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1.
使用R-矩阵方法,在库仑-玻恩非交换近似下(DCBNX)采用三态密耦图象,计算了类硼离子N2+的电子碰撞电离截面,并给出了总的能量微分截面及分波能量微分截面。计算结果揭示了明显的Rydberg系列共振,并指出共振对截面的贡献大于直接电离过程对截面的贡献,这与Chidichimo的结论一致。 相似文献
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钠蒸气中的双光子共振三光子电离和双光子混合并振三光子电离 总被引:2,自引:2,他引:0
在钠原子-分子混合样品中,分别运用双光子共振三光子电离以及双光子混合共振三光子电离,测得了钠原子4D态的电离流时间衰减曲线。由电离流与多光子动力学参数的关系,得到了4D态的光电离截面。 相似文献
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用R-矩阵方法,在三态密耦近似下计算了原子Na和离子Ng1+的电子碰撞电离截面,并给出了不同过程的能量损失微分截面dQ/dE,从结果我们看到明显的Rydberg系列共振,并且当能量较低时总截面结果与实验符合得较好 相似文献
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用飞行时间符合技术测量了1.5-7.5MeV非全裸氟离子与氦原子碰撞引起的氦的双、单重电离相对截面比,对非全裸离子核外电子对碰撞过程的影响进行了讨论。对碰撞系统还进行了多体经典轨道蒙特-卡罗模拟,得到氦的双、单重电离绝对截面,并对结果进行了讨论 相似文献
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用R-矩阵方法计算了类铍离子N~(3+)及O~(4+)的电子碰撞电离截面,并讨论了组态1s~22Pnl引起的共振以及一个2s电子被激发到2p轨道同时另一个被电离的截面对总截面的影响,计算结果表明与Jakubowicz的密耦近似结果相一致。 相似文献
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本文用组态相互作用理论研究He原子的非谐振光致电离。本文详细分析双重激发自电离态,考察第一电离阈值附近的非谐振谱,计算非谐振区的e-He+,1,3P散射位相移动及来自lsns1,3S的光致电离截面,本文计算结果与实验观测值及现有的理论结果相比较,相当符合。 相似文献
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对于能量为0.5-1MeV的入射质子,在计算中采用AuL1次壳层荧光产额的实验值代替相应的Dirac-Hartree-Slater值时,使用RPWBA-BC(经结合能和库仑歪曲修正的相对论平面波玻恩近似)电离截面计算得到的金原子LX射线相对产生截面与测量值相符。以前报道的对RPWBA-BC截面的各种修正都是不需要的 相似文献
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本文用组态相互作用理论研究He原子的非谐振光致电离。本文详细分析双重激发自电离态,考察第一电离阈值附近的非谐振谱,计算非谐振区的e-He^+,^1^,^3P散射位相移动及来自lsns^1^,^3S的光致电离截面。本文计算结果与实验观测值及现有的理论结果相比较,相当符合。 相似文献
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基于Dirac-slater自洽场方法,本文计算了C元素各价离子从低能到高能的光电离截面,考察了多极效应、相对论效应在不同能区对光电离截面的影响,并研究了光电离截面随光子能量、电离度、不同壳层变化的规律.通过各种理论计算结果的比较,分析了Kramers公式的适用性,计算中为了提高计算精度,我们采用了Grasp2程序包输出的束缚态波函数替换自洽场的波函数。 相似文献
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基于处理裸核离子与中性原子碰撞电离过程的OBKN和ECPSSR理论模型,系统计算了不同裸核离子与中性原子碰撞K壳层电子俘获截面和直接电离截面,并与其它文献已有的理论和实验结果进行了比较.研究结果表明:碰撞能量较低时,电子俘获截面大于直接电离截面,随着碰撞能量的增加,电子俘获截面和直接电离截面均是先增大后减小且直接电离截面减小地非常缓慢,高能时,直接电离截面大于电子俘获截面.当入射炮弹离子速度接近0.67倍靶原子K壳层电子速度时,电子俘获截面达到最大值,而当入射炮弹离子速度接近靶原子K壳层电子速度时,直接电离截面达到最大值. 相似文献
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基于处理裸核离子与中性原子碰撞电离过程的OBKN和ECPSSR理论模型,系统计算了不同裸核离子与中性原子碰撞K壳层电子俘获截面和直接电离截面,并与其它文献已有的理论和实验结果进行了比较.研究结果表明:碰撞能量较低时,电子俘获截面大于直接电离截面,随着碰撞能量的增加,电子俘获截面和直接电离截面均是先增大后减小且直接电离截面减小地非常缓慢,高能时,直接电离截面大于电子俘获截面.当入射炮弹离子速度接近0.67倍靶原子K壳层电子速度时,电子俘获截面达到最大值,而当入射炮弹离子速度接近靶原子K壳层电子速度时,直接电离截面达到最大值. 相似文献
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V. G. Vovchenko V. V. Polyakov O. Ya. Fedorov Yu. A. Chestnov 《Physics of Atomic Nuclei》2012,75(1):1-7
The cross section for the fission of actinide nuclei that is induced by fast neutrons is considered as a fraction of the cross
section for inelastic nucleon interaction with nuclei. In turn, inelastic nucleon interaction with a nucleus is treated as
scattering on intranuclear nucleons. It is shown that this interaction model describes satisfactorily the cross section for
the inelastic interaction of 60- to 2200-MeV nucleons for a broad set of nuclei and that the energy dependence of the cross
section for the fission of actinide nuclei that is induced by 400- to 1000–MeV protons replicates the energy dependence of
the cross section for inelastic interactions with respective nuclei. From the model used, it follows that the cross sections
for proton-nucleus interactions exceed cross sections for respective neutron-nucleus interactions in the energy range extending
up to 550 MeV; at higher energies neutron cross sections are larger than proton cross sections. 相似文献
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用统计擦碎模型计算了140AMeV40,48Ca+9Be和58,64Ni+9Be弹核碎裂反应产物的截面.通过对碎片截面计算结果和实验测量结果的比较发现,采用自由空间的核子-核子反应截面计算时,对非中心反应产物的截面拟合很好,而对中心反应产物的截面有较大高估,而采用饱和密度相关的核子-核子反应截面计算时,对非周边反应产物的截面拟合较好,而对周边反应产物的截面有一定程度的低估.在统计擦碎模型中,对核子-核子反应截面进行细致的介质密度关联,可能会改进计算值与实验值的符合程度. 相似文献
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用扭曲波方法计算Al~(10+)基态在Is~22s的Is,2s电子和第一激发态Is~22p的2p电子的电离截面以及基态的总电离截面(包括内壳层激发自电离).入射电子能量(?)(即(?)以2s电离能I_(2s)为单位)为1.05,1.125,l.25,1.5,2.25,4……同时计算出了电离阈值以下的激发截面(乘以所谓态密度),实现了在电离阈值处与阈值以上电离能量微分截面光滑联接;计算了光电离截面积分值,实现了在入射电子能量趋于无穷时与电子碰撞电离截面衔接.计算结果与其他方法进行了比较.
关键词: 相似文献
16.
薛思敏 《原子与分子物理学报》2015,32(6)
利用连续扭曲波方法(CDW)和初态程函近似-连续扭曲波方法(CDW-EIS)对质子碰撞电离氖原子 壳层随电离电子能量的单重和二重微分散射截面及总截面进行了计算,与实验数据进行了比较,详细分析了曲线结构,比较了模型之间的差异,研究了初态程函近似对单重和二重微分散射截面的影响,并对其内部碰撞电离机制进行了探讨.研究发现,初态程函近似对各壳层电离截面有较大影响,这种影响随着入射质子能量的增大而越来越小. 相似文献
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核子-核子碰撞截面(σNN)是描述原子核反应模型中的重要物理量。 核子-核子碰撞截面包括质子-质子碰撞截面(σpp)、中子-中子碰撞截面(σNN)和中子 质子碰撞截面(σnp), 它们随着核子能量与核物质密度的改变而变化。人们在目前研究中提出了多种核子-核子碰撞截面关于能量和核物质密度的参数化公式,通过计算12C+12C的完全反应截面,比较了不同入射能量下使用各种核子-核子碰撞截面参数化公式对12C完全反应截面的影响。 The nucleus-nucleus cross sections(σNN) include the proton-proton cross section, neutron-neutron cross section, and neutron-proton cross section. σNN change with the variations of the incident energies and the densities. Some parameterizations of σNNas a function of incident energy and density have been proposed in the theoretical and experimental study of nuclear reactions. Through the calculation of reaction cross sections of 12C+12C at different energies, the effect of different σNN parameterizations in the reaction cross sections of 12 are studied. 相似文献
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Differential, elastic integral and moment transfer cross sections for electron scattering from N2 at intermediate- and high-energies
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A complex optical model potential modified by incorporating the concept of bonded atom, with the overlapping effect of electron clouds between two atoms in a molecule taken into consideration, is firstly employed to calculate the differential cross sections, elastic integral cross sections, and moment transfer cross sections for electron scattering from molecular nitrogen over the energy range 300—1000eV by using additivity rule model at Hartree—Fock level. The bonded-atom concept is used in the study of the complex optical model potential composed of static, exchange, correlation polarization and absorption contributions. The calculated quantitative molecular differential cross sections, elastic integral cross sections, and moment transfer cross sections are compared with the experimental and theoretical ones wherever available, and they are found to be in good agreement with each other. It is shown that the additivity rule model together with the complex optical model potential modified by incorporating the concept of bonded atom is completely suitable for the calculations of differential cross section, elastic integral cross section and moment transfer cross section over the intermediate- and high-energy ranges. 相似文献
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A numerical study has been conducted to explore the role of photoemission cross sections in the impurity photovoltaic(IPV) effect for silicon solar cells doped with indium. The photovoltaic parameters(short-circuit current density, opencircuit voltage, and conversion efficiency) of the IPV solar cell were calculated as functions of variable electron and hole photoemission cross sections. The presented results show that the electron and hole photoemission cross sections play critical roles in the IPV effect. When the electron photoemission cross section is 10-20cm~2, the conversion efficiencyη of the IPV cell always has a negative gain(?η 0) if the IPV impurity is introduced. A large hole photoemission cross section can adversely impact IPV solar cell performance. The combination of a small hole photoemission cross section and a large electron photoemission cross section can achieve higher conversion efficiency for the IPV solar cell since a large electron photoemission cross section can enhance the necessary electron transition from the impurity level to the conduction band and a small hole photoemission cross section can reduce the needless sub-bandgap absorption. It is concluded that those impurities with small(large) hole photoemission cross section and large(small) electron photoemission cross section,whose energy levels are near the valence(or conduction) band edge, may be suitable for use in IPV solar cells. These results may help in judging whether or not an impurity is appropriate for use in IPV solar cells according to its electron and hole photoemission cross sections. 相似文献
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E. G. Sheikin 《Technical Physics》2010,55(1):1-9
A new model differential cross section is proposed for describing elastic scattering of electrons in simulating the passage
of electrons through a substance by the Monte Carlo method. This differential cross section correctly describes the first
and second transport scattering cross sections, but is characterized by the total elastic scattering cross section much smaller
than the actual value of the total elastic scattering cross section. The application of this differential cross section makes
it possible to considerably reduce the number of elastic collisions in the Monte Carlo simulation of passage of electrons
in a substance and to model the passage of high-energy electrons using the individual collision model. 相似文献