16 results on '"Chen, Xi-Meng"'
Search Results
2. Single-and-double electron loss of O 2+ in collisions with argon and helium
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Chen Lin, Shao Jian-Xiong, Gao Zhi-Min, Yin Yong-Zhi, Lu Yan-Xia, Chen Xi-Meng, Cui Ying, Liu Yu-Wen, Ding Bao-Wei, Sun Guang-Zhi, and Fu Hong-Bin
- Subjects
Physics ,Argon ,Monte Carlo method ,General Physics and Astronomy ,chemistry.chemical_element ,Collision ,Coincidence ,Effective nuclear charge ,Bohr model ,symbols.namesake ,chemistry ,symbols ,Coulomb ,Atomic physics ,Helium - Abstract
This paper reports that the ratios of double to single electron loss cross-section (R) of O2+ in collision with Ar and He at the velocity of 1–4ν0 (ν0 is the Bohr velocity) have been obtained by the coincidence technique. The trend of R – V in the experiment indicates that the effective charge varies with injected velocity. The effective charge can be obtained by the n-body classical trajectory Monte Carlo method, which is interpreted by the molecular Coulomb over barrier model.
- Published
- 2008
3. L -Shell X-Ray Yields and Production Cross Sections of Zr and Mo Bombarded by Slow Highly Charged Ar 16+ Ions
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Liu Yu-Wen, Shao Jian-Xiong, Yang Zhi-Hu, Chen Xi-Meng, Cui Ying, Gao Zhi-Min, XU Jin-zhang, and Du Juan
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Zirconium ,Materials science ,Binding energy ,General Physics and Astronomy ,chemistry.chemical_element ,Electronic structure ,Charged particle ,L-shell ,Ion ,chemistry ,Vacancy defect ,Ionization ,Physics::Atomic and Molecular Clusters ,Atomic physics - Abstract
The L-shell x-ray yields of Zr and Mo bombarded by slow Ar16+ions are measured. The energy of the Ar16+ions ranges from about 150 keV to 350 keV. The L-shell x-ray production cross sections of Zr and Mo are extracted from these yields data. The explanation of these experimental results is in the framework of the adiabatic direct-ionization and the binding energy modified BEA approximation. We consider, in the slow asymmetric collisions such as Ar and Mo/Zr, the transient united atoms (UA) are formed during the ion-surface interaction and the direct-ionization is the main mechanism for the inner-shell vacancy production. Generally, the theoretical results are in good agreement with the experimental data.
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- 2008
4. Investigation of transfer ionization in collisions of partially stripped carbon ions with helium at low to intermediate velocities
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Liu Zhao-Yuan, Shao Jian-Xiong, Sun Guang-Zhi, Zhang Hong-Qiang, Du Juan, Liu Yu-Wen, Fu Hong-Bin, Ding Bao-Wei, Gao Zhi-Min, Chen Xi-Meng, Cui Ying, and Lu Yan-Xia
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Physics ,Monte Carlo method ,General Physics and Astronomy ,chemistry.chemical_element ,Coincidence ,Effective nuclear charge ,Bohr model ,Ion ,symbols.namesake ,chemistry ,Ionization ,symbols ,Atomic physics ,Carbon ,Helium - Abstract
The ratios of transfer ionization (TI) to single-electron capture (SC) cross sections have been measured for the collisions of partially stripped Cq+ ions (q = 1-4) with He. The collision velocity ranges from 0.7 to 4.4v(0) (v(0) is the Bohr velocity). The projectile-ion and recoil-ion coincidence technique is used to separate the processes of TI and SC. The ratios reach the maximum when the velocity is about 3.7 v(0). This can be explained qualitatively based on the two-step mechanism. The experimental results are also compared with the results calculated using the classical trajectory Monte Carlo (CTMC) method. The CTMC results are in agreement with the experimental data basically. The discrepancies in higher velocity region are interpreted by the effective charge effect.
- Published
- 2007
5. Multi-Electron Processes in 4.15–11.08 keV/ u 13 C 6+ on Argon Collisions
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Xue Yingli, Lu Rongchun, Shao Jian-Xiong, Li Ming-Sheng, Chen Xi-Meng, Cui Ying, Ding Bao-Wei, Yang Zhi-Hu, Zhang Hong-Qiang, Yu Deyang, Shao Cao-Jie, Ruan Fang-Fang, QI De-Jun, and Cai Xiao-Hong
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Physics ,Work (thermodynamics) ,Argon ,chemistry ,Electron capture ,Ionization ,Coulomb ,General Physics and Astronomy ,Incident energy ,chemistry.chemical_element ,Electron ,Atomic physics ,Ion - Abstract
The relative partial cross sections for 13C6+–Ar collisions at 4.15–11.08 keV/u incident energy are measured. The cross-section ratios σ2E/σSC, σ3E/σSC, σ4E/σSC and σ5E/σSC are approximately the constants of 0.51±0.05, 0.20±0.03, 0.06±0.03 and 0.02±0.01 in this region. The significance of the multi-electron process in highly charged ions (HCIs) with argon collisions is demonstrated (σME/σSC as high as 0.79±0.06). In multi-electron processes, it is shown that transfer ionization is dominant while pure electron capture is weak and negligible. For all reaction channels, the cross-sections are independent of the incident energy in the present energy region, which is in agreement with the static characteristic of classic models, i.e. the molecular Coulomb over-the-barrier model (MCBM), the extended classical over-the-barrier model (ECBM) and the semiempirical scaling laws (SL). The result is compared with these classical models and with our previous work of 13C6+-Ne collisions [Chin. Phys. Lett. 23 (2006) 95].
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- 2007
6. Multi-Electron Processes in 13 C 6+ Ions with Neon Collisions in Energy Region 4.15–11.08 keV/u
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Yang Zhi-Hu, Lu Jun, Zhang Hong-Qiang, Xu Xu, Shao Cao-Jie, Shao Jian-Xiong, Ruan Fang-Fang, Yu Deyang, Chen Xi-Meng, Cui Ying, Lu Rongchun, Ding Bao-Wei, and Cai Xiao-Hong
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Physics ,Single electron ,Neon ,chemistry ,Coincident ,Coulomb ,General Physics and Astronomy ,chemistry.chemical_element ,Electron ,Atomic physics ,Collision ,Energy (signal processing) ,Ion - Abstract
The cross-section ratios of double-, triple-, quadruple-, and the total multi-electron processes to the single electron capture process (σDE/σSC, σTE/σSC, σQE/σSC and σME/σSC) as well as the relative ratios among reaction channels in double-electron active, triple-electron active and quadruple-electron active are measured in 13C6+–Ne collision in the energy region of 4.15–11.08 keV/u by employing position-sensitive and time-of-flight coincident techniques. It is determined that the cross-section ratios σDE/σSC, σTE/σSC, σQE/σSC and σME/σSC are approximately the constants of 0.20±0.03, 0.16±0.04, 0.06±0.02 and 0.42±0.05. These values are obviously smaller than the predictions of the molecular Coulomb over-the-barrier model (MCBM) [J. Phys. B 23 (1990) 4293], the extended classical over-the-barrier model (ECBM) [J. Phys. B 19 (1986) 2925] and the semiempirical scaling laws (SL) [Phys. Rev. A 54 (1996) 4127]. However, the relative ratios among partial processes of DE, TE and QE are found to depend on collision energy, which suggests that the collision dynamics depends on the collision velocity. The limitation of velocity-independent character of ECBM, MCBM and SL is undoubtedly shown.
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- 2006
7. Damage effects of proton beam irradiation on single layer graphene
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Chen Yi-Feng, Chen Xi-Meng, Shao Jian-Xiong, Zhang Ning, Feng Zhan-Zu, Yang Ai-Xiang, Zhang Xin, and Ba De-Dong
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Materials science ,Proton ,Silicon ,Graphene ,General Physics and Astronomy ,chemistry.chemical_element ,Electronic structure ,Molecular physics ,Ion ,law.invention ,symbols.namesake ,chemistry ,law ,Excited state ,symbols ,High-resolution transmission electron microscopy ,Raman spectroscopy - Abstract
Graphene was first discovered in 2004 (Novoselov K S, et al. 2004 Science 306 666), it is a single atomic layer of sp2-bonded carbon atoms arranged in a honeycomb-like lattice. According to its extraordinary electronic, mechanical, thermal and optical properties, one can expect it to have a variety of applications in nanoscale electronics, composite materials, energy storage, and biomedicine fields. Although many experimental and theoretical studies on graphene have been carried, there still exist many obstacles to its applications. A representative example is nanoscale electronics (e.g., field-effect transistors and optoelectronic devices) that requires non-zero band-gap. Therefore, introducing defects into graphene and leading to band-gap opening are key steps for its technique applications.Recently, ion beam irradiation as a defects introducing technique was performed by Lee et al. (2015 Appl. Surf. Sci. 344 52) and Zeng et al. (2016 Carbon 100 16) through 5, 10, and 15 MeV protons and highly charged ions (HCIs) irradiating the graphene separately. Considering the advantages of simplity for preparing samples and feasibility in atmospheric condition of Raman spectroscopy compared with common characterization techniques (high resolution transmission electron microscopy, scanning electron microscopy, atomic force microscopy) for nano-materials, in both studies, Raman spectroscopy is used to obtain the evolution of ID/IG (ID is the peak intensity excited by defects, IG is the peak intensity origining from lateral vibration of carbon atoms) with different energies and fluences, respectively. In this work, considered are the following points:1) the absence of quantitive characterization for defects in the above two studies; 2) the low displacement energy of 25 eV required for a carbon atom to be knocked out (Zhao S J, et al. 2012 Nanotechnology 23 285703); 3) the complex interaction between HCIs and material. The irradiation effects of single layer graphene on silicon substrate are investigated by 750 keV and 1 MeV proton bombarding. This introduces the defects into graphene and thus leads to band-gap opening. By comparing Raman spectra of the samples before and after irradiation, a quantitive characterization about defects in graphene is achieved. Detailed analysis shows that 1) the value of ID/IG increases with the energy loss of incident proton, which is consistent with the result of SRIM simulation; 2) the average distance of defects LD increases with the incident proton energy; 3) the defect density nD decreases with the incident proton energy. These indicate that the damage effect for MeV protons in single layer graphene with substrate is similar to those in three-dimensional materials. The method presented here may facilitate the understanding of the physical mechanism of MeV proton interaction with two-dimensional materials, and provide a potential way of controlling the electronic structure and band-gap.
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- 2017
8. Atomic Diffusion in Cu/Si (111) and Cu/SiO 2 /Si (111) Systems by Neutral Cluster Beam Deposition
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Kim Hee, Cao Bo, Chen Xi-Meng, Cho Seong-Jin, and Li Gong-Ping
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Diffraction ,Atomic diffusion ,Materials science ,chemistry ,Annealing (metallurgy) ,Ionization ,Cluster (physics) ,Analytical chemistry ,General Physics and Astronomy ,chemistry.chemical_element ,Rutherford backscattering spectrometry ,Copper - Abstract
The Cu films are deposited on two kinds of p-type Si (111) substrates by ionized cluster beam (ICB) technique. The interface reaction and atomic diffusion of Cu/Si (111) and Cu/SiO2/Si (111) systems are studied at different annealing temperatures by x-ray diffraction (XRD) and Rutherford backscattering spectrometry (RBS). Some significant results are obtained: For the Cu/Si (111) samples prepared by neutral clusters, the interdiffusion of Cu and Si atoms occurs when annealed at 230?C. The diffusion coefficients of the samples annealed at 230?C and 500?C are 8.5 ? 10-15 cm2?s-1 and 3.0 ? 10-14 cm2?s-1, respectively. The formation of the copper-silicide phase is observed by XRD, and its intensity becomes stronger with the increase of annealing temperature. For the Cu/SiO2/Si (111) samples prepared by neutral clusters, the interdiffusion of Cu and Si atoms occurs and copper silicides are formed when annealed at 450?C. The diffusion coefficients of Cu in Si are calculated to be 6.0 ? 10-16 cm2?s-1 at 450?C, due to the fact that the existence of the SiO2 layer suppresses the interdiffusion of Cu and Si.
- Published
- 2008
9. Double Electron Processes in Collisions of Partially Stripped Ions C q + ( q = 1−4) with Helium
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Xie Jiangshan, Shao Jian-Xiong, Gao Zhi-Min, Fu Hong-Bin, Liu Yu-Wen, Chen Xi-Meng, Liu Zhao-Yuan, Cui Ying, Ding Bao-Wei, Cai Xiao-Hong, Sun Guang-Zhi, Lu Yan-Xia, Du Juan, Chen Lin, Yu Deyang, and HE Zi-Feng
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Physics ,Single electron ,chemistry ,Ionization ,General Physics and Astronomy ,chemistry.chemical_element ,Charge (physics) ,Electron ,Atomic physics ,Helium ,Ion - Abstract
The multi-electron processes are investigated for 17.9–120 keV/u C1+, 30–323 keV/u C2+, 120–438 keV/u C3+, 287–480 keV/u C4+ incident on a helium target. The cross-section ratios of double electron (DE) process to the total of the single electron (SE) and the double electron process (i.e. SE+DE), the direct double electron (DDI) to the direct single ionization (DSI) as well as the contributions of DDI to DE and of TI to DE are measured using coincidence techniques. The energy and charge state dependences of the measured cross-section ratios are studied and discussed.
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- 2007
10. Double Electron Processes in Low Energy Isotope Bare Ions13C6+with Helium Collisions
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Xu Xu, Chen Xi-Meng, Yang Zhi-Hu, Cui Ying, Shao Jian-Xiong, Cai Xiao-Hong, Lu Rongchun, Zhang Hong-Qiang, Ruan Fang-Fang, Ding Bao-Wei, Shao Cao-Jie, Lu Jun, and Yu Deyang
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Physics ,education.field_of_study ,Isotope ,Projectile ,Population ,General Physics and Astronomy ,chemistry.chemical_element ,Electron ,Radiation ,Ion ,chemistry ,Ionization ,Atomic physics ,education ,Helium - Abstract
The isotopic bare ion 13C6+ was employed to collide with helium at 4.15–11.08 keV/u. The relative partial cross sections were measured by position-sensitive and time-of-flight coincident techniques. It is shown that the direct-ionization (DI) process can be completely ignored in this region, the transfer ionization (TI) process is the most important double-electron channel, and the probability of the pure double-electron capture (DC) process is quite small. The cross-section ratio of the total double-electron (DE) process (i.e. DC+TI) to the single-electron capture (SC) process is experimentally determined to be approximately a constant of 0.09±0.03 in this region, and this value is obviously smaller than the predictions of the classical over-barrier models and the semi-empirical scaling laws. It is found that the cross-section ratio of pure DC to DE decreases obviously as the projectile velocity increases. Because the pure DC process only comes from the radiation de-excitation following the DC process and are competed by the TI process (comes from the auto-ionization following the DC process), this implies that the population of the two captured electrons depends distinctly on the collision velocity. Comparison with works on Ar16+–He by Wu et al. [Phys. Rev. A 48 (1993) 3617] reveals that the strong projectile-dependent character of the pure DC process exists.
- Published
- 2005
11. Experimental study of cross-section ratios in the collisions of C q + and O q + ( q = 1–4) on atomic helium in strong-interaction region
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Wang Fan, Lü Xue-Yang, Lü Ying, Qiu Xi-Yu, Zhou Peng, Jiang Li-Juan, Shao Jian-Xiong, Wang Xing-An, Jia Juan-Juan, Lou Feng-Jun, Zhou Chun-Lin, Chen Lin, Chen Xi-Meng, Cui Ying, and Gao Zhi-Min
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Physics ,Cross section (physics) ,Range (particle radiation) ,chemistry ,Strong interaction ,Atomic helium ,General Physics and Astronomy ,chemistry.chemical_element ,Atomic physics ,Helium ,Coincidence ,Spectral line - Abstract
We have measured the cross-section ratios of helium induced by Cq+ and Oq+ (q = 1?4) in an energy range from 20 keV/amu to 500 keV/amu, and obtained the two-dimensional spectra by employing the coincidence method combined with the MPA-3 data acquisition system. Hence, we obtain the ratios of total single-ionization cross-sections (SI, SC, SLSI, and DLSI), total double-ionization cross-sections (DI, DC, TI, SLDI, and DLDI) and cross-sections of every process (SI, SC, SLSI, DLSI, DI, DC, TI, SLDI, and DLDI), which induce the single-ionization and double-ionization, to the total cross sections respectively. The competitive relations between the reaction-channels and the experimental data law of each reaction-channel are revealed explicitly, and the qualitative explanations involved in those results are also presented accordingly.
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- 2011
12. Atomic diffusion in annealed CU/SiO 2 /Si (100) system prepared by magnetron sputtering
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Cao Bo, Jia Yan-Hui, Li Gong-Ping, and Chen Xi-Meng
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Atomic diffusion ,Diffraction ,Materials science ,chemistry ,Annealing (metallurgy) ,Analytical chemistry ,General Physics and Astronomy ,chemistry.chemical_element ,Activation energy ,Sputter deposition ,Thin film ,Rutherford backscattering spectrometry ,Copper - Abstract
Cu thin films are deposited on p-type Si (100) substrates by magnetron sputtering at room temperature. The interface reaction and atomic diffusion of Cu/SiO2/Si (100) systems are studied by x-ray diffraction (XRD) and Rutherford backscattering spectrometry (RBS). Some significant results can be obtained. The onset temperature of interdiffusion for Cu/SiO2/Si(100) is 350 °C. With the annealing temperature increasing, the interdiffusion becomes more apparent. The calculated diffusion activation energy is about 0.91 eV. For the CU/SiO2/Si (100) systems copper silicides are not formed below an annealing temperature of 350 °C. The formation of the copper silicides phase is observed when the annealing temperature arrives at 450 °C.
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- 2010
13. Investigation of pure ionization cross-sections of neon induced by C3+ collision
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Chen Xi-Meng, Cui Ying, Fu Hong-Bin, Lu Yan-Xia, Zhang Hong-Qiang, Ding Bao-Wei, Shao Jian-Xiong, and Gao Zhi-Min
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Range (particle radiation) ,Auger effect ,Projectile ,Monte Carlo method ,General Physics and Astronomy ,chemistry.chemical_element ,Ion ,Neon ,symbols.namesake ,Recoil ,chemistry ,Ionization ,symbols ,Atomic physics - Abstract
This paper presents the measurement results of absolute cross-sections of ion-atom collision in detail. The pure cross-sections of Nei+(i=1—4) induced by C3+ were investigated using coincidence technique. Comparing our experimental results with those of n-body classical trajectory Monte Carlo method, it is found that the changes of pure cross sections with increasing energy have the same trend in the two cases. The causes of discrepancies between them are discussed. The mechanism of multiple-ionization is analyzed. The highly charged recoil ions come mainly from the Auger effect. The electron-electron interaction comes in to effect as the incident energy increases. The cross-sections of all kinds of reactions can be measured in this way using the same equipment and projectile ions can be various within a wide range of energy.
- Published
- 2007
14. X-ray emission in lithium-like and helium-like argon ions colliding with molybdenum surfaces
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Xiao Guo-Qing, Zhang Hong-Qiang, Yang Zhi-Hu, Shao Jian-Xiong, Zhang Yan-Ping, Xu Xu, Zhang Xiao-An, Du Shu-Bin, Chen Xi-Meng, Cui Ying, and Zhao Yong-Tao
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Materials science ,Argon ,Projectile ,Astrophysics::High Energy Astrophysical Phenomena ,Analytical chemistry ,General Physics and Astronomy ,chemistry.chemical_element ,Kinetic energy ,Computer Science::Digital Libraries ,Ion ,chemistry ,Molybdenum ,Physics::Space Physics ,Atom ,Astrophysics::Solar and Stellar Astrophysics ,Lithium ,Helium - Abstract
We have measured the spectra and yields for Ar K and Mo L x-rays from Ar 15+ and Ar16+ ions colliding with molybdenum (Mo) surfaces . The spec tra and yields are measured as a function of the projectile kinetic energy. In t he case of Ar15+ -Mo, both Ar K x-rays and Mo L x-rays are observe d, and the yields of Ar K x-rays are related to the projectile kinetic energ y, the potential energy of hollow atom formed in the interaction, the competitio n of the x-rays emitting from the projectile and the target etc. But in the case of Ar15+-Mo, Mo L x-rays are observed only. The yields of Mo L x- rays induced in both cases increase with the projectile kinetic energy.
- Published
- 2005
15. The x-ray spectra of hollow atoms
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Yang Zhi-Hu, Zhao Yong-Tao, Chen Xi-Meng, Cui Ying, Shao Jian-Xiong, Zhang Hong-Qiang, Xu Xu, Zhang Xiao-An, Zhang Yan-Ping, Xiao Guo-Qing, and Li Fu-Li
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Argon ,Physics::Instrumentation and Detectors ,General Physics and Astronomy ,chemistry.chemical_element ,Spectral line ,Ion source ,Electron cyclotron resonance ,Ion ,chemistry ,Physics::Plasma Physics ,Yield (chemistry) ,Physics::Atomic and Molecular Clusters ,Physics::Atomic Physics ,Physics::Chemical Physics ,Atomic physics ,Beryllium ,X ray spectra - Abstract
The x-ray spectra of hollow atoms in the interaction of highly charged argon ions with beryllium solid surface are reported. The interaction ions, provided by t he electron cyclotron resonance (ECR) ion source in the National Laboratory of t he Heavy Ion Research Facility in Lanzhou(HIRFL), include bare argon ions, which are produced by the ion source for the first time, and hydrogen-like, helium-li ke and lithium-like argon ions. We found that the K-shell x-ray yield of single particles in the interaction of hydrogen-like argon ions is 36×10-3, wh ich is 5 orders more than that of helium-like argon ions, and the K-shell x-ray cannot be measured in the interaction of lithium-like argon ions with beryllium surface.
- Published
- 2005
16. Study of the electron transfer in Xeq+-He collisions
- Author
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Cao Zhu-Rong, Chen Xi-Meng, Lu Rongchun, Cai Xiaohong, Shao Cao-Jie, Yu Deyang, and Yang Wei
- Subjects
Single electron ,Cross section (physics) ,Electron transfer ,Chemistry ,Position (vector) ,Transfer mechanism ,General Physics and Astronomy ,chemistry.chemical_element ,Atomic physics ,Helium ,Ion - Abstract
The cross section ratios of the double to single electron transfer of helium target induced by Xeq+(q=15,17,19,21,23) ions are measured by means of the position sensitive and timeofflight techniques. By considering an onestep transfer mechanism, we modify the extended classical overbarrier model. It is found that the calculated single and double electrontransfer cross sections using the modified model show excellent agreement with the experimental data of Andersson et al. and Selberg et al, and improves the agreement with the present measured double to single electrontransfer ratio considerably.
- Published
- 2004
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