This content has been downloaded from IOPscience. Please scroll down to see the full text. Download details: IP Address: 200.24.16.228 This content was downloaded on 24/01/2017 at 19:04 Please note that terms and conditions apply. On the behavior of the n1(K,T)An2 series of doubly excited states in He-like atoms immersed in weakly coupled plasmas View the table of contents for this issue, or go to the journal homepage for more 2014 J. Phys.: Conf. Ser. 488 062010 (http://iopscience.iop.org/1742-6596/488/6/062010) Home Search Collections Journals About Contact us My IOPscience You may also be interested in: Resonances of a hydrogen atom in strong parallel electric and magnetic fields using B-spline basis sets Zhang Yue-Xia, Meng Hui-Yan and Shi Ting-Yun Determination of Nonlinear Resonance Parameters in Electron Storage Rings Tsukasa Miyajima and Yukinori Kobayashi Photodetachment cross sections of the positronium negativeion Akinori Igarashi, Isao Shimamura and Nobuyuki Toshima Factorized cumulant expansion for homogeneous turbulence Tomomasa Tatsumi, Michio Yamada and Toshifumi Takei A new moving coil loud speaker Feshbach-like study of He resonant states in Debye plasmas using explicitly correlated wave functions J C Cardona, A F Ordoñez and J L Sanz-Vicario Computation of resonant states using explicitly correlated coordinates in Be-like B, C and N J C Cardona http://iopscience.iop.org/page/terms http://iopscience.iop.org/1742-6596/488/6 http://iopscience.iop.org/1742-6596 http://iopscience.iop.org/ http://iopscience.iop.org/search http://iopscience.iop.org/collections http://iopscience.iop.org/journals http://iopscience.iop.org/page/aboutioppublishing http://iopscience.iop.org/contact http://iopscience.iop.org/myiopscience http://iopscience.iop.org/article/10.1088/1674-1056/17/1/025 http://iopscience.iop.org/article/10.1088/1674-1056/17/1/025 http://iopscience.iop.org/article/10.1143/JJAP.44.2006 http://iopscience.iop.org/article/10.1088/1367-2630/2/1/317 http://iopscience.iop.org/article/10.1016/0169-5983(86)90007-9 http://iopscience.iop.org/article/10.1088/0950-7671/6/6/405 http://iopscience.iop.org/article/10.1088/1742-6596/388/15/152034 http://iopscience.iop.org/article/10.1088/1742-6596/388/15/152034 http://iopscience.iop.org/article/10.1088/1742-6596/388/15/152021 On the behavior of the n1 (K, T )An2 series of doubly excited states in He-like atoms immersed in weakly coupled plasmas A. F. Ordóñez∗, J. C. Cardona† and J. L. Sanz-Vicario∗ 1 ∗ Grupo de F́ısica Atómica y Molecular. Instituto de F́ısica, Universidad de Antioquia, Medelĺın, Colombia. † GEOEL, Universidad del Atlántico, Barranquilla, Colombia. Synopsis The stability of resonant states in Helium-like atoms while under the influence of a plasma environment is studied. We analyze the variation of resonance parameters (energies and lifetimes) against the strength of the screening parameter within the Debye-Hückel model. We use a Feshbach-like projection formalism with explicitly correlated CI-wave functions to uncover the evolution of resonance parameters until they cross the upper Aq+ (N=2) threshold, and a complex scaling method to analyze the survival of these Feshbach resonances across the threshold, which eventually makes them behave as shape resonances. The interest in the fundamental problem of atoms immersed in plasmas stems from its po- tential application in atomic physics, plasma physics, solid-state physics, and astrophysics. Plasma embedded He-like atoms represent here also a benchmark to understand the physics in- volved. The Hamiltonian for a two-electron atom immersed into a weakly coupled plasma reads H = − ∇2 1 2 − ∇2 2 2 − Zexp(−r1/D) r1 − Zexp(−r2/D) r2 + exp(−r12/D) r12 . (1) Here, the Debye length D=(kBT/4πe 2ρ)1/2 (a function of the plasma electron temperature T and density ρ) characterizes the interaction strength of the atomic system with the sur- rounding plasma. We use a Hylleraas config- uration interaction (HyCI) method to compute accurate energies and wave functions, the latter consisting of antisymmetrized correlated config- urations ψi(x1,x2)=A{φ(r1, r2)χ(s1, s2)} where the spatial part of the wave function is built in terms of correlated Slater type orbitals φ = rn1 1 rn2 2 rn12 12 e−αr1−βr2YL,M(Ω1,Ω2). Their advan- tage is that all integrals required for the solution of the plasma free (D=∞) as well as for finite val- ues of D may be calculated in closed form [1, 2]. We have also implemented a Feshbach-like projection method (at variance with previous extensive work by Ho et al [3] that uses the stabilization method) by solving separately the resonant QHQ (resonance energies), the non- resonant PHP (continuum discretized energies) eigenvalue problems and the QHP couplings ( from which the Auger widths are extracted). For instance, we perform a systematic study on the behavior of resonance parameters (energies, life- times and interelectronic angle) of the lowest series of plasma-embedded He 1,3Se, 1,3P o and 1,3De doubly excited states located below the He+(N=2) ionization threshold, as a function of the Debye characteristic length D. At vari- ance with one-electron atoms (where shape reso- nance widths vary monotonically with the screen- ing strength) the evolution of the Auger width with respect to screening is found to be different for each series of (K,T )A Herrick-Sinanoğlu-Lin pseudo-quantum numbers, until resonances cross the upper He+(2s,2p) thresholds, then merging into new open electronic continuum channels. The geometrical distribution of the electron pair as a function of the screening is also analyzed through the interelectronic angle for each reso- nance state. In addition, to shed light on the sur- vival of Feshbach resonances (below the thresh- old) transforming into shape resonances (above the threshold) we also implement the complex rotation method for the problem at hand. This transformation of the resonant character across the threshold [4] may involve dramatic changes in the wave function structure and particularly in the Auger widths. References [1] R.J. Tweed (1972) J. Phys. B: At. Mol. Phys., 5, 810; J.C. Cardona and J.L. Sanz-Vicario (2008) J. Phys. B: At. Mol. Opt. Phys., 41, 055003 [2] J.L. Calais and P.-O. Löwdin (1962) J. Mol. Spec- trosc., 8, 203 [3] S. Kar and Y.K. Ho (2005) Chem. Phys. Lett., 402, 544; (2009) J. Phys. B: At., Mol. Opt. Phys., 42, 044007 [4] S.B. Zhang, J.G. Wang and R.K. Janev (2010) Phys. Rev. Lett., 104, 023203; (2010) Phys. Rev. A, 81, 032707 1E-mail: sanjose@fisica.udea.edu.co XXVIII International Conference on Photonic, Electronic and Atomic Collisions (ICPEAC 2013) IOP Publishing Journal of Physics: Conference Series 488 (2014) 062010 doi:10.1088/1742-6596/488/6/062010 Content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. Published under licence by IOP Publishing Ltd 1