By taking full account of the non-orthogonality of the orbitals between the low-lying doubly excited states ^1po and the singly excited states ^1S^e and ^1D^e of He, the corresponding radiative decay rates have been i...By taking full account of the non-orthogonality of the orbitals between the low-lying doubly excited states ^1po and the singly excited states ^1S^e and ^1D^e of He, the corresponding radiative decay rates have been investigated theoretically via analytic generalized Laguerre-type atomic orbitals at a nearly numerical multi-conflguration self-consistent field accuracy in a general non-orthogonal configuration interaction scheme. From these rates, we calculate the VUV photon emission and metastable atom spectra, and both are found to be in good qualitative agreement with recent excellent measurements. We obtain, successfully, the enhancement of the VUV photon spectrum, experimentally observed at the energy of （2s4p-4s2p）/（2p,3d） ^1po as compared with other nearby lying states. The mechanism proposed by Odling-Smee et al is verified, implying that taking appropriate account of the overlap existing between orbitals of the low-lying doubly excited and singly excited states （especially important for the compact orbitals） can reveal basic physical dominant mechanism and is crucial in understanding these spectra.展开更多
In this paper, we have declined the formalism of the method of the Modified Atomic Orbital Theory (MAOT) applied to the calculations of energies of doubly excited states 2<em>snp</em>, 3<em>snp</e...In this paper, we have declined the formalism of the method of the Modified Atomic Orbital Theory (MAOT) applied to the calculations of energies of doubly excited states 2<em>snp</em>, 3<em>snp</em>, and 4<em>snp</em> Helium-like systems. Then we also applied the variational procedure of the Modified Atomic Orbital Theory to the computations of total energies, excitation energies of doubly-excited states 2<em>snp</em>, 3<em>snp</em>, 4<em>snp</em> types of Helium-like systems. The results obtained in this work are in good agreement with the experimental and theoretical values available.展开更多
In this paper, resonance energies and excitation energies of doubly 2<em>sns</em> <sup>1,3</sup><em>S</em><sup>e</sup>, 2<em>snp</em> <sup>1,3</sup&...In this paper, resonance energies and excitation energies of doubly 2<em>sns</em> <sup>1,3</sup><em>S</em><sup>e</sup>, 2<em>snp</em> <sup>1,3</sup><em>P</em><sup>0</sup>, 2<em>pnp</em> <sup>1,3</sup><em>D</em><sup>e</sup>, 2<em>pnd</em> <sup>1,3</sup><em>F</em><sup>0</sup> and 2<em>pnf</em> <sup>1,3</sup><em>G</em><sup>e</sup> excited states of the helium isoelectronic sequence with <em>Z</em> <span style="white-space:nowrap;">≤</span> 10 are calculated. Calculations are carried out in the framework of the variational procedure of the formalism of the Screening Constant per Unit Nuclear Charge (SCUNC). New correlated wave function of Hylleraas type is used. Precise resonance and excitation energies are tabulated and good agreement is obtained when a comparison is made with available literature values.展开更多
Precise energy eigenvalues of metastable bound doubly excited 1,3Fe states originating from 2 pnf(n=4–6)configuration of helium-like ions(Z=2–4)under weakly coupled plasma(WCP)environment have been estimated within ...Precise energy eigenvalues of metastable bound doubly excited 1,3Fe states originating from 2 pnf(n=4–6)configuration of helium-like ions(Z=2–4)under weakly coupled plasma(WCP)environment have been estimated within the framework of Ritz variational method.The wavefunction is expanded in explicitly correlated Hylleraas type basis set.The screened Coulomb potential is consideredas mimic the WCP environment.The atomic systems tend towards gradual instability and the number of excited metastable bound states reduces with increasing plasma strength.The wavelengths corresponding to 2 pnf(1,3F^e)→2 pnf(1,3Do)(n=4–6;n′=3–6)transitions occurring between doubly excited states of plasma embedded two-electron ions are also reported.展开更多
The multi-configuration Dirac-Fock （MCDF） method is implemented to study doubly excited 2s2p 1,3^P1 resonances of the helium atom and the interference between photoionization and photoexcitation autoionization proce...The multi-configuration Dirac-Fock （MCDF） method is implemented to study doubly excited 2s2p 1,3^P1 resonances of the helium atom and the interference between photoionization and photoexcitation autoionization processes. In order to reproduce the totM photoionization sprectra, the excited energies from the ground 1s^2 ^1S0 state to the doubly excited 2s2p 1,3^P1 states and the relevant Auger decay rates and widths are calculated in detail. Furthermore, the interference profile determined by the so-called Fano parameters q and p2 is also reproduced. Good agreement is found between the present results and other available theoretical and experimental results. This indeed shows a promising way to investigate the Fano resonances in photoionization of atoms within the MCDF scheme, although there are some discrepancies in the present calculations of the 2s2p 3^P1 state.展开更多
The energy levels, radiative and Auger rates of Be-iike ions are calculated using the conventional configuration-interaction method. The Be-like ions are different from He-like ions because the excited electrons in th...The energy levels, radiative and Auger rates of Be-iike ions are calculated using the conventional configuration-interaction method. The Be-like ions are different from He-like ions because the excited electrons in the former deviate from O(4) symmetry.展开更多
In this work, the total energies of doubly excited states (<em>ns</em><sup>2</sup>) <sup>1</sup>S<sup>e</sup>, (<em>np</em><sup>2</sup>) <sup&...In this work, the total energies of doubly excited states (<em>ns</em><sup>2</sup>) <sup>1</sup>S<sup>e</sup>, (<em>np</em><sup>2</sup>) <sup>1</sup>D<sup>e</sup>, (<em>nd</em><sup>2</sup>) <sup>1</sup>G<sup>e</sup>, (<em>nf</em><sup>2</sup>) <sup>1</sup>I<sup>e</sup>, (<em>ng</em><sup>2</sup>) <sup>1</sup>K<sup>e</sup>, and (<em>nh</em><sup>2</sup>) <sup>1</sup>M<sup>e</sup> of the helium isoelectronic sequence with Z ≤ 10 are calculated in the framework of the variational method of the Screening Constant by Unit Nuclear Charge (SCUNC). These calculations are performed using a new wavefunction correlated to Hylleraas-type. The possibility of using the SCUNC method in the investigation of high-lying Doubly Excited States(DES) in two-electron systems is demonstrated in the present work in the case of the (<em>nl</em><sup>2</sup>) <sup>1</sup><em>L</em><sup><span style="white-space:nowrap;"><span style="white-space:nowrap;"><span style="white-space:nowrap;"><em>π</em></span></span></span></sup> doubly excited states, where accurate total energies are tabulated up to <em>n</em> = 20. All the results obtained in this paper are in agreement with the values of the available literature and may be useful for future experimental and theoretical studies on the doubly excited (<em>nl</em><sup>2</sup>) <sup>1</sup><em>L</em><sup><span style="white-space:nowrap;"><span style="white-space:nowrap;"><em>π</em></span></span></sup> states of two-electron systems.展开更多
The N=2 and N=3 series of the 3~p^e helium states have been investigated by a partial-wave analysis, the inherent symmetries inspected and the one-body densities and the shape-densities observed. The angular, radial-r...The N=2 and N=3 series of the 3~p^e helium states have been investigated by a partial-wave analysis, the inherent symmetries inspected and the one-body densities and the shape-densities observed. The angular, radial-radial, and radial-angular correlations of the electrons have been studied and revealed in an intuitive manner; in particular the response of the inner electron to the invasion of the outer electron is inspected in detail. Besides, the anisotropism of the electronic cloud is found to have distinguished features and all the ~3p^e states have similar anisotropism.展开更多
This paper investigates the third series of the 2s+1 p0 helium states. The anisotropism of the electronic distribution is presented, the partial-wave compositions of the states are compared with each other, and the an...This paper investigates the third series of the 2s+1 p0 helium states. The anisotropism of the electronic distribution is presented, the partial-wave compositions of the states are compared with each other, and the angular correlation is intuitively shown by the shape-density. Two types of radial-radial correlation, namely, the "gradually push" and the "sudden transition", have been identified and the approximate symmetry with respect to the interchange of r1 and r2 has been evaluated.展开更多
铜原子能级结构的理论计算具有非常大的挑战性。本文基于多组态Dirac-Hartree-Fock(MCDHF)方法和相对论组态相互作用(RCI)方法,通过三个大规模的关联模型计算了单激发态3d^104p2P1/2、双激发态3d94s(3D)5s4D3/2,1/2,3d94s(3D)5s2D3/2,3d...铜原子能级结构的理论计算具有非常大的挑战性。本文基于多组态Dirac-Hartree-Fock(MCDHF)方法和相对论组态相互作用(RCI)方法,通过三个大规模的关联模型计算了单激发态3d^104p2P1/2、双激发态3d94s(3D)5s4D3/2,1/2,3d94s(3D)5s2D3/2,3d94s(1D)5s2D3/2以及离子态3d101S0能级和波函数。结果表明,铜原子能级结构对有限组态空间的选择极其敏感,双激发态3d94s(3D)5s4D3/2,1/2,3d94s(3D)5s2D3/2,3d94s(1D)5s2D3/2和离子态3d101S0与单激发态之间的能量差相对于已有实验结果均存在大约-0.4 e V的偏差,而计算得到的共振电子能量与实验结果符合得较好。此外,根据辐射跃迁矩阵元和非辐射跃迁矩阵元计算了双激发态的Fano参数q,并基于Fano理论得到了铜单激发态3d^104p2P1/2的总光电离截面,该理论考虑了直接光电离与光激发自电离之间的干涉效应,即共振3d94s(3D)5s4D3/2,1/2、3d94s(3D)5s2D3/2和3d94s(1D)5s2D3/2具有明显的非对称的Fano轮廓,表明光电离过程与光激发自电离过程之间的干涉对双激发态共振附近的光电离截面轮廓有着极其重要的影响。展开更多
基金Project supported by the National Natural Science Foundation of China （Grant No 10347126）, National High Technology Development Program of China （Grant No 2004AA306H10） and the Program ＂Excellence in the Research Institutes Supervised by the General Secretariat for Research and Technology / Ministry of Development＂, Greece.Acknowledgments Xiong Zhuang would like to express his appreciation for the partial support from the Greek State Scholarship Foundation （I.K.Y.） and the National Hellenic Research Foundation Scholarship for this work.
文摘By taking full account of the non-orthogonality of the orbitals between the low-lying doubly excited states ^1po and the singly excited states ^1S^e and ^1D^e of He, the corresponding radiative decay rates have been investigated theoretically via analytic generalized Laguerre-type atomic orbitals at a nearly numerical multi-conflguration self-consistent field accuracy in a general non-orthogonal configuration interaction scheme. From these rates, we calculate the VUV photon emission and metastable atom spectra, and both are found to be in good qualitative agreement with recent excellent measurements. We obtain, successfully, the enhancement of the VUV photon spectrum, experimentally observed at the energy of （2s4p-4s2p）/（2p,3d） ^1po as compared with other nearby lying states. The mechanism proposed by Odling-Smee et al is verified, implying that taking appropriate account of the overlap existing between orbitals of the low-lying doubly excited and singly excited states （especially important for the compact orbitals） can reveal basic physical dominant mechanism and is crucial in understanding these spectra.
文摘In this paper, we have declined the formalism of the method of the Modified Atomic Orbital Theory (MAOT) applied to the calculations of energies of doubly excited states 2<em>snp</em>, 3<em>snp</em>, and 4<em>snp</em> Helium-like systems. Then we also applied the variational procedure of the Modified Atomic Orbital Theory to the computations of total energies, excitation energies of doubly-excited states 2<em>snp</em>, 3<em>snp</em>, 4<em>snp</em> types of Helium-like systems. The results obtained in this work are in good agreement with the experimental and theoretical values available.
文摘In this paper, resonance energies and excitation energies of doubly 2<em>sns</em> <sup>1,3</sup><em>S</em><sup>e</sup>, 2<em>snp</em> <sup>1,3</sup><em>P</em><sup>0</sup>, 2<em>pnp</em> <sup>1,3</sup><em>D</em><sup>e</sup>, 2<em>pnd</em> <sup>1,3</sup><em>F</em><sup>0</sup> and 2<em>pnf</em> <sup>1,3</sup><em>G</em><sup>e</sup> excited states of the helium isoelectronic sequence with <em>Z</em> <span style="white-space:nowrap;">≤</span> 10 are calculated. Calculations are carried out in the framework of the variational procedure of the formalism of the Screening Constant per Unit Nuclear Charge (SCUNC). New correlated wave function of Hylleraas type is used. Precise resonance and excitation energies are tabulated and good agreement is obtained when a comparison is made with available literature values.
基金Supported under Grant No. EMR/2017/000737 from DST-SERB, Govt. of India, Grant No. 23(Sanc.)/ST/P/S&T/16G-35/2017 from DHESTB, Govt. of West Bengal, Indiaby the DHESTB,Govt.of West Bengal,India under Grant No.249(Sanc.)/ST/P/S&T/16G-26/2017
文摘Precise energy eigenvalues of metastable bound doubly excited 1,3Fe states originating from 2 pnf(n=4–6)configuration of helium-like ions(Z=2–4)under weakly coupled plasma(WCP)environment have been estimated within the framework of Ritz variational method.The wavefunction is expanded in explicitly correlated Hylleraas type basis set.The screened Coulomb potential is consideredas mimic the WCP environment.The atomic systems tend towards gradual instability and the number of excited metastable bound states reduces with increasing plasma strength.The wavelengths corresponding to 2 pnf(1,3F^e)→2 pnf(1,3Do)(n=4–6;n′=3–6)transitions occurring between doubly excited states of plasma embedded two-electron ions are also reported.
基金supported by the National Natural Science Foundation of China (Grant Nos 10774122 and 10876028)the China/Ireland Science and Technology Collaboration Research Fund (Contract No CI-2004-07)+1 种基金the Specialized Research Fund for the Doctoral Program of Higher Education of China (Grant No 20070736001)the Foundation of Northwest Normal University of China (Grant No NWNU-KJCXGC-03-21)
文摘The multi-configuration Dirac-Fock （MCDF） method is implemented to study doubly excited 2s2p 1,3^P1 resonances of the helium atom and the interference between photoionization and photoexcitation autoionization processes. In order to reproduce the totM photoionization sprectra, the excited energies from the ground 1s^2 ^1S0 state to the doubly excited 2s2p 1,3^P1 states and the relevant Auger decay rates and widths are calculated in detail. Furthermore, the interference profile determined by the so-called Fano parameters q and p2 is also reproduced. Good agreement is found between the present results and other available theoretical and experimental results. This indeed shows a promising way to investigate the Fano resonances in photoionization of atoms within the MCDF scheme, although there are some discrepancies in the present calculations of the 2s2p 3^P1 state.
基金Project supported by the National Natural Science Foundation of China.
文摘The energy levels, radiative and Auger rates of Be-iike ions are calculated using the conventional configuration-interaction method. The Be-like ions are different from He-like ions because the excited electrons in the former deviate from O(4) symmetry.
文摘In this work, the total energies of doubly excited states (<em>ns</em><sup>2</sup>) <sup>1</sup>S<sup>e</sup>, (<em>np</em><sup>2</sup>) <sup>1</sup>D<sup>e</sup>, (<em>nd</em><sup>2</sup>) <sup>1</sup>G<sup>e</sup>, (<em>nf</em><sup>2</sup>) <sup>1</sup>I<sup>e</sup>, (<em>ng</em><sup>2</sup>) <sup>1</sup>K<sup>e</sup>, and (<em>nh</em><sup>2</sup>) <sup>1</sup>M<sup>e</sup> of the helium isoelectronic sequence with Z ≤ 10 are calculated in the framework of the variational method of the Screening Constant by Unit Nuclear Charge (SCUNC). These calculations are performed using a new wavefunction correlated to Hylleraas-type. The possibility of using the SCUNC method in the investigation of high-lying Doubly Excited States(DES) in two-electron systems is demonstrated in the present work in the case of the (<em>nl</em><sup>2</sup>) <sup>1</sup><em>L</em><sup><span style="white-space:nowrap;"><span style="white-space:nowrap;"><span style="white-space:nowrap;"><em>π</em></span></span></span></sup> doubly excited states, where accurate total energies are tabulated up to <em>n</em> = 20. All the results obtained in this paper are in agreement with the values of the available literature and may be useful for future experimental and theoretical studies on the doubly excited (<em>nl</em><sup>2</sup>) <sup>1</sup><em>L</em><sup><span style="white-space:nowrap;"><span style="white-space:nowrap;"><em>π</em></span></span></sup> states of two-electron systems.
基金Project supported by the National Natural Science Foundation of China.
文摘The N=2 and N=3 series of the 3~p^e helium states have been investigated by a partial-wave analysis, the inherent symmetries inspected and the one-body densities and the shape-densities observed. The angular, radial-radial, and radial-angular correlations of the electrons have been studied and revealed in an intuitive manner; in particular the response of the inner electron to the invasion of the outer electron is inspected in detail. Besides, the anisotropism of the electronic cloud is found to have distinguished features and all the ~3p^e states have similar anisotropism.
文摘This paper investigates the third series of the 2s+1 p0 helium states. The anisotropism of the electronic distribution is presented, the partial-wave compositions of the states are compared with each other, and the angular correlation is intuitively shown by the shape-density. Two types of radial-radial correlation, namely, the "gradually push" and the "sudden transition", have been identified and the approximate symmetry with respect to the interchange of r1 and r2 has been evaluated.
基金National Natural Science Foundation of China(11320101003,11204243)Scientific Research Foundation of Physics of CPEE NWNU~~
文摘铜原子能级结构的理论计算具有非常大的挑战性。本文基于多组态Dirac-Hartree-Fock(MCDHF)方法和相对论组态相互作用(RCI)方法,通过三个大规模的关联模型计算了单激发态3d^104p2P1/2、双激发态3d94s(3D)5s4D3/2,1/2,3d94s(3D)5s2D3/2,3d94s(1D)5s2D3/2以及离子态3d101S0能级和波函数。结果表明,铜原子能级结构对有限组态空间的选择极其敏感,双激发态3d94s(3D)5s4D3/2,1/2,3d94s(3D)5s2D3/2,3d94s(1D)5s2D3/2和离子态3d101S0与单激发态之间的能量差相对于已有实验结果均存在大约-0.4 e V的偏差,而计算得到的共振电子能量与实验结果符合得较好。此外,根据辐射跃迁矩阵元和非辐射跃迁矩阵元计算了双激发态的Fano参数q,并基于Fano理论得到了铜单激发态3d^104p2P1/2的总光电离截面,该理论考虑了直接光电离与光激发自电离之间的干涉效应,即共振3d94s(3D)5s4D3/2,1/2、3d94s(3D)5s2D3/2和3d94s(1D)5s2D3/2具有明显的非对称的Fano轮廓,表明光电离过程与光激发自电离过程之间的干涉对双激发态共振附近的光电离截面轮廓有着极其重要的影响。
