A Monte Carlo code is developed to study mega-electron-volt （MeV） electron scattering and transport in plasma based on multiple scattering. A scaling law relating the angular width of a scattered beam to the inciden...A Monte Carlo code is developed to study mega-electron-volt （MeV） electron scattering and transport in plasma based on multiple scattering. A scaling law relating the angular width of a scattered beam to the incident electron energy and the areal density of plasma is found, which may provide a method of MeV electron radiography for diagnosing the area/density of high-temperature, dense plasma under fusion conditions. The study on the MeV electron beam radiography also shows that plasma density interfaces could be discriminated by electron scattering.展开更多
Ta/MgO/NiFe/MgO/Ta ultrathin films with and without intercalation of NiFe nanoparticles in MgO layers were prepared by magnetron sputtering, followed by a vacuum annealing process. The measured and calculated results ...Ta/MgO/NiFe/MgO/Ta ultrathin films with and without intercalation of NiFe nanoparticles in MgO layers were prepared by magnetron sputtering, followed by a vacuum annealing process. The measured and calculated results show that the former has higher specular electron scattering (SES) parameter at MgO/NiFe interfaces, lower resistivity, and higher magnetoresistance (MR). The improved transport properties (TPs) are mainly attributed to the suppressed diffuse electron scattering by means of the introduction of NiFe nanoparticles.展开更多
We report elastic cross sections for low-energy electron scattering with formamide-(H_(2)O)n complexes(n=1,2)in the energy region of 0.01-8 eV.The scattering calculations are performed using the R-matrix method in the...We report elastic cross sections for low-energy electron scattering with formamide-(H_(2)O)n complexes(n=1,2)in the energy region of 0.01-8 eV.The scattering calculations are performed using the R-matrix method in the static-exchange(SE)approximation.We consider three structures of formamide-H_(2)O and six structures of formamide-(H_(2)O)_(2)in the present work.Our purpose is to investigate effects of water molecules hydrogen-bonding to formamide.We focus on the influence of microsolvation on theπ*andσ*resonances of formamide.The scattering result for complexes shows that the position ofπ*resonance appears at lower or higher energies in the cluster than in the isolated formamide depending on the complex structure and the water role in the hydrogen bonding.We explain this behavior according to the net charge of the solute.It is found that the microsolvation environment has a substantial effect on the width ofπ*resonance.Our results indicate that surrounding water molecules may affect the lifetime of the resonances,and hence the process is driven by the anion state,such as the dissociative electron attachment.展开更多
We investigate the Terahertz （THz） plasma waves in a two-dimensional （2D） electron gas in a nanometer field effect transistor （FET） with quantum effects, the electron scattering, the thermal motion of electrons ...We investigate the Terahertz （THz） plasma waves in a two-dimensional （2D） electron gas in a nanometer field effect transistor （FET） with quantum effects, the electron scattering, the thermal motion of electrons and electron exchange-correlation. We find that, while the elec- tron scattering, the wave number along y direction and the electron exchange-correlation suppress the radiation power, but the thermal motion of electrons and the quantum effects can amplify the radiation power. The radiation frequency decreases with electron exchange-correlation con- tributions, but increases with quantum effects, motion of electrons. It is worth mentioning that radiation frequency. These properties could be plasma oscillations in nanometer FET. the wave number along y direction and thermal the electron scattering has scarce influence on the of great help to the realization of practical THz展开更多
Oscillator strengths and cross sections of the valence-shell excitations in NO_(2)are of great significance in testing the theoretical calculations and monitoring the state of the ozone layer in the earth’s atmospher...Oscillator strengths and cross sections of the valence-shell excitations in NO_(2)are of great significance in testing the theoretical calculations and monitoring the state of the ozone layer in the earth’s atmosphere. In the present work, the generalized oscillator strengths of the valence-shell excitations in NO_(2)were obtained based on the fast electron scattering technique at an incident electron energy of 1.5 ke V and an energy resolution of about 70 me V. By extrapolating the generalized oscillator strengths to the limit of a zero squared momentum transfer, the optical oscillator strengths for the dipole-allowed transitions have been obtained, which provide an independent cross check to the previous experimental results. Based on the BE-scaling method, the corresponding integral cross sections have also been derived systematically from the excitation threshold to 5000 eV. The present dynamic parameters can provide the fundamental spectroscopic data of NO_(2)and have important applications in the studies of atmospheric science. The datasets presented in this paper, including the GOSs, OOSs and ICSs, are openly available at https://doi.org/10.57760/sciencedb.j00113.00156.展开更多
Relativistic mean-field theory and phase-shift analysis are combined together to investigate the elasticCoulomb scattering between electrons and unstable nuclei.Electron scattering at several different energies is stu...Relativistic mean-field theory and phase-shift analysis are combined together to investigate the elasticCoulomb scattering between electrons and unstable nuclei.Electron scattering at several different energies is studiedand compared,in order to see the energy dependence of electron-nucleus scattering.It is shown that electron scattering at200 MeV or 300 MeV can be used to reveal electron-nucleus scattering information around the first diffraction minimum-Shiftsin opposite directions are obtained for the first diffraction minima of the electron scattering off the ground andfirst excited states of ^(17)F with ^(16)O as reference,and similar effects are obtained for ^(18)Ne.Besides,some neutron-richN = 8 isotones are also studied.Results show that electron scattering will be very useful and important in studyingboth proton- and neutron-rich nuclei in the future.展开更多
The optical-model approach has been used to investigate the electron-impact ionization of metastable rare-gas atoms. A complex equivalent-local polarization potential is obtained to describe the ionization continuum c...The optical-model approach has been used to investigate the electron-impact ionization of metastable rare-gas atoms. A complex equivalent-local polarization potential is obtained to describe the ionization continuum channels. We have calculated the cross sections for collisional ionization of the metastable atoms Ne＊ and Ar＊ by electrons in the energy range from threshold to 200 eV. The present results are in agreement with the available experimental measurements and other theoretical calculations.展开更多
As is known to all, the electron scattering in classical electromagnetic potential is one of the most widespread applications of quantum theory. Nevertheless, many discussions about electron scattering are based upon ...As is known to all, the electron scattering in classical electromagnetic potential is one of the most widespread applications of quantum theory. Nevertheless, many discussions about electron scattering are based upon single-particle Schrodinger equation or Dirac equation in quantum mechanics rather than the method of quantum field theory. In this paper, by using the path integral approach of quantum field theory, we perturbatively evaluate the scattering amplitude up to the second order for the electron scattering by the classical electromagnetic potential. The results we derive are convenient to apply to all sorts of potential forms. Furthermore, by means of the obtained results, we give explicit calculations for the one-dimensional electric potential.展开更多
The original additivity rule method cannot give good results for electron scattering from SO,SO2,SO2Cl2,SO2ClF,and SO2F2 molecules at low energy,because the electron-molecule scattering is simply reduced to electron-a...The original additivity rule method cannot give good results for electron scattering from SO,SO2,SO2Cl2,SO2ClF,and SO2F2 molecules at low energy,because the electron-molecule scattering is simply reduced to electron-atom scattering.Considering the difference between the bound atom in a molecule and the corresponding free atom,the original additivity rule is revised.With the revised additivity rule,the total cross sections for electron scattering from these molecules are calculated over a wide energy range below 3000 eV and compared with the available experimental and theoretical data.A better agreement between them is obtained.展开更多
We present elastic electron scattering cross sections with holmethane molecules CH_(2)Br_(2)and CCl_(2)Br_(2)in the lowenergy region ranging from 0.01 e V to 20 e V.The calculations are performed with the R-matrix met...We present elastic electron scattering cross sections with holmethane molecules CH_(2)Br_(2)and CCl_(2)Br_(2)in the lowenergy region ranging from 0.01 e V to 20 e V.The calculations are performed with the R-matrix method in static-exchange plus polarization(SEP)and close-coupling(CC)approximations.The integral,differential,and momentum transfer cross sections are calculated.The convergence of the obtained cross sections is checked at four different levels of SEP approximation.The predicted positions of the resonances agree well with available results.The precise resonance parameters are found to be sensitive to the treatment of polarization effects employed.We find that the polarization has a substantial effect on the cross sections,and this effect becomes even more important for lower impact energies.展开更多
The additivity rule for electron-molecule scattering is revised by considering the difference between the free atom and the bound atom in the molecule. The total cross sections for electron scattering from fluorometha...The additivity rule for electron-molecule scattering is revised by considering the difference between the free atom and the bound atom in the molecule. The total cross sections for electron scattering from fluoromethanes （CF4, CF3H, CF2H2, and CFH3） are calculated in an energy range from 100 eV to 1500 eV by the revised additivity rule. The present calculations are compared with the original additivity rule results and the available experimental data. Better agreement with each other is obtained.展开更多
The precise determination of neutron distribution has important implications for both nuclear structure and nuclear astrophysics. The purpose of this paper is to study the characteristics of neutron distribution of^20...The precise determination of neutron distribution has important implications for both nuclear structure and nuclear astrophysics. The purpose of this paper is to study the characteristics of neutron distribution of^208 Pb by parity-violating electron scattering（PVS）. Parity-violating asymmetries of^208 Pb with different types of neutron skins are systematically calculated and compared with the experimental data of PREx. The results indicate that the PVS experiments are very sensitive to the nuclear neutron distributions. From further PVS measurements, detailed information on nuclear neutron distributions can be extracted.展开更多
We investigate the differential cross sections （DCS） of elastic electron scattering from CH4, CF4 and SF6 at six impact energies in a range of 100 700eV by employing the independent atom model （IAM） together with ...We investigate the differential cross sections （DCS） of elastic electron scattering from CH4, CF4 and SF6 at six impact energies in a range of 100 700eV by employing the independent atom model （IAM） together with the relativistic partial waves. The atom is present in an optical potential which is complex, spherically symmetric, and energy dependent. The optical potential of the atom is the sum of the direct static, dynamic polarization, local exchange and modified absorption potentials. The results obtained by using a modified absorption potential show significant improvements on the unmodified absorption potential results. The present results are generally in good agreement with experimental data available. In addition, the present results indicate that the structure of molecule manifests the observable effects on electron- molecule scattering.展开更多
We present a novel numerical model and simulate preliminarily the charging process of a polymer subjected to electron irradiation of several 10 keV. The model includes the simultaneous processes of electron scattering...We present a novel numerical model and simulate preliminarily the charging process of a polymer subjected to electron irradiation of several 10 keV. The model includes the simultaneous processes of electron scattering and ambipolar transport and the influence of a self-consistent electric field on the scattering distribution of electrons. The dynamic spatial distribution of charges is obtained and validated by existing experimental data. Our simulations show that excess negative charges are concentrated near the edge of the electron range. However, the formed region of high charge density may extend to the surface and bottom of a kapton sample, due to the effects of the electric field on electron scattering and charge transport, respectively. Charge trapping is then demonstrated to significantly influence the charge motion. The charge distribution can be extended to the bottom as the trap density decreases. Charge accumulation is therefore balanced by the appearance and increase of leakage current. Accordingly, our model and numerical simulation provide a comprehensive insight into the charging dynamics of a polymer irradiated by electrons in the complex space environment.展开更多
Whistler mode waves are critical emissions in magnetized plasmas that usually influence the electron dynamics in a planetary magnetosphere.In this paper,we present a unique event in the Martian magnetosphere in which ...Whistler mode waves are critical emissions in magnetized plasmas that usually influence the electron dynamics in a planetary magnetosphere.In this paper,we present a unique event in the Martian magnetosphere in which enhanced whistler mode waves(~10^(−11) V^(2)/m^(2)/Hz)with frequency of 0.1 f_(ce)-0.5 f_(ce) occurred,based on MAVEN data,exactly corresponding to a significant decrease of suprathermal electron fluxes.The diffusion coefficients are calculated by using the observed electric field wave spectra.The pitch angle diffusion coefficient can approach 10^(−2) s^(−1),which is much larger,by~100 times,than the momentum diffusion coefficient,indicating that pitch angle scattering dominates the whistler-electron resonance process.The current results can successfully explain the dropout of the suprathermal electrons in this event.This study provides direct evidence for whistler-driven electron losses in the Martian magnetosphere.展开更多
The charge form factors of elastic electron scattering for isotones with N=20 and N=28 are calculated using the phase-shift analysis method,with corresponding charge density distributions from relativistic mean-field ...The charge form factors of elastic electron scattering for isotones with N=20 and N=28 are calculated using the phase-shift analysis method,with corresponding charge density distributions from relativistic mean-field theory.The results show that there are sharp variations at the inner parts of charge distributions with the proton number decreasing.The corresponding charge form factors are divided into two groups because of the unique properties of the s-states wave functions,though the proton numbers change uniformly in two isotonic chains.Meanwhile,the shift regularities of theminima are also discussed,and we give a clear relation between theminima of the charge form factors and the corresponding charge radii.This relation is caused by the diffraction effect of the electron.Under this conclusion,we calculate the charge density distributions and the charge form factors of the A=44 nuclei chain.The results are also useful for studying the central depression in light exotic nuclei.展开更多
Scaling analyses have been successfully applied to study the inclusive electron scattering(e, e') over the past few decades. In this study, we utilize the ψ' scaling function in momentum space to analyze the(...Scaling analyses have been successfully applied to study the inclusive electron scattering(e, e') over the past few decades. In this study, we utilize the ψ' scaling function in momentum space to analyze the(e, e') cross sections, where the nucleon momentum distributions are derived from self-consistent mean-field calculations. By further introducing the energy and momentum conservation in the scaling analysis, an improved ψ'scaling function is proposed to investigate the high-momentum part of the momentum distributions. Using the proposed scaling function, we systematically explore the effects of the nucleon-nucleon short-range correlation(NN-SRC) on the(e, e') cross sections. From the experimental(e, e') data, the NN-SRC strength is further extracted within the framework of the improved ψ'scaling function. The studies in this paper offer a new method to investigate the nucleon momentum distributions and the NN-SRC effects in nuclei.展开更多
We apply the derivative coupling model with ZM and ZM3 parameters to investigate the longitudinal response function in quasielastic electron scattering in the relativistic random phase approximation. The non-spectral ...We apply the derivative coupling model with ZM and ZM3 parameters to investigate the longitudinal response function in quasielastic electron scattering in the relativistic random phase approximation. The non-spectral method is chosen to describe the nucleon Green＇s function in a finite nucleus. Some remarks have been made in conclusion.展开更多
Total cross sections （TCSs） of electrons scattering from triatomic molecules over the energy range from 30 to 5000 eV are investigated employing a new semi-empirical formula. The TCSs of electrons scattering from tr...Total cross sections （TCSs） of electrons scattering from triatomic molecules over the energy range from 30 to 5000 eV are investigated employing a new semi-empirical formula. The TCSs of electrons scattering from triatomic molecules SO2, NO2, and CO2 are calculated. The quantitative TCSs are in good agreement with those obtained by experiments. It is shown that the results derived from the semi-empirical formula are much closer to the measurements than other calculations.展开更多
Hydride ion(H-)conductors have drawn much attention due to their potential applications in hydrideion-based devices.Rare earth metal hydrides(REH_(x))have fast H-conduction which,unfortunately,is accompanied by detrim...Hydride ion(H-)conductors have drawn much attention due to their potential applications in hydrideion-based devices.Rare earth metal hydrides(REH_(x))have fast H-conduction which,unfortunately,is accompanied by detrimental electron conduction preventing their application as ion conductors.Here,REH_(x)(RE=Nd,Ce,and Pr)with varied grain sizes,rich grain boundaries,and defects have been prepared by ball milling and subsequent sintering.The electronic conductivity of the ball-milled REH_(x)samples can be reduced by 2-4 orders of magnitude compared with the non-ball-milled samples.The relationship of electron conduction and miscrostructures in REH_(x)is studied and discussed based on experimental data and previously-proposed classical and quantum theories.The H-conductivity of all REH_(x)is about 10^(-4)to 10^(-3)S cm^(-1)at room temperature,showing promise for the development of H-conductors and their applications in clean energy storage and conversion.展开更多
基金Supported by the National Natural Science Foundation of China under Grant No 11375194
文摘A Monte Carlo code is developed to study mega-electron-volt （MeV） electron scattering and transport in plasma based on multiple scattering. A scaling law relating the angular width of a scattered beam to the incident electron energy and the areal density of plasma is found, which may provide a method of MeV electron radiography for diagnosing the area/density of high-temperature, dense plasma under fusion conditions. The study on the MeV electron beam radiography also shows that plasma density interfaces could be discriminated by electron scattering.
基金financially supported by the National Natural Science Foundation of China (Nos. 51071023,51101012)Funding Project for Academic Human Resources Development in Institutions of Higher Learning under the Jurisdiction of Beijing Municipality (No.PHR201007122)
文摘Ta/MgO/NiFe/MgO/Ta ultrathin films with and without intercalation of NiFe nanoparticles in MgO layers were prepared by magnetron sputtering, followed by a vacuum annealing process. The measured and calculated results show that the former has higher specular electron scattering (SES) parameter at MgO/NiFe interfaces, lower resistivity, and higher magnetoresistance (MR). The improved transport properties (TPs) are mainly attributed to the suppressed diffuse electron scattering by means of the introduction of NiFe nanoparticles.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.U1504109 and 11604085)the Program for Science and Technology Innovation Talents in the Universities of Henan Province,China(Grant No.19HASTIT018)。
文摘We report elastic cross sections for low-energy electron scattering with formamide-(H_(2)O)n complexes(n=1,2)in the energy region of 0.01-8 eV.The scattering calculations are performed using the R-matrix method in the static-exchange(SE)approximation.We consider three structures of formamide-H_(2)O and six structures of formamide-(H_(2)O)_(2)in the present work.Our purpose is to investigate effects of water molecules hydrogen-bonding to formamide.We focus on the influence of microsolvation on theπ*andσ*resonances of formamide.The scattering result for complexes shows that the position ofπ*resonance appears at lower or higher energies in the cluster than in the isolated formamide depending on the complex structure and the water role in the hydrogen bonding.We explain this behavior according to the net charge of the solute.It is found that the microsolvation environment has a substantial effect on the width ofπ*resonance.Our results indicate that surrounding water molecules may affect the lifetime of the resonances,and hence the process is driven by the anion state,such as the dissociative electron attachment.
基金supported by National Natural Science Foundation of China(No.10975114)
文摘We investigate the Terahertz （THz） plasma waves in a two-dimensional （2D） electron gas in a nanometer field effect transistor （FET） with quantum effects, the electron scattering, the thermal motion of electrons and electron exchange-correlation. We find that, while the elec- tron scattering, the wave number along y direction and the electron exchange-correlation suppress the radiation power, but the thermal motion of electrons and the quantum effects can amplify the radiation power. The radiation frequency decreases with electron exchange-correlation con- tributions, but increases with quantum effects, motion of electrons. It is worth mentioning that radiation frequency. These properties could be plasma oscillations in nanometer FET. the wave number along y direction and thermal the electron scattering has scarce influence on the of great help to the realization of practical THz
基金Project supported by the National Key Research and Development Program of China (Grant No. 2022YFA1602500)the National Natural Science Foundation of China (Grant Nos. 12334010 and U1932207)。
文摘Oscillator strengths and cross sections of the valence-shell excitations in NO_(2)are of great significance in testing the theoretical calculations and monitoring the state of the ozone layer in the earth’s atmosphere. In the present work, the generalized oscillator strengths of the valence-shell excitations in NO_(2)were obtained based on the fast electron scattering technique at an incident electron energy of 1.5 ke V and an energy resolution of about 70 me V. By extrapolating the generalized oscillator strengths to the limit of a zero squared momentum transfer, the optical oscillator strengths for the dipole-allowed transitions have been obtained, which provide an independent cross check to the previous experimental results. Based on the BE-scaling method, the corresponding integral cross sections have also been derived systematically from the excitation threshold to 5000 eV. The present dynamic parameters can provide the fundamental spectroscopic data of NO_(2)and have important applications in the studies of atmospheric science. The datasets presented in this paper, including the GOSs, OOSs and ICSs, are openly available at https://doi.org/10.57760/sciencedb.j00113.00156.
基金Supported by the National Natural Science Foundation of China under Grant Nos.10535010,10675090,10775068,and 10975072the 973 National Major State Basic Research and Development of China under Grant No.2007CB815004+1 种基金CAS Knowledge Innovation Project KJCX2-SW-N02the Research Fund of Doctoral Point (RFDP) under Grant No.20070284016
文摘Relativistic mean-field theory and phase-shift analysis are combined together to investigate the elasticCoulomb scattering between electrons and unstable nuclei.Electron scattering at several different energies is studiedand compared,in order to see the energy dependence of electron-nucleus scattering.It is shown that electron scattering at200 MeV or 300 MeV can be used to reveal electron-nucleus scattering information around the first diffraction minimum-Shiftsin opposite directions are obtained for the first diffraction minima of the electron scattering off the ground andfirst excited states of ^(17)F with ^(16)O as reference,and similar effects are obtained for ^(18)Ne.Besides,some neutron-richN = 8 isotones are also studied.Results show that electron scattering will be very useful and important in studyingboth proton- and neutron-rich nuclei in the future.
基金the National Natural Science Foundation of China(Grant No.10874035)
文摘The optical-model approach has been used to investigate the electron-impact ionization of metastable rare-gas atoms. A complex equivalent-local polarization potential is obtained to describe the ionization continuum channels. We have calculated the cross sections for collisional ionization of the metastable atoms Ne＊ and Ar＊ by electrons in the energy range from threshold to 200 eV. The present results are in agreement with the available experimental measurements and other theoretical calculations.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11374360,11405266,and 11505285)the National Basic Research Program of China(Grant No.2013CBA01504)
文摘As is known to all, the electron scattering in classical electromagnetic potential is one of the most widespread applications of quantum theory. Nevertheless, many discussions about electron scattering are based upon single-particle Schrodinger equation or Dirac equation in quantum mechanics rather than the method of quantum field theory. In this paper, by using the path integral approach of quantum field theory, we perturbatively evaluate the scattering amplitude up to the second order for the electron scattering by the classical electromagnetic potential. The results we derive are convenient to apply to all sorts of potential forms. Furthermore, by means of the obtained results, we give explicit calculations for the one-dimensional electric potential.
基金Project supported by the National Natural Science Foundation of China (Grant No. 11204121)the Natural Science Foundation of Shandong Province,China(Grant No. ZR2011AL021)+1 种基金the National Natural Science Foundation of China (Grant No. 11074104)the Discipline Construction Fund of Ludong University,China
文摘The original additivity rule method cannot give good results for electron scattering from SO,SO2,SO2Cl2,SO2ClF,and SO2F2 molecules at low energy,because the electron-molecule scattering is simply reduced to electron-atom scattering.Considering the difference between the bound atom in a molecule and the corresponding free atom,the original additivity rule is revised.With the revised additivity rule,the total cross sections for electron scattering from these molecules are calculated over a wide energy range below 3000 eV and compared with the available experimental and theoretical data.A better agreement between them is obtained.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.U1504109 and 11604085)the Natural Science Foundation of Henan Province,China(Grant No.212300410054)。
文摘We present elastic electron scattering cross sections with holmethane molecules CH_(2)Br_(2)and CCl_(2)Br_(2)in the lowenergy region ranging from 0.01 e V to 20 e V.The calculations are performed with the R-matrix method in static-exchange plus polarization(SEP)and close-coupling(CC)approximations.The integral,differential,and momentum transfer cross sections are calculated.The convergence of the obtained cross sections is checked at four different levels of SEP approximation.The predicted positions of the resonances agree well with available results.The precise resonance parameters are found to be sensitive to the treatment of polarization effects employed.We find that the polarization has a substantial effect on the cross sections,and this effect becomes even more important for lower impact energies.
基金Project supported by the Natural Science Foundation of Shandong Province,China (Grant No. ZR2011AL021)the National Natural Science Foundation of China (Grant No. 11074104)+1 种基金the Research Foundation of Ludong University,China (Grant No. LY20072801)the Discipline Construction Fund of Ludong University,China
文摘The additivity rule for electron-molecule scattering is revised by considering the difference between the free atom and the bound atom in the molecule. The total cross sections for electron scattering from fluoromethanes （CF4, CF3H, CF2H2, and CFH3） are calculated in an energy range from 100 eV to 1500 eV by the revised additivity rule. The present calculations are compared with the original additivity rule results and the available experimental data. Better agreement with each other is obtained.
基金Supported by the National Natural Science Foundation of China(11505292,11175085,11235001,11447226)the Shandong Provincial Natural Science Foundation,China(BS2014SF007)the Fundamental Research Funds for the Central Universities(15CX02072A,15CX02070A,15CX05026A,13CX10022A,14CX02157A)
文摘The precise determination of neutron distribution has important implications for both nuclear structure and nuclear astrophysics. The purpose of this paper is to study the characteristics of neutron distribution of^208 Pb by parity-violating electron scattering（PVS）. Parity-violating asymmetries of^208 Pb with different types of neutron skins are systematically calculated and compared with the experimental data of PREx. The results indicate that the PVS experiments are very sensitive to the nuclear neutron distributions. From further PVS measurements, detailed information on nuclear neutron distributions can be extracted.
基金Project supported by the Shanghai Development Foundation from Science and Technology, China （Grant Nos 06JC14082 and 06QA14062）, the National Natural Science Foundation of China （Grant No 10535010）, and the Knowledge Innovation Project of Chinese Academy of Sciences （Grant No KJXC3-SYW-N2）.
文摘We investigate the differential cross sections （DCS） of elastic electron scattering from CH4, CF4 and SF6 at six impact energies in a range of 100 700eV by employing the independent atom model （IAM） together with the relativistic partial waves. The atom is present in an optical potential which is complex, spherically symmetric, and energy dependent. The optical potential of the atom is the sum of the direct static, dynamic polarization, local exchange and modified absorption potentials. The results obtained by using a modified absorption potential show significant improvements on the unmodified absorption potential results. The present results are generally in good agreement with experimental data available. In addition, the present results indicate that the structure of molecule manifests the observable effects on electron- molecule scattering.
基金Project supported by the National Natural Science Foundation of China(Grant No.11175140)the Fundamental Research Funds for the Central Universities
文摘We present a novel numerical model and simulate preliminarily the charging process of a polymer subjected to electron irradiation of several 10 keV. The model includes the simultaneous processes of electron scattering and ambipolar transport and the influence of a self-consistent electric field on the scattering distribution of electrons. The dynamic spatial distribution of charges is obtained and validated by existing experimental data. Our simulations show that excess negative charges are concentrated near the edge of the electron range. However, the formed region of high charge density may extend to the surface and bottom of a kapton sample, due to the effects of the electric field on electron scattering and charge transport, respectively. Charge trapping is then demonstrated to significantly influence the charge motion. The charge distribution can be extended to the bottom as the trap density decreases. Charge accumulation is therefore balanced by the appearance and increase of leakage current. Accordingly, our model and numerical simulation provide a comprehensive insight into the charging dynamics of a polymer irradiated by electrons in the complex space environment.
基金the National Natural Science Foundation of China grants 42230209, 42241136, 42374199, 42204171, 42274212the Natural Science Foundation of Hunan province Grant 2021JJ20010, 2023JJ20038
文摘Whistler mode waves are critical emissions in magnetized plasmas that usually influence the electron dynamics in a planetary magnetosphere.In this paper,we present a unique event in the Martian magnetosphere in which enhanced whistler mode waves(~10^(−11) V^(2)/m^(2)/Hz)with frequency of 0.1 f_(ce)-0.5 f_(ce) occurred,based on MAVEN data,exactly corresponding to a significant decrease of suprathermal electron fluxes.The diffusion coefficients are calculated by using the observed electric field wave spectra.The pitch angle diffusion coefficient can approach 10^(−2) s^(−1),which is much larger,by~100 times,than the momentum diffusion coefficient,indicating that pitch angle scattering dominates the whistler-electron resonance process.The current results can successfully explain the dropout of the suprathermal electrons in this event.This study provides direct evidence for whistler-driven electron losses in the Martian magnetosphere.
基金Supported by National Natural Science Foundation of China (10775068,10735010,10975072,11035001)973 National Major State Basic Research and Development of China (2007CB815004,2010CB327803)+1 种基金CAS Knowledge Innovation Project (KJCX2-SW-N02)Research Fund of Doctoral Point (RFDP) (20070284016,20100091110028)
文摘The charge form factors of elastic electron scattering for isotones with N=20 and N=28 are calculated using the phase-shift analysis method,with corresponding charge density distributions from relativistic mean-field theory.The results show that there are sharp variations at the inner parts of charge distributions with the proton number decreasing.The corresponding charge form factors are divided into two groups because of the unique properties of the s-states wave functions,though the proton numbers change uniformly in two isotonic chains.Meanwhile,the shift regularities of theminima are also discussed,and we give a clear relation between theminima of the charge form factors and the corresponding charge radii.This relation is caused by the diffraction effect of the electron.Under this conclusion,we calculate the charge density distributions and the charge form factors of the A=44 nuclei chain.The results are also useful for studying the central depression in light exotic nuclei.
基金supported by the National Natural Science Foundation of China(Grant Nos.12035011,11975167,11947211,11905103,11881240623,11961141003,and 11505292)the National Key R&D Program of China(Grant No.2018YFA0404403)+3 种基金the Science and Technology Development Fund of Macao(Grant Nos.0048/2020/A1,and 008/2017/AFJ)the Shandong Provincial Natural Science Foundation,China(Grant No.ZR2020MA096)the Open Project of Guangxi Key Laboratory of Nuclear Physics and Nuclear Technology(Grant No.NLK2021-03)the Key Laboratory of High Precision Nuclear Spectroscopy,Institute of Modern Physics,Chinese Academy of Sciences(Grant No.IMPKFKT2021001)。
文摘Scaling analyses have been successfully applied to study the inclusive electron scattering(e, e') over the past few decades. In this study, we utilize the ψ' scaling function in momentum space to analyze the(e, e') cross sections, where the nucleon momentum distributions are derived from self-consistent mean-field calculations. By further introducing the energy and momentum conservation in the scaling analysis, an improved ψ'scaling function is proposed to investigate the high-momentum part of the momentum distributions. Using the proposed scaling function, we systematically explore the effects of the nucleon-nucleon short-range correlation(NN-SRC) on the(e, e') cross sections. From the experimental(e, e') data, the NN-SRC strength is further extracted within the framework of the improved ψ'scaling function. The studies in this paper offer a new method to investigate the nucleon momentum distributions and the NN-SRC effects in nuclei.
基金Supported by National Basic Research Program of China (2009CB824800)National Natural Science Foundation of China (11103001)+1 种基金Hunan Provincial Natural Science Foundation of China (11JJ3006)Research Grants of Changsha University of Science and Technology,the Construct Program of the Key Discipline in Hunan Province and Aid Program for Science and Technology Innovative Research Team in Higher Educational Institute of Hunan Province
文摘We apply the derivative coupling model with ZM and ZM3 parameters to investigate the longitudinal response function in quasielastic electron scattering in the relativistic random phase approximation. The non-spectral method is chosen to describe the nucleon Green＇s function in a finite nucleus. Some remarks have been made in conclusion.
基金This work was supported by the National Natural Sci-ence Foundation of China under Grant No. 10174019
文摘Total cross sections （TCSs） of electrons scattering from triatomic molecules over the energy range from 30 to 5000 eV are investigated employing a new semi-empirical formula. The TCSs of electrons scattering from triatomic molecules SO2, NO2, and CO2 are calculated. The quantitative TCSs are in good agreement with those obtained by experiments. It is shown that the results derived from the semi-empirical formula are much closer to the measurements than other calculations.
基金supported by the National Key Research and Development Program of China(2021YFB4000602)the National Natural Science Foundation of China(21988101,22279130,21633011)+1 种基金the Dalian Science and Technology Innovation Fund(2023RJ016)the Liaoning Revitalization Talents Program(x LYC2002076)。
文摘Hydride ion(H-)conductors have drawn much attention due to their potential applications in hydrideion-based devices.Rare earth metal hydrides(REH_(x))have fast H-conduction which,unfortunately,is accompanied by detrimental electron conduction preventing their application as ion conductors.Here,REH_(x)(RE=Nd,Ce,and Pr)with varied grain sizes,rich grain boundaries,and defects have been prepared by ball milling and subsequent sintering.The electronic conductivity of the ball-milled REH_(x)samples can be reduced by 2-4 orders of magnitude compared with the non-ball-milled samples.The relationship of electron conduction and miscrostructures in REH_(x)is studied and discussed based on experimental data and previously-proposed classical and quantum theories.The H-conductivity of all REH_(x)is about 10^(-4)to 10^(-3)S cm^(-1)at room temperature,showing promise for the development of H-conductors and their applications in clean energy storage and conversion.
