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Photoelectron Spectroscopy of the Hexafluorobenzene Cluster Anions: (C<sub>6</sub>F<sub>6</sub>)<sub><i>n</i></sub><sup>?</sup> (<i>n</i> = 1 – 5) and I<sup>?</sup>(C<sub>6</sub>F<sub>6</sub>)
摘要： Frequency-resolved (2D) photoelectron (PE) spectra of the anionic clusters (C6F6)n?, for n = 1 – 5, and time-resolved PE spectra of I?C6F6 are presented using a newly built instrument and supported by electronic structure calculations. From the 2D PE spectra, the vertical detachment energy (VDE) of C6F6? was measured to be 1.60 ± 0.01 eV and the adiabatic detachment energy (ADE) ≤ 0.70 eV. The PE spectra also contain fingerprints of resonance dynamics over certain photon energy ranges, in agreement with the calculations. An action spectrum over the lowest resonance is also presented. The 2D spectra of (C6F6)n? show that the cluster can be described as C6F6?(C6F6)n?1. The VDE increases linearly (200 ± 20 meV n?1) due to the stabilising influence on the anion of the solvating C6F6 molecules. For I?C6F6, action spectra of the absorption just below both detachment channels are presented. Time-resolved PE spectra of I?C6F6 excited at 3.10 eV and probed at 1.55 eV reveal a short-lived non-valence state of C6F6? that coherently evolves into the valence ground state of the anion and induces vibrational motion along a specific buckling coordinate. Electronic structure calculations along the displacement of this mode show that at the extreme buckling angle, the probe can access an excited state of the anion that is bound at that geometry, but adiabatically unbound. Hence, slow electrons are emitted and show dynamics that probe predominantly the outer-turning point of the motion. A PE spectrum taken at t = 0 contains vibrational structure, assigned to a specific Raman and/or IR active mode of C6F6.
关键词： electron attachment,non-valence states,cluster anions,hexafluorobenzene,ultrafast dynamics,photoelectron spectroscopy
更新于2025-09-19 17:15:36
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Thiacalix[4]arene-Supported Tetranuclear Tb <sup>III</sup> and Eu <sup>III</sup> Compounds: Synthesis, Structure, Luminescence, and Magnetism
摘要： Two tetranuclear compounds [Ln4Na(μ4-OH)(TC4A)2(acac)4] [Ln = Tb (1), Eu (2)] (acac = acetylacetonate) were synthesized and characterized based on p-tert-butylthiacalix[4]arene (H4TC4A). Compounds 1 and 2 are isostructural and crystallize in the monoclinic C2/c space group. There are two crystallographically independent metal atoms in one asymmetric unit. Ln1, Ln2, and two metal atoms generated by the symmetry operation are bridged by one μ4-OH group to form a planar tetragonal Ln4(μ4-OH) unit. Each Ln4(μ4-OH) unit is surrounded by four acac anions and two disordered sodium ions in the planar direction. The upper and lower positions of the Ln4(μ4-OH) unit are further coordinated by two cone-shaped TC4A ligands to form a sandwich-type molecular structure. Luminescent measurements reveal that both compounds 1 and 2 exhibit good photoluminescent properties. Moreover, the static and dynamic magnetic properties of compound 1 were also investigated, which demonstrates that 1 is one functional material candidate combining luminescent and antiferromagnetic properties in one molecule.
关键词： Thiacalix[4]arene,Lanthanides,Cluster compounds,Magnetic properties / Luminescence,Coordination chemistry
更新于2025-09-19 17:15:36
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Aggregation-Induced Electrochemiluminescence of Carboranyl Carbazoles in Aqueous Media
摘要： The aggregation-induced electrochemiluminescence (AIECL) of carboranyl carbazoles in aqueous media was investigated for the first time. Quantum yields, morphologies, and particle sizes were observed to determine the electrochemiluminescence (ECL) performance of these aggregated organic dots (ODs). All compounds exhibit much higher ECL stability and intensity than the carborane-free compound, demonstrating the essential role of the carboranyl motif. Moreover, the results of cyclic voltammetry (CV) suggest that redox take place at the carboranyl motif. The excited states of ODs were proposed to be generated by the mechanism of surface state transitions. More importantly, these compounds with reductive-oxidative mechanism is exclusive from other organic materials with oxidative-reductive mechanism. Our experiments and data have established the relation between AIE organic structures and ECL properties that has a strong potential for biological and diagnostic applications.
关键词： aggregation induced emission,boron cluster,organic dots,carborane,electrochemiluminescence
更新于2025-09-19 17:15:36
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Three-layer voltage/var control strategy for PV cluster considering steady-state voltage stability
摘要： Different from the distributed photovoltaic (PV) system, large-scale PV cluster is regarded as a weakly connected sending-end system, encountering severe voltage issues. This paper proposes a three-layer voltage/var control (VVC) strategy for the coordination of VVC devices in PV cluster, which considers not only voltage deviation, but also steady-state voltage stability (SVS) of the system. The central approaches are adopted into the former two layers. In the first layer, capacitor banks and on-load tap changer are scheduled based on 30-min interval PV active power forecast. In the second layer, PV inverters and static synchronous compensator (STATCOM) are scheduled based on 10-min interval PV active power forecast. Considering computation effort and communication delay, in the third layer, the PV inverters and STATCOM continue to respond to real-time PV active power via the local approach. For improving the application performance of the centralized approaches, model prediction control is applied in the first control layer for enhancing robustness of the control. The sensitivity analysis is used for reducing optimization time in the second layer. Simulation results indicate that the proposed VVC strategy is effective for PV cluster to ensure the voltage within the safe range and improve SVS of the whole PV cluster.
关键词： Photovoltaic cluster,Voltage/var control,Voltage deviation,Steady-state voltage stability
更新于2025-09-19 17:15:36
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New quantum key agreement protocols based on cluster states
摘要： A new two-party quantum key agreement (QKA) protocol is proposed based on four-qubit cluster states. Encoded four-qubit cluster states can be transmitted directly by means of order rearrangement operation. In contrast to existing QKA protocols based on four-qubit cluster states, it is unnecessary to perform two-way quantum communication. We analyze the security of this protocol and prove that it is secure in ideal conditions. We also propose the method to ensure the security of this protocol in noisy channel. Finally, we analyze the expansibility of the proposed QKA protocol and propose a three-party QKA protocol based on four-qubit cluster states.
关键词： Quantum key agreement,Quantum cryptography,Cluster state
更新于2025-09-19 17:15:36
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Reversible Wide‐Range Tuneable Luminescence of a Dual‐Stimuli‐ Responsive Silver Cluster‐Assembled Material
摘要： Silver cluster-assembled materials (SCAMs) are emerging multi-functional materials and have attracted great attention recently. In this work, we have prepared a new SCAM of {[Ag18(StBu)10(CF3COO)2(PhPO3)(PhPO3H)4(bpy-NH2)2]?(PhPO3H2)}n (denoted as Ag18bpy-NH2), by a facile one-pot method. Ag18bpy-NH2 adopts a chain-like structure made of Ag18 clusters bridged by bipyridyl linkers. Ag18bpy-NH2 exhibits reversible luminescent mechanochromism upon mechanical stimulation and solvent treatment. Moreover, it also displays luminescent thermochromism with a linear relationship of the temperature to the intensity ratio of the dual emissions over a wide temperature range of 83 to 303 K. This work might provide new insights into the assembly of multifunctional stimuli-responsive SCAMs.
关键词： luminescent mechanochromism,cluster-assembled material,silver cluster,luminescent thermochromism
更新于2025-09-19 17:13:59
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High-Fidelity Hyperentangled Cluster States of Two-Photon Systems and Their Applications
摘要： An efficient scheme is proposed in this study to prepare four symmetric hyperentangled cluster states in the polarization degrees of freedom (DOF) and spatial DOF with a two-photon system. This system consists of two nitrogen-vacancy (NV) centers which are coupled to two microtoroidal resonators. The two-photon polarization-spatial hyperentangled cluster states can be generated with our system by virtue of the input and output process. Compared with previous works, our quantum circuit for preparing the hyperentangled cluster states is simple and economic. Moreover, our scheme works deterministically and does not need any extra qubits, making it applicable to existing technologies. Our calculations show that our scheme has high fidelity with current technology, which can help hyperentangled cluster states to play a very useful role in quantum communication networks with long distances and high capacity.
关键词： spatial,polarization,cluster states,hyperentangled,NV center
更新于2025-09-19 17:13:59
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In-Depth Spectroscopy and New Heights for Organic Solar Cells
摘要： In this issue of Joule, Lami et al. describe a method that enables UV photoemission spectroscopy (UPS) in the transverse dimension of polymeric semiconductor layers with nanometer-scale resolution. The approach is based on the use of Argon gas cluster ion beam (GCIB) etching instead of monoatomic ion beam bombardment. The use of GCIB reduces surface damage, enabling in depth UPS. The method is applied to the study of critical electronic levels and photovoltage in organic solar cells.
关键词： Argon gas cluster ion beam,photovoltage,UV photoemission spectroscopy,electronic levels,organic solar cells
更新于2025-09-19 17:13:59
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Hermitian second-order methods for excited electronic states: Unitary coupled cluster in comparison with algebraica??diagrammatic construction schemes
摘要： Employing an intermediate state representation (ISR) approach, Hermitian second-order methods for the calculation of electronic excitation energies are presented and compared in detail. These comprise the algebraic–diagrammatic construction scheme for the polarization propagator, a hybrid second-order ISR scheme based on traditional coupled-cluster theory as well as two similar approaches based on a unitary coupled-cluster (UCC) ansatz. Although in a strict perturbation-theoretical framework all prove to be identical, differences emerge when the corresponding converged cluster amplitudes are used and depending on how the similarity-transformed UCC Hamiltonian is evaluated. The resulting excitation energies, however, do not significantly differ for systems well described by means of perturbation theory.
关键词： unitary coupled-cluster,electronic excitation energies,intermediate state representation,perturbation theory,Hermitian second-order methods,algebraic–diagrammatic construction scheme
更新于2025-09-19 17:13:59
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Electron transfer mediated by iron carbonyl clusters enhance lighta??driven hydrogen evolution in water by quantum dots
摘要： Photocatalytic water splitting has become a promising strategy for converting solar energy into clean and carbon-neutral solar fuels via a low-cost and environmentally benign way. Hydrogen gas is such a potential solar fuel/energy carrier. In a classical artificial photosynthetic system, a photosensitizer is generally associated with a co-catalyst to convert photogenerated charge into (a) chemical bond(s). In the present study, assemblies consisting of CdSe quantum dots that are coupled with one of two [Fe2S2(CO)6] or [Fe3Te2(CO)9], using an interface-directed approach, have been tested as catalytic systems for hydrogen production in aqueous solution/organic solution. In the presence of ascorbic acid as a sacrificial electron donor and proton source, these assemblies exhibit enhanced activities for the rate of hydrogen production under visible light irradiation for 8 hrs in aqueous solution at pH 4.0 with up to 110 μmol of H2 per mg of assembly, almost 8.5 times that of pure CdSe quantum dots under the same conditions. Transient absorption and time-resolved photoluminescence spectroscopies have been used to investigate the charge carrier transfer dynamics in the quantum dot/iron carbonyl cluster assemblies. The spectroscopic results indicate that effective electron transfer from the molecular iron complex to the valence band of the excited CdSe quantum dots to the significantly inhibits the recombination of photogenerated charge carriers, boosting the photocatalytic activity for hydrogen generation; i.e. the iron clusters function as effective intermediaries for electron transfer from the sacrificial electron donor to the valence band of the quantum dots.
关键词： iron carbonyl cluster,quantum dot,electron transfer,proton reduction
更新于2025-09-19 17:13:59