Lifetime measurements of excited levels in C II and C III by beam-foil experiments

Nandi, T.; Bhattacharya, Nandini; Kurup, M.B.; Prasad, K. Krishna

doi:10.1088/0031-8949/54/2/011

Cited by 8 publications

(3 citation statements)

References 24 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Therefore, for the 2p3d 1 P o level the measured τ of appears to be incorrect. Nandi et al (1996) have measured τ for 2p 2 1 D and 2s3p 3 P o to be 6.9±0.2 and 11.6±0.3 ns, respectively and for both there is no large discrepancy with our calculations (7.5 and 13.1 ns, respectively) or other earlier experimental values.…”

Section: Lifetimessupporting

confidence: 51%

Energy levels, radiative rates and electron impact excitation rates for transitions in C iii

Aggarwal

Keenan

2015

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

We report energy levels, radiative rates (A-values) and lifetimes for the astrophysicallyimportant Be-like ion C III. For the calculations, 166 levels belonging to the n 5 configurations are considered and the grasp (General-purpose Relativistic Atomic Structure Package) is adopted. Einstein A-coefficients are provided for all E1, E2, M1 and M2 transitions, while lifetimes are compared with available measurements as well as theoretical results, and no large discrepancies noted. Our energy levels are assessed to be accurate to better than 1% for a majority of levels, and A-values to better than 20% for most transitions. Collision strengths are also calculated, for which the Dirac Atomic R-matrix Code (darc) is used. A wide energy range, up to 21 Ryd, is considered and resonances resolved in a fine energy mesh in the thresholds region. The collision strengths are subsequently averaged over a Maxwellian velocity distribution to determine effective collision strengths up to a temperature of 8.0×10 5 K, sufficient for most astrophysical applications. Our data are compared with the recent R-matrix calculations of Fernández-Menchero, Del Zanna & Badnell (2014), and significant differences (up to over an order of magnitude) are noted for several transitions over the complete temperature range of the results.

show abstract

Section: Lifetimessupporting

confidence: 51%

Energy levels, radiative rates and electron impact excitation rates for transitions in C iii

Aggarwal

Keenan

2015

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

show abstract

“…The result given by the latter measurement is closer to earlier 𝑎𝑏 𝑖𝑛𝑖𝑡𝑖𝑜 calculations ranging between 100 and 104 s −1 (Fleming et al 1994;Fischer 1994; Ynnerman & Fischer 1995). Several measurements have also been performed for the lifetimes of the low-lying levels of C Mickey 1970;Nandi et al 1996;Buchet-Poulizac & Buchet 1973a).…”

Section: Introductionsupporting

confidence: 84%

Extended theoretical transition data in C I - IV

Li,

Amarsi,

Papoulia

et al. 2021

Preprint

View full text Add to dashboard Cite

Accurate atomic data are essential for opacity calculations and for abundance analyses of the Sun and other stars. The aim of this work is to provide accurate and extensive results of energy levels and transition data for C -.The Multiconfiguration Dirac-Hartree-Fock and relativistic configuration interaction methods were used in the present work. To improve the quality of the wave functions and reduce the relative differences between length and velocity forms for transition data involving high Rydberg states, alternative computational strategies were employed by imposing restrictions on the electron substitutions when constructing the orbital basis for each atom and ion.Transition data, e.g., weighted oscillator strengths and transition probabilities, are given for radiative electric dipole (E1) transitions involving levels up to 1s 2 2s 2 2p6s for C , up to 1s 2 2s 2 7f for C , up to 1s 2 2s7f for C , and up to 1s 2 8g for C . Using the difference between the transition rates in length and velocity gauges as an internal validation, the average uncertainties of all presented E1 transitions are estimated to be 8.05%, 7.20%, 1.77%, and 0.28%, respectively, for C -. Extensive comparisons with available experimental and theoretical results are performed and good agreement is observed for most of the transitions. In addition, the C data were employed in a reanalysis of the solar carbon abundance. The new transition data give a line-by-line dispersion similar to the one obtained when using transition data that are typically used in stellar spectroscopic applications today.

show abstract

“…Experimentally, reliable laboratory lifetime measurements based on the beam-foil excitation technique have been reported for the short-lived states of C II and N III (Reistad et al 1986, Bengtsson et al 1995, Nandi et al 1996 and for metastable levels of Fe XXII by Hutton et al (1997). Also, by recording the spontaneous emission time from metastable ions stored in a cylindrical radio-frequency ion trap, Fang et al (1993aFang et al ( , 1993b succeeded in determining radiative rates in C II and N III.…”

Section: Introductionmentioning

confidence: 99%

Forbidden emission coefficients for intraconfiguration transitions 2p_3/2→2p_1/2along the boron sequence

Charro

López-Ferrero

Martı́n

2001

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

View full text Add to dashboard Cite

Relativistic quantum defect orbital calculations of transition probabilities for E2 and M1 transitions in the boron sequence have been performed. The present data are analysed on the grounds of other theoretical data available in the literature. Regularities in the transition intensities along the isoelectronic sequence for each line are also tested. The analysis of forbidden lines in the spectrum is important for the study of the plasma in astrophysical objects and fusion devices.

show abstract

Lifetime measurements of excited levels in C II and C III by beam-foil experiments

Cited by 8 publications

References 24 publications

Energy levels, radiative rates and electron impact excitation rates for transitions in C iii

Energy levels, radiative rates and electron impact excitation rates for transitions in C iii

Extended theoretical transition data in C I - IV

Forbidden emission coefficients for intraconfiguration transitions 2p_3/2→2p_1/2along the boron sequence

Contact Info

Product

Resources

About

Lifetime measurements of excited levels in C II and C III by beam-foil experiments

Cited by 8 publications

References 24 publications

Energy levels, radiative rates and electron impact excitation rates for transitions in C iii

Energy levels, radiative rates and electron impact excitation rates for transitions in C iii

Extended theoretical transition data in C I - IV

Forbidden emission coefficients for intraconfiguration transitions 2p3/2→2p1/2along the boron sequence

Contact Info

Product

Resources

About

Forbidden emission coefficients for intraconfiguration transitions 2p_3/2→2p_1/2along the boron sequence