Mn22+离子1s22s-1s2np的偶极跃迁能和振子强度

用全实加关联方法计算了类锂Mn22 离子1s22s-1s2np(2≤n≤9)的偶极跃迁能和振子强度.1s2np(2≤n≤9)态的精细结构通过计算自旋-轨道与自旋-其他轨道相互作用算符的期待值确定.依据单通道量子亏损理论,确定了Rydberg系列1s2np的量子数亏损.从而可以用这些作为能量的缓变函数的量子亏损,实现对任意高激发态(n≥10)的能量的可靠预言.将这些分立态振子强度与单通道量子亏损理论相结合,得到在电离阈附近束缚态-束缚态跃迁振子强度以及束缚态-连续态跃迁的振子强度密度,从而将Mn22 离子的这一重要光谱特性的理论预言外推到整个能域.     

外电场下TCNQ的激发与光谱性质研究

采用密度泛函B3PLY方法优化了不同外电场下TCNQ分子的基态稳定构型、电偶极矩和分子的总能量，并且分析了TCNQ分子的HOMO-2到LUMO+2轨道的能量变化。然后利用杂化CIS-DFT方法在同样的基组下计算了外电场下TCNQ分子的前9个激发态的激发能、波长和振子强度，结果表明在没有外电场的情况下，TCNQ分子只有一个激发态能够激发，从基态跃迁到第1激发态。在有外电场的作用下，总能量随外电场的增加而逐渐减少，偶极矩随外电场的增加而不断增加。其前线轨道的能量也随外电场的增加不断减少，轨道分布也受外电场很大的影响。另外，外电场对TCNQ分子的激发波长也产生了一定影响。     

Method of the quantum defect Green’s function for calculation of dynamic atomic polarizabilities

The quantum defect Green’s function enabling one to take into account exactly the contribution of highly excited and continuum states to the polarizability is found. The contribution of the ground and low-lying excited states is taken into account by using experimental values of the corresponding oscillator strengths. The good accuracy of the method proposed is demonstrated by calculation of the scalar dipole dynamic polarizabilities of noble gas atoms with consideration of the fine structure of the terms.     

Determination of static dipole polarizabilities of Yb atom

We determine the static values of the scalar and tensor dipole polarizabilities of the ground, 6s6p~3P_0~o, and 6s6p~3P_1~o states of the Yb atom. These results can be useful in many experiments undertaken using this atom. We employed a combined configuration interaction(CI) method and a second-order many-body perturbation theory(MBPT) to evaluate energies and electric dipole(E1) matrix elements of many low-lying excited states of the above atom. These values are compared with the other available theoretical calculations and experimental values. By combining these E1 matrix elements with the experimental excitation energies, we estimate the dominant valence correlation contributions to the dipole polarizabilities of the above states. The core contribution is obtained from the finite field approach. We also compare these values with the other theoretical results as there are no precise experimental values that are available for these properties.     

The hydrogen atom confined in both Debye screening potential and impenetrable spherical box

The ground state energy, some low-lying excited state energies and oscillator strengths for a hydrogen atom confined in both a Debye screening potential and finite impenetrable spherical box have been calculated. These have been calculated using a linear variational method based on B-spline basis functions. The results have been compared with those of other authors. The evaluated energies and oscillator strengths with respect to different plasma screening parameters with a certain confinement radii are discussed.     

Cr~(21+)离子1s~23d-1s~2nf的跃迁能和偶极振子强度(英文)

用全实加关联方法计算了类锂Cr21+离子1s23d-1s2nf(4≤n≤9)的跃迁能和1s2nf(n≤9)态的精细结构.在类氢近似下估算了对能量的高阶相对论修正.依据量子亏损理论,确定了Rydberg系列1s2nf的量子数亏损.据此可以实现对任意高激发态(n≥10)的能量的可靠预言.计算了Cr21+离子1s23d-1s2nf(4≤n≤9)跃迁的振子强度.与量子亏损理论相结合,得到该离子从1s23d态到电离阈附近高激发束缚态间的偶极跃迁振子强度以及到相应连续态跃迁的振子强度密度,从而将Cr21+离子的这一重     

Sc+18离子1s23d-1s2nf的跃迁能和偶极振子强度

用全实加关联方法计算了类锂Sc 18离子1s23d-1s2nf(4≤n≤9)的跃迁能和1s2nf(n≤9)态的精细结构。依据量子亏损理论确定了该Rydberg系列的量子数亏损,用这些作为能量的缓变函数的量子亏损,可以实现对任意高激发态(n≥10)的能量可靠的预言。利用在计算能量过程中确定的波函数,计算了Sc 18离子1s23d-1s2nf的偶极跃迁在三种规范下振子强度;将这些分立态振子强度与量子亏损理论相结合,得到在电离阈附近束缚态-束缚态跃迁振子强度以及束缚态-连续态跃迁振子强度密度,从而将Sc 18离子的这一重要光谱特性的理论预言外推到整个能域。     

Polarizabilities and Hyperpolarizabilities for Lithium Atoms in Debye Plasmas

The effects of plasma environments on energies, oscillator strengths, polarizabilities and hyperpolarizabilities for lithium atom have been calculated by combining the l-dependent model potential of free lithium atom and linear variation method based on B-spline basis functions. The influence of plasma on lithium atom is represented by the Debye screened potential, which describes effectively the averaged effect of the plasma environment on atomic spectra. The results are in agreement with other reported ones.     

外电场下TCNQ的激发与光谱性质研究

采用密度泛函B3PLY方法优化了不同外电场下TCNQ分子的基态稳定构型、电偶极矩和分子的总能量,并且分析了TCNQ分子的HOMO-2到LUMO+2轨道的能量变化。然后利用杂化CIS-DFT方法在同样的基组下计算了外电场下TCNQ分子的前9个激发态的激发能、波长和振子强度,结果表明在没有外电场的情况下,TCNQ分子只有一个激发态能够激发,从基态跃迁到第1激发态。在有外电场的作用下,总能量随外电场的增加而逐渐减少,偶极矩随外电场的增加而不断增加。其前线轨道的能量也随外电场的增加不断减少,轨道分布也受外电场很大的影响。另外,外电场对TCNQ分子的激发波长也产生了一定影响。     

V+20离子的能量和偶极振子强度

用全实加关联方法计算了类锂V+20离子 1s2nl(l=s,p, d;n≤9) 态的电离势和精细结构.依据单通道量子亏损理论, 确定了这三个Rydberg系列的量子数亏损.用这些作为能量的缓变函数的量子亏损,可以实现对任意高激发态(n≥10)的能量的可靠预言.用在计算能量过程中确定的波函数,计算了V+20离子1s22s-1s2np及1s22p-1s2nd (n≤9)跃迁的振子强度.将这些分立态振子强度与单通道量子亏损理论相结合,得到在电离域附近束缚态间的偶极跃迁振子强度以及束缚态-连续态跃迁的振子强度密度,从而将V+20离子的这一重要光谱特性的理论预言外推到整个能域.     

Oscillator strengths and polarizabilities of the hot-dense plasma-embedded helium atom

The effect of weakly coupled hot plasma environment on the oscillator strengths of the ultraviolet and visible series and the polarizabilities of helium has been investigated using variational highly correlated wave functions within the non-relativistic framework. The Debye shielding approach that admits a variety of plasma conditions is used to simulate the plasma effects. For each shielding parameter, dipole oscillator strengths are calculated for the 1 ¹S-n¹P (n=2, 3), 2 ¹S-2 ¹P, 2 ³S-n³P (n=2, 3) and 2 ^1,3P-n^1,3D (n=3, 4) transitions. The dipole and quadrupole polarizabilities for the ground He (1s²¹S) state are also reported for each screening parameter. Results obtained are useful in plasma diagnostic purposes besides several other applications.     

Dipole Polarizabilities of the Ground States for Berylliumlike Ions

Dipole polarizabilities of the ground states for berylliumlike ions with nuclear charge Z = 4 to 10 are calculated by using the Rayleigh-Ritz variational method with multiconfiguration interaction wave functions. The representative models of convergence are listed and compared with other theoretical data for nuclear charge Z = 4 to 6. The present dipole polarizabilities are in good agreement with previous accurate theoretical values available in the literature. For results with greater nuclear charge number, the present calculations may provide benchmarked data for future theoretical and experimental studies. Dynamic dipole polarizabilities of the ground state for the beryllium atom at selected frequencies are also calculated and compared with other theoretical values in the literature.     

Electron impact excitation cross sections for phosphorus

An analytic atomic independent-particle-model is used to generate wave functions for the valence and excited states of the neutral phosphorus atom. These wave functions are used to calculate generalized oscillator strengths, and from these quantities the cross sections are obtained in Born approximation. Various excitations from the ground state are considered, and results are presented for electron impact energies up to 5 keV. Received: 6 May 1997 / Revised: 21 October 1997 / Accepted: 5 December 1997     

Oscillator strengths for 2 ^2P-n ^2D transitions of lithium-like systems with Z=11 to 20

The dipole-length, velocity and acceleration absorption oscillator strengths for the 1s^22p－1s^2nd(3≤n≤9) transitions of the lithium-like systems with Z=11 to 20 are calculated using the energies and the multiconfiguration interaction wavefunctions obtained from a full core plus correlation method. The agreement between the f-values calculated from the length, velocity and acceleration formulae is excellent. Our results agree closely with the experimental data available in the literature. Combining these discrete oscillator strengths with the single-channel quantum defect theory, the discrete oscillator strengths for the transitions from 1s^22p state to highly excited states (n≥10) and the oscillator strength densities corresponding to the bound-free transitions are obtained.     

Lithium dipole properties and van der Waals constants using a pseudo spectral one-centre method

A pseudo spectral one-centre method is used to evaluate the moments of the dipole oscillator strength distribution for the ground-state Li atom and the van der Waals constants for the ground-state Li-Li, Li-He and Li-H interactions. Various combinations of C.I. type Li atom ground and excited ² P ⁰-state wavefunctions are used to construct the required pseudo spectral dipole oscillator strengths and excitation energies. The analysis of all the pseudo-state data yields recommended values for the Li dipole properties and van der Waals constants that are probably more accurate than those obtained previously. The calculations illustrate some of the advantages of the pseudo spectral approach for the evaluation of atomic and molecular properties and interaction energies.     

二氢化钚分子激发态结构的外场效应

采用密度泛函(DFT)方法B3LYP/Gen，在Pu为SDD基组、H为6-311++G^**基组水平上优化得到了分子轴方向不同电偶极场(-0.005—0.005a.u.)作用下，二氢化钚的基态电子状态、几何结构、电偶极矩和分子总能量.在优化构型下用同样的基组采用含时密度泛函(TDDFT)方法(TD-B3LYP)研究了同样外电场条件下对二氢化钚的激发能和振子强度的影响.计算结果表明，分子几何构型与电场大小和方向呈现较强的依赖，电场强度增加基态偶极矩随电场强度线性增加，H-Pu-H的角度线性减小，分子总能量线性减小；激发能随电场强度增加而减小，且对电场方向的依赖呈现近似对称性，满足Grozema关系.电场对振子强度的影响比较复杂，但仍满足跃迁选择定则. 关键词： 二氢化钚 激发态 电偶极场 TD-DFT     

Oscillator strength calculations in color centers of diamond and the role of spin

A generalized Hubbard model based on a molecular approach is used to calculate many electron wavefunctions of diamond vacancies. We have calculated the oscillator strength of the dipole transition rates from the ground states of the neutral and negatively charged vacancies. The ratio of the oscillator strengths is in very good quantitative agreement with the reported optical spectroscopic data. Electronic configurations in the ground and dipole allowed excited states are presented. With the proposed picture, the much larger oscillator strength of the negatively charged vacancy with respect to other experimentally investigated color centers N-V, H3, N3 and H4 is explained.Received: 9 March 2004, Published online: 23 July 2004PACS: 61.72.Bb Theories and models of crystal defects - 61.72.Ji Point defects (vacancies, interstitials, color centers, etc.) and defect clusters - 71.55.-i Impurity and defect levels     

Time-dependent perturbation calculations for transition properties of two-electron atoms under Debye plasma

Systematic investigation have been performed for the dynamic polarizabilities, energy levels, oscillator strengths and transition probabilities for the first few members of helium isoelectronic series He, Li⁺,Be²⁺,B³⁺ and C⁴⁺ embedded in the Debye plasma. The effect of plasma is described by introducing an exponential screening (the Debye screening) to the nuclear Coulomb potential. Systematic trend is observed for all the properties under study with respect to increased screening. The ionization potential decreases with an increased screening and the number of bound excited states supported by the Debye screened potential is finite.     

氯乙烯在外电场下的激发态结构研究

采用密度泛函B3P86方法在6-311G基组上优化了不同外电场作用下氯乙烯分子的基态几何结构、电偶极矩和分子的总能量,然后利用杂化CIS-DFT方法(CIS-B3P86)在相同基组下探讨了无电场时氯乙烯分子前9个激发态的激发能、波长和振子强度和外电场对氯乙烯分子激发态的影响规律.结果表明,分子的几何构型与外电场大小有着强烈的依赖关系.随着外电场的增大,分子总能量先增大后减小,电偶极矩μ先减小后增大.激发能随电场增加快速减小,表明在外电场作用下,氯乙烯分子易于激发和离解.激发态波长随电场的增大而不断增大,且其电子跃迁光谱都集中在紫外区.