共查询到18条相似文献,搜索用时 93 毫秒
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利用基于多组态Dirac-Fock方法的程序包GRASP92和RATIP以及在此基础上最新发展的RERR06程序,计算了锂原子1s2nl(n=2,3; l=s, p) 的内壳层和外壳层的光电离截面. 计算中详细考虑了光电离过程中的弛豫效应. 结果表明:在锂原子内壳层电子的光电离过程中弛豫效应较强,而在外壳层电子的光电离过程中弛豫效应较弱. 另外,相应于不同态的内壳层光电离过程,其弛豫效应的影响也不同,对激发态的影响比对基态的影响大,对高激发态
关键词:
多组态Dirac-Fock方法
光电离截面
弛豫效应 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
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应用连续扭曲波程函初态近似方法(CDW-EIS)计算了入射粒子能量从30 keV到10 MeV α粒子与各价碳原子1s壳层的碰撞电离的总截面,进而得出在惯性约束核聚变(Inertial Controlled Fusion, 简称ICF)聚变条件下该反应的速率系数.同时利用Bethe公式,我们也计算了电子与各价碳原子1s壳层碰撞电离总截面及ICF环境下该反应的速率系数.通过比较α粒子及电子与碳原子碰撞K-壳层电离Kα信号贡献大小,探讨Kα信号利用诊断α粒子分布的可能性. 相似文献
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在中能区测量了Cq+(q=1-4)与He,Ne,Ar气体原子碰撞的电子损失截面,计算分析了入射离子损失两个电子与一个电子的总截面比 R21. 单反应道分析无法完全解释所有实验结果,必须同时考虑入射离子的电子损失、电子俘获和靶原子电离各种出射道间的耦合作用. 对于不同靶原子的碰撞,入射离子损失一个电子和两个电子的速度阈值可以由屏蔽和反屏蔽理论解释. 然而,该理论不能完全解释截面比 R21
关键词:
离子-原子碰撞
截面
电子损失 相似文献
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H.F. Nelson 《Journal of Quantitative Spectroscopy & Radiative Transfer》1974,14(12):1303-1315
This numerical study investigates the sensitivity of non-equilibrium shockwave structure to uncertainties in (a) the ground and excited state continuum radiative cross section and (b) the bound-bound radiative cross section in a three level (ground, excited, and free electronic states considered) argon-like gas at Mach 18 and a pressure of 1 cm Hg. Changing the values of the radiative cross sections by an order of magnitude does not significantly influence the relaxation region; however, a large change occurs in not only the magnitude but also the extent of both the electron and excited state precursors. Increasing either the ground state continuum or the bound-bound cross section decreases the number of free electrons in front of the shock wave. These cross sections also influence the extent of the electron precursor through their influence on the ratio of the electrons produced by ground state photoionization to those produced by ground state photoexcitation followed by excited state photoionization. The bound-bound cross section also controls the excited state precursor, because the production of excited states is entirely due to line radiation. Increasing the excited state photoionization cross section increases both the magnitude and extent of the electron precursor, because the cross section influences the ratio of the two processes that compete to produce free electrons, and at the same time it influences the magnitude of the excited state precursor. 相似文献
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Calculations are presented for the double photoionization (with excitation) and triple photoionization of the Li atom. The motion of all three electrons is treated equally by solving the time-dependent Schr?dinger equation in nine dimensions. A radial lattice is used to represent three of the nine dimensions, while a coupled channel expansion is used to represent the other six dimensions. Probabilities for photoionization are obtained by t--> infinity projection onto fully antisymmetric spatial and spin functions. Double photoionization cross sections for lithium leaving the ion in the 1s, 2s, and 2p states are presented. Good agreement is found with the measurements of Huang et al. [Phys. Rev. A 59, 3397 (1999)]] for the total double photoionization cross section and with the measurements of Wehlitz et al. [Phys. Rev. Lett. 81, 1813 (1998)]] for the triple photoionization cross section. 相似文献
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Satyabrata Sahoo Y.K. Ho 《Journal of Quantitative Spectroscopy & Radiative Transfer》2010,111(1):52-62
We present theoretical photoionization cross sections for He 1s2s 1S and He 1s2p 1P states in a Debye plasma environment by the complex coordinate rotation method, using a finite L2 basis set constructed from one electron Laguerre orbitals. The plasma environment is found to appreciably influence the photoionization cross sections near the ionization threshold. In this regard, the photoionization cross sections of isolated He are compared with other theoretical and experimental results. Our results are in good agreement with the previous results. A new minimum appears in the photoionization cross section curve for the metastable 1s2s 1S state. Results are given for the S- and D-wave partial photoionization for the excited 1s2p 1P state. 相似文献
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Interference effects on the photoionization cross sections between two neighbouring atoms: nitrogen as an example 下载免费PDF全文
Interference effects on the photoionization cross sections between two neighbouring atoms are considered based on the coherent scattering of the ionized electrons by the two nuclei when their separation is less than or comparable to the de Broglie wave length of the ionized electrons.As an example,the single atomic nitrogen ionization cross section and the total cross sections of two nitrogen atoms with coherently added photoionization amplitudes are calculated from the threshold to about 60 A (1 A=0.1 nm) of the photon energy.The photoionization cross sections of atomic nitrogen are obtained by using the close-coupling R-matrix method.In the calculation 19 states are included.The ionization energy of the atomic nitrogen and the photoionization cross sections agree well with the experimental results.Based on the R-matrix results of atomic nitrogen,the interference effects between two neighbouring nitrogen atoms are obtained.It is shown that the interference effects are considerable when electrons are ionized just above the threshold,even for the separations between the two atoms are larger than two times of the bond length of N 2 molecules.Therefore,in hot and dense samples,effects caused by the coherent interference between the neighbours are expected to be observable for the total photoionization cross sections. 相似文献
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利用相对论平均自洽场理论,研究了光电离截面在不同交换势下的差异,在对这种差异进行分析的基础上,对其变化规律做了较详细的理论说明.计算结果表明:光电离截面随交换系数的增大而增大;电子所感受到的平均核势场越小,交换势所起的作用则相对地有所增加,从而对光电离截面的影响更大. 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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马堃 《原子与分子物理学报》2018,35(2):181-185
基于多组态Dirac-Fock理论方法及其相应的GRASP2K和修改后的RATIP2012程序包,计算了极化光子入射Al原子K壳层光电离截面,并利用最新发展的RPI-E计算程序研究了K壳层光电子角分布,重点讨论了辐射场的非偶极项对光电离截面和光电子角分布的影响.结果表明,在入射光子5000 e V能量范围内,辐射场的非偶极效应对光电离总截面的影响可以忽略不计.随着入射光子能量的增加,辐射场的非偶极效应对光电子角分布的影响越来越大,入射光子能量在5000 eV,一级非偶极参数γ的数值达到1.5. 相似文献