A scheme for controlled teleportation of an arbitrary two-particle state using a maximally entangled EPR pair and a cluster state as the quantum channel is proposed. After receiving Alice's Bell state measurement res...A scheme for controlled teleportation of an arbitrary two-particle state using a maximally entangled EPR pair and a cluster state as the quantum channel is proposed. After receiving Alice's Bell state measurement results, the controller performs a joint measurement on his particles under a non-maximally entangled Bell-basis. The receiver needs to introduce an auxiliary qubit, and performs a series of appropriate unitary transformations on his particles. The original state can be teleported successfully with the probability 2 cos2θ.展开更多
We study the geometries, stabilities, electronic and magnetic properties of (MgO)n (n=2-10) clusters doped with a single Mn atom using the density functional theory with the gener- alized gradient approximation. T...We study the geometries, stabilities, electronic and magnetic properties of (MgO)n (n=2-10) clusters doped with a single Mn atom using the density functional theory with the gener- alized gradient approximation. The optimized geometries show that the impurity Mn atom prefers to replace the Mg atom which has low coordination number in all the lowest-energy MnMgn-1On (n=2-10) structures. The stability analysis clearly represents that the average binding energies of the doped clusters are larger than those of the corresponding pure (MgO)n clusters. Maximum peaks of the second order energy differences are observed for MnMg~_1On clusters at n=6, 9, implying that these clusters exhibit higher stability than their neighboring clusters. In addition, all the Mn-doped Mg clusters exhibit high total magnetic moments with the exception of MnMgO2 which has 3.00μB. Their magnetic behavior is attributed to the impurity Mn atom, the charge transfer modes, and the size of MnMgn- 1On clusters.展开更多
Concrete specimens made with ordinary portland cement or ordinary portland cement incorporating fly ash with the replacement of 10% or 20%, ground blast furnace slag with the replacement of 15% or 30%, or 15% fly ash ...Concrete specimens made with ordinary portland cement or ordinary portland cement incorporating fly ash with the replacement of 10% or 20%, ground blast furnace slag with the replacement of 15% or 30%, or 15% fly ash and 15% ground blast furnace slag were made and exposed to a cyclic sulfate environment. Concrete properties including relative dynamic elastic modulus, chloride ion diffusion coefficient, compressive strength and flexural strength were measured. Effect of mineral admixtures on the cyclic sulfate resistance of concrete was assessed based on the grey clustering theory. The experimental results indicate that the cyclic sulfate resistance of concrete incorporating ground blast furnace slag belongs to the higher grey grade, which exhibits that it possesses excellent cyclic sulfate resistance. With increasing addition of fly ash, the cyclic sulfate resistance of concrete changes from the medium grey grade to the lower grey grade, which shows that incorporation of fly ash is disadvantageous for the cyclic sulfate resistance of concrete.展开更多
This paper proposes a clustering technique that minimizes the need for subjective human intervention and is based on elements of rough set theory (RST). The proposed algorithm is unified in its approach to clusterin...This paper proposes a clustering technique that minimizes the need for subjective human intervention and is based on elements of rough set theory (RST). The proposed algorithm is unified in its approach to clustering and makes use of both local and global data properties to obtain clustering solutions. It handles single-type and mixed attribute data sets with ease. The results from three data sets of single and mixed attribute types are used to illustrate the technique and establish its efficiency.展开更多
The geometries of MgnNi2(n = 1 6) clusters are studied by using the hybrid density functional theory (B3LYP) with LANL2DZ basis sets. For the ground-state structures of MgnNi2 clusters, the stabilities and the ele...The geometries of MgnNi2(n = 1 6) clusters are studied by using the hybrid density functional theory (B3LYP) with LANL2DZ basis sets. For the ground-state structures of MgnNi2 clusters, the stabilities and the electronic properties are investigated. The results show that the groundstate structures and symmetries of Mg clusters change greatly due to the Ni atoms. The average binding energies have a growing tendency while the energy gaps have a declining tendency. In addition, the ionization energies exhibit an odd-even oscillation feature. We also conclude that n = 3, 5 are the magic numbers of the MgnNi2 clusters. The Mg3Ni2 and Mg5Ni2 clusters are more stable than neighbouring clusters, and the MgaNi2 cluster exhibits a higher chemical activity.展开更多
Density functional theory calculations have been performed to study the interaction of small silver clusters, Ag2-Ag9, with HCN. The adsorption of HCN on-top site of the silver cluster, among various possible sites, i...Density functional theory calculations have been performed to study the interaction of small silver clusters, Ag2-Ag9, with HCN. The adsorption of HCN on-top site of the silver cluster, among various possible sites, is energetically preferred. The adsorption energies of HCN on the silver clusters reach a local maximum at n = 4, which is only about 0.450 eV, indicating that the adsorbed HCN molecule is weakly perturbed. The adsorbed C-N and C-H stretching frequencies are blue- and red-shifted compared with the values of free HCN, respectively.展开更多
The electronic and physical properties of PtmPdn (m+n≤5) metal clusters and their interactions with dioxygen have been studied by using hybrid density functional B3LYP method. The total energies, atomization energ...The electronic and physical properties of PtmPdn (m+n≤5) metal clusters and their interactions with dioxygen have been studied by using hybrid density functional B3LYP method. The total energies, atomization energies, vibration frequencies, and charge distributions were reported. The Pt-Pt bridge site modified by Pd atoms was found to be the most active site for the dissociation of dioxygen, which was mainly due to the change of electronic structures of the Pt atoms in bimetallic Pt-Pd clusters.展开更多
Structural and electronic properties of bimetallic clusters AlnCom with n=1~7 and m=1~2 have been investigated using the B3LYP-DFT method.Structural optimization and frequency analysis were performed at the CEP-121G...Structural and electronic properties of bimetallic clusters AlnCom with n=1~7 and m=1~2 have been investigated using the B3LYP-DFT method.Structural optimization and frequency analysis were performed at the CEP-121G level.The charge-induced structural changes in these anions were discussed.In addition,the corresponding total energies,binding energies,adiabatic electron affinities and vertical electron affinity were also presented and discussed.Our predicted vertical ionization potentials are in reasonable agreement with the experimental ionization potentials.Among different AlnCom and AlnCom-anions (n=1~7,m=1~2),Al4Co,Al6Co,Al4Co-,Al6Co-and Al4Co2-are predicted to be species with high stabilities.展开更多
Entropic contribution to the interaction parameter (?) in the model incompressible polymer/oligomer system iscalculated by the lattice cluster theory(LCT).It is found that in the oligomer solvent,there exists a wide c...Entropic contribution to the interaction parameter (?) in the model incompressible polymer/oligomer system iscalculated by the lattice cluster theory(LCT).It is found that in the oligomer solvent,there exists a wide concentration rangethat the non-combinatorial“entropic interaction”term (?)φ_1φ_2 perceptibly counteracts the mean field combinary entropy△S_(MF).With the increase of the solvent size,both (?) and the ratio (?)φ_1φ_2/△S_(MF) first reach their maximum and finallybecome trivially to zero.It is worth noting that no any demixing was found in the current calculation.This makes thecontroversial idea“entropically driven demixing”even elusive.However,we propose that further work on compressiblepolymer solution with structured monomer will witness the demixing owning to an increased configurational correlation.展开更多
The geometries, electronic structures and related properties of SimN8-m(0 〈 m 〈 8) clusters are studied using density functional theory (DFT) with hybrid functional B3LYP. The calculated results reveal several t...The geometries, electronic structures and related properties of SimN8-m(0 〈 m 〈 8) clusters are studied using density functional theory (DFT) with hybrid functional B3LYP. The calculated results reveal several trends. For any stoichiometric clusters, the lowest energy isomers with an alteration of N and Si atoms are favourable in energy if the numbers of Si and N atoms are large enough to form ... Si N-Si-N... alternative chains. The bond lengths of single Si-N bonds are very close to the corresponding values of the bulk and other SiN clusters. The geometries for N-rich and Si4N4 clusters are planar structures, but three-dimensional structures are favourable in energy for Si-rich clusters. With the increase of m, the isotropic polarizability and average polarizability increase, the total binding energies generally decrease, the HOMO-LUMO gap and vertical ionization potential oscillate with increasing number of valence electrons, and their values with even valence electrons are larger than those with odd valence electrons. The atomic charges, IR and Raman properties are also reported.展开更多
A theoretical study was carried out on the adsorption of hydrocyanic acid on small Aun (n ≤ 7) clusters using density functional methods. For HCN adsorption on gold clusters, no dependence was found with respect to...A theoretical study was carried out on the adsorption of hydrocyanic acid on small Aun (n ≤ 7) clusters using density functional methods. For HCN adsorption on gold clusters, no dependence was found with respect to the even-odd alternation in relation to the number of gold atoms in the cluster. The HCN molecule is adsorbed at simple adsorption sites (1-fold coordination), perpendicular to the adsorption site. The largest adsorption energy is only about 74.61 kJ·mol^-1, which indicates that the HCN molecule does not decompose and the C-N bond retains triple bond, and that the C-H and C-N stretching frequencies are only weakly perturbed. The adsorbed C-N and C-H stretching frequencies are blue- and red-shifted compared with the values of free HCN, respectively.展开更多
The geometry and electronic topology properties of Mg/Al hydrotalcite cluster models were comparatively investigated by means of density functional theory at GGA/DND levels.The results suggested that cluster model con...The geometry and electronic topology properties of Mg/Al hydrotalcite cluster models were comparatively investigated by means of density functional theory at GGA/DND levels.The results suggested that cluster model containing seven octahedral cations was the smallest size to be employed to simulate other properties.The fact that the n+ charge of cluster models containing n aluminum atoms can reflect electronic properties of anionic clay layer sheet.The bond lengths of clusters can be modified by terminating with or without OH-/H2O groups in terms of principle of bond order conservation.展开更多
This paper investigates the geometrical structures and relative stabilities of neutral A1Sn (n=2-9) using the density functional theory. Structural optimisation and frequency analysis are performed at the B3LYP/6-3...This paper investigates the geometrical structures and relative stabilities of neutral A1Sn (n=2-9) using the density functional theory. Structural optimisation and frequency analysis are performed at the B3LYP/6-311C(d) level. The ground state structures of the A1Sn show that the sulfur atoms prefer not only to evenly distribute on both sides of the aluminum atom but also to form stable structures in AlSn clusters. The structures of pure Sn are fundamentally changed due to the doping of the Al atom. The fragmentation energies and the second-order energy differences are calculated and discussed. Among neutral AlSn (n = 2-9) clusters, AlS4 and AlS6 are the most stable.展开更多
In this work, a systematic study of some possible isomer structures of the Cu5 cluster obtained from density functional theory methods is presented. The polarisation and pseudopotential basis sets are employed in the ...In this work, a systematic study of some possible isomer structures of the Cu5 cluster obtained from density functional theory methods is presented. The polarisation and pseudopotential basis sets are employed in the calculations. The results show that the binding energies, frequencies, coordination numbers and average bond lengths are in reasonable agreement with reported experimental data. Moreover, four isomers of the Cu5 cluster are obtained according to calculations, in which the most stable configuration is the planar structure. Meanwhile, two three-dimensional structures of the Cu5 cluster are obtained in this work, which might be valuable for further theoretical and experimental studies. In addition, our study proves the possibility of the isomer structures of the Cu5 cluster.展开更多
This paper investigates the lowest-energy structures, stabilities and electronic properties of (BAs)n clusters (n=1- 14) by means of the density-functional theory. The results show that the lowest-energy structure...This paper investigates the lowest-energy structures, stabilities and electronic properties of (BAs)n clusters (n=1- 14) by means of the density-functional theory. The results show that the lowest-energy structures undergo a structural change from two-dimensional to three-dimensional when n : 4. With the increase of the cluster size (n=6), the (BAs)n clusters tend to adopt cage-like structures, which can be considered as being built from B2As2 and six-membered rings with B-As bond alternative arrangement. The binding energy per atom, second-order energy differences, vertical electron affinity and vertical ionization potential are calculated and discussed. The caculated HOMO-LUMO gaps reveal that the clusters have typical semiconductor characteristics. The analysis of partial density of states suggests that there are strong covalence and molecular characteristics in the clusters.展开更多
This paper studies supersonic jet-cooled 1-fluoronaphthalene (1FN) clusters by ultraviolet (UV) laser ionization at 281 nm in a time-of-flight mass spectrometer. The (1FN)+ (n=1-3) series cluster ions are obs...This paper studies supersonic jet-cooled 1-fluoronaphthalene (1FN) clusters by ultraviolet (UV) laser ionization at 281 nm in a time-of-flight mass spectrometer. The (1FN)+ (n=1-3) series cluster ions are observed where the signal intensity decreases with increasing cluster size. The effects of sample inlet pressures and ionization laser fluxes to mass spectral distribution are measured. Using density functional theory calculations, it obtains a planar geometric structure of 1FN dimer which is combined through two hydrogen bonds. The mass spectra indicate that the intensity of 1FN trimer is much weaker than that of 1FN dimer and this feature is attributed to the fact that the dimer may form the first "shell" in geometric structure while the larger clusters are generated based on this fundamental unit.展开更多
The possible geometrical and the electronic structures of small MgnNi (n = 1 - 7) clusters are optimised by the density functional theory with a LANL2DZ basis set. The binding energy, the energy gap, the electron af...The possible geometrical and the electronic structures of small MgnNi (n = 1 - 7) clusters are optimised by the density functional theory with a LANL2DZ basis set. The binding energy, the energy gap, the electron affinity, the dissociation energy and the second difference in energy are calculated and discussed. The properties of MgnNi clusters are also discussed when the number of Mg atom increases.展开更多
The equilibrium geometries, relative stabilities, and electronic properties of MnAgm(M=Na, Li; n + m ≤ 7) as well as pure Agn, Nan, Lin (n ≤ 7) clusters are systematically investigated by means of the density f...The equilibrium geometries, relative stabilities, and electronic properties of MnAgm(M=Na, Li; n + m ≤ 7) as well as pure Agn, Nan, Lin (n ≤ 7) clusters are systematically investigated by means of the density functional theory. The optimized geometries reveal that for 2 ≤ n ≤ 7, there are significant similarities in geometry among pure Agn, Nan, and Lin clusters, and the transitions from planar to three-dimensional configurations occur at n = 7, 7, and 6, respectively. In contrast, the first three-dimensional (3D) structures are observed at n + m = 5 for both NanAgm and LinAgm clusters. When n + m ≥5, a striking feature is that the trigonal bipyramid becomes the main subunit of LinAgm. Furthermore, dramatic odd-even alternative behaviours are obtained in the fragmentation energies, secondorder difference energies, highest occupied and lowest unoccupied molecular orbital energy gaps, and chemical hardness for both pure and doped clusters. The analytic results exhibit that clusters with an even electronic configuration (2, 4, 6) possess the weakest chemical reactivity and more enhanced stability.展开更多
基金Supported by the National Natural Science Foundation of China under Grant No. 10774108the Foundation for University Key Young Teacher of Henan Province under Grant No. 2009GGJS-163
文摘A scheme for controlled teleportation of an arbitrary two-particle state using a maximally entangled EPR pair and a cluster state as the quantum channel is proposed. After receiving Alice's Bell state measurement results, the controller performs a joint measurement on his particles under a non-maximally entangled Bell-basis. The receiver needs to introduce an auxiliary qubit, and performs a series of appropriate unitary transformations on his particles. The original state can be teleported successfully with the probability 2 cos2θ.
文摘We study the geometries, stabilities, electronic and magnetic properties of (MgO)n (n=2-10) clusters doped with a single Mn atom using the density functional theory with the gener- alized gradient approximation. The optimized geometries show that the impurity Mn atom prefers to replace the Mg atom which has low coordination number in all the lowest-energy MnMgn-1On (n=2-10) structures. The stability analysis clearly represents that the average binding energies of the doped clusters are larger than those of the corresponding pure (MgO)n clusters. Maximum peaks of the second order energy differences are observed for MnMg~_1On clusters at n=6, 9, implying that these clusters exhibit higher stability than their neighboring clusters. In addition, all the Mn-doped Mg clusters exhibit high total magnetic moments with the exception of MnMgO2 which has 3.00μB. Their magnetic behavior is attributed to the impurity Mn atom, the charge transfer modes, and the size of MnMgn- 1On clusters.
基金Funded by the Western Communication Construction Science and Technology Item (SN: 200631822302-08)
文摘Concrete specimens made with ordinary portland cement or ordinary portland cement incorporating fly ash with the replacement of 10% or 20%, ground blast furnace slag with the replacement of 15% or 30%, or 15% fly ash and 15% ground blast furnace slag were made and exposed to a cyclic sulfate environment. Concrete properties including relative dynamic elastic modulus, chloride ion diffusion coefficient, compressive strength and flexural strength were measured. Effect of mineral admixtures on the cyclic sulfate resistance of concrete was assessed based on the grey clustering theory. The experimental results indicate that the cyclic sulfate resistance of concrete incorporating ground blast furnace slag belongs to the higher grey grade, which exhibits that it possesses excellent cyclic sulfate resistance. With increasing addition of fly ash, the cyclic sulfate resistance of concrete changes from the medium grey grade to the lower grey grade, which shows that incorporation of fly ash is disadvantageous for the cyclic sulfate resistance of concrete.
文摘This paper proposes a clustering technique that minimizes the need for subjective human intervention and is based on elements of rough set theory (RST). The proposed algorithm is unified in its approach to clustering and makes use of both local and global data properties to obtain clustering solutions. It handles single-type and mixed attribute data sets with ease. The results from three data sets of single and mixed attribute types are used to illustrate the technique and establish its efficiency.
基金Project supported by the National Natural Science Foundation of China (Grant No. 10676022)
文摘The geometries of MgnNi2(n = 1 6) clusters are studied by using the hybrid density functional theory (B3LYP) with LANL2DZ basis sets. For the ground-state structures of MgnNi2 clusters, the stabilities and the electronic properties are investigated. The results show that the groundstate structures and symmetries of Mg clusters change greatly due to the Ni atoms. The average binding energies have a growing tendency while the energy gaps have a declining tendency. In addition, the ionization energies exhibit an odd-even oscillation feature. We also conclude that n = 3, 5 are the magic numbers of the MgnNi2 clusters. The Mg3Ni2 and Mg5Ni2 clusters are more stable than neighbouring clusters, and the MgaNi2 cluster exhibits a higher chemical activity.
基金supported by the National Natural Science Foundation of China(21203027,21073035,21373048)Funds of Fujian Province(2012J01032,2012J01041)Fuzhou University(2012-XQ-11)
文摘Density functional theory calculations have been performed to study the interaction of small silver clusters, Ag2-Ag9, with HCN. The adsorption of HCN on-top site of the silver cluster, among various possible sites, is energetically preferred. The adsorption energies of HCN on the silver clusters reach a local maximum at n = 4, which is only about 0.450 eV, indicating that the adsorbed HCN molecule is weakly perturbed. The adsorbed C-N and C-H stretching frequencies are blue- and red-shifted compared with the values of free HCN, respectively.
基金This work was partly supported by Innovation Foundation of the Chinese Academy of Sciences (K2003D2), National Natural Science Foundation of China (No. 20173060), Hi-tech Research and Development Program of China (2003AA517040) and Knowledge Innovation Program of the Chinese Academy of Sciences (KGCX2-SW-310)
文摘The electronic and physical properties of PtmPdn (m+n≤5) metal clusters and their interactions with dioxygen have been studied by using hybrid density functional B3LYP method. The total energies, atomization energies, vibration frequencies, and charge distributions were reported. The Pt-Pt bridge site modified by Pd atoms was found to be the most active site for the dissociation of dioxygen, which was mainly due to the change of electronic structures of the Pt atoms in bimetallic Pt-Pd clusters.
基金supported by the National Natural Science Foundation of China (20603021)Youth Foundation of Shanxi Province (2007021009)
文摘Structural and electronic properties of bimetallic clusters AlnCom with n=1~7 and m=1~2 have been investigated using the B3LYP-DFT method.Structural optimization and frequency analysis were performed at the CEP-121G level.The charge-induced structural changes in these anions were discussed.In addition,the corresponding total energies,binding energies,adiabatic electron affinities and vertical electron affinity were also presented and discussed.Our predicted vertical ionization potentials are in reasonable agreement with the experimental ionization potentials.Among different AlnCom and AlnCom-anions (n=1~7,m=1~2),Al4Co,Al6Co,Al4Co-,Al6Co-and Al4Co2-are predicted to be species with high stabilities.
基金This work was support by the National Natural Science Foundation of China(NSFC,No.2037402790103036).
文摘Entropic contribution to the interaction parameter (?) in the model incompressible polymer/oligomer system iscalculated by the lattice cluster theory(LCT).It is found that in the oligomer solvent,there exists a wide concentration rangethat the non-combinatorial“entropic interaction”term (?)φ_1φ_2 perceptibly counteracts the mean field combinary entropy△S_(MF).With the increase of the solvent size,both (?) and the ratio (?)φ_1φ_2/△S_(MF) first reach their maximum and finallybecome trivially to zero.It is worth noting that no any demixing was found in the current calculation.This makes thecontroversial idea“entropically driven demixing”even elusive.However,we propose that further work on compressiblepolymer solution with structured monomer will witness the demixing owning to an increased configurational correlation.
基金supported by the National Natural Science Foundation of China (Grant Nos 10647006 and 10547007)the Natural Science Foundation of Gansu Province of China (Grant No 3ZS042-B25-023)the Prominent Youth Foundation (Grant No Q200704) of LUT and the Scientific Developmental Foundation of LUT
文摘The geometries, electronic structures and related properties of SimN8-m(0 〈 m 〈 8) clusters are studied using density functional theory (DFT) with hybrid functional B3LYP. The calculated results reveal several trends. For any stoichiometric clusters, the lowest energy isomers with an alteration of N and Si atoms are favourable in energy if the numbers of Si and N atoms are large enough to form ... Si N-Si-N... alternative chains. The bond lengths of single Si-N bonds are very close to the corresponding values of the bulk and other SiN clusters. The geometries for N-rich and Si4N4 clusters are planar structures, but three-dimensional structures are favourable in energy for Si-rich clusters. With the increase of m, the isotropic polarizability and average polarizability increase, the total binding energies generally decrease, the HOMO-LUMO gap and vertical ionization potential oscillate with increasing number of valence electrons, and their values with even valence electrons are larger than those with odd valence electrons. The atomic charges, IR and Raman properties are also reported.
基金Supported by the NNSFC (20673019, 20773024)the funds of Fuzhou University (2008-XQ-07, XRC-0732)
文摘A theoretical study was carried out on the adsorption of hydrocyanic acid on small Aun (n ≤ 7) clusters using density functional methods. For HCN adsorption on gold clusters, no dependence was found with respect to the even-odd alternation in relation to the number of gold atoms in the cluster. The HCN molecule is adsorbed at simple adsorption sites (1-fold coordination), perpendicular to the adsorption site. The largest adsorption energy is only about 74.61 kJ·mol^-1, which indicates that the HCN molecule does not decompose and the C-N bond retains triple bond, and that the C-H and C-N stretching frequencies are only weakly perturbed. The adsorbed C-N and C-H stretching frequencies are blue- and red-shifted compared with the values of free HCN, respectively.
基金supported by China University of Petroleum (East China) (grant 09CX04045A)
文摘The geometry and electronic topology properties of Mg/Al hydrotalcite cluster models were comparatively investigated by means of density functional theory at GGA/DND levels.The results suggested that cluster model containing seven octahedral cations was the smallest size to be employed to simulate other properties.The fact that the n+ charge of cluster models containing n aluminum atoms can reflect electronic properties of anionic clay layer sheet.The bond lengths of clusters can be modified by terminating with or without OH-/H2O groups in terms of principle of bond order conservation.
基金supported by the National Natural Science Foundation of China (Grant Nos. 10647008 and 50971099)the Research Fund for the Higher Education Doctoral Program (Grant No. 20096101110017)+1 种基金Key Project of Natural Science Foundation of Shaanxi Province of China (Grant No. 2010JZ002)the Graduate Innovation Fund of the Northwest University of China(Grant No. 09YZZ44)
文摘This paper investigates the geometrical structures and relative stabilities of neutral A1Sn (n=2-9) using the density functional theory. Structural optimisation and frequency analysis are performed at the B3LYP/6-311C(d) level. The ground state structures of the A1Sn show that the sulfur atoms prefer not only to evenly distribute on both sides of the aluminum atom but also to form stable structures in AlSn clusters. The structures of pure Sn are fundamentally changed due to the doping of the Al atom. The fragmentation energies and the second-order energy differences are calculated and discussed. Among neutral AlSn (n = 2-9) clusters, AlS4 and AlS6 are the most stable.
基金supported by the National Natural Science Foundation of China (Grant No. 10375028)
文摘In this work, a systematic study of some possible isomer structures of the Cu5 cluster obtained from density functional theory methods is presented. The polarisation and pseudopotential basis sets are employed in the calculations. The results show that the binding energies, frequencies, coordination numbers and average bond lengths are in reasonable agreement with reported experimental data. Moreover, four isomers of the Cu5 cluster are obtained according to calculations, in which the most stable configuration is the planar structure. Meanwhile, two three-dimensional structures of the Cu5 cluster are obtained in this work, which might be valuable for further theoretical and experimental studies. In addition, our study proves the possibility of the isomer structures of the Cu5 cluster.
基金supported by the National Natural Science Foundation of China (Grant No. 10964012)the Priority Subject Program for Theoretical Physics of Xinjiang Normal University and the Fund of the Education Department of Xinjiang Uygur Autonomous Region of China (Grant No. xjedu2009i27)the Science and Technology Innovation Foundation for Graduate Students of Xinjiang Normal University (Grant No. 20101205)
文摘This paper investigates the lowest-energy structures, stabilities and electronic properties of (BAs)n clusters (n=1- 14) by means of the density-functional theory. The results show that the lowest-energy structures undergo a structural change from two-dimensional to three-dimensional when n : 4. With the increase of the cluster size (n=6), the (BAs)n clusters tend to adopt cage-like structures, which can be considered as being built from B2As2 and six-membered rings with B-As bond alternative arrangement. The binding energy per atom, second-order energy differences, vertical electron affinity and vertical ionization potential are calculated and discussed. The caculated HOMO-LUMO gaps reveal that the clusters have typical semiconductor characteristics. The analysis of partial density of states suggests that there are strong covalence and molecular characteristics in the clusters.
文摘This paper studies supersonic jet-cooled 1-fluoronaphthalene (1FN) clusters by ultraviolet (UV) laser ionization at 281 nm in a time-of-flight mass spectrometer. The (1FN)+ (n=1-3) series cluster ions are observed where the signal intensity decreases with increasing cluster size. The effects of sample inlet pressures and ionization laser fluxes to mass spectral distribution are measured. Using density functional theory calculations, it obtains a planar geometric structure of 1FN dimer which is combined through two hydrogen bonds. The mass spectra indicate that the intensity of 1FN trimer is much weaker than that of 1FN dimer and this feature is attributed to the fact that the dimer may form the first "shell" in geometric structure while the larger clusters are generated based on this fundamental unit.
基金Project supported by the National Natural Science Foundation of China (Grant No. 10676022)
文摘The possible geometrical and the electronic structures of small MgnNi (n = 1 - 7) clusters are optimised by the density functional theory with a LANL2DZ basis set. The binding energy, the energy gap, the electron affinity, the dissociation energy and the second difference in energy are calculated and discussed. The properties of MgnNi clusters are also discussed when the number of Mg atom increases.
基金Project supported by the Doctoral Education Fund of the Education Ministry of Chain (Grant No. 20100181110086) and the National Natural Science Foundation of China (Grant Nos. 11104190 and 10974138).
文摘The equilibrium geometries, relative stabilities, and electronic properties of MnAgm(M=Na, Li; n + m ≤ 7) as well as pure Agn, Nan, Lin (n ≤ 7) clusters are systematically investigated by means of the density functional theory. The optimized geometries reveal that for 2 ≤ n ≤ 7, there are significant similarities in geometry among pure Agn, Nan, and Lin clusters, and the transitions from planar to three-dimensional configurations occur at n = 7, 7, and 6, respectively. In contrast, the first three-dimensional (3D) structures are observed at n + m = 5 for both NanAgm and LinAgm clusters. When n + m ≥5, a striking feature is that the trigonal bipyramid becomes the main subunit of LinAgm. Furthermore, dramatic odd-even alternative behaviours are obtained in the fragmentation energies, secondorder difference energies, highest occupied and lowest unoccupied molecular orbital energy gaps, and chemical hardness for both pure and doped clusters. The analytic results exhibit that clusters with an even electronic configuration (2, 4, 6) possess the weakest chemical reactivity and more enhanced stability.