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The growing interest in atomic structures of moderately-stripped alkali-like ions in diagnostic study and modeling of astrophysical and laboratory plasma makes an accurate many-body study of atomic properties inevitable. This work presents…

Atomic Physics · Physics 2023-03-30 Swapan Biswas , Anal Bhowmik , Arghya Das , Radha Raman Pal , Sonjoy Majumder

New theoretical results from large-scale relativistic close coupling calculations reveal the precise effect of resonances in collisional excitation of x-ray lines of Ne-like Fe XVII. Employing the Breit-Pauli R-matrix method and a 89-level…

Astrophysics · Physics 2008-11-26 Guo-Xin Chen , Anil K. Pradhan

Employing two state-of-the-art methods, second-order many-body perturbation theory and multiconfiguration Dirac-Fock, highly accurate calculations are performed for the lowest 318 fine-structure levels arising from the $2s^{2} 2p^{4}$, $2s…

Atomic Physics · Physics 2019-09-04 Kai Wang , Wei Zhang , Xiao Hui Zhao , Zhan Bin Chen , Chong Yang Chen , Jun Yan

Theoretical electron density-sensitive line ratios $R_1 - R_6$ of Ar XIV soft X-ray emission lines are presented. We found that these line ratios are sensitive to electron density $n_e$, and the ratio $R_1$ is insensitive to electron…

Plasma Physics · Physics 2007-05-23 G. Y. Liang , G. Zhao , J. L. Zeng , J. R. Shi

The effect of autoionizing resonances in atomic systems and processes is reviewed. Theoretical framework for treating resonances in the coupled channel approximation using the R-matrix method, as well as approximations related to plasma…

High Energy Astrophysical Phenomena · Physics 2024-05-16 Anil Pradhan

Energy levels and transition rates for electric-dipole, electric-quadrupole, electric-octupole, magnetic-dipole, and magnetic-quadrupole transitions among the levels arising from the $n\ \leq$ 5 configurations in B-like Kr XXXII are…

Atomic Physics · Physics 2020-05-20 Yanting Li , Ra Si , Jinqing Li , Chunyu Zhang , Ke Yao , Kai Wang , Mingfeng Gu , Chongyang Chen

For crucial tests between theory and experiment, ab initio close coupling calculations are carried out for photoionization of O II, O III, O IV, O V. The relativistic fine structure and resonance effects are studied using the R-matrix and…

Astrophysics · Physics 2009-11-10 Sultana N. Nahar

New laboratory measurements using an Electron Beam Ion Trap (EBIT) and an x-ray microcalorimeter are presented for the n=3 to n=2 Fe XVII emission lines in the 15 {\AA} to 17 {\AA} range, along with new theoretical predictions for a variety…

Instrumentation and Methods for Astrophysics · Physics 2011-06-15 J. D. Gillaspy , T. Lin , L. Tedesco , J. N. Tan , J. M. Pomeroy , J. M. Laming , N. Brickhouse , G. -X. Chen , E. Silver

Ionization is critical in the formation and evolution of plasma dynamics; collisional ionization, in particular, is an often overlooked source of electrons when dealing with laser-plasma interactions. Ionization plays a crucial role in…

Plasma Physics · Physics 2026-03-19 Stephen DiIorio , Ricardo Fonseca , Frank Tsung , Benjamin J. Winjum , Alec G. R. Thomas

There has been a growing request from the X-ray astronomy community for a quantitative estimate of systematic uncertainties originating from the atomic data used in plasma codes. Though there have been several studies looking into atomic…

A general formulation is developed to demonstrate that atomic autoionizing (AI) resonances are broadened and shifted significantly due to plasma effects across bound-free continua. The theoretical and computational method presented accounts…

Solar and Stellar Astrophysics · Physics 2023-01-20 Anil Pradhan

An alternative method is introduced to solve a simple two-dimensional models describing vibrational excitation and dissociation processes during the electron-molecule collisions. The model works with one electronic and one nuclear degree of…

Chemical Physics · Physics 2018-12-19 Roman Čurík , Dávid Hvizdoš , Chris H. Greene

We construct a nuclear interaction in chiral effective field theory with explicit inclusion of the $\Delta$-isobar $\Delta(1232)$ degree of freedom at all orders up to next-to-next-to-leading order (NNLO). We use pion-nucleon ($\pi N$)…

Nuclear Theory · Physics 2018-02-27 A. Ekström , G. Hagen , T. D. Morris , T. Papenbrock , P. D. Schwartz

The calculations of the ratios of the Helium-like ion X-ray lines from C V to Si XIII are revisited in order to apply the results to density, temperature and ionization process diagnostics of data from high-resolution spectroscopy of the…

Astrophysics · Physics 2007-05-23 D. Porquet , R. Mewe , J. S. Kaastra , J. Dubau , A. J. J. Raassen

X-ray lasers based on transitions in highly charged \textit{Ni}-like ions generating in the "water window" wavelength range can be pumped by compact laboratory discharge sources. This makes them promising candidates for use as compact…

Plasma Physics · Physics 2021-05-21 N. V. Kalinin , R. M. Feshchenko , I. A. Artyukov , V. A. Burtsev

Stark broadening theory is currently operated for calculating widths and shifts of spectral lines that are needed for spectroscopic diagnostics and modelling in astrophysics, laboratory and technological plasmas. We have calculated a great…

Solar and Stellar Astrophysics · Physics 2018-03-14 Sylvie Sahal-Brechot , Milan S. Dimitrijevic , Nebil Ben Nessib

X-ray emission K-spectra of highly charged He- and Li-like argon ions recorded with high spectral, spatial, and temporal resolution at the TEXTOR tokamak were employed to develop a self-consistent approach (SCA) for deriving information on…

Atomic Physics · Physics 2020-06-30 F. Goryaev , A. Urnov

We report calculations of energy levels, radiative rates, collision strengths, and effective collision strengths for transitions among the lowest 25 levels of the n <= 5 configurations of He~II. The general-purpose relativistic atomic…

Solar and Stellar Astrophysics · Physics 2017-04-25 K. M. Aggarwal , A. Igarashi , F. P. Keenan , S. Nakazaki

We present benchmark integrated and differential cross-sections for electron collisions with H$_2$ using two different theoretical approaches, namely, the R-matrix and molecular convergent close-coupling (MCCC). This is similar to…

Chemical Physics · Physics 2020-08-31 T. Meltzer , J. Tennyson , Z. Mašín , M. C. Zammit , L. H. Scarlett , D. V. Fursa , I. Bray

Energy levels, radiative rates and lifetimes are calculated among the lowest 98 levels of the n <= 4 configurations of Be-like Al X. The GRASP (General-purpose Relativistic Atomic Structure Package) is adopted and data are provided for all…

Solar and Stellar Astrophysics · Physics 2015-06-18 K. M. Aggarwal , F. P. Keenan