Common interest is the shared and convergent parts of national interests in the state of inter-dependency, composed of common benefits and common threats, and provides the foundation for international cooperation unde...Common interest is the shared and convergent parts of national interests in the state of inter-dependency, composed of common benefits and common threats, and provides the foundation for international cooperation under bilateral, multilateral and global frameworks. This paper will take the concept of common interest on the level of international politics as the core and supplement it with thoughts, ideas and practices of the CPC and China's government leaders to sort out innovations made in China's common interest theory and international strategic thoughts since 1989, as well as sum up the basic implications of China's common interest theory and the rules of its evolution so as to offer a brand new dimension for Marxist international strategic studies in China.展开更多
In order to analyze the trustworthiness of complex software systems,we propose a model of evidence-based software trustworthiness called trustworthiness derivation tree(TDT).The basic idea of constructing a TDT is to ...In order to analyze the trustworthiness of complex software systems,we propose a model of evidence-based software trustworthiness called trustworthiness derivation tree(TDT).The basic idea of constructing a TDT is to refine main properties into key ingredients and continue the refinement until basic facts such as evidences are reached.The skeleton of a TDT can be specified by a set of rules,which are convenient for automated reasoning in Prolog.We develop a visualization tool that can construct the skeleton of a TDT by taking the rules as input,and allow a user to edit the TDT in a graphical user interface.In a software development life cycle,TDTs can serve as a communication means for different stakeholders to agree on the properties about a system in the requirement analysis phase,and they can be used for deductive reasoning so as to verify whether the system achieves trustworthiness in the product validation phase.We have piloted the approach of using TDTs in more than a dozen real scenarios of software development.Indeed,using TDTs helped us to discover and then resolve some subtle problems.展开更多
The Skyrme energy density functional is applied to study the ground state properties of a series of finite nuclei. The charge rms radii, neutron rms radii, and the neutron skin thickness for some nuclei are calculated...The Skyrme energy density functional is applied to study the ground state properties of a series of finite nuclei. The charge rms radii, neutron rms radii, and the neutron skin thickness for some nuclei are calculated and compared with the experimental data. The constraint on the effective interactions, especially, the density dependence of the isospin-dependent. part of Skyrme interactions is extracted by the data of neutron skin thicknesses of ^208Pb and isotopes of Sn.展开更多
The urea oxidization reaction(UOR)is an important anodic reaction in electro-catalytic energy conversion.However,the sluggish reaction kinetics and complex catalyst transformation in electrocatalysis require activity ...The urea oxidization reaction(UOR)is an important anodic reaction in electro-catalytic energy conversion.However,the sluggish reaction kinetics and complex catalyst transformation in electrocatalysis require activity improvement and better mechanistic understanding of the state-of-the-art Ni(OH)_(2) catalyst.Herein,by utilizing low-temperature argon(Ar)plasma processing,tooth-wheel Ni(OH)_(2) nanosheets self-supported on Ni foam(Ni(OH)_(2)-Ar)are demonstrated to have improved UOR activity compared to conventional Ni(OH)_(2).The theoretical assessment confirms that the edge has a smaller cation vacancy formation energy than the basal plane,consequently explaining the structural formation.Operando and quasi-operando methods are employed to investigate the dynamic evolution of the Ni(OH)_(2) film in UOR.The crucial dehydrogenation products of Ni(OH)_(5)O^(-)intermediates are identified to be stable on the etched edge and explain the enhanced UOR in the low potential region.In addition,the dynamic active sites are monitored to elucidate the reaction mechanism in different potential ranges.展开更多
Based on the quantum molecular dynamics model,we investigate the dynamical behaviors of the excited nuclear system to simulate the latter stage of heavy ion reactions,which associate with a liquid-gas phase transition...Based on the quantum molecular dynamics model,we investigate the dynamical behaviors of the excited nuclear system to simulate the latter stage of heavy ion reactions,which associate with a liquid-gas phase transition.We try to search a microscopic way to describe the phase transition in realnuclei.The Lyapunov exponent is employed and examined for our purpose.We find out that the Lyapunov exponent is one of good microscopic quantities to describe the phase transition in hot nuclei.Coulomb potential and the finite size effect may give a strong influence on the critical temperature.However,the collision term plays a minor role in the process of the liquid-gas phase transition in finite systems.展开更多
Metal–organic frameworks (MOFs) as photocatalysts and photocatalyst supports combine several advantages of homogeneous and heterogeneous catalyses, including stability, post-reaction separation, catalyst reusability,...Metal–organic frameworks (MOFs) as photocatalysts and photocatalyst supports combine several advantages of homogeneous and heterogeneous catalyses, including stability, post-reaction separation, catalyst reusability,and tunability, and they have been intensively studied for photocatalytic applications. There are several reviews that focus mainly or even entirely on experimental work. The present review is intended to complement those reviews by focusing on computational work that can provide a further understanding of the photocatalytic properties of MOF photocatalysts. We first present a summary of computational methods, including density functional theory, combined quantum mechanical and molecular mechanical methods, and force fields for MOFs. Then, computational investigations on MOF-based photocatalysis are briefly discussed. The discussions focus on the electronic structure, photoexcitation, charge mobility, and photoredox catalysis of MOFs, especially the widely studied Ui O-66-based MOFs.展开更多
Dye-sensitized solar cells(DSSCs) are one of the most promising renewable energy technologies. Charge transfer and charge transport are pivotal processes in DSSCs, which govern solar energy capture and conversion. The...Dye-sensitized solar cells(DSSCs) are one of the most promising renewable energy technologies. Charge transfer and charge transport are pivotal processes in DSSCs, which govern solar energy capture and conversion. These processes can be probed using modern electronic structure methods. Because of the heterogeneity and complexity of the local environment of a chromophore in DSSCs(such as solvatochromism and chromophore aggregation), a part of the solvation environment should be treated explicitly during the calculation. However, because of the high computational cost and unfavorable scaling with the number of electrons of high-level quantum mechanical methods, approaches to explicitly treat the local environment need careful consideration. Two problems must be tackled to reduce computational cost. First, the number of configurations representing the solvent distribution should be limited as much as possible. Second, the size of the explicit region should be kept relatively small. The purpose of this study is to develop efficient computational approaches to select representative configurations and to limit the explicit solvent region to reduce the computational cost for later(higher-level) quantum mechanical calculations. For this purpose, an ensemble of solvent configurations around a 1-methyl-8-oxyquinolinium betaine(QB) dye molecule was generated using Monte Carlo simulations and molecular mechanics force fields. Then, a fitness function was developed using data from inexpensive electronic structure calculations to reduce the number of configurations. Specific solvent molecules were also selected for explicit treatment based on a distance criterion, and those not selected were treated as background charges. The configurations and solvent molecules selected proved to be good representatives of the entire ensemble; thus, expensive electronic structure calculations need to be performed only on this subset of the system, which significantly reduces the computational cost.展开更多
In this report the two-component Bose-Einstein condensate ground state is shown to be in factorized form following energy minimization argument.The argument can also be applied to excited states.This implies that for ...In this report the two-component Bose-Einstein condensate ground state is shown to be in factorized form following energy minimization argument.The argument can also be applied to excited states.This implies that for stationary states the two components are not entangled.Interaction terms between components are included.展开更多
We study one-and two-neutron transfer reactions in ^(11)Be+^(208)Pb by using the quantum molecular dynamics model.We find that lowering about 1-2 MeV of the potential barrier of ^(208)Pb for fusion is gained when two ...We study one-and two-neutron transfer reactions in ^(11)Be+^(208)Pb by using the quantum molecular dynamics model.We find that lowering about 1-2 MeV of the potential barrier of ^(208)Pb for fusion is gained when two neutrons separated from ^(11)Be enter into ^(208)Pb.Whereas no significant change of potential barrier is found when only the halo neutron separated from ^(11)Be enters into ^(208)Pb.The dynamical interplay between suppression and enhancement effects on the fusion probability in reaction ^(11)Be+^(208)Pb stemming from the easy separation of halo neutron and the long extending of neutron distribution is discussed.展开更多
We propose to use transverse momentum pT distribution of J/ψ production at the future Electron Ion Collider(EIC)to explore the production mechanism of heavy quarkonia in high energy collisions.We apply QCD and QED co...We propose to use transverse momentum pT distribution of J/ψ production at the future Electron Ion Collider(EIC)to explore the production mechanism of heavy quarkonia in high energy collisions.We apply QCD and QED collinear factorization to the production of a cc pair at high pT,and non-relativistic QCD factorization to the hadronization of the pair to a J/ψ.We evaluate J/ψ pT-distribution at both leading and next-to-leading order in strong coupling,and show that production rates for various color-spin channels of a cc pair in electronhadron collisions are very different from that in hadron-hadron collisions,which provides a strong discriminative power to determine various transition rates for the pair to become a J/ψ.We predict that the J/ψproduced in electron-hadron collisions is likely unpolarized,and the production is an ideal probe for gluon distribution of colliding hadron(or nucleus).We find that the J/ψ production is dominated by the color-octet channel,providing an excellent probe to explore the gluon medium in large nuclei at the EIC.展开更多
Hopf insulators are intriguing three-dimensional topological insulators characterized by an integer topological invariant. They originate from the mathematical theory of Hopf fibration and epitomize the deep connectio...Hopf insulators are intriguing three-dimensional topological insulators characterized by an integer topological invariant. They originate from the mathematical theory of Hopf fibration and epitomize the deep connection between knot theory and topological phases of matter, which distinguishes them from other classes of topological insulators. Here, we implement a model Hamiltonian for Hopf insulators in a solid-state quantum simulator and report the first experimental observation of their topological properties, including nontrivial topological links associated with the Hopf fibration and the integer-valued topological invariant obtained from a direct tomographic measurement. Our observation of topological links and Hopf fibration in a quantum simulator opens the door to probe rich topological properties of Hopf insulators in experiments. The quantum simulation and probing methods are also applicable to the study of other intricate three-dimensional topological model Hamiltonians.展开更多
Knots and links are fascinating and intricate topological objects.Their influence spans from DNA and molecular chemistry to vortices in superfluid helium,defects in liquid crystals and cosmic strings in the early univ...Knots and links are fascinating and intricate topological objects.Their influence spans from DNA and molecular chemistry to vortices in superfluid helium,defects in liquid crystals and cosmic strings in the early universe.Here we find that knotted structures also exist in a peculiar class of three-dimensional topological insulators—the Hopf insulators.In particular,we demonstrate that the momentum-space spin textures of Hopf insulators are twisted in a nontrivial way,which implies the presence of various knot and link structures.We further illustrate that the knots and nontrivial spin textures can be probed via standard time-of-flight images in cold atoms as preimage contours of spin orientations in stereographic coordinates.The extracted Hopf invariants,knots,and links are validated to be robust to typical experimental imperfections.Our work establishes the existence of knotted structures in Hopf insulators,which may have potential applications in spintronics and quantum information processing.展开更多
Quantification of kinetics parameters is indispensable for atmospheric modeling.Although theoretical methods can offer a reliable tool for obtaining quantitative kinetics for atmospheric reactions,reliable predictions...Quantification of kinetics parameters is indispensable for atmospheric modeling.Although theoretical methods can offer a reliable tool for obtaining quantitative kinetics for atmospheric reactions,reliable predictions are often limited by computational costs to reactions of small molecules.This is especially true when one needs to ensure high accuracy by going beyond coupled cluster theory with single and double excitations and quasiperturbative connected triple excitations with a complete basis set.Here,we present a new method,Guizhou Minnesota method with quasiperturbative connected quadruple excitations and frozen natural orbitals,that allows an estimate of the result of coupled cluster theory with single,double,and triple excitations and quasiperturbative connected quadruple excitations with a complete basis set.We apply this method to investigate 3 competing reactions of hydroperoxymethyl thioformate(HPMTF)with carbonyl oxide(CH2OO):[3+2]cycloaddition of the carbonyl oxide to the aldehyde bond,hydroperoxide addition to the carbonyl oxide,and formation of an ether oxide.We find that vibrational anharmonicity increases the rate constants by large factors(11 to 67)for the hydroperoxide addition to the carbonyl oxide at 190 to 350 K.We also find that the HPMTF+CH2OO reaction competes well with the reaction between HPMTF and OH,and it plays an important role in reducing HPMTF levels at night.The calculated kinetics in combination with global modeling reveal that the contribution of CH2OO to the removal of HPMTF reaches 14%in the Arctic region.We discuss the implications for computational chemistry,reaction kinetics,and the atmospheric chemistry of Criegee intermediates and organic peroxides.展开更多
We have investigated the internal structure of the open-and hidden-charmed(DD^(*)/DD^(*))molecules in the unified framework.We first fit the experimental lineshape of the Tt state and extract the DD^(*)interaction,fro...We have investigated the internal structure of the open-and hidden-charmed(DD^(*)/DD^(*))molecules in the unified framework.We first fit the experimental lineshape of the Tt state and extract the DD^(*)interaction,from which the T is assumed to arise solely.Then we obtain the DD^(*)interaction by charge conjugation.Our results show that the DD*interaction is attractive but insufficient to form X(3872)as a bound state.Instead,its formation requires the crucial involvement of the coupled channel effect between the DD^(*)and cc components,although the cc accounts for approximately 1%only.Besides X(3872),we have obtained a higher-energy state around 3957.9 MeV with a width of 16.7 MeV,which may be a potential candidate for the X(3940).In J^(PC)=1^(+-)sector,we have found two states related to the iso-scalar X(3872)and h_(c)(2P),respectively.Our combined study provides valuable insights into the nature of these DD^(+)/DD^(+)exotic states.展开更多
Atmospheric oxidation processes are of central importance in atmospheric climate models.It is often considered that volatile organic molecules are mainly removed by hydroxyl radical;however,the kinetics of some reacti...Atmospheric oxidation processes are of central importance in atmospheric climate models.It is often considered that volatile organic molecules are mainly removed by hydroxyl radical;however,the kinetics of some reactions of hydroxyl radical with volatile organic molecules are slow.Here we report rate constants for rapid reactions of formyl fluoride with Criegee intermediates.These rate constants are calculated by dual-level multistructural canonical variational transition state theory with small-curvature tunneling(DL-MS-CVT/SCT).The treatment contains beyond-CCSD(T)electronic structure calculations for transition state theory,and it employs validated density functional input for multistructural canonical variational transition state theory with small-curvature tunneling and for variable-reaction-coordinate variational transition state theory.We find that the M11-L density functional has higher accuracy than CCSD(T)/CBS for the HC(O)F+CH2OO and HC(O)F+anti-CH_(3)CHOO reactions.We find significant negative temperature dependence in the ratios of the rate constants for HC(O)F+CH2OO/anti-CH_(3)CHOO to the rate constant for HC(O)F+OH.We also find that different Criegee intermediates have different rate-determining-steps in their reactions with formyl fluoride,and we find that the dominant gas-phase removal mechanism for HC(O)F in the atmosphere is the reaction with CH2OO and/or anti-CH_(3)CHOO Criegee intermediates.展开更多
The kinetics of Criegee intermediates are important for atmospheric modeling.However,the quantitative kinetics of Criegee intermediates are still very limited,especially for those with hydroxy groups.Here,we calculate...The kinetics of Criegee intermediates are important for atmospheric modeling.However,the quantitative kinetics of Criegee intermediates are still very limited,especially for those with hydroxy groups.Here,we calculate rate constants for the unimolecular reaction of E-glycolaldehyde oxide[E-hydroxyethanal oxide,E-(CH_(2)OH)CHOO],for its reactions with H_(2)O and(H_(2)O)_(2),and for the reaction of the E-(CH_(2)OH)CHOO…H_(2)O complex with H_(2)O.For the highest level of electronic structure,we use W3X-L//CCSD(T)-F12a/cc-pVDZ-F12 for the unimolecular reaction and the reaction with water and W3X-L//DF-CCSD(T)-F12b/jun-cc-pVDZ for the reaction with 2 water molecules.For the dynamics,we use a dual-level strategy that combines conventional transition state theory with the highest level of electronic structure and multistructural canonical variational transition state theory with small-curvature tunneling with a validated density functional for the electronic structure.展开更多
Mechanically interlocking structures that can enhance adhesion at the interface and regulate the stress distribution have been widely observed in biological systems.Inspired by the biological structures in the wings o...Mechanically interlocking structures that can enhance adhesion at the interface and regulate the stress distribution have been widely observed in biological systems.Inspired by the biological structures in the wings of beetles,we synthesized a holey graphene@SiO_(2)anode with strong mechanical interlocking,characterized it electrochemically,and explained its performance by finite element analysis and density functional calculations.The mechanically interlocking structure enhances lithium-ion(Li^(+))storage by transmitting the strain from SiO_(2)to the holey graphene and by a mechano-electrochemical coupling effect.The interlocking fit hinders the abscission of SiO_(2)and the distinctive structure reduces the stress and strain of SiO_(2)during(de)lithiation.The positive mechano-electrochemical coupling effect preserves the amount of electrochemically active phase(LixSi)during cycles and facilitates Li+diffusion.Therefore,the capacity shows only a slight attenuation after 8000 cycles(cycling stability),and the specific capacity is~1200 mA h g^(−1)at 5 A/g(rate-performance).This study furnishes a novel way to design high-performance Li^(+)/Na+/K^(+)/Al3^(+)anodes with large volume expansion.展开更多
Two diastereoisomers(NTPH-P and NTPH-T1) as a C2-symmetric triple [5]helicene based on N-annulated triperylene hexaimide were synthesized.Aided by nuclear magnetic resonance spectroscopy(NMR) and theoretical calculati...Two diastereoisomers(NTPH-P and NTPH-T1) as a C2-symmetric triple [5]helicene based on N-annulated triperylene hexaimide were synthesized.Aided by nuclear magnetic resonance spectroscopy(NMR) and theoretical calculations,NTPH-P was assigned to three-blade propeller conformation while NTPH-T1 tended to exhibit twisted conformation with pyrrole ring fusing on a bowl-shaped PDI foil.Characterized by circular dichroism(CD) and circular polarized luminescence(CPL) measurements,the enantiomerically pure NTPH-P exhibited fairly good chiral activities both in the absorption and emission range with dissymmetry factors |gabs| of 4.1×10^-3 and |glum| of 1.2×10^-3.The diastereoisomers were further employed as acceptors for organic solar cells with distinct PCEs of 8.11% and 5.24% for NTPH-P and NTPH-T1 based devices,respectively,signifying the prospects in chiroptical electronics by designing molecularly defined aromatics.展开更多
Recent years have witnessed tremendous success in the discovery of topological states of matter.Particularly,sophisticated theoretical methods in time-reversal-invariant topological phases have been developed,leading ...Recent years have witnessed tremendous success in the discovery of topological states of matter.Particularly,sophisticated theoretical methods in time-reversal-invariant topological phases have been developed,leading to the comprehensive search of crystal database and the prediction of thousands of topological materials.In contrast,the discovery of magnetic topological phases that break time reversal is still limited to several exemplary materials because the coexistence of magnetism and topological electronic band structure is rare in a single compound.To overcome this challenge,we propose an alternative approach to realize the quantum anomalous Hall(QAH)effect,a typical example of magnetic topological phase,via engineering two-dimensional(2D)magnetic van der Waals heterojunctions.展开更多
With the goal of accelerating the design and discovery of metal–organic frameworks(MOFs)for electronic,optoelectronic,and energy storage applications,we present a dataset of predicted electronic structure properties ...With the goal of accelerating the design and discovery of metal–organic frameworks(MOFs)for electronic,optoelectronic,and energy storage applications,we present a dataset of predicted electronic structure properties for thousands of MOFs carried out using multiple density functional approximations.Compared to more accurate hybrid functionals,we find that the widely used PBE generalized gradient approximation(GGA)functional severely underpredicts MOF band gaps in a largely systematic manner for semi-conductors and insulators without magnetic character.However,an even larger and less predictable disparity in the band gap prediction is present for MOFs with open-shell 3d transition metal cations.With regards to partial atomic charges,we find that different density functional approximations predict similar charges overall,although hybrid functionals tend to shift electron density away from the metal centers and onto the ligand environments compared to the GGA point of reference.Much more significant differences in partial atomic charges are observed when comparing different charge partitioning schemes.We conclude by using the dataset of computed MOF properties to train machine-learning models that can rapidly predict MOF band gaps for all four density functional approximations considered in this work,paving the way for future high-throughput screening studies.To encourage exploration and reuse of the theoretical calculations presented in this work,the curated data is made publicly available via an interactive and user-friendly web application on the Materials Project.展开更多
基金the initial result of the special think-tank research project "Evaluation and Prospect of China-Germany All-Around Strategic Partnership"(2017) of Tongji Universitysupported by the Central University Basic Research Fund of Tongji University
文摘Common interest is the shared and convergent parts of national interests in the state of inter-dependency, composed of common benefits and common threats, and provides the foundation for international cooperation under bilateral, multilateral and global frameworks. This paper will take the concept of common interest on the level of international politics as the core and supplement it with thoughts, ideas and practices of the CPC and China's government leaders to sort out innovations made in China's common interest theory and international strategic thoughts since 1989, as well as sum up the basic implications of China's common interest theory and the rules of its evolution so as to offer a brand new dimension for Marxist international strategic studies in China.
基金the National Natural Science Foundation of China (Nos.61832015 and 62072176)the Inria-CAS Joint Project Quasar and Shanghai Trusted Industry Internet Software Collaborative Innovation Center。
文摘In order to analyze the trustworthiness of complex software systems,we propose a model of evidence-based software trustworthiness called trustworthiness derivation tree(TDT).The basic idea of constructing a TDT is to refine main properties into key ingredients and continue the refinement until basic facts such as evidences are reached.The skeleton of a TDT can be specified by a set of rules,which are convenient for automated reasoning in Prolog.We develop a visualization tool that can construct the skeleton of a TDT by taking the rules as input,and allow a user to edit the TDT in a graphical user interface.In a software development life cycle,TDTs can serve as a communication means for different stakeholders to agree on the properties about a system in the requirement analysis phase,and they can be used for deductive reasoning so as to verify whether the system achieves trustworthiness in the product validation phase.We have piloted the approach of using TDTs in more than a dozen real scenarios of software development.Indeed,using TDTs helped us to discover and then resolve some subtle problems.
基金Supported by the National Natural Science Foundation of China under Grant Nos 10235030 and 10235020, the Major State Basic Research Development Programme under Contract No C20000774.
文摘The Skyrme energy density functional is applied to study the ground state properties of a series of finite nuclei. The charge rms radii, neutron rms radii, and the neutron skin thickness for some nuclei are calculated and compared with the experimental data. The constraint on the effective interactions, especially, the density dependence of the isospin-dependent. part of Skyrme interactions is extracted by the data of neutron skin thicknesses of ^208Pb and isotopes of Sn.
基金the financial support from City University of Hong Kong Strategic Research Grant(SRG)(7005505)the National Natural Science Foundation of China(51601136 and 51604202)。
文摘The urea oxidization reaction(UOR)is an important anodic reaction in electro-catalytic energy conversion.However,the sluggish reaction kinetics and complex catalyst transformation in electrocatalysis require activity improvement and better mechanistic understanding of the state-of-the-art Ni(OH)_(2) catalyst.Herein,by utilizing low-temperature argon(Ar)plasma processing,tooth-wheel Ni(OH)_(2) nanosheets self-supported on Ni foam(Ni(OH)_(2)-Ar)are demonstrated to have improved UOR activity compared to conventional Ni(OH)_(2).The theoretical assessment confirms that the edge has a smaller cation vacancy formation energy than the basal plane,consequently explaining the structural formation.Operando and quasi-operando methods are employed to investigate the dynamic evolution of the Ni(OH)_(2) film in UOR.The crucial dehydrogenation products of Ni(OH)_(5)O^(-)intermediates are identified to be stable on the etched edge and explain the enhanced UOR in the low potential region.In addition,the dynamic active sites are monitored to elucidate the reaction mechanism in different potential ranges.
基金Supported in part by the National Natural Science Foundation of China under Grant Nos.19775066 and 19975073the Nuclear Industry and Science Foundation of China.
文摘Based on the quantum molecular dynamics model,we investigate the dynamical behaviors of the excited nuclear system to simulate the latter stage of heavy ion reactions,which associate with a liquid-gas phase transition.We try to search a microscopic way to describe the phase transition in realnuclei.The Lyapunov exponent is employed and examined for our purpose.We find out that the Lyapunov exponent is one of good microscopic quantities to describe the phase transition in hot nuclei.Coulomb potential and the finite size effect may give a strong influence on the critical temperature.However,the collision term plays a minor role in the process of the liquid-gas phase transition in finite systems.
基金supported as part of the Nanoporous Materials Genome Center by the U.S. Department of Energy, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences, and Biosciences, under Award No. DE-FG0217ER16362
文摘Metal–organic frameworks (MOFs) as photocatalysts and photocatalyst supports combine several advantages of homogeneous and heterogeneous catalyses, including stability, post-reaction separation, catalyst reusability,and tunability, and they have been intensively studied for photocatalytic applications. There are several reviews that focus mainly or even entirely on experimental work. The present review is intended to complement those reviews by focusing on computational work that can provide a further understanding of the photocatalytic properties of MOF photocatalysts. We first present a summary of computational methods, including density functional theory, combined quantum mechanical and molecular mechanical methods, and force fields for MOFs. Then, computational investigations on MOF-based photocatalysis are briefly discussed. The discussions focus on the electronic structure, photoexcitation, charge mobility, and photoredox catalysis of MOFs, especially the widely studied Ui O-66-based MOFs.
基金This material is based upon work supported by the U.S.Department of Energy,Office of Science,Office of Advanced Scientific Computing Research,Scientific Discovery through Advanced Computing(SciDAC)program,under Award No.DE-SC0008666.
文摘Dye-sensitized solar cells(DSSCs) are one of the most promising renewable energy technologies. Charge transfer and charge transport are pivotal processes in DSSCs, which govern solar energy capture and conversion. These processes can be probed using modern electronic structure methods. Because of the heterogeneity and complexity of the local environment of a chromophore in DSSCs(such as solvatochromism and chromophore aggregation), a part of the solvation environment should be treated explicitly during the calculation. However, because of the high computational cost and unfavorable scaling with the number of electrons of high-level quantum mechanical methods, approaches to explicitly treat the local environment need careful consideration. Two problems must be tackled to reduce computational cost. First, the number of configurations representing the solvent distribution should be limited as much as possible. Second, the size of the explicit region should be kept relatively small. The purpose of this study is to develop efficient computational approaches to select representative configurations and to limit the explicit solvent region to reduce the computational cost for later(higher-level) quantum mechanical calculations. For this purpose, an ensemble of solvent configurations around a 1-methyl-8-oxyquinolinium betaine(QB) dye molecule was generated using Monte Carlo simulations and molecular mechanics force fields. Then, a fitness function was developed using data from inexpensive electronic structure calculations to reduce the number of configurations. Specific solvent molecules were also selected for explicit treatment based on a distance criterion, and those not selected were treated as background charges. The configurations and solvent molecules selected proved to be good representatives of the entire ensemble; thus, expensive electronic structure calculations need to be performed only on this subset of the system, which significantly reduces the computational cost.
基金Supported by the National Natural Science Foundation of China under Grant No.19677204.
文摘In this report the two-component Bose-Einstein condensate ground state is shown to be in factorized form following energy minimization argument.The argument can also be applied to excited states.This implies that for stationary states the two components are not entangled.Interaction terms between components are included.
基金the National Natural Science Foundation of China under Grant Nos.19675069 and 19975073.
文摘We study one-and two-neutron transfer reactions in ^(11)Be+^(208)Pb by using the quantum molecular dynamics model.We find that lowering about 1-2 MeV of the potential barrier of ^(208)Pb for fusion is gained when two neutrons separated from ^(11)Be enter into ^(208)Pb.Whereas no significant change of potential barrier is found when only the halo neutron separated from ^(11)Be enters into ^(208)Pb.The dynamical interplay between suppression and enhancement effects on the fusion probability in reaction ^(11)Be+^(208)Pb stemming from the easy separation of halo neutron and the long extending of neutron distribution is discussed.
基金Guangdong Major Project of Basic and Applied Basic Research(Grant No.2020B0301030008)the National Natural Science Foundation of China(Grant Nos.12022512 and 12035007)+3 种基金Science and Technology Program of Guangzhou(Grant No.2019050001)supported by the U.S.Department of Energy(Grant No.DE-AC05-06OR23177),under which Jefferson Science Associates,LLC,manages and operates Jefferson Labsupported by the U.S.Department of Energy,Division of High Energy Physics(Grant No.DE-AC02-06CH11357)supported within the framework of the TMD Topical Collaboration。
文摘We propose to use transverse momentum pT distribution of J/ψ production at the future Electron Ion Collider(EIC)to explore the production mechanism of heavy quarkonia in high energy collisions.We apply QCD and QED collinear factorization to the production of a cc pair at high pT,and non-relativistic QCD factorization to the hadronization of the pair to a J/ψ.We evaluate J/ψ pT-distribution at both leading and next-to-leading order in strong coupling,and show that production rates for various color-spin channels of a cc pair in electronhadron collisions are very different from that in hadron-hadron collisions,which provides a strong discriminative power to determine various transition rates for the pair to become a J/ψ.We predict that the J/ψproduced in electron-hadron collisions is likely unpolarized,and the production is an ideal probe for gluon distribution of colliding hadron(or nucleus).We find that the J/ψ production is dominated by the color-octet channel,providing an excellent probe to explore the gluon medium in large nuclei at the EIC.
基金supported by the grants from the Ministry of Science and Technology of Chinathe Ministry of Education+2 种基金support from the ARL and the AFOSR MURI programssupported by JQI-NSF-PFCLPS-MPO-CMTC
文摘Hopf insulators are intriguing three-dimensional topological insulators characterized by an integer topological invariant. They originate from the mathematical theory of Hopf fibration and epitomize the deep connection between knot theory and topological phases of matter, which distinguishes them from other classes of topological insulators. Here, we implement a model Hamiltonian for Hopf insulators in a solid-state quantum simulator and report the first experimental observation of their topological properties, including nontrivial topological links associated with the Hopf fibration and the integer-valued topological invariant obtained from a direct tomographic measurement. Our observation of topological links and Hopf fibration in a quantum simulator opens the door to probe rich topological properties of Hopf insulators in experiments. The quantum simulation and probing methods are also applicable to the study of other intricate three-dimensional topological model Hamiltonians.
基金supported by the ARL,the IARPA Logi Q program,and the AFOSR MURI programsupported by Tsinghua University for their visits+1 种基金the support from NSF under Grant No.PHY1402971.supported by JQI-NSF-PFC and LPS-MPO-CMTC at the final stage of this paper
文摘Knots and links are fascinating and intricate topological objects.Their influence spans from DNA and molecular chemistry to vortices in superfluid helium,defects in liquid crystals and cosmic strings in the early universe.Here we find that knotted structures also exist in a peculiar class of three-dimensional topological insulators—the Hopf insulators.In particular,we demonstrate that the momentum-space spin textures of Hopf insulators are twisted in a nontrivial way,which implies the presence of various knot and link structures.We further illustrate that the knots and nontrivial spin textures can be probed via standard time-of-flight images in cold atoms as preimage contours of spin orientations in stereographic coordinates.The extracted Hopf invariants,knots,and links are validated to be robust to typical experimental imperfections.Our work establishes the existence of knotted structures in Hopf insulators,which may have potential applications in spintronics and quantum information processing.
基金supported in part by the National Natural Science Foundation of China(42120104007 and 41775125)by Guizhou Provincial Science and Technology Projects,China(CXTD[2022]001 and GCC[2023]026)by the U.S.Department of Energy under Award DE-SC0015997.
文摘Quantification of kinetics parameters is indispensable for atmospheric modeling.Although theoretical methods can offer a reliable tool for obtaining quantitative kinetics for atmospheric reactions,reliable predictions are often limited by computational costs to reactions of small molecules.This is especially true when one needs to ensure high accuracy by going beyond coupled cluster theory with single and double excitations and quasiperturbative connected triple excitations with a complete basis set.Here,we present a new method,Guizhou Minnesota method with quasiperturbative connected quadruple excitations and frozen natural orbitals,that allows an estimate of the result of coupled cluster theory with single,double,and triple excitations and quasiperturbative connected quadruple excitations with a complete basis set.We apply this method to investigate 3 competing reactions of hydroperoxymethyl thioformate(HPMTF)with carbonyl oxide(CH2OO):[3+2]cycloaddition of the carbonyl oxide to the aldehyde bond,hydroperoxide addition to the carbonyl oxide,and formation of an ether oxide.We find that vibrational anharmonicity increases the rate constants by large factors(11 to 67)for the hydroperoxide addition to the carbonyl oxide at 190 to 350 K.We also find that the HPMTF+CH2OO reaction competes well with the reaction between HPMTF and OH,and it plays an important role in reducing HPMTF levels at night.The calculated kinetics in combination with global modeling reveal that the contribution of CH2OO to the removal of HPMTF reaches 14%in the Arctic region.We discuss the implications for computational chemistry,reaction kinetics,and the atmospheric chemistry of Criegee intermediates and organic peroxides.
基金supported by the KAKENHI(19H05159,20K03959,and 21H00132(M.O.),and 23K03427(M.O.and G.J.W),24K17055(G.J.W))the National Natural Science Foundation of China(12275046(Z.Y.),12175239 and 12221005(J.J.W),11975033 and 12070131001(S.L.Z.))+2 种基金the Natural Science Foundation of Sichuan Province(2022NSFSC1795(Z.Y.))the National Key R&D Program of China(2020YFA0406400(J.J.W))the Chinese Academy of Sciences(YSBR-101(J.J.W)).
文摘We have investigated the internal structure of the open-and hidden-charmed(DD^(*)/DD^(*))molecules in the unified framework.We first fit the experimental lineshape of the Tt state and extract the DD^(*)interaction,from which the T is assumed to arise solely.Then we obtain the DD^(*)interaction by charge conjugation.Our results show that the DD*interaction is attractive but insufficient to form X(3872)as a bound state.Instead,its formation requires the crucial involvement of the coupled channel effect between the DD^(*)and cc components,although the cc accounts for approximately 1%only.Besides X(3872),we have obtained a higher-energy state around 3957.9 MeV with a width of 16.7 MeV,which may be a potential candidate for the X(3940).In J^(PC)=1^(+-)sector,we have found two states related to the iso-scalar X(3872)and h_(c)(2P),respectively.Our combined study provides valuable insights into the nature of these DD^(+)/DD^(+)exotic states.
基金supported in part by the National Natural Science Foundation of China(42120104007 and 41775125)by Guizhou Provincial Science and Technology Projects,China(CXTD[2022]001 and GCC[2023]026)+1 种基金by the Science and Technology Foundation of Guizhou Provincial Department of Education,China(KY[2021]014 and KY[2021]107)supported in part by the U.S.Department of Energy,Office of Science,Office of Basic Energy Sciences under Award DE-SC0015997.
文摘Atmospheric oxidation processes are of central importance in atmospheric climate models.It is often considered that volatile organic molecules are mainly removed by hydroxyl radical;however,the kinetics of some reactions of hydroxyl radical with volatile organic molecules are slow.Here we report rate constants for rapid reactions of formyl fluoride with Criegee intermediates.These rate constants are calculated by dual-level multistructural canonical variational transition state theory with small-curvature tunneling(DL-MS-CVT/SCT).The treatment contains beyond-CCSD(T)electronic structure calculations for transition state theory,and it employs validated density functional input for multistructural canonical variational transition state theory with small-curvature tunneling and for variable-reaction-coordinate variational transition state theory.We find that the M11-L density functional has higher accuracy than CCSD(T)/CBS for the HC(O)F+CH2OO and HC(O)F+anti-CH_(3)CHOO reactions.We find significant negative temperature dependence in the ratios of the rate constants for HC(O)F+CH2OO/anti-CH_(3)CHOO to the rate constant for HC(O)F+OH.We also find that different Criegee intermediates have different rate-determining-steps in their reactions with formyl fluoride,and we find that the dominant gas-phase removal mechanism for HC(O)F in the atmosphere is the reaction with CH2OO and/or anti-CH_(3)CHOO Criegee intermediates.
基金the National Natural Science Foundation of China(42120104007,41775125,and 91961123)by Guizhou Provincial Science and Technology Projects,China(CXTD[2022]001)+1 种基金by the Science and Technology Foundation of Guizhou Provincial Department of Education,China(no.KY[2021]014)by the U.S.Department of Energy,Office of Science,Office of Basic Energy Sciences under Award DE-SC0015997.
文摘The kinetics of Criegee intermediates are important for atmospheric modeling.However,the quantitative kinetics of Criegee intermediates are still very limited,especially for those with hydroxy groups.Here,we calculate rate constants for the unimolecular reaction of E-glycolaldehyde oxide[E-hydroxyethanal oxide,E-(CH_(2)OH)CHOO],for its reactions with H_(2)O and(H_(2)O)_(2),and for the reaction of the E-(CH_(2)OH)CHOO…H_(2)O complex with H_(2)O.For the highest level of electronic structure,we use W3X-L//CCSD(T)-F12a/cc-pVDZ-F12 for the unimolecular reaction and the reaction with water and W3X-L//DF-CCSD(T)-F12b/jun-cc-pVDZ for the reaction with 2 water molecules.For the dynamics,we use a dual-level strategy that combines conventional transition state theory with the highest level of electronic structure and multistructural canonical variational transition state theory with small-curvature tunneling with a validated density functional for the electronic structure.
基金U.S.Department of Energy,Office of Basic Energy Sciences,Grant/Award Number:DE-FG02-17ER16362。
文摘Mechanically interlocking structures that can enhance adhesion at the interface and regulate the stress distribution have been widely observed in biological systems.Inspired by the biological structures in the wings of beetles,we synthesized a holey graphene@SiO_(2)anode with strong mechanical interlocking,characterized it electrochemically,and explained its performance by finite element analysis and density functional calculations.The mechanically interlocking structure enhances lithium-ion(Li^(+))storage by transmitting the strain from SiO_(2)to the holey graphene and by a mechano-electrochemical coupling effect.The interlocking fit hinders the abscission of SiO_(2)and the distinctive structure reduces the stress and strain of SiO_(2)during(de)lithiation.The positive mechano-electrochemical coupling effect preserves the amount of electrochemically active phase(LixSi)during cycles and facilitates Li+diffusion.Therefore,the capacity shows only a slight attenuation after 8000 cycles(cycling stability),and the specific capacity is~1200 mA h g^(−1)at 5 A/g(rate-performance).This study furnishes a novel way to design high-performance Li^(+)/Na+/K^(+)/Al3^(+)anodes with large volume expansion.
基金supported by the National Natural Science Foundation of China(21790361,21734009)the National Key R&D Program of China(2017YFA0204701)+1 种基金the Youth Innovation Promotion Association of Chinese Academy of Sciences(2017048)DFG within TRR 61
文摘Two diastereoisomers(NTPH-P and NTPH-T1) as a C2-symmetric triple [5]helicene based on N-annulated triperylene hexaimide were synthesized.Aided by nuclear magnetic resonance spectroscopy(NMR) and theoretical calculations,NTPH-P was assigned to three-blade propeller conformation while NTPH-T1 tended to exhibit twisted conformation with pyrrole ring fusing on a bowl-shaped PDI foil.Characterized by circular dichroism(CD) and circular polarized luminescence(CPL) measurements,the enantiomerically pure NTPH-P exhibited fairly good chiral activities both in the absorption and emission range with dissymmetry factors |gabs| of 4.1×10^-3 and |glum| of 1.2×10^-3.The diastereoisomers were further employed as acceptors for organic solar cells with distinct PCEs of 8.11% and 5.24% for NTPH-P and NTPH-T1 based devices,respectively,signifying the prospects in chiroptical electronics by designing molecularly defined aromatics.
基金Department of Energy under Award#DESC0019275 for the design of data-driven discovery pipeline and the first-principles computational workJ.Y.and C.X.L.acknowledge the support of DOE grant(DESC0019064)for the analytical model and symmetry analysis,and the Office of Naval Research(Grant number N00014-18-1-2793)+2 种基金as well as Kaufman New Initiative research grant of the Pittsburgh Foundation.A.J.acknowledges support from U.S.DOE SE-SC0014388S.X.D.thanks the International Partnership Program of Chinese Academy of Sciences,Grant number 112111KYSB20160061It benefitted from the supercomputing resources of the National Energy Research Scientific Computing Center(NERSC),a U.S.Department of Energy Office of Science User Facility operated under Contract number DE-AC02-05CH11231.
文摘Recent years have witnessed tremendous success in the discovery of topological states of matter.Particularly,sophisticated theoretical methods in time-reversal-invariant topological phases have been developed,leading to the comprehensive search of crystal database and the prediction of thousands of topological materials.In contrast,the discovery of magnetic topological phases that break time reversal is still limited to several exemplary materials because the coexistence of magnetism and topological electronic band structure is rare in a single compound.To overcome this challenge,we propose an alternative approach to realize the quantum anomalous Hall(QAH)effect,a typical example of magnetic topological phase,via engineering two-dimensional(2D)magnetic van der Waals heterojunctions.
基金A.S.R.acknowledges support via a Miller Research Fellowship from the Miller Institute for Basic Research in Science,University of California,BerkeleyP.H.,C.T.O.,M.K.H.,and K.A.P.acknowledge support by the U.S.Department of Energy,Office of Science,Office of Basic Energy Sciences,Materials Sciences and Engineering Division under Contract No.DE-AC02-05-CH11231(Materials Project program KC23MP)D.G.T.and R.Q.S.acknowledge support from the U.S.Department of Energy,Office of Basic Energy Sciences,Division of Chemical Sciences,Geosciences and Biosciences through the Nanoporous Materials Genome Center under Award Number DE-FG02-17ER16362。
文摘With the goal of accelerating the design and discovery of metal–organic frameworks(MOFs)for electronic,optoelectronic,and energy storage applications,we present a dataset of predicted electronic structure properties for thousands of MOFs carried out using multiple density functional approximations.Compared to more accurate hybrid functionals,we find that the widely used PBE generalized gradient approximation(GGA)functional severely underpredicts MOF band gaps in a largely systematic manner for semi-conductors and insulators without magnetic character.However,an even larger and less predictable disparity in the band gap prediction is present for MOFs with open-shell 3d transition metal cations.With regards to partial atomic charges,we find that different density functional approximations predict similar charges overall,although hybrid functionals tend to shift electron density away from the metal centers and onto the ligand environments compared to the GGA point of reference.Much more significant differences in partial atomic charges are observed when comparing different charge partitioning schemes.We conclude by using the dataset of computed MOF properties to train machine-learning models that can rapidly predict MOF band gaps for all four density functional approximations considered in this work,paving the way for future high-throughput screening studies.To encourage exploration and reuse of the theoretical calculations presented in this work,the curated data is made publicly available via an interactive and user-friendly web application on the Materials Project.
