We present an optimum metallic-bond scheme to study the geometric structures of sodium clusters Nan (n≤15) systematically by combining the characteristics of metallic bonds and the first principle molecular dynamics ...We present an optimum metallic-bond scheme to study the geometric structures of sodium clusters Nan (n≤15) systematically by combining the characteristics of metallic bonds and the first principle molecular dynamics simulation. The scheme provides an optimum way to examine almost all stable structures of sodium clusters and to determine their ground state structures. It is interesting to note that for the larger sodium clusters (13≤n≤15), there are some plane-like substructures on their surfaces, which resemble the fragments of the (110) plane with the highest atomic area density in the bulk bcc sodium crystal. We also propose a possible way to understand the formation of large icosahedral sodium clusters (1500＜n＜22000).展开更多
Structures of stable compositions of sodium oxide cluster cations (NanOm+,n≤11) have been investigated by ion mobility mass spectrometry. Stoichiometric compositions series, Na(Na2O)(n-1)/2^+(n=3, 5, 7, 9, and 11), w...Structures of stable compositions of sodium oxide cluster cations (NanOm+,n≤11) have been investigated by ion mobility mass spectrometry. Stoichiometric compositions series, Na(Na2O)(n-1)/2^+(n=3, 5, 7, 9, and 11), were observed as stable composition series, and NaO(Na2O)(n-1)/2^+ series (n=5, 7, 9, and 11) were observed as secondary stable series in the mass spectra. To assign the structures of these cluster ion series, collision cross sections between the ions and helium buffer gas were determined experimentally from the ion mobility measurements. Theoretical collision cross sections were also calculated for optimized structures of these compositions. Finally, the structures of Na(Na2O)(n-1)/2^+ and NaO(Na2O)(n-1)/2^+ were assigned to those having similar structural frames for each n except for n=9. All bonds in the assigned structures of Na(Na2O)(n-1)/2^+ were between sodium and oxygen. On the other hand, there was one O-O bond in addition to Na-O bonds in NaO(Na2O)(n-1)/2^+. This result indicates that NaO(Na2O)(n-1)/2^+ have a peroxide ion (O22-) as a substitute for an oxide ion (O2-) of Na(Na2O)(n-1)/2^+. As a result, both stable series, Na(Na2O)(n-1)/2^+ and NaO(Na2O)(n-1)/2^+, are closed-shell compositions. These closed-shell characteristics have a strong influence on the stability of sodium oxide cluster cations.展开更多
Heat capacities of small aluminium clusters A111-20 are investigated using MD simulation with empirical many- body Gupta potential. The heat capacities of some clusters A111, A112, A113 and A119 show well-defined peak...Heat capacities of small aluminium clusters A111-20 are investigated using MD simulation with empirical many- body Gupta potential. The heat capacities of some clusters A111, A112, A113 and A119 show well-defined peaks while the heat capacities of Alls-ls indicate a gradual melting transition. The spectra of isomers obtained by quenches along the MD trajectory give good interpretation for those results.展开更多
Alkali halide clusters are interesting model systems that can provide information about how crystal properties evolve. To study these properties, a high-resolution atmospheric pressure inlet time-of-flight mass spectr...Alkali halide clusters are interesting model systems that can provide information about how crystal properties evolve. To study these properties, a high-resolution atmospheric pressure inlet time-of-flight mass spectrometry （APi-TOF-MS） study of the sequential sodium halides series, C1-（NaC1）n and Br-（NaBr）m, has been reported, and the viability of the APi-TOF- MS equipped with an electrospray ionization source in determining cluster compositions has been demonstrated. The isotopic patterns were well resolved, as n=4 and 7 were determined to be the magic numbers for C1-（NaC1）n clusters, which were particularly abundant in the mass spectra. A global minimum search based on density functional theory enabled basin hopping yield the most stable structures for the mentioned series. The structures exhibit several distinct motifs which can be roughly categorized as linear chain, rock salt, and hexag- onal ring. This work provides an effective way to discover and elucidate the nonstoichiometry sodium halide clusters. These clusters possess very high vertical detachment energies and are generally called as superhalogens, which play important roles in chemistry because they are widely used in the synthesis of new classes of charge-transfer salts.展开更多
A novel 3D hetero-nuclear framework,namely{[K_(5)Na_(6)Cu^(Ⅱ)_(5)(CH_(3)COO)_(20)(CH_(3)CN)]Cl}_(n)(1),was obtained by hydrothermal reaction.Triple metal centers(including sodium/potassium or/and copper)were coordina...A novel 3D hetero-nuclear framework,namely{[K_(5)Na_(6)Cu^(Ⅱ)_(5)(CH_(3)COO)_(20)(CH_(3)CN)]Cl}_(n)(1),was obtained by hydrothermal reaction.Triple metal centers(including sodium/potassium or/and copper)were coordinated to acetate anions in such two heteronuclear clusters,respectively.Moreover,nine kinds of binding modes for acetate anions were illustrated in polymer 1,with the first reported pentadentate coordination mode for acetate ligand.展开更多
Water-solube iron-sulfur cluster nanoparticles were synthesized by using tri-sodium citrate as a stabilizer. The effect of factors such as the amount of reactants, the type of reactants, pH value, dripping order was s...Water-solube iron-sulfur cluster nanoparticles were synthesized by using tri-sodium citrate as a stabilizer. The effect of factors such as the amount of reactants, the type of reactants, pH value, dripping order was studied on the formation of iron-sulfur cluster nanoparticles. The structure, photo- and electro- chemical performance were characterized by UV-Vis, Raman, TEM, ED, EDS and Cyclic Voltammetry were used to characterize the structure and properties. The UV-Vis peaks at 436, 532 and 636 nm are attributed to the characteristic peaks of [4Fe-4S]+ and [2Fe-2S]2+. The Raman results indicate that citrate anions have been adsorbed on the surface of iron-sulfur cluster nanoparticles. TEM image shows the particles are about 5 nm, and EDS result further proves that iron-sulfur cluster coated by tri-sodium citrate has been obtained. Cyclic Voltammetry result demonstrates that iron-sulfur cluster has similar electrochemical property to that in organism.展开更多
基金This work was supported by the National Natural Science Foundation of China (Grant No.19734003) the National High-Tech ICF Committee in China, Ministry of Science & Technology and Ministry of Education of China.
文摘We present an optimum metallic-bond scheme to study the geometric structures of sodium clusters Nan (n≤15) systematically by combining the characteristics of metallic bonds and the first principle molecular dynamics simulation. The scheme provides an optimum way to examine almost all stable structures of sodium clusters and to determine their ground state structures. It is interesting to note that for the larger sodium clusters (13≤n≤15), there are some plane-like substructures on their surfaces, which resemble the fragments of the (110) plane with the highest atomic area density in the bulk bcc sodium crystal. We also propose a possible way to understand the formation of large icosahedral sodium clusters (1500＜n＜22000).
基金supported by JSPS KAKENHI Grant (No.JP18K14173, No.JP17K14433, and No.JP17J02017)a JSPS Research Fellowship
文摘Structures of stable compositions of sodium oxide cluster cations (NanOm+,n≤11) have been investigated by ion mobility mass spectrometry. Stoichiometric compositions series, Na(Na2O)(n-1)/2^+(n=3, 5, 7, 9, and 11), were observed as stable composition series, and NaO(Na2O)(n-1)/2^+ series (n=5, 7, 9, and 11) were observed as secondary stable series in the mass spectra. To assign the structures of these cluster ion series, collision cross sections between the ions and helium buffer gas were determined experimentally from the ion mobility measurements. Theoretical collision cross sections were also calculated for optimized structures of these compositions. Finally, the structures of Na(Na2O)(n-1)/2^+ and NaO(Na2O)(n-1)/2^+ were assigned to those having similar structural frames for each n except for n=9. All bonds in the assigned structures of Na(Na2O)(n-1)/2^+ were between sodium and oxygen. On the other hand, there was one O-O bond in addition to Na-O bonds in NaO(Na2O)(n-1)/2^+. This result indicates that NaO(Na2O)(n-1)/2^+ have a peroxide ion (O22-) as a substitute for an oxide ion (O2-) of Na(Na2O)(n-1)/2^+. As a result, both stable series, Na(Na2O)(n-1)/2^+ and NaO(Na2O)(n-1)/2^+, are closed-shell compositions. These closed-shell characteristics have a strong influence on the stability of sodium oxide cluster cations.
基金Supported by the Natural Science Foundation of China under Grant Nos 10575012 and 10435020, the Science Foundation of Beijing, and the Science Foundation of the Ministry of Education of China.
文摘Heat capacities of small aluminium clusters A111-20 are investigated using MD simulation with empirical many- body Gupta potential. The heat capacities of some clusters A111, A112, A113 and A119 show well-defined peaks while the heat capacities of Alls-ls indicate a gradual melting transition. The spectra of isomers obtained by quenches along the MD trajectory give good interpretation for those results.
文摘Alkali halide clusters are interesting model systems that can provide information about how crystal properties evolve. To study these properties, a high-resolution atmospheric pressure inlet time-of-flight mass spectrometry （APi-TOF-MS） study of the sequential sodium halides series, C1-（NaC1）n and Br-（NaBr）m, has been reported, and the viability of the APi-TOF- MS equipped with an electrospray ionization source in determining cluster compositions has been demonstrated. The isotopic patterns were well resolved, as n=4 and 7 were determined to be the magic numbers for C1-（NaC1）n clusters, which were particularly abundant in the mass spectra. A global minimum search based on density functional theory enabled basin hopping yield the most stable structures for the mentioned series. The structures exhibit several distinct motifs which can be roughly categorized as linear chain, rock salt, and hexag- onal ring. This work provides an effective way to discover and elucidate the nonstoichiometry sodium halide clusters. These clusters possess very high vertical detachment energies and are generally called as superhalogens, which play important roles in chemistry because they are widely used in the synthesis of new classes of charge-transfer salts.
基金financially supported by the Youth Teachers'Training Foundation of Minnan Science and Technology InstituteYoung and Middle-age academic leader plan of Quanzhou universitythe undergraduate education teaching reform in Fujian province(2017)
文摘A novel 3D hetero-nuclear framework,namely{[K_(5)Na_(6)Cu^(Ⅱ)_(5)(CH_(3)COO)_(20)(CH_(3)CN)]Cl}_(n)(1),was obtained by hydrothermal reaction.Triple metal centers(including sodium/potassium or/and copper)were coordinated to acetate anions in such two heteronuclear clusters,respectively.Moreover,nine kinds of binding modes for acetate anions were illustrated in polymer 1,with the first reported pentadentate coordination mode for acetate ligand.
文摘Water-solube iron-sulfur cluster nanoparticles were synthesized by using tri-sodium citrate as a stabilizer. The effect of factors such as the amount of reactants, the type of reactants, pH value, dripping order was studied on the formation of iron-sulfur cluster nanoparticles. The structure, photo- and electro- chemical performance were characterized by UV-Vis, Raman, TEM, ED, EDS and Cyclic Voltammetry were used to characterize the structure and properties. The UV-Vis peaks at 436, 532 and 636 nm are attributed to the characteristic peaks of [4Fe-4S]+ and [2Fe-2S]2+. The Raman results indicate that citrate anions have been adsorbed on the surface of iron-sulfur cluster nanoparticles. TEM image shows the particles are about 5 nm, and EDS result further proves that iron-sulfur cluster coated by tri-sodium citrate has been obtained. Cyclic Voltammetry result demonstrates that iron-sulfur cluster has similar electrochemical property to that in organism.
