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Search Publications by: Yuri Ralchenko (Fed)

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Displaying 51 - 75 of 199

EBIT Observation of Low Charge State Ar Dielectronic Recombination Features Near the Unknown Faint X-Ray Feature Found in the Stacked Spectrum of Galaxy Clusters

February 20, 2019
Author(s)
A. Gall, A. Foster, R. Silwal, Joan M. Dreiling, A. Borovik, E. Kilgore, M. Ajello, John Gillaspy, Yuri Ralchenko, Endre Takacs
Motivated by possible atomic origins of the unidentified emission line detected at 3.55 keV - 3.57 keV in a stacked spectrum of galaxy clusters (Bulbul et al. 2014), an electron beam ion trap (EBIT) was used to investigate resonant dielectronic

Recommended electron-impact excitation and ionization cross sections for Be I

November 23, 2018
Author(s)
FNU Dipti, Tapasi Das, klaus Bartschat, I Bray, D Fursa, O Zatsarinny, C Ballance, H-K Chung, Yuri Ralchenko
Analytic fits to the recommended electron-impact excitation and ionization cross sections for Be I are presented. The lowest 19 terms of configurations 2snl (n 4) and 2p2 terms below the first ionization limit are considered. The fits are based on the

Measuring the difference in nuclear charge radius of Xe isotopes by EUV spectroscopy of highly charged Na-like ions

November 5, 2018
Author(s)
Roshani Silwal, A. Lapierre, John D. Gillaspy, Joan M. Dreiling, S A. Blundell, Dipti Goyal, A. Borovik, Jr., G Gwinner, A.C.C. Villari, Yuri Ralchenko, Endre Takacs
The difference in the mean-square nuclear charge radius of xenon isotopes was measured utilizing a method based on extreme ultraviolet spectroscopy of highly charged Na-like ions. The isotope shift of the Na-like D1 (3s 2S1/2 − 3p 2P1/2) transition between

Standard Reference Data Workshop Report

June 12, 2018
Author(s)
Debra L. Kaiser, Neil Alderoty, Richard R. Cavanagh, Barbara Guttman, Robert J. Hanisch, Adam G. Morey, Jeanita Pritchett, Yuri Ralchenko, Stacy S. Schuur, William E. Wallace
On October 17, 2017, the ODI sponsored a day-long Standard Reference Data Workshop. More than 120 NIST staff members and associates from four NIST laboratories and three offices registered for this workshop. The workshop format consisted of presentations

Relativistic all-order many-body calculation of energies, wavelengths, and M1 and E2 transition rates for the 3d^n configurations in tungsten ions

January 3, 2018
Author(s)
M S. Safronova, U I. Safronova, S. G. Porsev, M G. Kozlov, Yuri Ralchenko
Energy levels, wavelengths, magnetic-dipole and electric-quadrupole transition rates between the low-lying states are evaluated for W51+ to W54+ ions with 3dn (n = 2 to 5) electronic con gurations using an approach combining con guration interaction with

Infrared and visible laser spectroscopy for highly-charged Ni-like ions

April 12, 2017
Author(s)
Yuri Ralchenko
Application of visible or infrared (IR) lasers for spectroscopy of highly-charged ions (HCI) has not been particularly extensive so far due to a mismatch in typical energies. We show here that the energy difference between the two lowest levels within the

Review of the 9th NLTE code comparison workshop

February 24, 2017
Author(s)
R. Piron, F. Gilleron, Y Aglitskiy, H.-K. Chung, C. J. Fontes, S. B. Hansen, O. Marchuk, H. Scott, E. Stambulchik, Yuri Ralchenko
We review the 9th NLTE code comparison workshop, which was held in the Jussieu campus, Paris, from November 30th to December 4th, 2015. This time, the workshop was mainly focused on a systematic investigation of iron NLTE steady-state kinetics and

Multi-configuration Dirac-Hartree-Fock calculations of forbidden transitions within the 3d^k ground configurations of highly charged ions (Z = 72 - 83)

February 21, 2017
Author(s)
Z.L. Zhao, K. Wang, S. Li, R. Si, C.Y. Chen, J. Yan, Yuri Ralchenko
Extensive self-consistent multi-configuration Dirac-Hartree-Fock (MCDHF) calculations are performed for the 3s^2 3p^6 3d^k(k = 1−9) ground configurations of highly charged ions (Z = 72−83). Complete and consistent data sets of level energies,wavelengths

Validation and Verification of Collisional-Radiative Models

February 25, 2016
Author(s)
Yuri Ralchenko
Quality control is as relevant to scientific computing as to any other software. For complex collisional-radiative (CR) models that are used to calculate plasma population kinetic parameters and spectra, each computer code is expected to be thoroughly