The photodissociationdynamicsof small(H_(2)O)_(n)^(+)(n=2-5)clusters have been studied at 308 nm using a high resolution cryogenic cylindrical ion trap velocity map imaging spectrometer.Time-of-flight mass spectra and...The photodissociationdynamicsof small(H_(2)O)_(n)^(+)(n=2-5)clusters have been studied at 308 nm using a high resolution cryogenic cylindrical ion trap velocity map imaging spectrometer.Time-of-flight mass spectra and images of ionic photofragments are recorded.(H_(2)O)_(2)^(+)clusters dissociate to yield H_(3)O^(+)and H_(2)O^(+)photofragments,indicating the presence of both proton-transferred(H_(3)O^(+)-OH)and hemibonded(H_(2)O-OH_(2))^(+)structures for the dimer cluster.(H_(2)O)_(n)^(+)(n=3-5)clusters prevailingly dissociate to the H+(H_(2)O)_(n-2,...1)photofragments by losing both of OH and H_(2)O components,and the(H_(2)O)_(5)^(+)cluster shows an additional channel to produce H^(+)(H_(2)O)_(4)by only losing OH.The former suggests the(H_(2)O)_(n-2)H_(3)_(O)^(+)OH structures for the(H_(2)O)_(n)^(+)(n=3-5)clusters,while the latter suggests in(H_(2)O)_(5)^(+)that,the H_(3)O^(+)core and OH are separated by H_(2)O.The results elucidate the structure progresses of small(H_(2)O)_(n)^(+)clusters.The experimental images yield negative and small values for the anisotropy parameters of photofragments,indicating that(H_(2)O)_(n)^(+)(n=2-5)clusters undergo vertical electronic transitions upon photon absorption followed by slow dissociation,and lead to highly internally excited photofragments.展开更多
The dependence of charged particle pseudorapidity distributions on centrality in Pb-Pb collisions at√sNN=2.76 TeV is studied by using a multi-source thermal model(previously the two-cylinder model or the multi-source...The dependence of charged particle pseudorapidity distributions on centrality in Pb-Pb collisions at√sNN=2.76 TeV is studied by using a multi-source thermal model(previously the two-cylinder model or the multi-source ideal gas model).The rapidity shifts of the interacting system are almost independent of the centrality class.The contribution of leading nucleons increases with the increasing centrality class(percent).The calculated results are compared and found to be in agreement with the experimental data of the ATLAS,ALICE,and CMS collaborations.展开更多
Structural and electronic properties of Pb_(n)Ag_(n)(n=2–12)clusters were investigated by density functional theory with generalized gradient approximation at BLYP level in DMol3 program package.The optimized bimetal...Structural and electronic properties of Pb_(n)Ag_(n)(n=2–12)clusters were investigated by density functional theory with generalized gradient approximation at BLYP level in DMol3 program package.The optimized bimetallic Pb_(n)Ag_(n)(n=2–12)clusters were viewed as the initial structures,then,those were calculated by ab initio molecular dynamics(AIMD)to search possible global minimum energy structures of Pb_(n)Ag_(n)clusters,finally,the ground state structures of Pb_(n)Ag_(n)(n=2–12)clusters were achieved.According to the structural evolution of lowest energy structures,Ag atoms prefer gather in the central sites while Pb atoms prefer external positions in Pb_(n)Ag_(n)(n=2–12)clusters,which is in excellent agreement with experimental results from literature and the application in metallurgy.The average binding energies,HOMO-LUMO gaps,vertical ionization potentials,vertical electron affinities,chemical hardnessη,HOMO orbits,LUMO orbits and density of states of Pb_(n)Ag_(n)(n=2–12)clusters were calculated.The results indicate that the values of HOMO-LUMO gaps,vertical ionization potentials,vertical electron affinities and chemical hardnessηshow obvious odd-even oscillations when n≤5,Pb_(n)Ag_(n)(n=2–12)clusters become less chemically stable and show insulator-to-metal transition with the variation of cluster size n,Pb_(n)Ag_(n)(n≥9)cluster are good candidates to study the properties of PbAg alloys.Those can be well explained by the density of states(DOS)distributions of Pb atoms and Ag atoms between–0.5 Ha and 0.25 Ha in Pb_(n)Ag_(n)(n=2–12)clusters.展开更多
Divalent metal clusters have received great attention due to the interesting size-induced nonmetal-to-metal transition and fascinating properties dependent on cluster size,shape,and doping.In this work,the combination...Divalent metal clusters have received great attention due to the interesting size-induced nonmetal-to-metal transition and fascinating properties dependent on cluster size,shape,and doping.In this work,the combination of the CALYPSO code and density functional theory(DFT)optimization is employed to explore the structural properties of neutral and anionic Mg_(n+1) and SrMgn(n=2-12)clusters.The results exhibit that as the atomic number of Mg increases,Sr atoms are more likely to replace Mg atoms located in the skeleton convex cap.By analyzing the binding energy,second-order energy difference and the charge transfer,it can be found the SrMg9 cluster with tower framework presents outstanding stability in a studied size range.Further,bonding characteristic analysis reveals that the stability of SrMg9 can be improved due to the strong s-p interaction among the atomic orbitals of Sr and Mg atoms.展开更多
We revisit the novel symmetries in N=2 supersymmetric quantum mechanical models by considering specific examples of coupled systems.Further,we extend our analysis to a general case and list out all the novel symmetrie...We revisit the novel symmetries in N=2 supersymmetric quantum mechanical models by considering specific examples of coupled systems.Further,we extend our analysis to a general case and list out all the novel symmetries.In each case,we show the existence of two sets of discrete symmetries that correspond to the Hodge duality operator of differential geometry.Thus,we are able to provide a proof of the conjecture which points out the existence of more than one set of discrete symmetry transformations corresponding to the Hodge duality operator.Moreover,we derive on-shell nilpotent symmetries for a generalized superpotential within the framework of supervariable approach.展开更多
We combine the Freund-Rubin(FR)type anaatz with the nonlinear sigma model,a new solution of the chiral N=2,D=10 supergravity compactified on manifold M^(4)×N^(4)×H^(2) is obtained.Its properties are discussed.
基金This work is supported by the National Natural Science Foundation of China(No.22103075,No.21827804,and No.22173089)the National Key R&D Program of China(No.2021YFA0716801and No.2017YFA0303502).
文摘The photodissociationdynamicsof small(H_(2)O)_(n)^(+)(n=2-5)clusters have been studied at 308 nm using a high resolution cryogenic cylindrical ion trap velocity map imaging spectrometer.Time-of-flight mass spectra and images of ionic photofragments are recorded.(H_(2)O)_(2)^(+)clusters dissociate to yield H_(3)O^(+)and H_(2)O^(+)photofragments,indicating the presence of both proton-transferred(H_(3)O^(+)-OH)and hemibonded(H_(2)O-OH_(2))^(+)structures for the dimer cluster.(H_(2)O)_(n)^(+)(n=3-5)clusters prevailingly dissociate to the H+(H_(2)O)_(n-2,...1)photofragments by losing both of OH and H_(2)O components,and the(H_(2)O)_(5)^(+)cluster shows an additional channel to produce H^(+)(H_(2)O)_(4)by only losing OH.The former suggests the(H_(2)O)_(n-2)H_(3)_(O)^(+)OH structures for the(H_(2)O)_(n)^(+)(n=3-5)clusters,while the latter suggests in(H_(2)O)_(5)^(+)that,the H_(3)O^(+)core and OH are separated by H_(2)O.The results elucidate the structure progresses of small(H_(2)O)_(n)^(+)clusters.The experimental images yield negative and small values for the anisotropy parameters of photofragments,indicating that(H_(2)O)_(n)^(+)(n=2-5)clusters undergo vertical electronic transitions upon photon absorption followed by slow dissociation,and lead to highly internally excited photofragments.
基金Supported by the National Natural Science Foundation of China under Grant No 10975095the National Fundamental Fund of Personnel Training under Grant No J1103210the Foundation of Shanxi Scholarship Council of China under Grant No 2012-012.
文摘The dependence of charged particle pseudorapidity distributions on centrality in Pb-Pb collisions at√sNN=2.76 TeV is studied by using a multi-source thermal model(previously the two-cylinder model or the multi-source ideal gas model).The rapidity shifts of the interacting system are almost independent of the centrality class.The contribution of leading nucleons increases with the increasing centrality class(percent).The calculated results are compared and found to be in agreement with the experimental data of the ATLAS,ALICE,and CMS collaborations.
基金Project(51664032)supported by the Regional Foundation of the National Natural Science Foundation of ChinaProject(51474116)supported by the General Program of the National Natural Science Foundation of China+5 种基金Project(U1502271)supported by the Joint Foundation of the NSFC-Yunnan Province,ChinaProject(2014HA003)supported by the Cultivating Plan Program for the Leader in Science and Technology of Yunnan Province,ChinaProject(2014RA4018)supported by the Program for Nonferrous Metals Vacuum Metallurgy Innovation Team of Ministry of Science and Technology,ChinaProject(2016YFC0400404)supported by the National Key Research and Development Program of ChinaProject(51504115)supported by the Youth Program of National Natural Science Foundation of ChinaProject(IRT_17R48)supported by the Program for Innovative Research Team in University of Ministry of Education of China
文摘Structural and electronic properties of Pb_(n)Ag_(n)(n=2–12)clusters were investigated by density functional theory with generalized gradient approximation at BLYP level in DMol3 program package.The optimized bimetallic Pb_(n)Ag_(n)(n=2–12)clusters were viewed as the initial structures,then,those were calculated by ab initio molecular dynamics(AIMD)to search possible global minimum energy structures of Pb_(n)Ag_(n)clusters,finally,the ground state structures of Pb_(n)Ag_(n)(n=2–12)clusters were achieved.According to the structural evolution of lowest energy structures,Ag atoms prefer gather in the central sites while Pb atoms prefer external positions in Pb_(n)Ag_(n)(n=2–12)clusters,which is in excellent agreement with experimental results from literature and the application in metallurgy.The average binding energies,HOMO-LUMO gaps,vertical ionization potentials,vertical electron affinities,chemical hardnessη,HOMO orbits,LUMO orbits and density of states of Pb_(n)Ag_(n)(n=2–12)clusters were calculated.The results indicate that the values of HOMO-LUMO gaps,vertical ionization potentials,vertical electron affinities and chemical hardnessηshow obvious odd-even oscillations when n≤5,Pb_(n)Ag_(n)(n=2–12)clusters become less chemically stable and show insulator-to-metal transition with the variation of cluster size n,Pb_(n)Ag_(n)(n≥9)cluster are good candidates to study the properties of PbAg alloys.Those can be well explained by the density of states(DOS)distributions of Pb atoms and Ag atoms between–0.5 Ha and 0.25 Ha in Pb_(n)Ag_(n)(n=2–12)clusters.
基金the National Natural Science Foundation of China(Grant No.11404008)the Artificial Intelligence Key Laboratory of Sichuan Province,China(Grant No.2018RYJ07)+2 种基金the Innovation Fund of Postgraduate Sichuan University of Science&Engineering,China(Grant Nos.y202007 and y2021008)the Innovation and Entrepreneurship Training Program of Sichuan Province,China(Grant Nos.S202010622080 and S202010622082)the Innovation and Entrepreneurship Training Program of Sichuan University of Science&Engineering,China(Grant No.cx2019005)。
文摘Divalent metal clusters have received great attention due to the interesting size-induced nonmetal-to-metal transition and fascinating properties dependent on cluster size,shape,and doping.In this work,the combination of the CALYPSO code and density functional theory(DFT)optimization is employed to explore the structural properties of neutral and anionic Mg_(n+1) and SrMgn(n=2-12)clusters.The results exhibit that as the atomic number of Mg increases,Sr atoms are more likely to replace Mg atoms located in the skeleton convex cap.By analyzing the binding energy,second-order energy difference and the charge transfer,it can be found the SrMg9 cluster with tower framework presents outstanding stability in a studied size range.Further,bonding characteristic analysis reveals that the stability of SrMg9 can be improved due to the strong s-p interaction among the atomic orbitals of Sr and Mg atoms.
基金support from the FRG scheme of National Institute of Technology Calicut。
文摘We revisit the novel symmetries in N=2 supersymmetric quantum mechanical models by considering specific examples of coupled systems.Further,we extend our analysis to a general case and list out all the novel symmetries.In each case,we show the existence of two sets of discrete symmetries that correspond to the Hodge duality operator of differential geometry.Thus,we are able to provide a proof of the conjecture which points out the existence of more than one set of discrete symmetry transformations corresponding to the Hodge duality operator.Moreover,we derive on-shell nilpotent symmetries for a generalized superpotential within the framework of supervariable approach.
文摘We combine the Freund-Rubin(FR)type anaatz with the nonlinear sigma model,a new solution of the chiral N=2,D=10 supergravity compactified on manifold M^(4)×N^(4)×H^(2) is obtained.Its properties are discussed.
