Fe K-shell ionization cross sections induced by 2.4-6.0 MeV Xe^20＋ are measured and compared with different binary- encounter-approximation （BEA） models. The results indicate that the BEA model corrected both by th...Fe K-shell ionization cross sections induced by 2.4-6.0 MeV Xe^20＋ are measured and compared with different binary- encounter-approximation （BEA） models. The results indicate that the BEA model corrected both by the Coulomb repulsion and by the effective nuclear charge （Zeff） agrees well with the experimental data. Comparison of Fe K-shell X-ray emission induced by 5 MeV xenon ions with different initial charge states （20＋, 22＋, 26＋, 30＋） verifies the applicability of the effective nuclear charge （Zeff） correction for the BEA model. It is found that Zeff correction is reasonable to describe direct ionization induced by xenon ions with no initial M-shell vacancies. However, when the M shell is opened, the Zeff corrected BEA model is unable to explain the inner-shell ionization, and the electron transfer by molecular-orbital promotion should be considered.展开更多
A comprehensive theoretical study of correlation effects on the fine-structure splitting within the ground configuration 3d9 of the Co-like HI45＋, Ta46＋, W47＋, and Au52＋ ions is performed by employing the multi-co...A comprehensive theoretical study of correlation effects on the fine-structure splitting within the ground configuration 3d9 of the Co-like HI45＋, Ta46＋, W47＋, and Au52＋ ions is performed by employing the multi-configuration Dirac-Hartree- Fock method in the active space approximation. It shows that the core-valence correlation with the inner-core 2p electron is more significant than with the outer 3p and 3s electrons, and the correlation with the 2s electron is also noticeable. The core-core correlation seems to be small and can be ignored. The calculated 2D3/2,5/2 splitting energies agree with the recent electron-beam ion-trap measurements [Phys. Rev. A 83 032517 （2011）, Eur. Phys. J. D 66 286 （2012）] to within the experimental uncertainties.展开更多
The H+H2 reaction is the simplest chemical reaction system and has long been the prototype model in the study of reaction dynamics. Here we report a high resolution experimental investigation of the state-to-state rea...The H+H2 reaction is the simplest chemical reaction system and has long been the prototype model in the study of reaction dynamics. Here we report a high resolution experimental investigation of the state-to-state reaction dynamics in the H+HD→H2+D reaction by using the crossed molecular beams method and velocity map ion imaging technique at the collision energy of 1.17 eV. D atom products in this reaction were probed by the near threshold 1+1'(vacuum ultraviolet+ultraviolet) laser ionization scheme. The ion image with both high angular and energy resolution were acquired. State-to-state differential cross sections was accurately derived. Fast forward scattering oscillations, relating with interference effects in the scattering process, were clearly observed for H2 products at H2(v'=0,j'=1) and H2(v'=0,j'=3) rovibrational levels. This study further demonstrates the importance of measuring high-resolution differential cross sections in the study of state-to-state reaction dynamics in the gas phase.展开更多
The excitation spectra in the wavelength range of 19—40 nm for highly ionized sulphur ions were measured by using the beam-foil method at the Heavy lon Research Facility in Lanzhou. In this experiment, more than 30 s...The excitation spectra in the wavelength range of 19—40 nm for highly ionized sulphur ions were measured by using the beam-foil method at the Heavy lon Research Facility in Lanzhou. In this experiment, more than 30 spectral lines were observed, which belonged to the transitions of the excitation energy levels for highly ionized SX—SXV ions, and 5 new lines were determined. The experimental results were compared with those from other experiments and theoretical calculations.展开更多
利用柱后分流频率调制Chirp Z变换离子迁移谱(IMS),建立了高效液相色谱与纳流电喷雾阵列Chirp Z变换离子迁移谱(HPLC-Nano ESI-Chirp Z IMS)联用分析方法,考察了喷雾电压、溶剂组成、溶液流速等参数对Nano ESI-Chirp Z IMS信噪比的影响...利用柱后分流频率调制Chirp Z变换离子迁移谱(IMS),建立了高效液相色谱与纳流电喷雾阵列Chirp Z变换离子迁移谱(HPLC-Nano ESI-Chirp Z IMS)联用分析方法,考察了喷雾电压、溶剂组成、溶液流速等参数对Nano ESI-Chirp Z IMS信噪比的影响。在此基础上,利用建立的方法对一系列四烷基溴化铵类化合物进行测定,并比较了Chirp Z变换法和FT变换法两种方法的信噪比和分辨率。实验结果表明,最佳实验条件为:喷雾电压4.5 k V;溶剂组成90%甲醇;ESI溶液流速为8μL/min。利用HPLC-Nano ESI-Chirp Z IMS联用方法成功测定了四丁基溴化铵、四戊基溴化铵、四己基溴化铵、四庚基溴化铵、四辛基溴化铵烷、四癸基溴化铵组成的混合样品。与传统信号平均离子迁移谱相比,Chirp Z变换离子迁移谱的信噪比更高,其迁移时间的测定精度优于傅里叶变换离子迁移谱。展开更多
In this work, highly charged ions have been extracted from the advanced Electron Beam Ion Source （EBIS-A） developed in a scientific cooperation between the Dresden University of Technology and the DREEBIT GmbH Dresd...In this work, highly charged ions have been extracted from the advanced Electron Beam Ion Source （EBIS-A） developed in a scientific cooperation between the Dresden University of Technology and the DREEBIT GmbH Dresden. The charge state distributions of ions extracted from the EBIS-A are measured in the pulse and leaky modes under different operation conditions. Aris＋ ions with current of 2 pA are produced and extracted in the leaky mode. 3×10^5 Ar^18＋ ions per pulse are extracted in the pulse mode. The ion charge state distribution is a function of the ionization time.展开更多
Magnetic clouds(MCs) frequently show abnormal high-ionization states of heavy ions. The abnormal high-charge distributions are related to the coronal temperature of their source regions. We examined the plasma and mag...Magnetic clouds(MCs) frequently show abnormal high-ionization states of heavy ions. The abnormal high-charge distributions are related to the coronal temperature of their source regions. We examined the plasma and magnetic field data of 74 MCs observed by the Advanced Composition Explorer from February 1998 to December 2008. We determined that 14 of the 74 events showed local high-temperature phenomena. We analyzed the correlation between proton temperature and O7/O6ratio(or high mean Fe charge state ?Fe?) within the local high-temperature regions in the 14 MCs. Results show that proton temperature and O7/O6 ratio(or high mean Fe charge state) had good correlations in nine MCs, but had no evident correlation in the other five MCs. The local high-temperature phenomena within the nine MCs have resulted from the Sun.展开更多
基金Project supported by the National Basic Research Program of China(Grant No.2010CB832902)the National Natural Science Foundation of China(Grant Nos.11275241,11205225,11105192,and 11275238)
文摘Fe K-shell ionization cross sections induced by 2.4-6.0 MeV Xe^20＋ are measured and compared with different binary- encounter-approximation （BEA） models. The results indicate that the BEA model corrected both by the Coulomb repulsion and by the effective nuclear charge （Zeff） agrees well with the experimental data. Comparison of Fe K-shell X-ray emission induced by 5 MeV xenon ions with different initial charge states （20＋, 22＋, 26＋, 30＋） verifies the applicability of the effective nuclear charge （Zeff） correction for the BEA model. It is found that Zeff correction is reasonable to describe direct ionization induced by xenon ions with no initial M-shell vacancies. However, when the M shell is opened, the Zeff corrected BEA model is unable to explain the inner-shell ionization, and the electron transfer by molecular-orbital promotion should be considered.
基金supported by the National Natural Science Foundation of China(Grant Nos.11076009 and 11374062)the Chinese Association of Atomic and Molecular Data+1 种基金the Chinese National Fusion Project for ITER(Grant No.2015GB117000)the Leading Academic Discipline Project of Shanghai City,China(Grant No.B107)
文摘A comprehensive theoretical study of correlation effects on the fine-structure splitting within the ground configuration 3d9 of the Co-like HI45＋, Ta46＋, W47＋, and Au52＋ ions is performed by employing the multi-configuration Dirac-Hartree- Fock method in the active space approximation. It shows that the core-valence correlation with the inner-core 2p electron is more significant than with the outer 3p and 3s electrons, and the correlation with the 2s electron is also noticeable. The core-core correlation seems to be small and can be ignored. The calculated 2D3/2,5/2 splitting energies agree with the recent electron-beam ion-trap measurements [Phys. Rev. A 83 032517 （2011）, Eur. Phys. J. D 66 286 （2012）] to within the experimental uncertainties.
基金supported by the National Key R&D Program of China (No.2016YFF0200500)the National Natural Science Foundation of China (No.21473173, No.21590802, No.21403207, No.21503206)the Strategic Priority Research Program of Chinese Academy of Sciences (No.XDB17000000)
文摘The H+H2 reaction is the simplest chemical reaction system and has long been the prototype model in the study of reaction dynamics. Here we report a high resolution experimental investigation of the state-to-state reaction dynamics in the H+HD→H2+D reaction by using the crossed molecular beams method and velocity map ion imaging technique at the collision energy of 1.17 eV. D atom products in this reaction were probed by the near threshold 1+1'(vacuum ultraviolet+ultraviolet) laser ionization scheme. The ion image with both high angular and energy resolution were acquired. State-to-state differential cross sections was accurately derived. Fast forward scattering oscillations, relating with interference effects in the scattering process, were clearly observed for H2 products at H2(v'=0,j'=1) and H2(v'=0,j'=3) rovibrational levels. This study further demonstrates the importance of measuring high-resolution differential cross sections in the study of state-to-state reaction dynamics in the gas phase.
基金This work was supported by the National Natural Science Foundation of China(Grant No.19974057)
文摘The excitation spectra in the wavelength range of 19—40 nm for highly ionized sulphur ions were measured by using the beam-foil method at the Heavy lon Research Facility in Lanzhou. In this experiment, more than 30 spectral lines were observed, which belonged to the transitions of the excitation energy levels for highly ionized SX—SXV ions, and 5 new lines were determined. The experimental results were compared with those from other experiments and theoretical calculations.
文摘利用柱后分流频率调制Chirp Z变换离子迁移谱(IMS),建立了高效液相色谱与纳流电喷雾阵列Chirp Z变换离子迁移谱(HPLC-Nano ESI-Chirp Z IMS)联用分析方法,考察了喷雾电压、溶剂组成、溶液流速等参数对Nano ESI-Chirp Z IMS信噪比的影响。在此基础上,利用建立的方法对一系列四烷基溴化铵类化合物进行测定,并比较了Chirp Z变换法和FT变换法两种方法的信噪比和分辨率。实验结果表明,最佳实验条件为:喷雾电压4.5 k V;溶剂组成90%甲醇;ESI溶液流速为8μL/min。利用HPLC-Nano ESI-Chirp Z IMS联用方法成功测定了四丁基溴化铵、四戊基溴化铵、四己基溴化铵、四庚基溴化铵、四辛基溴化铵烷、四癸基溴化铵组成的混合样品。与传统信号平均离子迁移谱相比,Chirp Z变换离子迁移谱的信噪比更高,其迁移时间的测定精度优于傅里叶变换离子迁移谱。
基金National Natural Science Foundation of China(10475035)
文摘In this work, highly charged ions have been extracted from the advanced Electron Beam Ion Source （EBIS-A） developed in a scientific cooperation between the Dresden University of Technology and the DREEBIT GmbH Dresden. The charge state distributions of ions extracted from the EBIS-A are measured in the pulse and leaky modes under different operation conditions. Aris＋ ions with current of 2 pA are produced and extracted in the leaky mode. 3×10^5 Ar^18＋ ions per pulse are extracted in the pulse mode. The ion charge state distribution is a function of the ionization time.
基金supported by the National Natural Science Foundation of China (Grant Nos. 41274180 & 41231068)the Program for Science and Technology Innovation Research Team in University of Henan Province (Grant No. 13IRTSTHN020)
文摘Magnetic clouds(MCs) frequently show abnormal high-ionization states of heavy ions. The abnormal high-charge distributions are related to the coronal temperature of their source regions. We examined the plasma and magnetic field data of 74 MCs observed by the Advanced Composition Explorer from February 1998 to December 2008. We determined that 14 of the 74 events showed local high-temperature phenomena. We analyzed the correlation between proton temperature and O7/O6ratio(or high mean Fe charge state ?Fe?) within the local high-temperature regions in the 14 MCs. Results show that proton temperature and O7/O6 ratio(or high mean Fe charge state) had good correlations in nine MCs, but had no evident correlation in the other five MCs. The local high-temperature phenomena within the nine MCs have resulted from the Sun.
