Author Archives: Paul Barklem

Testing atomic collision theory with the two-photon continuum of astrophysical nebulae

Guzmán, F.; Badnell, N. R.; Chatzikos, M.; van Hoof, P. A. M.; Williams, R. J. R.; Ferland, G. J. Accurate rates for energy-degenerate l-changing collisions are needed to determine cosmological abundances and recombination. There are now several competing theories for … Continue reading

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K-shell photoionization of O4 + and O5 + ions: experiment and theory

McLaughlin, B. M.; Bizau, J.-M.; Cubaynes, D.; Guilbaud, S.; Douix, S.; Shorman, M. M. Al; Ghazaly, M. O. A. El; Sakho, I.; Gharaibeh, M. F. Absolute cross-sections for the K-shell photoionization of Be-like (O4 +) and Li-like (O5 +) atomic … Continue reading

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Electron impact excitation for He-like ions with Z = 20-42

Si, R.; Li, S.; Wang, K.; Guo, X. L.; Chen, Z. B.; Yan, J.; Chen, C. Y.; Brage, T.; Zou, Y. M. Aims: Spectral lines of He-like ions are among the most prominent features in X-ray spectra from a large … Continue reading

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Extended Calculations of Spectroscopic Data: Energy Levels, Lifetimes, and Transition Rates for O-like Ions from Cr xvii to Zn xxiii

Wang, K.; Jönsson, P.; Ekman, J.; Gaigalas, G.; Godefroid, M. R.; Si, R.; Chen, Z. B.; Li, S.; Chen, C. Y.; Yan, J. Employing two state-of-the-art methods, multiconfiguration Dirac–Hartree–Fock and second-order many-body perturbation theory, the excitation energies and lifetimes for … Continue reading

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New Fe i Level Energies and Line Identifications from Stellar Spectra. II. Initial Results from New Ultraviolet Spectra of Metal-poor Stars

Peterson, Ruth C.; Kurucz, Robert L.; Ayres, Thomas R. The Fe i spectrum is critical to many areas of astrophysics, yet many of the high-lying levels remain uncharacterized. To remedy this deficiency, Peterson & Kurucz identified Fe i lines in … Continue reading

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Radiative data for highly excited 3d84d levels in Ni II from laboratory measurements and atomic calculations

Hartman, H.; Engström, L.; Lundberg, H.; Nilsson, H.; Quinet, P.; Fivet, V.; Palmeri, P.; Malcheva, G.; Blagoev, K. Aims: This work reports new experimental radiative lifetimes and calculated oscillator strengths for transitions from 3d84d levels of astrophysical interest in singly … Continue reading

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A study on missing lines in the synthetic solar spectrum near the Ca triplet

Kitamura, Jessica R.; Martins, Lucimara P.; Coelho, Paula Synthetic stellar spectra are extensively used for many different applications in astronomy, from stellar studies (such as in the determination of atmospheric parameters of observed stellar spectra), to extragalactic studies (e.g. as … Continue reading

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