Strong Relativistic Effects and Natural Linewidths Observed in Dielectronic Recombination of Lithiumlike Carbon

Mannervik, S.; DeWitt, D. R.; Engström, Lars; Lidberg, J.; Lindroth, Eva; Schuch, R.; Zong, W.

doi:10.1103/physrevlett.81.313

Cited by 77 publications

(81 citation statements)

References 15 publications

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“…3 shows the detailed comparison of the BPRM results with the TSR data over the region covered by the experiement. Schippers et al had earlier found that the previous LS coupling calculations for carbon and nitrogen ions (Nahar and Pradhan 1997) gave total C III rate coefficients that agreed with the sum of RR and experimental DR rate coefficients to within experimental uncertainties for all temperatures T > 5000 K. The discrepancy at lower temperatures was due to the 2p4ℓ complex, as discussed in detail by Mannervik et al (1998) and , and resolved by the higher accuracy BPRM calculations shown in Fig. 3.…”

Section: Unified (E + Ion) Recombination Cross Sectionsmentioning

confidence: 67%

Self-consistent R-matrix approach to photoionization and unified electron–ion recombination

Nahar

Pradhan

2004

Radiation Physics and Chemistry

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A unified scheme using the R-matrix method has been developed for electron-ion recombination subsuming heretofore separate treatments of radiative and dielectronic recombination (RR and DR). The ab initio approach within the coupled channel approximation has several inherent advantages in addition to the natural unification of resonant and non-resonant phenomena. It enables a general and self-consistent treatment of photoionization and electron-ion recombination employing idential wavefunction expansion. Detailed balance takes account of interference effects due to resonances in cross sections, calculated explicitly for a large number of recombined (e + ion) bound levels over extended energy regions. The theory of DR by Bell and Seaton is adapted for high-n resonances in the region below series limits. The R-matrix method is employed for (A) partial and total photoionization and photorecombination cross sections of (e + ion) bound levels, and (B) DR and (e + ion) scattering cross sections. Relativistic effects and fine structure are considered in the Breit-Pauli approximation. Effects such as radiation damping may be taken into account where necessary. Unfiied recombination cross sections are in excellent agreement with measurements on ion storage rings to about 10-20%. In addition to high accuracy, the strengths of the method are: (I) both total and level-specific cross sections and rate coefficients are obtained, and (II) a single (e + ion) recombination rate coefficient for any given atom or ion is obtained over the entire temperature range of practical importance in laboratory and astrophysical plasmas, (III) self-consistent results are obtained for the inverse processes of photoionization and recombination; comprehensive datasets have been computed for over 50 atoms and ions. Selected data are presented for iron ions.

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Section: Unified (E + Ion) Recombination Cross Sectionsmentioning

confidence: 67%

Self-consistent R-matrix approach to photoionization and unified electron–ion recombination

Nahar

Pradhan

2004

Radiation Physics and Chemistry

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“…In particular, measurements for PI of C 2· [8] and for PR of C 3· [9,10] have already been published. The two data sets are compared in Fig.…”

Section: Resultsmentioning

confidence: 99%

“…The ionization potential of ground state C 2· is I i = 47.888 eV. The solid circles with statistical error bars originate from a previous PR experiment [10], the associated thin solid line stems from many-body-perturbation-theory (MBPT) [9] and was scaled by a factor 0.8 to match the experimental PR data. The thick solid line in the lower portion of the figure shows the 2p4d 1 P contribution to PI of ground-state C 2· obtained by a Fano-Voigt fit to the PI data maintaining the resonance energy and the resonance width from the MBPT PR calculation.…”

Section: Resultsmentioning

confidence: 99%

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Time-reversal Studies in Photorecombination and Photoionization Experiments with Ion Beams

Müller¹,

Schippers²,

Aguilar³

et al. 2003

AIP Conference Proceedings

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Abstract. The principle of detailed balance relates the cross sections σ PR for photorecombination (PR) and σ PI for photoionization (PI) of ions on a state-to-state level. Measuring one or the other of the two cross sections provides direct information about the time-reversed process. Measurements carried out at the Advanced Light Source, Berkeley, for PI of C 2· and Sc 2· are compared with experimental results from the heavy-ion storage ring TSR, Heidelberg, on PR of C 3· and Sc 3· , respectively. From that comparison, state selective cross sections can be inferred both for PR and PI. Both experimental approaches provide possibilities for high-resolution spectroscopy of multiply excited states.

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“…Fu et al 2008, where depending on the description, 50% difference was observed in the DR rate coefficients of Ne-like Mg). Additionally, calculation of the DR spectra of even relatively low-Z and lowcharged ions require relativistic treatment (Mannervik et al 1998). Storage rings equipped with electron cooler devices presently yield the most accurate low-energy recombination spectra and can benchmark the different theoretical descriptions.…”

Section: Introductionmentioning

confidence: 99%

Experimental dielectronic recombination rate coefficients for Na-like S VI and Na-like Ar VIII

Orbán¹,

Altun

Källberg

et al. 2009

A&A

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Aims. Absolute recombination rate coefficients for two astrophysically relevant Na-like ions are presented.Methods. Recombination rate coefficients of S vi and Ar viii are determined from merged-beam type experiments at the CRYRING electron cooler. Calculated rate coefficients are used to account for recombination into states that are field-ionized and therefore not detected in the experiment. Results. Dielectronic recombination rate coefficients were obtained over an energy range covering Δ n = 0 core excitations. For Na-like Ar a measurement was also performed over the Δ n = 1 type of resonances. In the low-energy part of the Ar viii spectrum, enhancements of more than one order of magnitude are observed as compared to the calculated radiative recombination. The plasma recombination rate coefficients of the two Na-like ions are compared with calculated results from the literature. In the 10 3 −10 4 K range, large discrepancies are observed between calculated plasma rate coefficients and our data. At higher temperatures, above 10 5 K, in the case of both ions our data is 30% higher than two calculated plasma rate coefficients, other data from the literature having even lower values. Conclusions. Discrepancies below 10 4 K show that at such temperatures even state-of-the-art calculations yield plasma rate coefficients that have large uncertainties. The main reason for these uncertainties are the contributions from low-energy resonances, which are difficult to calculate accurately.

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Strong Relativistic Effects and Natural Linewidths Observed in Dielectronic Recombination of Lithiumlike Carbon

Cited by 77 publications

References 15 publications

Self-consistent R-matrix approach to photoionization and unified electron–ion recombination

Self-consistent R-matrix approach to photoionization and unified electron–ion recombination

Time-reversal Studies in Photorecombination and Photoionization Experiments with Ion Beams

Experimental dielectronic recombination rate coefficients for Na-like S VI and Na-like Ar VIII

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