Detailed Theoretical Investigations on the L-Shell Absorption of Open-M-Shell Germanium Plasmas:Effect of Autoionization Resonance Broadening

Xiang, Wenjun; Zeng, Jiaolong; Fu, Yongsheng; Cheng, Guangquan

doi:10.4236/jmp.2012.330204

Cited by 5 publications

(11 citation statements)

References 26 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…G(z) is an effective Gaunt factor for electron impact excitation of positive ions, empirically determined for line broadening work in OP [12] to be The behavior of G(z) with ion charge z and temperature T has been further studied for electron impact broadening, and we adopt an improved expression ( [29,18,38])…”

Section: Electron Impact Broadeningmentioning

confidence: 99%

“…At the same time, plasma perturbations markedly affect atomic spectra susceptible to varying temperature, density, and other factors. Whereas a vast body of literature exists on line broadening in laboratory and astrophysics plasma environments [1,2,3,4,12,10], there is relatively little work on systematic theoretical treatment of autoionizing resonances that are more readily susceptible to plasma interactions [6,38], though results have been obtained for K-shell spectra (viz. [23]) observed astrophysically [24].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

R-Matrix calculations of astrophysical opacities (RMOP)

Pradhan¹,

Nahar²

2023

Preprint

View full text Add to dashboard Cite

A general formulation is employed to study and quantitatively ascertain the effect of plasma broadening of intrinsic autoionizing (AI) resonances in photoionization cross sections. In particular, R-matrix data for iron ions described in the previous paper in the RMOP series (RMOP-II, hereafter RMOP2) are used to demonstrate underlying physical mechanisms due to electron collisions, ion microfields (Stark), thermal Doppler effects, core excitations, and free-free transitions. Breit-Pauli R-matrix (BPRM) cross section for the large number of bound levels of Fe ions are considered, 454 levels of Fe XVII, 1,184 levels of Fe XVIII and 508 levels of Fe XIX. Following a description of theoretical and computational methods, a sample of results is presented to show significant broadening and shifting of AI resonances due to Extrinsic plasma broadening as a function of temperature and density. Redistribution of AI resonance strengths broadly preserves their integrated strengths as well as the naturally intrinsic asymmetric shapes of resonance complexes which are broadened, smeared and flattened, eventually dissolving into the bound-free continua.

show abstract

Section: Electron Impact Broadeningmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

R-Matrix calculations of astrophysical opacities (RMOP)

Pradhan¹,

Nahar²

2023

Preprint

View full text Add to dashboard Cite

show abstract

“…The considered data have been useful for articles with radiative emission and absorption as the subject. Examples of such papers consider a line-by-line approach of determining emission coefficients for thermal plasmas consisting of monoatomic species [137]; theoretically obtained results for radiative emission for argon and copper thermal plasmas [138]; net emission coefficients for Ar-Fe thermal plasmas [139,140]; complex thermal plasmas, which are used in single-wall carbon nanotube synthesis [141]; net emission coefficients at atmospheric pressure for argon-aluminum, argon-iron, and argon-copper mixtures in welding processes using plasmas [142]; research of the L-shell absorption of open-M-shell Ge plasmas and its effect of autoionization resonance broadening [143]; and autoionization widths of open-M-shell Ge ions and their influence on inner-shell absorption [144].…”

Section: Radiative Propertiesmentioning

confidence: 99%

Forty Years of the Applications of Stark Broadening Data Determined with the Modified Semiempirical Method

Dimitrijević

2020

Data

View full text Add to dashboard Cite

The aim of this paper is to analyze the various uses of Stark broadening data for non-hydrogenic lines emitted from plasma, obtained with the modified semiempirical method formulated 40 years ago (1980), which are continuously implemented in the STARK-B database. In such a way one can identify research fields where they are applied and better see the needs of users in order to better plan future work. This is done by analysis of citations of the modified semiempirical method and the corresponding data in international scientific journals, excluding cases when they are used for comparison with other experimental or theoretical Stark broadening data or for development of the theory of Stark broadening. On the basis of our analysis, one can conclude that the principal applications of such data are in astronomy (white dwarfs, A and B stars, and opacity), investigations of laser produced plasmas, laser design and optimization and their applications in industry and technology (ablation, laser melting, deposition, plasma during electrolytic oxidation, laser micro sintering), as well as for the determination of radiative properties of various plasmas, plasma diagnostics, and investigations of regularities and systematic trends of Stark broadening parameters.

show abstract

“…where T, N e , z, and A are the temperature, electron density, ion charge and atomic weight respectively, and ν i is the effective quantum number relative to each core ion threshold i : 13,7,22,19]). A factor (n x /n g ) 4 is introduced for Γ c to allow for doubly excited AI levels with excited core evels n x relative to the ground configuration n g (e.g.…”

Section: Introductionmentioning

confidence: 99%

“…A treatment of the Stark effect for complex systems entails two approaches, one where both electron and ion perturbations are combined (viz. [8,22]), or separately (viz. [4,13]) employed herein.…”

Section: Introductionmentioning

confidence: 99%

Plasma broadening of autoionizing resonances

Pradhan¹

2023

Preprint

View full text Add to dashboard Cite

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 for broadening mechanisms: electron collisional, ion microfields (Stark), thermal Doppler, core excitations, and free-free transitions. Extrinsic plasma broadening redistributes and shifts AI resonance strengths while broadly preserving naturally intrinsic asymmetries of resonance profiles. Integrated oscillator strengths are conserved as resonance structures dissolve into continua with increasing electron density. As exemplar, the plasma attenuation of photoionization cross sections computed using the R-matrix method is studied in neon-like Fe XVII in a critical range N e = 10 21−24 cc along isotherms T = 1 − 2 × 10 6 K, and its impact on Rosseland Mean opacities. The energy-temperature-density dependent cross sections would elicit and introduce physical features in resonant processes in photoionization, (e + ion) excitation and recombination. The method should be generally applicable to atomic species in high-energy-density (HED) sources such as fusion plasmas and stellar interiors.Whereas the main broadening mechanisms in AI broadening are physically similar to line broadening, their theoretical and computational treatment is quite different. Superimposed on intrinsic AI broadening in atomic cross sections the extent of resonances owing to extrinsic plasma effects renders much of the line broadening theory inapplicable, particularly for multi-electron systems. The unbroadened AI resonances themselves vary by orders of magnitude in width, shapes and heights, and incorporate two types: large features due to photoexcitation-of-core (PEC) below thresholds corresponding to dipole core transitions [10], and infinite Rydberg series of resonances converging on to each excited core level of the (e + ion) system. The generally employed Voigt line profiles obtained by convolution of a Lorentzian function for radiative and collisional broadening, and a Gaussian function for Doppler or thermal broadening, are found to be practically inapplicable for AI broadening. Numerically, the Voigt kernel is ill-conditioned since the collisional-to-Doppler width ratio Γ c /Γ d varies over a far wider range for resonances than lines and therefore unconstrained a priori [11,12].

show abstract

Detailed Theoretical Investigations on the L-Shell Absorption of Open-M-Shell Germanium Plasmas:Effect of Autoionization Resonance Broadening

Cited by 5 publications

References 26 publications

R-Matrix calculations of astrophysical opacities (RMOP)

R-Matrix calculations of astrophysical opacities (RMOP)

Forty Years of the Applications of Stark Broadening Data Determined with the Modified Semiempirical Method

Plasma broadening of autoionizing resonances

Contact Info

Product

Resources

About