atom collision investigations, established at the Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, China. Its time-of-flight (TOF) spectrometer employs an innovative flight-time focusing method consisting of two acceleration regions, providing optimal time focusing conditions for charged fragments with diverse initial velocities. The TOF spectrometer’s axis intentionally tilts by 12° relative to the ion beam direction, preventing potential obstructions from the TOF grid electrodes. The introduced focusing method allows for a flexible time-focusing TOF spectrometer design without restricting the length ratio of the two regions. In addition, this configuration in our case significantly suppresses noise on the recoil ion detector produced by residual gas in the ion beam trajectory, which is a considerable challenge in longitudinal spectrometers. In a test experiment on the single electron capture reaction involving 62.5 keV/u He2+ ions and a helium atomic beam, the recoil longitudinal momentum resolution achieved 0.068 atomic units. This novel configuration and successful test run show excellent precision for ion–atom collision studies.

The sensitizing ability of a catalytic system is closely related to the visible-light absorption ability, excited-state lifetime, redox potential, and electron-transfer rate of photosensitizers (PSs), however it remains a great challenge to concurrently mediate these factors to boost CO 2 photoreduction. Herein, a series of Ir(III)-based PSs ( Ir-1 – Ir-6 ) were prepared as molecular platforms to understand the interplay of these factors and identify the primary factors for efficient CO 2 photoreduction. Among them, less efficient visible-light absorption capacity results in lower CO yields of Ir-1 , Ir-2 or Ir-4 . Ir-3 shows the most efficient photocatalytic activity among these mononuclear PSs due to some comprehensive parameters. Although the K obs of Ir-3 is ≈10 times higher than that of Ir-5 , the CO yield of Ir-3 is slightly higher than that of Ir-5 due to the compensation of Ir-5 ’s strong visible-light-absorbing ability. Ir-6 exhibits excellent photocatalytic performance due to the strong visible-light absorption ability, comparable thermodynamic driving force, and electron transfer rate among these PSs. Remarkably, the CO 2 photoreduction to CO with Ir-6 can achieve 91.5 μmol, over 54 times higher than Ir-1 , and the optimized TON C-1 can reach up to 28160. Various photophysical properties of the PSs were concurrently adjusted by fine ligand modification to promote CO 2 photoreduction.

We report an experimental and theoretical study of state-selective charge exchange processes in Ar8+ on He collisions at 1 and 3 keV/amu, benchmarking the fundamental electron capture dynamics under strong perturbations. The quantum-state selectivity has been experimentally resolved for one 1s electron of He capture into 4s, 4p, 4d + 4 f, and 5s states of Ar7+ ion along with the corresponding scattering angle differential cross sections. By comparing to theoretical calculations with a two-active-electron semiclassical asymptotic-state close-coupling approach, we are able to verify the important role of electronic correlations during the collisions and that the impact parameter sensitive transition probability significantly mediates the state-selective specifics.

Controllable methanol production in artificial photosynthesis is highly desirable due to its high energy density and ease of storage. Herein, single atom Fe is implanted into TiO2 /SrTiO3 (TSr) nanotube arrays by two-step anodization and Sr-induced crystallization. The resulting Fe-TSr with both single Fe reduction centers and dominant oxidation facets (001) contributes to efficient CO2 photoreduction and water oxidation for controlled production of CH3 OH and CO/CH4 . The methanol yield can reach to 154.20 µmol gcat -1 h-1 with 98.90% selectivity by immersing all the catalyst in pure water, and the yield of CO/CH4 is 147.48 µmol gcat -1 h-1 with >99.99% selectivity when the catalyst completely outside water. This CH3 OH yield is 50 and 3 times higher than that of TiO2 and TSr and stands among all the state-of-the-art catalysts. The facile gas-solid and gas-liquid-solid phase switch can selectively control CH3 OH production from ≈0% (above H2 O) to 98.90% (in H2 O) via slowly immersing the catalyst into water, where abundant •OH and H2 O around Fe sites play important role in selective CH3 OH production. This work highlights a new insight for water-mediated CO2 photoreduction to controllably produce CH3 OH.

The three-body fragmentation of C2H23+ to H+ + C+ + CH+ as a consequence of one CH and one CC bond breaking is investigated by 50-keV/u Ne8+ impact. All three fragments are detected in coincidence with a scattered projectile (either Ne7+ or Ne6+) employing a reaction microscope, and their momentum vectors as well as the kinetic energies were obtained. Four distinguished structures are observed in the energy correlation spectra, indicating that abundant fragmentation mechanisms contribute to the H+ + C+ + CH+ channel. The Newton diagrams and Dalitz plots are employed to trace fragmentation mechanisms. We found that both the concerted fragmentation and the sequential pathway with CH bond breaking prior to CC contribute to this channel. The possible electronic states of the C2H23+ precursor that may contribute to the identified fragmentation mechanisms are analyzed with the help of quantum chemical calculations. Furthermore, the influence of the collision dynamics between the projectile and the target to the dissociation mechanisms is discussed by comparing the contributions from the reaction channel with transferring one electron while ionizing the other two, i.e., T1I2, and the reversed channel T2I1. The T2I1 channel is observed to be more efficient to initiate fragmentation mechanisms leading to higher kinetic-energy release.

The cross sections of state-selective charge exchange (CX) between highly charged ions and neutrals are important for modeling extreme ultraviolet and soft X-ray emissions in many astrophysical objects with hot plasma impacting cold media. By using cold-target recoil-ion momentum spectroscopy, we measure O 6+ CX collisions with He and H 2 in the collision energy range of 19.5 to 100 keV amu −1 . The relative cross sections of state-selective single CX are reported for electron capture into O 5+ (1 s 2 nl ) n = 2, 3, 4, 5, ≥6 and n = 3, 4, 5, ≥6 for He and H 2 , respectively. With the collision energy increasing to 100 keV amu −1 , the main capture channel shifts to higher n for both target species as compared to available theoretical results. We also report state-selective cross sections for double CX with He, where doubly excited states of O 4 + ( 1 s 2 nln ′ l ′ ) with nln ′ l ′ being 2 s 2 ( 1 S), 2 s 2 p ( 1 P), 2 p 2 ( 1 D), and 2 p 2 ( 1 S) [symmetric configurations] and 2 s 3 l , 2 p 3 l −2 s 4 l , and 2 s 5 l −2 p 5 l [asymmetric configurations] are distinguished. It is found that the contributions of doubly excited states with asymmetric configurations are dominant and symmetric configurations increasingly come into play with the increase of collision energy. The present results provide experimental benchmarks available for theoretical calculations.

Because of the half-filled t_{2g}-electron configuration, the BO_{6} octahedral distortion in a 3d^{3} perovskite system is usually very limited. In this Letter, a perovskitelike oxide Hg_{0.75}Pb_{0.25}MnO_{3} (HPMO) with a 3d^{3} Mn^{4+} state was synthesized by using high pressure and high temperature methods. This compound exhibits an unusually large octahedral distortion enhanced by approximately 2 orders of magnitude compared with that observed in other 3d^{3} perovskite systems like RCr^{3+}O_{3} (R=rare earth). Essentially different from centrosymmetric HgMnO_{3} and PbMnO_{3}, the A-site doped HPMO presents a polar crystal structure with the space group Ama2 and a substantial spontaneous electric polarization (26.5  μC/cm^{2} in theory) arising from the off-center displacements of A- and B-site ions. More interestingly, a prominent net photocurrent and switchable photovoltaic effect with a sustainable photoresponse were observed in the current polycrystalline HPMO. This Letter provides an exceptional d^{3} material system which shows unusually large octahedral distortion and displacement-type ferroelectricity violating the "d^{0}-ness" rule.

The response of carbon dioxide to radiolysis is crucial for understanding the atmospheric chemistry of planets. Here, we present a combined experimental and theoretical investigation of the three-body fragmentation dynamics of CO22+ to C+ + O+ + O initiated by 1 keV/u Ar2+ impact. Taking advantage of the kinematic complete measurement employing a reaction microscope, three dissociation mechanisms are distinguished, and their branching ratios are determined. The concerted fragmentation with two C-O bonds breaking simultaneously is dominant, while the sequential pathway with CO+ as the intermediate also makes a significant contribution. Also, a novel isomerization pathway with transitory formation of O2+ is identified. The identified mechanisms can contribute to O+ and O escaping from the Martian atmosphere, since the kinetic energies of most of the fragments are observed to be higher than the escape energy of oxygen.

The three-body fragmentation dynamics of propyne $({\mathrm{CH}}_{3}\mathrm{C}\mathrm{C}\mathrm{H})$ to ${\mathrm{H}}^{+}$ $+$ $\mathrm{C}{\mathrm{H}}^{+}$ $+$ ${\mathrm{C}}_{2}{\mathrm{H}}_{2}{}^{+}$ and ${\mathrm{H}}^{+}$ $+$ ${\mathrm{CH}}_{2}{}^{+}$ $+$ ${\mathrm{C}}_{2}{\mathrm{H}}^{+}$ is investigated by 50-keV/u ${\mathrm{Ne}}^{8+}$ ion impact. Employing the reaction microscope, all three ionic fragments are detected in coincidence, and the momentum vector as well as kinetic energy of each fragment is obtained. By analyzing the momentum and kinetic energy correlation between different fragments, various fragmentation mechanisms are identified, and the relative ratio of each mechanism is determined. We find that the concerted fragmentation with CH and CC bonds breaking simultaneously and the sequential pathway with CH breakage prior to the CC breakage are the major contributions to both channels. In contrast, the sequential pathway with CC breakage prior to CH breakage was found to make a minor contribution only to the ${\mathrm{H}}^{+}$ $+$ $\mathrm{C}{\mathrm{H}}^{+}$ $+$ ${\mathrm{C}}_{2}{\mathrm{H}}_{2}{}^{+}$ channel. In addition, we compare the present results for ${\mathrm{CH}}_{3}\mathrm{C}\mathrm{C}\mathrm{H}$ with ${\mathrm{CH}}_{2}{\mathrm{CCH}}_{2}$ published in Ma et al. [C. Ma, S. Xu, D. Zhao, D. Guo, S. Yan, W. Feng, X. Zhu, and X. Ma, Phys. Rev. A 101, 052701 (2020)]. The location of the CH and CC bonds' breakage, either from distinct C atoms or from the same C atom, leads to similar dissociation mechanisms but different ionic fragments for the two isomers.

The research progresses on the investigations of atomic structure and collision dynamics with highly charged ions based on the heavy ion storage rings and electron ion beam traps in recent 20 years are reviewed. The structure part covers test of quantum electrodynamics and electron correlation in strong Coulomb field studied through dielectronic recombination spectroscopy and VUV/x-ray spectroscopy. The collision dynamics part includes charge exchange dynamics in ion-atom collisions mainly in Bohr velocity region, ion-induced fragmentation mechanisms of molecules, hydrogen-bound and van de Waals bound clusters, interference, and phase information observed in ion-atom/molecule collisions. With this achievements, two aspects of theoretical studies related to low energy and relativistic energy collisions are presented. The applications of data relevant to key atomic processes like dielectronic recombination and charge exchanges involving highly charged ions are discussed. At the end of this review, some future prospects of research related to highly charged ions are proposed.