Zr-based amorphous alloys have attracted extensive attention because of their large glassy formation ability, wide supercooled liquid region, high elasticity, and unique mechanical strength induced by their icosahedra...Zr-based amorphous alloys have attracted extensive attention because of their large glassy formation ability, wide supercooled liquid region, high elasticity, and unique mechanical strength induced by their icosahedral local structures.To determine the microstructures of Zr–Cu clusters, the stable and metastable geometry of Zr_(n)Cu(n=2–12) clusters are screened out via the CALYPSO method using machine-learning potentials, and then the electronic structures are investigated using density functional theory. The results show that the Zr_(n)Cu(n ≥ 3) clusters possess three-dimensional geometries, Zr_(n)Cu(n≥9) possess cage-like geometries, and the Zr_(12)Cu cluster has icosahedral geometry. The binding energy per atom gradually gets enlarged with the increase in the size of the clusters, and Zr_(n)Cu(n=5,7,9,12) have relatively better stability than their neighbors. The magnetic moment of most Zr_(n)Cu clusters is just 1μB, and the main components of the highest occupied molecular orbitals(HOMOs) in the Zr_(12)Cu cluster come from the Zr-d state. There are hardly any localized two-center bonds, and there are about 20 σ-type delocalized three-center bonds.展开更多
Hydrogen,with the merits of zero emissions and high energy density,is one of the promising green energy sources.Seeking for high efficiency and low-cost catalysts is one of the key issues for hydrogen evolution and it...Hydrogen,with the merits of zero emissions and high energy density,is one of the promising green energy sources.Seeking for high efficiency and low-cost catalysts is one of the key issues for hydrogen evolution and its practical applications.Nano-structured metal cocatalysts are widely used to improve the photocatalytic performance via surface electronic structure/properties optimization of the catalyst.Herein,we report ultra-fine(*1 nm)Cu clusters decorated hydrangea-like TiO_(2)systems for photocatalytic hydrogen evolution.The pristine hydrangea-like TiO_(2)support shows a promising performance of hydrogen evolution(1.8 mmol·h^(-1)·g^(-1)),which is*10.7 times higher than that of the commercial P25(168 lmol·h^(-1)·g^(-1)).After ultra-fine Cu clusters decoration,a maximal hydrogen evolution performance(3.7 mmol·h^(-1)·g^(-1))is achieved in the optimized system 6Cu–TiO_(2)(6 wt%).Experimental and theoretical studies demonstrate that the ultra-fine Cu clusters decoration could promote the charge separation and transfer process effectively.The Cu clusters also act as reaction sites for reduction of H_(2)O to H2.These results are of great importance for the study of Cu-based co-catalyst systems and also shed light on the development of other non-noble metal co-catalysts in photocatalysis hydrogen evolution.展开更多
Using density functional theory with generalized gradient approximation and hybrid functional, we studied the properties of energy, charge population, and vibration of CH2 and CH3 adsorbed on Cun （n=1-6） clusters. T...Using density functional theory with generalized gradient approximation and hybrid functional, we studied the properties of energy, charge population, and vibration of CH2 and CH3 adsorbed on Cun （n=1-6） clusters. The results show that the DFT calculation with the hybrid functional matches the experimental results better in both cases. The calculation results indicate that the adsorption of CH2 is stronger than that of CH3. During adsorption, the charges transfer from Cu to CH2 or CH3. The obtained vibrational frequencies for different modes of CH2 and CH3 adsorbed on Cun agree well with the experimental results for the adsorption on Cu（111） surface.展开更多
Metal-doped carbon materials, as one of the most important electrocatalytic catalysts for CO_(2)reduction reaction(CO_(2)RR), have attracted increasing attention. Herein, a series of Cu cluster embedded highly porous ...Metal-doped carbon materials, as one of the most important electrocatalytic catalysts for CO_(2)reduction reaction(CO_(2)RR), have attracted increasing attention. Herein, a series of Cu cluster embedded highly porous nanofibers have been prepared through the carbonization of electro-spun MOF/PAN nanofibers.The obtained Cu cluster doped porous nanofibers possessed fibrous morphology, high porosity, conductivity, and uniformly dispersed Cu clusters, which could be applied as promising CO_(2)RR catalysts. Specifically, best of them, MCP-500 exhibited high catalytic performance for CO_(2)RR, in which the Faradaic efficiency of CO(FECO) was as high as 98% at-0.8 V and maintained above 95% after 10 h continuous electrocatalysis. The high performance might be attributed to the synergistic effect of tremendously layered graphene skeleton and uniformly dispersed Cu clusters that could largely promote the electron conductivity, mass transfer and catalytic activity during the electrocatalytic CO_(2)RR process. This attempt will provide a new idea to design highly active CO_(2)RR electrocatalyst.展开更多
The properties of C-H vibration softening for CH2 and CHa radicals absorbed on Cun（n=1-6） clusters have been investigated, using the density functional theory with hybrid functional. The results indicate that the ab...The properties of C-H vibration softening for CH2 and CHa radicals absorbed on Cun（n=1-6） clusters have been investigated, using the density functional theory with hybrid functional. The results indicate that the absorption of CH2 on Cu clusters is stronger than the case of CH3. The vibrational frequencies of C-H bonding agree with the experimental results obtained for CH2 and CH3 absorbed on Cu（111）. With the increase of cluster size, the softening （Einstein shift） of C-H vibrational modes become stronger.展开更多
The possible stable geometrical configurations and the relative stabilities of the lowest-lying isomers of copperdoped gold clusters, AunCu （n = 1-7）, are investigated using the density functional theory. Several lo...The possible stable geometrical configurations and the relative stabilities of the lowest-lying isomers of copperdoped gold clusters, AunCu （n = 1-7）, are investigated using the density functional theory. Several low-lying isomers are determined. The results indicate that the ground-state AunCu clusters have planar structures for n = 1-7. The stability trend of the AunCu clusters （n = 1-7）, shows that odd-numbered AunCu clusters are more stable than the neighbouring even-numbered ones, thereby indicating the AusCu clusters are magic cluster with high chemical stability.展开更多
Using the meta-generalized gradient approximation （meta-GGA） exchange correlation TPSS functional, the geo-metric structures, the relative stabilities, and the electronic properties of bimetallic AgnX （X=Au, Cu; n=...Using the meta-generalized gradient approximation （meta-GGA） exchange correlation TPSS functional, the geo-metric structures, the relative stabilities, and the electronic properties of bimetallic AgnX （X=Au, Cu; n=1-8） clusters are systematically investigated and compared with those of pure silver clusters. The optimized structures show that the transition point from preferentially planar to three-dimensional structure occurs at n = 6 for the AgnAu clusters, and at n = 5 for AgnCu clusters. For different-sized AgnX clusters, one X （X=Au or Cu） atom substituted Agn＋l structure is a dominant growth pattern. The calculated fragmentation energies, second-order differences in energies, and the highest occupied molecular orbital-lowest unoccupied molecular orbital （HOMO LUMO） energy gaps show interesting odd-even oscillation behaviours, indicating that Ag2,4,6,s and Agl,3,5,7X （X=Au, Cu） clusters keep high stabilities in comparison with their neighbouring clusters. The natural population analysis reveals that the charges transfer from the Agn host to the impurity atom except for the Ag2Cu cluster. Moreover, vertical ionization potential （VIP）, vertical electronic affinity （VEA）, and chemical hardness （η） are discussed and compared in depth. The same odd even oscillations are found for the VIP and η of the AgnX （X=Au, Cu; n=1-8） clusters.展开更多
The self-assembly reactions of [MOS3]^2- （M = W, Mo） with CuS2COCH3 in DMF produced two novel dodecanuclear Mo（W）/Cu/S heterometallic clusters, [Et4N]4[{MOS3}3Cu6S2- （CuS2COCH3）3]·H2O （1： M = W; 2： M = M...The self-assembly reactions of [MOS3]^2- （M = W, Mo） with CuS2COCH3 in DMF produced two novel dodecanuclear Mo（W）/Cu/S heterometallic clusters, [Et4N]4[{MOS3}3Cu6S2- （CuS2COCH3）3]·H2O （1： M = W; 2： M = Mo）. Cluster 1 crystallizes in hexagonal, space group P-62c with a = 16.5612（3）, b = 16.5612（3）, c = 16.4660（5）A, Z = 2, V = 3911.13（16）A^3, Dc = 1.935 g/cm^3, μ（MoKα） = 7.269 mm^-1, F（000） = 2192, the final R = 0.0289 and wR = 0.0789 for 2425 observed reflections （I 〉 2σ（I））. Cluster 2 is isomorphous to 1 with similar crystal parameters. X-ray analysis reveals that both clusters consist of three incomplete cubane-like cluster units {MOS3Cu3S2COCH3}, which are linked together by two μ3-S atoms.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
An unusual 3D porous network assembled by tridentate ligand Tbmiz [1,3,5- tris（benzimidazol-1-ylmethyl）-2,4,6-trimethylbenzene] and Cu-I cluster was synthesized by means of hydrothermal process. It crystallizes in t...An unusual 3D porous network assembled by tridentate ligand Tbmiz [1,3,5- tris（benzimidazol-1-ylmethyl）-2,4,6-trimethylbenzene] and Cu-I cluster was synthesized by means of hydrothermal process. It crystallizes in the trigonal system, space group P-3c1 with a = 14.2362（8）, b = 14.2362（8）, c = 36.4017（35）A, γ = 120.00°, V = 6389.1（8）, Dc = 1.976 g/cm^3, Z = 2, μ（MoKα） = 0.71073 and F（000） = 3692.0. Of the 40832 total reflections, 3948 were unique （Rint = 0.0366）. The final R = 0.0460 and wR = 0.1335 for 3948 observed reflections with I 〉 2σ（I）.展开更多
The polymeric chalcogenide [W2O2S6Cu4(NCMe)4]n (compound 1) was synthesized by the self-assembly reaction of (NH4)2(WOS3) with CuBr in MeCN in the presence of tricyclohexylphosphane (PCy3) under a purified nitrogen at...The polymeric chalcogenide [W2O2S6Cu4(NCMe)4]n (compound 1) was synthesized by the self-assembly reaction of (NH4)2(WOS3) with CuBr in MeCN in the presence of tricyclohexylphosphane (PCy3) under a purified nitrogen atmosphere using standard Schlenk techniques. It gives rise to a novel 1D polymeric compound 1 with solvent MeCN coordinated to the copper atom. This situation is unprecedented in the W(Mo)/Cu/S system. The crystals were characterized by elemental analysis, IR and single-crystal X-ray crystallography. The configuration of the polymeric compound can be viewed as a helical chain which is propagated along the crystallographic c axis. The excited state absorption and refraction of compound 1 in CH3CN solution were studied by using the Z-scan technique with laser pulses of 40 ps pulse-width at a wavelength of 532 nm. The polymeric compound possesses an optical self-focusing performance. The positive nonlinear refraction is attributed to population transitions between singlet states. Compound 1 displays a strong excited-state absorption.展开更多
In this paper, the total energies and the density of the states of triatomic systems of Cu. Ag. and An were calculated by discret-variational Xa method. Furthermore, the optimized geometry of triatomic copper,silver, ...In this paper, the total energies and the density of the states of triatomic systems of Cu. Ag. and An were calculated by discret-variational Xa method. Furthermore, the optimized geometry of triatomic copper,silver, and gold clusters were obtained. The results showed that the optimaaed geometry of Cu3 was different from that of Ag3. and An3. Cu3 cluster has two nearlydegenerate candidates for the ground state. Ag3 and Au3 clusters have bent isosceles triangular structure only. The ground configuration for the triatomic clusters is and the ground state is 2B2. The present evidences arc in agreement results with the experimental and with those by other complex theoretical method.展开更多
In the previous paper,the geometry of the triatomic clusters for Cu, Ag,and An was obtained using the Dy-Xa method. In this investigation the atomic. orbital interactions of atom Cu, Ag, An in the triatomic clusters a...In the previous paper,the geometry of the triatomic clusters for Cu, Ag,and An was obtained using the Dy-Xa method. In this investigation the atomic. orbital interactions of atom Cu, Ag, An in the triatomic clusters are analyzed. The magnitudes of the atomic orbital interactions of the atoms in the clusters are measured by the splitting of corresponding atomic orbital. The calculation results show the atomic orbital interactions of Cu triatomic cluster differ greatly from those of Ag and Au triatomic cluster house of the mixture radio of 4s-Orbital with 3d-Orbital in the Cu cluster more than those in the Ag and Au cluster. The values of atomic orbital interactions of Au in the of cluster are larger than corresponding atomic Orbital interactions of Ag in the cluster.展开更多
This paper presents the synthetic and structure studies of molybdenum（tungsten）-copper-sulphur-dialkyldithiocarbamate cluster compounds.The reactions of（M=Mo,W;n=0,2）,CuCl,and R<sub>2</sub>dtc￣-（R<...This paper presents the synthetic and structure studies of molybdenum（tungsten）-copper-sulphur-dialkyldithiocarbamate cluster compounds.The reactions of（M=Mo,W;n=0,2）,CuCl,and R<sub>2</sub>dtc￣-（R<sub>2</sub>=Me<sub>2</sub>,Et<sub>2</sub>,C<sub>4</sub>H<sub>8</sub>,C<sub>5</sub>H<sub>1</sub>0） yield a series of tetra-,hexa-,and heptanuclear cluster compounds.Their spectroscopic properties and the synthetic reaction mechanism are discussed.展开更多
The structures of Al 14 Cu 12 clusters were optimized by B3LYP method and the six geometries ground states were obtained. Al 71 Cu 29 alloy melt has been investigated using X ray diffractometry at 700 ℃. The experime...The structures of Al 14 Cu 12 clusters were optimized by B3LYP method and the six geometries ground states were obtained. Al 71 Cu 29 alloy melt has been investigated using X ray diffractometry at 700 ℃. The experimental data were compared with calculated results to find the relation between the structures of Al Cu clusters and melt structure. It is shown that there exists a strong interaction between Al and Cu atoms. The bond length in some geometries is very close to the experimental atomic distance. Such optimized geometries have close correlation with the liquid structure of Al Cu alloy.展开更多
基金Project supported by the National Natural Science Foundation of China (Grant Nos.11864040,11964037,and 11664038)。
文摘Zr-based amorphous alloys have attracted extensive attention because of their large glassy formation ability, wide supercooled liquid region, high elasticity, and unique mechanical strength induced by their icosahedral local structures.To determine the microstructures of Zr–Cu clusters, the stable and metastable geometry of Zr_(n)Cu(n=2–12) clusters are screened out via the CALYPSO method using machine-learning potentials, and then the electronic structures are investigated using density functional theory. The results show that the Zr_(n)Cu(n ≥ 3) clusters possess three-dimensional geometries, Zr_(n)Cu(n≥9) possess cage-like geometries, and the Zr_(12)Cu cluster has icosahedral geometry. The binding energy per atom gradually gets enlarged with the increase in the size of the clusters, and Zr_(n)Cu(n=5,7,9,12) have relatively better stability than their neighbors. The magnetic moment of most Zr_(n)Cu clusters is just 1μB, and the main components of the highest occupied molecular orbitals(HOMOs) in the Zr_(12)Cu cluster come from the Zr-d state. There are hardly any localized two-center bonds, and there are about 20 σ-type delocalized three-center bonds.
基金This work was financially supported by the National Natural Science Foundation of China(Nos.11874356,11904039,51772035 and 52071041)the Project for Fundamental and Frontier Research in Chongqing(Nos.cstc2019jcyjjqX0002 and cstc2020jcyj-msxmX0777)the Fundamental Research Funds for the Central Universities(No.106112016CDJZR308808).The work conducted at Chongqing Institute of Green and Intelligent Technology(Chinese Academy of Sciences)is also supported by Key Research Program of Frontier Sciences,CAS(No.QYZDB-SSWSLH016).
文摘Hydrogen,with the merits of zero emissions and high energy density,is one of the promising green energy sources.Seeking for high efficiency and low-cost catalysts is one of the key issues for hydrogen evolution and its practical applications.Nano-structured metal cocatalysts are widely used to improve the photocatalytic performance via surface electronic structure/properties optimization of the catalyst.Herein,we report ultra-fine(*1 nm)Cu clusters decorated hydrangea-like TiO_(2)systems for photocatalytic hydrogen evolution.The pristine hydrangea-like TiO_(2)support shows a promising performance of hydrogen evolution(1.8 mmol·h^(-1)·g^(-1)),which is*10.7 times higher than that of the commercial P25(168 lmol·h^(-1)·g^(-1)).After ultra-fine Cu clusters decoration,a maximal hydrogen evolution performance(3.7 mmol·h^(-1)·g^(-1))is achieved in the optimized system 6Cu–TiO_(2)(6 wt%).Experimental and theoretical studies demonstrate that the ultra-fine Cu clusters decoration could promote the charge separation and transfer process effectively.The Cu clusters also act as reaction sites for reduction of H_(2)O to H2.These results are of great importance for the study of Cu-based co-catalyst systems and also shed light on the development of other non-noble metal co-catalysts in photocatalysis hydrogen evolution.
基金This work was supported by the Chinese Academy of Engineering Physics （No.51480030105JW1301） and the National Natural Science Foundation of China （No.10534010, No.10374036, and No.10374037）.
文摘Using density functional theory with generalized gradient approximation and hybrid functional, we studied the properties of energy, charge population, and vibration of CH2 and CH3 adsorbed on Cun （n=1-6） clusters. The results show that the DFT calculation with the hybrid functional matches the experimental results better in both cases. The calculation results indicate that the adsorption of CH2 is stronger than that of CH3. During adsorption, the charges transfer from Cu to CH2 or CH3. The obtained vibrational frequencies for different modes of CH2 and CH3 adsorbed on Cun agree well with the experimental results for the adsorption on Cu（111） surface.
基金financially supported by the National Natural Science Foundation of China (Nos. 21471003, 21871141, 21871142,21701085 and 21901122)Natural Science Foundation of Educational Commission of Anhui Province of China (No. KJ2020A0240)+1 种基金the Natural Science Research of Jiangsu Higher Education Institutions of China (No. 19KJB150011)Project funded by China Postdoctoral Science Foundation (No. 2019M651873)。
文摘Metal-doped carbon materials, as one of the most important electrocatalytic catalysts for CO_(2)reduction reaction(CO_(2)RR), have attracted increasing attention. Herein, a series of Cu cluster embedded highly porous nanofibers have been prepared through the carbonization of electro-spun MOF/PAN nanofibers.The obtained Cu cluster doped porous nanofibers possessed fibrous morphology, high porosity, conductivity, and uniformly dispersed Cu clusters, which could be applied as promising CO_(2)RR catalysts. Specifically, best of them, MCP-500 exhibited high catalytic performance for CO_(2)RR, in which the Faradaic efficiency of CO(FECO) was as high as 98% at-0.8 V and maintained above 95% after 10 h continuous electrocatalysis. The high performance might be attributed to the synergistic effect of tremendously layered graphene skeleton and uniformly dispersed Cu clusters that could largely promote the electron conductivity, mass transfer and catalytic activity during the electrocatalytic CO_(2)RR process. This attempt will provide a new idea to design highly active CO_(2)RR electrocatalyst.
文摘The properties of C-H vibration softening for CH2 and CHa radicals absorbed on Cun（n=1-6） clusters have been investigated, using the density functional theory with hybrid functional. The results indicate that the absorption of CH2 on Cu clusters is stronger than the case of CH3. The vibrational frequencies of C-H bonding agree with the experimental results obtained for CH2 and CH3 absorbed on Cu（111）. With the increase of cluster size, the softening （Einstein shift） of C-H vibrational modes become stronger.
基金Project supported by the Foundation from the Education Commission of Sichuan Province,China (Grant No. 2006B042)
文摘The possible stable geometrical configurations and the relative stabilities of the lowest-lying isomers of copperdoped gold clusters, AunCu （n = 1-7）, are investigated using the density functional theory. Several low-lying isomers are determined. The results indicate that the ground-state AunCu clusters have planar structures for n = 1-7. The stability trend of the AunCu clusters （n = 1-7）, shows that odd-numbered AunCu clusters are more stable than the neighbouring even-numbered ones, thereby indicating the AusCu clusters are magic cluster with high chemical stability.
基金supported by the National Natural Science Foundation of China (Grant Nos. 10774103 and 10974138)
文摘Using the meta-generalized gradient approximation （meta-GGA） exchange correlation TPSS functional, the geo-metric structures, the relative stabilities, and the electronic properties of bimetallic AgnX （X=Au, Cu; n=1-8） clusters are systematically investigated and compared with those of pure silver clusters. The optimized structures show that the transition point from preferentially planar to three-dimensional structure occurs at n = 6 for the AgnAu clusters, and at n = 5 for AgnCu clusters. For different-sized AgnX clusters, one X （X=Au or Cu） atom substituted Agn＋l structure is a dominant growth pattern. The calculated fragmentation energies, second-order differences in energies, and the highest occupied molecular orbital-lowest unoccupied molecular orbital （HOMO LUMO） energy gaps show interesting odd-even oscillation behaviours, indicating that Ag2,4,6,s and Agl,3,5,7X （X=Au, Cu） clusters keep high stabilities in comparison with their neighbouring clusters. The natural population analysis reveals that the charges transfer from the Agn host to the impurity atom except for the Ag2Cu cluster. Moreover, vertical ionization potential （VIP）, vertical electronic affinity （VEA）, and chemical hardness （η） are discussed and compared in depth. The same odd even oscillations are found for the VIP and η of the AgnX （X=Au, Cu; n=1-8） clusters.
基金supported by CAS (SZD08002-2)973 Program (2007CB815306)+1 种基金the NNSFC (20733003 and 20673117)the Young Scientist’s Foundation of Fujian Province (2006F3136)
文摘The self-assembly reactions of [MOS3]^2- （M = W, Mo） with CuS2COCH3 in DMF produced two novel dodecanuclear Mo（W）/Cu/S heterometallic clusters, [Et4N]4[{MOS3}3Cu6S2- （CuS2COCH3）3]·H2O （1： M = W; 2： M = Mo）. Cluster 1 crystallizes in hexagonal, space group P-62c with a = 16.5612（3）, b = 16.5612（3）, c = 16.4660（5）A, Z = 2, V = 3911.13（16）A^3, Dc = 1.935 g/cm^3, μ（MoKα） = 7.269 mm^-1, F（000） = 2192, the final R = 0.0289 and wR = 0.0789 for 2425 observed reflections （I 〉 2σ（I））. Cluster 2 is isomorphous to 1 with similar crystal parameters. X-ray analysis reveals that both clusters consist of three incomplete cubane-like cluster units {MOS3Cu3S2COCH3}, which are linked together by two μ3-S atoms.
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 Young Talent Program of Fujian Province (No. 2007F3117)Natural Science Foundation of Fujian Province (No. 2007J0001)
文摘An unusual 3D porous network assembled by tridentate ligand Tbmiz [1,3,5- tris（benzimidazol-1-ylmethyl）-2,4,6-trimethylbenzene] and Cu-I cluster was synthesized by means of hydrothermal process. It crystallizes in the trigonal system, space group P-3c1 with a = 14.2362（8）, b = 14.2362（8）, c = 36.4017（35）A, γ = 120.00°, V = 6389.1（8）, Dc = 1.976 g/cm^3, Z = 2, μ（MoKα） = 0.71073 and F（000） = 3692.0. Of the 40832 total reflections, 3948 were unique （Rint = 0.0366）. The final R = 0.0460 and wR = 0.1335 for 3948 observed reflections with I 〉 2σ（I）.
基金Project (2005038557) supported by the Post-Doctor Programs Foundation of Ministry of Education of China
文摘The polymeric chalcogenide [W2O2S6Cu4(NCMe)4]n (compound 1) was synthesized by the self-assembly reaction of (NH4)2(WOS3) with CuBr in MeCN in the presence of tricyclohexylphosphane (PCy3) under a purified nitrogen atmosphere using standard Schlenk techniques. It gives rise to a novel 1D polymeric compound 1 with solvent MeCN coordinated to the copper atom. This situation is unprecedented in the W(Mo)/Cu/S system. The crystals were characterized by elemental analysis, IR and single-crystal X-ray crystallography. The configuration of the polymeric compound can be viewed as a helical chain which is propagated along the crystallographic c axis. The excited state absorption and refraction of compound 1 in CH3CN solution were studied by using the Z-scan technique with laser pulses of 40 ps pulse-width at a wavelength of 532 nm. The polymeric compound possesses an optical self-focusing performance. The positive nonlinear refraction is attributed to population transitions between singlet states. Compound 1 displays a strong excited-state absorption.
文摘In this paper, the total energies and the density of the states of triatomic systems of Cu. Ag. and An were calculated by discret-variational Xa method. Furthermore, the optimized geometry of triatomic copper,silver, and gold clusters were obtained. The results showed that the optimaaed geometry of Cu3 was different from that of Ag3. and An3. Cu3 cluster has two nearlydegenerate candidates for the ground state. Ag3 and Au3 clusters have bent isosceles triangular structure only. The ground configuration for the triatomic clusters is and the ground state is 2B2. The present evidences arc in agreement results with the experimental and with those by other complex theoretical method.
文摘In the previous paper,the geometry of the triatomic clusters for Cu, Ag,and An was obtained using the Dy-Xa method. In this investigation the atomic. orbital interactions of atom Cu, Ag, An in the triatomic clusters are analyzed. The magnitudes of the atomic orbital interactions of the atoms in the clusters are measured by the splitting of corresponding atomic orbital. The calculation results show the atomic orbital interactions of Cu triatomic cluster differ greatly from those of Ag and Au triatomic cluster house of the mixture radio of 4s-Orbital with 3d-Orbital in the Cu cluster more than those in the Ag and Au cluster. The values of atomic orbital interactions of Au in the of cluster are larger than corresponding atomic Orbital interactions of Ag in the cluster.
文摘This paper presents the synthetic and structure studies of molybdenum（tungsten）-copper-sulphur-dialkyldithiocarbamate cluster compounds.The reactions of（M=Mo,W;n=0,2）,CuCl,and R<sub>2</sub>dtc￣-（R<sub>2</sub>=Me<sub>2</sub>,Et<sub>2</sub>,C<sub>4</sub>H<sub>8</sub>,C<sub>5</sub>H<sub>1</sub>0） yield a series of tetra-,hexa-,and heptanuclear cluster compounds.Their spectroscopic properties and the synthetic reaction mechanism are discussed.
文摘The structures of Al 14 Cu 12 clusters were optimized by B3LYP method and the six geometries ground states were obtained. Al 71 Cu 29 alloy melt has been investigated using X ray diffractometry at 700 ℃. The experimental data were compared with calculated results to find the relation between the structures of Al Cu clusters and melt structure. It is shown that there exists a strong interaction between Al and Cu atoms. The bond length in some geometries is very close to the experimental atomic distance. Such optimized geometries have close correlation with the liquid structure of Al Cu alloy.
