Radiative lifetimes of triply excited states of the Li isoelectronic sequence

Piangos, Nicos A.; Nicolaides, Cleanthes A.

doi:10.1103/physreva.48.4142

Cited by 28 publications

(29 citation statements)

References 30 publications

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“…Several approximations have been exploited to compute the energies (and sometimes the widths) of a number of multiply excited states in lithium [11][12][13][14][15]. It is, however, only the most recent developments in R-matrix theory which have allowed a comprehensive photoionization calculation including resonances to be carried out.…”

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confidence: 99%

High Resolution Measurements of Partial Photoionization Cross Sections in Hollow Lithium: A Critical Comparison with Advanced Many-Body Calculations

et al. 1996

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Photoelectron data for hollow lithium states obtained with unprecedented high spectral resolution and sensitivity are presented. A critical comparison is made with the most recent theoretical results. Partial cross sections are measured providing the first definitive test of advanced ab initio calculations for this highly excited four-body atomic system. [S0031-9007(96)00241-4] PACS numbers: 32.80. Fb, 32.80.Hd In this Letter, we present photoelectron data for hollow lithium states obtained with unprecedented spectral resolution (0.019 eV) and sensitivity which allows a critical comparison with the most advanced recent theoretical calculations. The partial cross sections are measured and resonance profile parameters are determined. In addition, we have used the R-matrix approximation to calculate ab initio the partial photoionization cross sections into all continuum channels of the Li 1 ion over a wide photon energy range. The experimental results provide the first definitive test of such advanced calculations for this highly excited atomic system.The photoexcitation and decay dynamics of hollow lithium atoms, in which all three electrons are in excited states, have become the subject of intense recent experimental and theoretical interest. The single-photon threeelectron excitations depend entirely on electron-electron correlation interactions and so hollow lithium atoms constitute an ideal four-body Coulomb system for testing the most advanced atomic theories. Following the first photon-excited observation [1] of the lowest hollow atom resonance (1s 2 2s 2 S ! 2s 2 2p 2 P), two total ion yield photoion experiments at high [2] and medium [3] spectral resolution measured the autoionization of several hollow states in both the Li 1 and Li 21 decay channels. Photoelectron spectrometry [4] was also used with low resolution to study the decay of the hollow lithium 2s 2 2p state into the different continua of the Li 1 ion. The 0.5 eV spectral bandpass of the latest experiment however limited the critical nature of the comparison with theory.Double K-shell excitations in atomic helium have culminated in recent ultrahigh resolution measurements [5]. The third electron makes the theoretical and experimental study of hollow lithium states an even greater challenge than that of helium. Although triply excited states of lithium were first observed in collision experiments [6][7][8], only photon-excitation experiments provide the selectivity, sensitivity, and resolution required to unravel the many hollow lithium resonances. The dipole selection rules ensure that only 2 P o final states can be photoexcited from the ground state of the lithium atom. Photoelectron spectrometry combines the advantages of photon excitation with the unique capacity to measure separately the many decay channels and to provide insight into decay dynamics. The key role played by hollow atom states in ion-surface interactions has also been recognized [9]. 0031-9007͞96͞76(21)͞3915(4)$10.00

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confidence: 99%

High Resolution Measurements of Partial Photoionization Cross Sections in Hollow Lithium: A Critical Comparison with Advanced Many-Body Calculations

et al. 1996

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“…In a later work, Safronova and Senashenko [16] performed a detailed and systematic study on the n = 2 intrashell states of the Li-isoelectronic series employing a 1/Z expansion approach for a wide range of Z. Thereafter, a multitude of theoretical methodologies have been proposed which provide results in fairly good agreement with the experimental works, namely, the joint saddle point (SP) and complex coordinate rotation (CCR) method [17][18][19][20], the state-specific theory [21,22], the space partition and stabilization approach [23], the R-matrix theory along with many of its variants [24,25], the truncated diagonalization method (TDM) [26][27][28], the hyperspherical coordinate formalism [29,30], etc.…”

Section: Introductionmentioning

confidence: 99%

Understanding of the Switching Mechanism of a Pt/Ni-Doped SrTiO₃ Junction via Current–Voltage and Capacitance–Voltage Measurements

Seong

Lee

Pyun

et al. 2008

jjap

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Following from our work on triply excited hollow resonances in threeelectron atomic systems, a density functional theory (DFT)-based formalism is employed to investigate similar resonances in the Li-isoelectronic series (Z = 4-10). A combination of the work-function-based local nonvariational exchange potential and the popular gradient plus Laplacian-included Lee-Yang-Parr correlation energy functional is used. The generalized pseudospectral method provides nonuniform and optimal spatial discretization of the radial Kohn-Sham equation. First, all the eight n = 2 intrashell states of B 2+ , N 4+ and F 6+ are presented, which are relatively less studied in the literature compared to the remaining four members. Then calculations are performed for the eight 2l2l nl (3 n 6) hollow resonance series, namely 2s 2 ns 2 S e , 2s 2 np 2 P o , 2s 2 nd 2 D e , 2s2pns 4 P o , 2s2pnp 4 D e , 2p 2 ns 4 P e , 2p 2 np 4 D o and 2p 2 ns 2 D e , of all the seven positive ions. Next, as an illustration, higher resonance positions of the 2s 2 ns 2 S e series are calculated for all the ions with a maximum of n = 25. The calculated excitation energies are in excellent agreement with the available literature data (for the n = 2 intrashell states the deviation is within 0.125% and excepting only one case, the same for the resonance series is well below 0.5%). With an increase in Z, the deviations tend to decrease. Radial densities are also presented for some of the selected states. The only result available in the literature for the lower resonances (corresponding to a maximum of n = 17) have been reported very recently. The n > 16 (17 for F 6+ ) resonances are examined here for the first time. This gives a promising viable and general DFT scheme for the accurate calculation of these and other hollow resonances in many-electron atoms.

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“…Later other formalisms such as the 1/Z expansion method [17], many-body perturbation theory [18] were also used to investigate these states. Some other recent theoretical works include the state-specific theory [19][20][21], the configuration interaction (CI) type approach [22], joint saddle point (SP) and complex coordinate rotation (CCR) method [23][24][25], the space partition and stabilization procedure [26], a density functional formalism [27], several variants of the R-matrix theory [28][29][30][31] as well as the TDM [32,33], the hyperspherical coordinate approach [34,35], etc. Although the most natural and commonest choice in these works was neutral atom (Li), other atomic systems such as the negative ions (e.g., He − ), positive ions like Li-isoelectronic series or N 2+ [22] have also received considerable attention.…”

Section: Introductionmentioning

confidence: 99%

Studies on the hollow states of atomic lithium using a density functional approach

Roy¹

2004

J. Phys. B: At. Mol. Opt. Phys.

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Density functional calculations are performed for twelve 2l2l ′ nl ′′ (n≥2) triply excited hollow resonance series of Li, viz., 2s 2 ns 2 S e , 2s 2 np 2 P o , 2s 2 nd 2 D e , 2p 2 ns 2 D e , 4 P e , 2s2pns 4 P o , 2s2pnp 4 D e , 2p 2 np 2 F o , 4 D o , 2p 2 nd 2 G e , 4 F e and 2s2pnd 4 F o , covering a total of about 270 low-, moderately highand high-lying states, with n as high as up to 25. The work-function-based exchange potential and the nonlinear gradient plus Laplacian included Lee-Yang-Parr correlation energy functional is used.The relevant Kohn-Sham-type equation is solved numerically using the generalized pseudospectral method offering nonuniform, optimal spatial discretization to obtain the orbitals and densities. The present single determinantal approach yields fairly accurate results for the nonrelativistic energies, excitation energies as well as the radial densities and other expectation values. Except for the one state, the discrepancy in the calculated state energies remains well within 0.98%, whereas the excitation energies deviate by 0.02-0.58% compared to the available experimental and other theoretical results. Additionally companion calculations are also presented for the 37 3l3l ′ nl ′′ (n≥3) doubly hollow states (seven are n=3 intrashell type) of Li with both K and L shells empty (up to n=6) in the photon energy range 175.63-180.51 eV, with varying symmetries and multiplicities.Our calculation shows good agreement with the recent literature data for the only two such doubly hollow states reported so far, viz., 3s 2 3p 2 P o and 3s3p 2 4 P e . The resonance series are found to be inextricably entangled to each other, leading to complicated behavior in their positions. Many new states are reported here for the first time. This provides a simple, efficient and general scheme for the accurate calculation of these and other multiply excited Rydberg series of many-electron atomic systems within density functional theory.

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Radiative lifetimes of triply excited states of the Li isoelectronic sequence

Cited by 28 publications

References 30 publications

High Resolution Measurements of Partial Photoionization Cross Sections in Hollow Lithium: A Critical Comparison with Advanced Many-Body Calculations

High Resolution Measurements of Partial Photoionization Cross Sections in Hollow Lithium: A Critical Comparison with Advanced Many-Body Calculations

Understanding of the Switching Mechanism of a Pt/Ni-Doped SrTiO₃ Junction via Current–Voltage and Capacitance–Voltage Measurements

Studies on the hollow states of atomic lithium using a density functional approach

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Radiative lifetimes of triply excited states of the Li isoelectronic sequence

Cited by 28 publications

References 30 publications

High Resolution Measurements of Partial Photoionization Cross Sections in Hollow Lithium: A Critical Comparison with Advanced Many-Body Calculations

High Resolution Measurements of Partial Photoionization Cross Sections in Hollow Lithium: A Critical Comparison with Advanced Many-Body Calculations

Understanding of the Switching Mechanism of a Pt/Ni-Doped SrTiO3 Junction via Current–Voltage and Capacitance–Voltage Measurements

Studies on the hollow states of atomic lithium using a density functional approach

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Understanding of the Switching Mechanism of a Pt/Ni-Doped SrTiO₃ Junction via Current–Voltage and Capacitance–Voltage Measurements