首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 125 毫秒
1.
此文采用由原子轨道线性组合构成的自洽场分子轨道,用一级玻恩近似计算了能量为100-5000eV的电子与N2(^1Σ^+g、CO(^1Σ^+)弹性散射的微分截面和全截面。由于采用Gauss函数的线性组合拟合Slater函数的方法,得到了弹性散射微分截面的解析表达式,使计算大大简化,计算得到的电子和N2,CO散射的总截面和实验结果进行了比较,当入射电子的能量大于1keV时,理论值和实验值之间符合得很好  相似文献   

2.
H+F弹性碰撞微分截面的计算   总被引:1,自引:0,他引:1  
采用经典力学的方法对H与F碰撞动力学问题进行了研究,计算了碰撞的轨迹,偏转函数和微分截面。HF(X^1Σ^+)的势能函数采用Murrel-Sorbie函数形式。  相似文献   

3.
刘景之 《计算物理》2000,17(3):268-272
采用托马斯-费米近似和二体碰撞近似,计算了多电荷离子10Ne^q+与中性原子H和He碰撞的电荷损失截面以及电子的动量分布和离子势函数分布。  相似文献   

4.
同位旋相关的Boltzmann—Langevin方程及新核素^19Na产?…   总被引:1,自引:1,他引:0  
介绍了一种同位旋相关的输运方程,研究了在入射能量为28.7和60.0MeV/u时^12C+^12C的反应,对模型进行检验,发现计算结果较好地符合实验结果,说明了方程的可靠性,利用该模型研究了在入射能量为28.7MeV/u下反应系统^17-20,22Ne+^12C中核素^19Na的产生截面,发现缺中子核引起的反映,具有更大^19Na的产生截面,为新核素的探测找到了理论依据。  相似文献   

5.
研究了10Ne^q+(q=1,4,5)分别与中性原子H和He碰撞的电荷剥离截面,计算了10Ne^q+的电九电子动量分布,所用的公式和计算程序可以推广应用于任何一个多电荷离子,因而具有一定的普适性。  相似文献   

6.
用定域的Xα交换势模拟高Rydberg电子同原子实中电子的交换作用,给出高里德堡电子的径向波函数,并计算了Na^**+He热碰撞的l-混合跃迁截面,计算 其它理论方法有明显改善。  相似文献   

7.
在Coulomb-Born交换似和Z标度类氢模型下,计算了“水窗”波段Cr^21+离子精细结构能级的电子碰撞激发截面和速率系数。计算过程中对有效核电荷的计算作了修改,使其更有效地反映碰撞过程中电子的关联和相对论效应。  相似文献   

8.
F/Cl与Eu^2+:BaFcl中F色心的浓度和光激励截面的关系   总被引:1,自引:1,他引:0  
王永生  熊光楠 《光学学报》1995,15(7):66-870
研究了Eu^2+:BaFxCl2-x在紫外线辐照下的光激励发光。通过改变激励方式激励光的扫描方向,给出了Eu^2+:BaFxCl2-x光激励发光过程中,两种F色心的浓度比值与光激励截面比值的测定方法。利用这种测定方法,进一步研究了两种F色心的浓度比值和光激励截面比值与F/Cl比值的关系。  相似文献   

9.
利用双光子吸收,将Na(3S)原子激发到4D态,测量了Na(4D)+Na(3S)=Na(4F)+Na(3S)碰撞能量转移截面,因为直接由4F→3D的荧光不能探测,所以检测3D→3P级联荧光讯号。结合基态钠原子密度的测量,给出了截面值σ4D→4F-1.3×10^-14±28%(cm^2)。  相似文献   

10.
吴涛  邓佩珍 《光学学报》1997,17(7):66-869
测量了Cr^4+,YAG、Cr^4+,Mg2SiO4晶体在室温和液氮温度下的荧光光谱,吸收光谱和激发态寿命,讨论了温度变化时,两种晶体中Cr^4+近红外辐射积分强度变化与激光发态寿命变化的关系,得出结论:在77K ̄300K范围内,Cr^4+的^3T2能级荧光辐射截面本身受温度影响不大,Cr^4+辐射荧光的变化,主要是由无辐射弛豫速率随温度变化而引起的。  相似文献   

11.
《物理学报》1999,48(7):2
In the text we have calculated the potential function,electron momentum distributions and charge stripping cross sections for 36Krq+ collision with H and He using binary encounter approximation and Thomas-Fermi approximation methods.  相似文献   

12.
36Krq+(q=1,2)与H和He碰撞的电荷剥离截面   总被引:4,自引:0,他引:4       下载免费PDF全文
刘之景 《物理学报》1999,48(7):1210-1214
采用二体碰撞近似和托马斯-费密近似方法计算了多电荷离子36Krq+的势函数和电子动量分布,以及它与中性原子H和He碰撞的电荷剥离截面. 关键词:  相似文献   

13.
H+ and He2+ impact single and double ionization cross sections of ground state lead atoms have been calculated in the binary encounter approximation. Calculations of direct double ionization cross sections have been performed in the modified double binary encounter model. The accurate expressions of σΔE (cross-section for energy transfer ΔE) and Hartree-Fock velocity distributions for the target electrons have been used throughout the calculations. Contributions to double ionization from Auger effect following ionization of inner shells have been considered in the present work. Our H+ impact single and double ionization cross sections are in good agreement with the experimental observations. In calculations of He2+ impact cross sections, the present theoretical approach shows limited success in the experimentally investigated region (50–350 keV amu-1).  相似文献   

14.
According to the plane wave Born approximation (PWBA) and the binary encounter approximation (BEA) models, it is possible to fit the cross sections obtained with any atomic element at any particle energy using a scaling law for a K‐shell. The semi‐empirical K‐shell ionization cross sections are then deduced by fitting the available experimental data normalized to their corresponding theoretical values. For the empirical K‐shell ionization cross sections, a third‐order polynomial was used to fit the same experimental data for protons. Our results are compared with the predictions of the ECPSSR theory and with other earlier works. Good agreement is obtained, but it is emphasized that the ultimate solution is to deduce the cross sections by fitting the available experimental data for each element separately. Copyright © 2008 John Wiley & Sons, Ltd.  相似文献   

15.
Theoretical studies of electron impact double ionization cross sections of Ne5+ and Ne6+ ions have been performed in the binary encounter approximation (BEA). Direct double ionization (DDI) has been investigated in the modified double binary encounter model. The K-shell ionization cross sections have been also calculated in the BEA to take into account the contributions to double ionization from the ionization-autoionization (IA) process. The effect of the Coulombic field of the target ion on the incident electron has been considered in the present work. Accurate expression of σ ΔE (cross section for energy transfer ΔE) and the Hartree-Fock (HF) velocity distributions for the target electrons have been used throughout the calculations. The present results are in overall moderate agreement with the experimental observations. Possible reasons behind the discrepancies between the theory and the experiment have been discussed.  相似文献   

16.
The K-shell x-rays of Ti, V, Fe, Co, Ni, Cu, and Zn induced by 424-MeV/u C~(6+) ion impact are measured. It is found that the K x-ray shifts to the high energy side and the intensity ratio of Kβ/Kα is larger than the atomic data, owing to the L-shell multiple-ionization. The x-ray production cross sections are deduced from the experimental counts and compared with the binary encounter approximation(BEA), plane wave approximation(PWBA) and energy-loss Coulomb-repulsion perturbed-stationary-state relativistic(ECPSSR) theoretical predictions. The BEA model with considering the multipleionization fluorescence yield is in better consistence with the experimental results. In addition, the cross section as a function of target atomic K-shell binding energy is presented.  相似文献   

17.
The N‐subshell ionizations cross sections of heavy elements by proton impact have been calculated in the binary‐encounter approximation. The momentum distribution of target electrons is taken into account by the use of the nonrelativistic and relativistic hydrogenic models and the Hartree–Fock–Roothaan and the relativistic Hartree–Fock–Roothaan methods. The obtained subshell ionization cross sections are compared with the experimental data and other theoretical calculations. The electronic relativistic effect and the wave‐function effect on N‐shell ionization cross sections are discussed.  相似文献   

18.
测量了2.4—6.0 MeV Xe~(20+)离子轰击V靶表面过程中辐射的X射线.计算了V的K壳层X射线发射截面,并将实验结果与平面波恩近似、ECPSSR、两体碰撞近似的理论计算进行了对比.讨论了近玻尔速度非对称碰撞过程中,BEA模型估算高电荷态重离子激发内壳层电离的修正因素.结果表明,综合考虑库仑偏转和有效电荷态修正后,BEA理论与实验结果符合较好.  相似文献   

19.
H+ impact single and He2+ impact single and double electron capture cross sections of magnesium atoms have been calculated in the modified binary encounter approximation (BEA). The accurate expressions of ion impact sDE\sigma _{\Delta {E}} (cross section for energy transfer DE\Delta E) and Hartree-Fock momentum distributions of the target electrons have been used throughout the calculations. On the basis of the present work it is concluded that inner shell captures by H+ and He2+ ions incident on magnesium atoms contribute partly to single electron capture and partly to transfer ionization cross sections. The calculated He2+ impact double electron capture cross sections of magnesium are in reasonably good agreement with the experimental observations. This indicates the success of the present theoretical approach in study of charge transfer cross sections of atoms as indirect mechanisms do not interfere with double electron capture processes in this case.  相似文献   

20.
Theoretical studies of electron impact double ionisation cross sections of Mg+ ions have been performed in the binary encounter approximation (BEA). Direct double ionisation has been investigated in the modified double binary encounter model. Ionization cross sections of different shells have been also calculated in order to analyse the contributions to double ionisation from ionisation-autoionization. The effect of the Coulombic field of the target ion on the incident electron has been considered in the present work. Accurate expression of σ ΔE (cross-section for energy transfer ΔE) and Hartree-Fock velocity distributions for the target electrons have been used throughout the calculations. The theoretical results show satisfactory agreement with the experimental observations.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号