ccording to the chemical bond theory we designed geometric structures ofcluster ions Nb_nS generated by laser ablation and calculated their electronic struc-tures using DV-X_a method of quantum chemistry. The results...ccording to the chemical bond theory we designed geometric structures ofcluster ions Nb_nS generated by laser ablation and calculated their electronic struc-tures using DV-X_a method of quantum chemistry. The results show that with theincrease of the cluster size the structures of the cluster ions change from a single-chain to a double-chain, then to a planar-net, and linking up to a net at Nb_3. Thenegative cluster ions tend to form a divergent configuration due to the extra chargeson it.展开更多
This paper investigates the structures and stabilities of neutral GaTAs7 cluster and its ions in detail by using first-principles density functional theory. Many low energy structures of GaTAs7 cluster are found. It c...This paper investigates the structures and stabilities of neutral GaTAs7 cluster and its ions in detail by using first-principles density functional theory. Many low energy structures of GaTAs7 cluster are found. It confirms that the ground state structure of neutral GaTAs7 cluster is a pentagonal prism with four face atoms like a basket structure, as reported by previous works. The ground state structures of positive Ga7As7 cluster ions are different from that of the neutral cluster. These investigations suggest that Ga atoms occupy the capping positions more easily than As atoms. Mulliken population analyses also show that Ga atoms can lose or obtain charge more easily than As atoms. It finds that the neutral GaTAs7 cluster can become more stable by gaining one or two additional electrons but further more electrons would cause the decrease of binding energy. The ionisation energy increases with the increase of the number of the removed electrons. These calculated results indicate that the net magnetic moment of the neutral GaTAs7 cluster is zero because all electrons axe paired together in their respective moleculax orbits. But for the ionic GaTAs7 cluster with odd number of electrons, the net magnetic moment is 1.0 μB due to an unpaired electron.展开更多
A gas cluster ion beam(GCIB) system with cluster energy up to 12 keV has been designed. To facilitate pumping of the nozzle chamber and increased pressure of the gas source up to 10 atm, pulse mode was used for the ...A gas cluster ion beam(GCIB) system with cluster energy up to 12 keV has been designed. To facilitate pumping of the nozzle chamber and increased pressure of the gas source up to 10 atm, pulse mode was used for the gas feeding. Argon was employed as the working gas. To separate monomers from clusters, both electromagnet and retarding electrode were utilized. A maximal pulsed cluster current of 90 nA has been achieved. The shape of pulsed ion beam currents has been analyzed in detail at different applied magnetic and retarding electric fields.展开更多
The laser ablation-molecular beam(LA-MB) method is useful for studying the reactions of metal ions with molecular clusters. Reactions of magnesium plasma with methanol clusters were studied by using this method. A s...The laser ablation-molecular beam(LA-MB) method is useful for studying the reactions of metal ions with molecular clusters. Reactions of magnesium plasma with methanol clusters were studied by using this method. A specially designed reaction cell was used as a fast flow reactor operated under thermal conditions, and the reaction products were measured with a time-of-flight(TOF) mass spectrometer. Surprisingly, several series of cluster ions with complex sizes and intensity distributions were obtained when the laser ablating was applied to different parts of the molecular beam. In the front part of the molecular beam, strong Mg^+ (CH3OH)n( n = 0-5) and weak H^+ (CH3OH)n( n = 0-5 ) cluster ions were observed with relatively small cluster sizes ; in the middle part of the molecular beam, the main cluster ions were H^+ ( CH3OH)n ( n = 6-17 ) and H^+( H2O) 2 ( CH3OH)n( n = 6-17 ) with a relatively large cluster size and a weak intensity; in the back part of the molecular beam, two new series of cluster ions, MgO^+ ( H2O) ( CH3 OH)n( n = 6-10 ) and MgOCH3^+ ( CH3OH)n( n = 6-10), were obtained and accompanied by weak H^+(CH3OH)n(n = 4-7) and H^+( H2O)2 (CH3OH)n( n = 3-6). The formation mechanisms and speed characteristics of the cluster ions are discussed in this article.展开更多
The photoionization of seeded carbon bisulfide molecular beam by a 1064nm nanosecond Nd-YAG laser with intensities varying from 0.8 × 10^11 to 5.6 × 10^11 W/cm^2 have been studied by time-of-flight mass spec...The photoionization of seeded carbon bisulfide molecular beam by a 1064nm nanosecond Nd-YAG laser with intensities varying from 0.8 × 10^11 to 5.6 × 10^11 W/cm^2 have been studied by time-of-flight mass spectrometry. Multiply charged ions of S^q+ (q = 2 6) and C^q+ (q = 2-4) with kinetic energy of hundreds of electron volts have been observed, and there are strong experimental evidences indicating that those multicharged ions originate from the ionization of CS2 neat clusters in the beam. An electron reeolliding ionization model is proposed to explain the appearance of those multiply charged atomic ions under such low laser intensities.展开更多
This paper proposes a simple scheme to generate a four-atom entangled cluster state in cavity quantum electrodynamics. With the assistantce of a strong classical field the cavity is only virtually excited and no quant...This paper proposes a simple scheme to generate a four-atom entangled cluster state in cavity quantum electrodynamics. With the assistantce of a strong classical field the cavity is only virtually excited and no quantum information will be transferred from the atoms to the cavity during the preparation for a four-atom entangled cluster state, and thus the scheme is insensitive to the cavity field states and cavity decay. Assuming that deviation of laser intensity is 0.01 and that of simultaneity for the interaction is 0.01, it shows that the fidelity of the resulting four-atom entangled cluster state is about 0.9886. The scheme can also be used to generate a four-ion entangled cluster state in a hot trapped-ion system. Assuming that deviation of laser intensity is 0.01, it shows that the fidelity of the resulting four-ion entangled cluster state is about 0.9990. Experimental feasibility for achieving this scheme is also discussed.展开更多
We developed a cluster ion beam system that produces negative cluster beams of C 1-C 10 with ion current of 4.5 nA-50 A at extraction voltages ranging from 6 to 20 kV.The system uses the injector of a tandetron accele...We developed a cluster ion beam system that produces negative cluster beams of C 1-C 10 with ion current of 4.5 nA-50 A at extraction voltages ranging from 6 to 20 kV.The system uses the injector of a tandetron accelerator and was established by inserting an electrostatic scanner on its ion-optical line and modifying its Faraday cup into a substrate holder.Utilization of clusters enables ultrashallow ion implantation at energies as low as 600 eV/atom without deceleration.Small carbon clusters C 2 and C 4 were implanted into Ni/SiO 2 /Si substrates and following post-thermal treatment graphene was obtained.Raman spectroscopy showed characteristic 2D peaks with G-to-2D peak ratios revealing formation of 2-3 layers of graphene.The Raman data reveals clear effect of nonlinear cluster-surface interaction in ion beam synthesis of two-dimensional nanomaterials.展开更多
The multi-charged sulfur ions of Sq^+ (q ≤ 6) have been generated when hydrogen sulfide cluster beams are irradiated by a nanosecond laser of 1064 and 532 nm with an intensity of 10^10- 10^12W.cm^-2. S^6+ is the ...The multi-charged sulfur ions of Sq^+ (q ≤ 6) have been generated when hydrogen sulfide cluster beams are irradiated by a nanosecond laser of 1064 and 532 nm with an intensity of 10^10- 10^12W.cm^-2. S^6+ is the dominant multicharged species at 1064 nm, while S^4+, S^3+ and S^2+ ions are the main multi-charged species at 532 nm. A three-step model (i.e., multiphoton ionization triggering, inverse bremsstrahlung heating, electron collision ionizing) is proposed to explain the generation of these multi-charged ions at the laser intensity stated above. The high ionization level of the clusters and the increasing charge state of the ion products with increasing laser wavelength are supposed mainly due to the rate-limiting step, i.e., electron heating by absorption energy from the laser field via inverse bremsstrahlung, which is proportional to λ2,λA being the laser wavelength.展开更多
We propose a scheme for the preparation of one-dimensional and two-dimensional cluster states by using hot trapped ions. The scheme is based on the interaction between two ions and bichromatic radiation. The vibration...We propose a scheme for the preparation of one-dimensional and two-dimensional cluster states by using hot trapped ions. The scheme is based on the interaction between two ions and bichromatic radiation. The vibrational mode in our protocol is only virtually excited so that the system is insensitive to the thermal field. In addition, we only use two levels of ions as qubits and the successful probability may achieve 100%.展开更多
A variety of iron phosphide cluster ions were produced by laser ablation.It is indicated that the reaction between iron ion and neutral phosphorus cluster results in the production of these cluster ions,explaining qua...A variety of iron phosphide cluster ions were produced by laser ablation.It is indicated that the reaction between iron ion and neutral phosphorus cluster results in the production of these cluster ions,explaining qualitatively the odd-even variation of mass abundance.Also investigated were the properties of photolysis of these cluster ions at 248 nm,which shows some basic units,FeP_2^+ and Fe_2P^+,or complexes composed of several basic units existing in larger cluster ions,based on which a chain structure of duster ions was then formed The above conclusions are supported by the theoretical calculation of the DV-Xα method.展开更多
Mathematical modeling for nanofiltration of ionic liquids(ILs) solutions could assist to understand transfer mechanism and predict experimental values. In this work, modeling by solution-diffusion model for nanofiltra...Mathematical modeling for nanofiltration of ionic liquids(ILs) solutions could assist to understand transfer mechanism and predict experimental values. In this work, modeling by solution-diffusion model for nanofiltration of long-alkyl-chain ILs aqueous solutions was proposed. Molecular simulations were performed to validate the existence of ion cluster in long-alkyl-chain ILs aqueous solution. Based on the results of simulations, parameters used in the solution-diffusion model were modified, such as concentration of ILs and diameter of ion cluster.The modeling process was developed for three long-alkyl-chain ILs aqueous solutions with different concentrations(1-alkyl-3-methylimidazolium chloride: [C6 mim]Cl, [C8 mim]Cl, [C10 mim]Cl). The calculated values obtained from modified solution-diffusion model could well match the experimental values.展开更多
MTBPyP (meso-tetrakis(4-N-benzylpyridyl)porphyrin, M=H-2, Zn) bearing positive charge has been shown to associate with SiW12O404- in water solution. The spectral evolution and Job's plots analyses reveal that the ...MTBPyP (meso-tetrakis(4-N-benzylpyridyl)porphyrin, M=H-2, Zn) bearing positive charge has been shown to associate with SiW12O404- in water solution. The spectral evolution and Job's plots analyses reveal that the relatively stable aggregates contain equal numbers of MTBPyP4(+) and SiW12O404-.展开更多
A theoretical model is established to simulate the penetration process of C20 clusters in oxides (Al2O3, SiO2) at different incident velocities. The induced spatial potential by the incident clusters is described by...A theoretical model is established to simulate the penetration process of C20 clusters in oxides (Al2O3, SiO2) at different incident velocities. The induced spatial potential by the incident clusters is described by the dielectric response formalism, in which the Mermin-type dielectric function is adopted to provide a realistic evaluation of the electronic properties of the oxides. The charge distribution of individual ions is derived by using the Brandt-Kitagawa effective charge model, also under the consideration of the asymmetric influence from the wake potential. The stopping power of the clusters and the Coulomb explosion processes are derived by solving the motion equation of the individual ions, when taking into account the multiple scattering effect simulated by using the Monte Carlo method. It is found that the dynamical interaction potential between ions leads to a spatial asymmetry to the cluster structure and the charge distribution for high velocity clusters, and will not be in effect as the incident velocities decrease.展开更多
An approach was made to correlate the proposed model of ion-cluster structure and structural parameter of TiO_2-bearing pentan system of molten slag with properties.Re- sults showed that an increase of ions with 4-coo...An approach was made to correlate the proposed model of ion-cluster structure and structural parameter of TiO_2-bearing pentan system of molten slag with properties.Re- sults showed that an increase of ions with 4-coordination number in molten slag makes the increase of bulk viscosity and the decrease of density,while ions with 6-coordination number are the contrary.The structural parameter proposed is so fairly interrelated to the properties of slag,that it may be available for the prediction about properties.In comparison with ions of 4-coordination number.Ti is more effective than Al and Si.展开更多
Within the framework of the dynamical classical over-barrier model,the soft collisions between slow highly charged ions(SHCIs) Ar 17+ and the large copper clusters under large impact parameters have been studied in...Within the framework of the dynamical classical over-barrier model,the soft collisions between slow highly charged ions(SHCIs) Ar 17+ and the large copper clusters under large impact parameters have been studied in this paper.We present the dominant mechanism of the electron transfer between SHCIs and a large metal cluster by computational simulation.The evolution of the occupation of projectile ions,KL x satellite lines,X-ray yields,Auger electron spectrum and scattering angles are provided.展开更多
The interaction of (Br-)i(H2O)50-i, 0 ≤ i ≤ 6 clusters with oxygen and ozone molecules is investigated by the method of molecular dynamics simulation. The ozone molecules as well as the bromine ions do not leave...The interaction of (Br-)i(H2O)50-i, 0 ≤ i ≤ 6 clusters with oxygen and ozone molecules is investigated by the method of molecular dynamics simulation. The ozone molecules as well as the bromine ions do not leave the cluster during the calculation of 25 ps. The ability of the cluster containing molecular oxygen to absorb the infrared (IR) radiation is reduced in the frequency range of 0≤ w ≤ 3500 cm-1 when the number of the bromine ions in the cluster grows. The intensity of the Raman spectrum is not changed significantly when the Brions are added to the ozone- containing system. The power of the emitted IR radiation is increased when the number of bromine ions grows in the oxygen-containing system. The data obtained in this study on the IR and the Raman spectra of the water clusters that contain ozone, oxygen, and Br- can be used to develop an investigation of the mechanisms of ozone depletion.展开更多
In this paper, we studied the process of dissociation unimolecular of the evaporation of H+2n+1 hydrogen clusters according to size, using the Rice-Ramsperger-Kassel-Marcus (RRKM) theory. The rate constants k(E) were ...In this paper, we studied the process of dissociation unimolecular of the evaporation of H+2n+1 hydrogen clusters according to size, using the Rice-Ramsperger-Kassel-Marcus (RRKM) theory. The rate constants k(E) were determined with the use of statistical theory of unimolecular reactions using various approximations. In our work, we used the products frequencies instead of transitions frequencies in the calculation of unimolecular dissociation rates obtained by three models RRKM. The agreement between the experimental cross section ratio and calculated rate ratio with direct count approximation seems to be reasonable.展开更多
We report on few-layer graphene synthesized on Cu foils by ion implantation using negative carbon cluster ions,followed by annealing at 950?C in vacuum. Raman spectroscopy reveals IG/I2 Dvalues varying from 1.55 to 2...We report on few-layer graphene synthesized on Cu foils by ion implantation using negative carbon cluster ions,followed by annealing at 950?C in vacuum. Raman spectroscopy reveals IG/I2 Dvalues varying from 1.55 to 2.38 depending on energy and dose of the cluster ions, indicating formation of multilayer graphene. The measurements show that the samples with more graphene layers have fewer defects. This is interpreted by graphene growth seeded by the first layers formed via outward diffusion of C from the Cu foil, though nonlinear damage and smoothing effects also play a role. Cluster ion implantation overcomes the solubility limit of carbon in Cu, providing a technique for multilayer graphene synthesis.展开更多
We propose a practical scheme to generate cluster states by simultaneously accomplishing two-qubit conditional gating on an array of equidistant ions by using transverse modes. Our operation is robust to heating and i...We propose a practical scheme to generate cluster states by simultaneously accomplishing two-qubit conditional gating on an array of equidistant ions by using transverse modes. Our operation is robust to heating and insensitive to Lamb-Dicke parameter. Meanwhile, as it is carried out in a geometric quantum computing fashion, our scheme enables the fast and high-fidelity generation of cluster states. The experimental feasibility is discussed with sophisticated ion trap techniques.展开更多
文摘ccording to the chemical bond theory we designed geometric structures ofcluster ions Nb_nS generated by laser ablation and calculated their electronic struc-tures using DV-X_a method of quantum chemistry. The results show that with theincrease of the cluster size the structures of the cluster ions change from a single-chain to a double-chain, then to a planar-net, and linking up to a net at Nb_3. Thenegative cluster ions tend to form a divergent configuration due to the extra chargeson it.
基金supported by the Foundation for the Author of National Excellent Doctoral Dissertation of China (Grant No. 200320)the National Natural Science Foundation of China (Grant No.10674039)
文摘This paper investigates the structures and stabilities of neutral GaTAs7 cluster and its ions in detail by using first-principles density functional theory. Many low energy structures of GaTAs7 cluster are found. It confirms that the ground state structure of neutral GaTAs7 cluster is a pentagonal prism with four face atoms like a basket structure, as reported by previous works. The ground state structures of positive Ga7As7 cluster ions are different from that of the neutral cluster. These investigations suggest that Ga atoms occupy the capping positions more easily than As atoms. Mulliken population analyses also show that Ga atoms can lose or obtain charge more easily than As atoms. It finds that the neutral GaTAs7 cluster can become more stable by gaining one or two additional electrons but further more electrons would cause the decrease of binding energy. The ionisation energy increases with the increase of the number of the removed electrons. These calculated results indicate that the net magnetic moment of the neutral GaTAs7 cluster is zero because all electrons axe paired together in their respective moleculax orbits. But for the ionic GaTAs7 cluster with odd number of electrons, the net magnetic moment is 1.0 μB due to an unpaired electron.
基金Supported by International Cooperation Program of the Ministry of Science and Technology of China(2015DFR00720)Wuhan Municipal Science and Technology Bureau(2016030409020219)+1 种基金Suzhou Scientific Development Project(ZXG201448)Hubei Province Technological Innovation Project(2016AHB004)
文摘A gas cluster ion beam(GCIB) system with cluster energy up to 12 keV has been designed. To facilitate pumping of the nozzle chamber and increased pressure of the gas source up to 10 atm, pulse mode was used for the gas feeding. Argon was employed as the working gas. To separate monomers from clusters, both electromagnet and retarding electrode were utilized. A maximal pulsed cluster current of 90 nA has been achieved. The shape of pulsed ion beam currents has been analyzed in detail at different applied magnetic and retarding electric fields.
基金Supported by the Doctoral Startup Foundation from Qufu Normal University.
文摘The laser ablation-molecular beam(LA-MB) method is useful for studying the reactions of metal ions with molecular clusters. Reactions of magnesium plasma with methanol clusters were studied by using this method. A specially designed reaction cell was used as a fast flow reactor operated under thermal conditions, and the reaction products were measured with a time-of-flight(TOF) mass spectrometer. Surprisingly, several series of cluster ions with complex sizes and intensity distributions were obtained when the laser ablating was applied to different parts of the molecular beam. In the front part of the molecular beam, strong Mg^+ (CH3OH)n( n = 0-5) and weak H^+ (CH3OH)n( n = 0-5 ) cluster ions were observed with relatively small cluster sizes ; in the middle part of the molecular beam, the main cluster ions were H^+ ( CH3OH)n ( n = 6-17 ) and H^+( H2O) 2 ( CH3OH)n( n = 6-17 ) with a relatively large cluster size and a weak intensity; in the back part of the molecular beam, two new series of cluster ions, MgO^+ ( H2O) ( CH3 OH)n( n = 6-10 ) and MgOCH3^+ ( CH3OH)n( n = 6-10), were obtained and accompanied by weak H^+(CH3OH)n(n = 4-7) and H^+( H2O)2 (CH3OH)n( n = 3-6). The formation mechanisms and speed characteristics of the cluster ions are discussed in this article.
基金Project supported by the National Natural Science Foundation of China (Grant No 20573111) and the Centre for Computational Science, Hefei Institutes of Physics, China (Grant No 0331405002). Acknowledgment We thank Professor Cunhao Zhang and Professor Guohe Sha for their instructive discussion.
文摘The photoionization of seeded carbon bisulfide molecular beam by a 1064nm nanosecond Nd-YAG laser with intensities varying from 0.8 × 10^11 to 5.6 × 10^11 W/cm^2 have been studied by time-of-flight mass spectrometry. Multiply charged ions of S^q+ (q = 2 6) and C^q+ (q = 2-4) with kinetic energy of hundreds of electron volts have been observed, and there are strong experimental evidences indicating that those multicharged ions originate from the ionization of CS2 neat clusters in the beam. An electron reeolliding ionization model is proposed to explain the appearance of those multiply charged atomic ions under such low laser intensities.
基金Project supported by the Postdoctal Foundation of Central South University of Chinathe Important Program of Hunan Provincial Education Department of China (Grant No. 06A038)+1 种基金Department of Education of Hunan Province of China (Grant No. 06C080)Hunan Provincial Natural Science Foundation,China (Grant No. 07JJ3013)
文摘This paper proposes a simple scheme to generate a four-atom entangled cluster state in cavity quantum electrodynamics. With the assistantce of a strong classical field the cavity is only virtually excited and no quantum information will be transferred from the atoms to the cavity during the preparation for a four-atom entangled cluster state, and thus the scheme is insensitive to the cavity field states and cavity decay. Assuming that deviation of laser intensity is 0.01 and that of simultaneity for the interaction is 0.01, it shows that the fidelity of the resulting four-atom entangled cluster state is about 0.9886. The scheme can also be used to generate a four-ion entangled cluster state in a hot trapped-ion system. Assuming that deviation of laser intensity is 0.01, it shows that the fidelity of the resulting four-ion entangled cluster state is about 0.9990. Experimental feasibility for achieving this scheme is also discussed.
基金supported by the International Cooperation Program of the Ministry of Science and Technology of China (2010DFA02010)
文摘We developed a cluster ion beam system that produces negative cluster beams of C 1-C 10 with ion current of 4.5 nA-50 A at extraction voltages ranging from 6 to 20 kV.The system uses the injector of a tandetron accelerator and was established by inserting an electrostatic scanner on its ion-optical line and modifying its Faraday cup into a substrate holder.Utilization of clusters enables ultrashallow ion implantation at energies as low as 600 eV/atom without deceleration.Small carbon clusters C 2 and C 4 were implanted into Ni/SiO 2 /Si substrates and following post-thermal treatment graphene was obtained.Raman spectroscopy showed characteristic 2D peaks with G-to-2D peak ratios revealing formation of 2-3 layers of graphene.The Raman data reveals clear effect of nonlinear cluster-surface interaction in ion beam synthesis of two-dimensional nanomaterials.
基金Project supported by the National Natural Science Foundation of China (Grant No 20573111) and partly supported by the Center for Computational Science, Hefei Institutes of Physical Sciences, China (Grant No 0331405002).
文摘The multi-charged sulfur ions of Sq^+ (q ≤ 6) have been generated when hydrogen sulfide cluster beams are irradiated by a nanosecond laser of 1064 and 532 nm with an intensity of 10^10- 10^12W.cm^-2. S^6+ is the dominant multicharged species at 1064 nm, while S^4+, S^3+ and S^2+ ions are the main multi-charged species at 532 nm. A three-step model (i.e., multiphoton ionization triggering, inverse bremsstrahlung heating, electron collision ionizing) is proposed to explain the generation of these multi-charged ions at the laser intensity stated above. The high ionization level of the clusters and the increasing charge state of the ion products with increasing laser wavelength are supposed mainly due to the rate-limiting step, i.e., electron heating by absorption energy from the laser field via inverse bremsstrahlung, which is proportional to λ2,λA being the laser wavelength.
基金Project supported by the National Natural Science Foundation of China (Grant No 10574022), and the Funds of the Natural . Science of Fujian Province, China (Grant No Z0512006).
文摘We propose a scheme for the preparation of one-dimensional and two-dimensional cluster states by using hot trapped ions. The scheme is based on the interaction between two ions and bichromatic radiation. The vibrational mode in our protocol is only virtually excited so that the system is insensitive to the thermal field. In addition, we only use two levels of ions as qubits and the successful probability may achieve 100%.
文摘A variety of iron phosphide cluster ions were produced by laser ablation.It is indicated that the reaction between iron ion and neutral phosphorus cluster results in the production of these cluster ions,explaining qualitatively the odd-even variation of mass abundance.Also investigated were the properties of photolysis of these cluster ions at 248 nm,which shows some basic units,FeP_2^+ and Fe_2P^+,or complexes composed of several basic units existing in larger cluster ions,based on which a chain structure of duster ions was then formed The above conclusions are supported by the theoretical calculation of the DV-Xα method.
基金financially supported by National Key Research and Develop Program of China (2017YFA0206803)National Science Fund for Excellent Young Scholars (21722610)+2 种基金National Natural Science Foundation of China (21676277)Key Program of National Natural Science Foundation of China (91434203)CAS-SAFEA International PartnershipProgramforCreativeResearchTeams (20140491518)
文摘Mathematical modeling for nanofiltration of ionic liquids(ILs) solutions could assist to understand transfer mechanism and predict experimental values. In this work, modeling by solution-diffusion model for nanofiltration of long-alkyl-chain ILs aqueous solutions was proposed. Molecular simulations were performed to validate the existence of ion cluster in long-alkyl-chain ILs aqueous solution. Based on the results of simulations, parameters used in the solution-diffusion model were modified, such as concentration of ILs and diameter of ion cluster.The modeling process was developed for three long-alkyl-chain ILs aqueous solutions with different concentrations(1-alkyl-3-methylimidazolium chloride: [C6 mim]Cl, [C8 mim]Cl, [C10 mim]Cl). The calculated values obtained from modified solution-diffusion model could well match the experimental values.
基金This work was supported by the National NatUral Science Foundation of China under grant! No.29733090 and No. 29803003 the Re
文摘MTBPyP (meso-tetrakis(4-N-benzylpyridyl)porphyrin, M=H-2, Zn) bearing positive charge has been shown to associate with SiW12O404- in water solution. The spectral evolution and Job's plots analyses reveal that the relatively stable aggregates contain equal numbers of MTBPyP4(+) and SiW12O404-.
基金Supported by the National Natural Science Foundation of China under Grant No 10275009.
文摘A theoretical model is established to simulate the penetration process of C20 clusters in oxides (Al2O3, SiO2) at different incident velocities. The induced spatial potential by the incident clusters is described by the dielectric response formalism, in which the Mermin-type dielectric function is adopted to provide a realistic evaluation of the electronic properties of the oxides. The charge distribution of individual ions is derived by using the Brandt-Kitagawa effective charge model, also under the consideration of the asymmetric influence from the wake potential. The stopping power of the clusters and the Coulomb explosion processes are derived by solving the motion equation of the individual ions, when taking into account the multiple scattering effect simulated by using the Monte Carlo method. It is found that the dynamical interaction potential between ions leads to a spatial asymmetry to the cluster structure and the charge distribution for high velocity clusters, and will not be in effect as the incident velocities decrease.
文摘An approach was made to correlate the proposed model of ion-cluster structure and structural parameter of TiO_2-bearing pentan system of molten slag with properties.Re- sults showed that an increase of ions with 4-coordination number in molten slag makes the increase of bulk viscosity and the decrease of density,while ions with 6-coordination number are the contrary.The structural parameter proposed is so fairly interrelated to the properties of slag,that it may be available for the prediction about properties.In comparison with ions of 4-coordination number.Ti is more effective than Al and Si.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 11135002,91026021,11075068,11075069,and 10975065)the Fundamental Research Funds for the Central Universities of China (Grant No. lzujbky-2010-k08)
文摘Within the framework of the dynamical classical over-barrier model,the soft collisions between slow highly charged ions(SHCIs) Ar 17+ and the large copper clusters under large impact parameters have been studied in this paper.We present the dominant mechanism of the electron transfer between SHCIs and a large metal cluster by computational simulation.The evolution of the occupation of projectile ions,KL x satellite lines,X-ray yields,Auger electron spectrum and scattering angles are provided.
基金Project supported by the Russian Foundation of Basic Research (Grant No. 08-08-00136-a)
文摘The interaction of (Br-)i(H2O)50-i, 0 ≤ i ≤ 6 clusters with oxygen and ozone molecules is investigated by the method of molecular dynamics simulation. The ozone molecules as well as the bromine ions do not leave the cluster during the calculation of 25 ps. The ability of the cluster containing molecular oxygen to absorb the infrared (IR) radiation is reduced in the frequency range of 0≤ w ≤ 3500 cm-1 when the number of the bromine ions in the cluster grows. The intensity of the Raman spectrum is not changed significantly when the Brions are added to the ozone- containing system. The power of the emitted IR radiation is increased when the number of bromine ions grows in the oxygen-containing system. The data obtained in this study on the IR and the Raman spectra of the water clusters that contain ozone, oxygen, and Br- can be used to develop an investigation of the mechanisms of ozone depletion.
文摘In this paper, we studied the process of dissociation unimolecular of the evaporation of H+2n+1 hydrogen clusters according to size, using the Rice-Ramsperger-Kassel-Marcus (RRKM) theory. The rate constants k(E) were determined with the use of statistical theory of unimolecular reactions using various approximations. In our work, we used the products frequencies instead of transitions frequencies in the calculation of unimolecular dissociation rates obtained by three models RRKM. The agreement between the experimental cross section ratio and calculated rate ratio with direct count approximation seems to be reasonable.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11105100,11205116,and 11375135)the State Key Laboratory of Advanced Welding and Joining,Harbin Institute of Technology,China(Grant No.AWJ-M13-03)
文摘We report on few-layer graphene synthesized on Cu foils by ion implantation using negative carbon cluster ions,followed by annealing at 950?C in vacuum. Raman spectroscopy reveals IG/I2 Dvalues varying from 1.55 to 2.38 depending on energy and dose of the cluster ions, indicating formation of multilayer graphene. The measurements show that the samples with more graphene layers have fewer defects. This is interpreted by graphene growth seeded by the first layers formed via outward diffusion of C from the Cu foil, though nonlinear damage and smoothing effects also play a role. Cluster ion implantation overcomes the solubility limit of carbon in Cu, providing a technique for multilayer graphene synthesis.
基金supported by the National Natural Science Foundation of China (Grant Nos.10774163 and 10804132)
文摘We propose a practical scheme to generate cluster states by simultaneously accomplishing two-qubit conditional gating on an array of equidistant ions by using transverse modes. Our operation is robust to heating and insensitive to Lamb-Dicke parameter. Meanwhile, as it is carried out in a geometric quantum computing fashion, our scheme enables the fast and high-fidelity generation of cluster states. The experimental feasibility is discussed with sophisticated ion trap techniques.