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Search Publications by: Yuri Ralchenko (Fed)

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Displaying 1 - 25 of 104

Benford's law in atomic spectra and opacity databases

April 21, 2024
Author(s)
Yuri Ralchenko, Jean-Christophe Pain
The intriguing law of anomalous numbers, also named Benford's law, states that the significant digits of data follow a logarithmic distribution favoring the smallest values. In this work, we test the compliance with this law of the atomic databases

Atomic and Molecular Databases Open Science for a sustainable world

March 19, 2024
Author(s)
Yuri Ralchenko, Marie-Lise Dubernet, Bruce Berriman, Paul Barklem, K Choi, Adam Foster, Iouli Gordon, Christian Hill, J Kim, DH Kwon, Harold Linnartz, Farid Salama, Hanna Shmagun, P Schilke, D Seo, J Shim, S Shin, Mi-Yong Song, Jonathan Tennyson, Charlotte VASTEL
The building of online atomic and molecular databases for astrophysics and for other research fields started with the beginning of the internet. These databases have encompassed different forms: databases of individual research groups exposing their own

Zeeman effect in the weak and intermediate field regime of Kr isotopes at the linear plasma device PSI-2

February 16, 2024
Author(s)
Yuri Ralchenko, DIPTI DIPTI, Oleksandr Marchuk, Marc Sackers, Stephan Ertmer, Sebastijan Brezinsek, Arkadi Kreter
Laser absorption spectroscopy provides high-resolution spectra of atomic transitions that reveal many often inaccessible nuances. Correctly analyzing the absorption spectra is impossible without accurately capturing the line shape. We demonstrate in this

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

January 9, 2024
Author(s)
DIPTI DIPTI, Christian Hill, Dmitry Fursa, Haadi Umer, Igor Bray, Yuri Ralchenko
An overview of the current status of electron-impact excitation and ionization cross sections for Be II is given and the recommended data sets for use in plasma modeling are presented. Accurate cross sections between the lowest 14 atomic terms of 1s2nl (n

The NIST Plan for Providing Public Access to Results of Federally Funded Research

October 2, 2023
Author(s)
Katherine E. Sharpless, Regina L. Avila, Ronald F. Boisvert, A Kirk Dohne, James Fowler, Rachel B. Glenn, Gretchen Greene, Robert Hanisch, Andrea Medina-Smith, Alan Munter, Julie Petrousky, Yuri Ralchenko, Carolyn D. Rowland, James A. St Pierre, Adam Wunderlich, Jon Zhang
In 2013 White House Office of Science and Technology Policy (OSTP) issued a memo, "Increasing Access to the Results of Federally Funded Scientific Research." In response, he National Institute of Standards and Technology (NIST) developed a public access

Observations and identifications of extreme ultraviolet spectra of Ca-like to Na-like neodymium ions using an electron beam ion trap

August 23, 2023
Author(s)
Yang Yang, Dipti Dipti, Chihiro Suzukic, A. C. Gall, R. Silwal, Samuel Sanders, Joseph N. Tan, Aung S. Naing, Endre Takacs, Yuri Ralchenko
Extreme ultraviolet (EUV) radiation from M-shell Ca-like, Nd40+, through Nalike, Nd49+, highly charged ions have been measured at an electron beam ion trap (EBIT) facility at the National Institute of Standards and Technology. To produce the ionization

Electron Scattering Cross Sections for the Ground and Excited States of Tin

May 13, 2023
Author(s)
H. Umer, Yuri Ralchenko, I. Bray, D. V. Fursa
A comprehensive set of cross sections for electron scattering from the ground and first four excited states of tin has been calculated using the Relativistic Convergent Close-Coupling method. Elastic scattering, momentum transfer, total scattering, and

Determination of electron beam energy in measuring the electron-impact ionization cross section of He-like Fe24+

March 17, 2023
Author(s)
Yuri Ralchenko, Galen O'Neil, Paul Szypryt, Joseph N. Tan, Aung S. Naing, Yang Yang, Dipti Dipti, Amy Gall, Adam Hosier, David Schultz, Randall Smith, Nancy Brickhouse, Endre Takacs
In an effort to measure electron-impact ionization (EII) cross sections of He-like $Fe^24+}$ at the electron beam ion trap (EBIT) facility of the National Institute of Standards and Technology (NIST), we have experimentally determined the corrections to

Background and blended spectral line reduction in precision spectroscopy of EUV and x-ray transitions in highly charged ions

March 3, 2023
Author(s)
Yuri Ralchenko, Joseph N. Tan, Aung S. Naing, Galen O'Neil, Paul Szypryt, Dipti Dipti, Grant Mondeel, Roshani Silwal, Alain Lapierre, Steven Blundell, Gerald Gwinner, Antonio Camargo Villari, Endre Takacs
We report a method in EBIT spectral analysis that reduces signal from contaminant lines of 1 known or unknown origin. We utilize similar ion charge distributions of heavy highly charged ions 2 that create similar potentials for lighter contaminating

Analysis of E3 Transitions in Ag-like High-Z Ions Observed with the NIST EBIT

March 1, 2023
Author(s)
Yuri Ralchenko, David La Mantia, Aung S. Naing, Paul Szypryt, Joseph N. Tan, Endre Takacs, Dipti Dipti, Yang Yang, Adam Hosier, Hunter Staiger
We report measurements and identification of the E3 4f$_7/2,5/2}$-5s$_1⁄2$ transitions and E1 allowed transitions in Ag-like W (Z=74), Re (Z=75), and Ir (Z=77). The spectra were recorded at the NIST EBIT using a grazing-incidence EUV spectrometer. The

Complete collision data set for electrons scattering on molecular hydrogen and its isotopologues: IV. Vibrationally-resolved ionization of the ground and excited electronic states.

January 31, 2023
Author(s)
Yuri Ralchenko, Barry I. Schneider, Liam Scarlett, Eric Jong, Igor Bray, Starsha Odelia, Mark Zammit, Dmitry Fursa
We present a comprehensive set of vibrationally-resolved cross sections for electron-impact ionization of molecular hydrogen and its isotopologues (H2, D2, T2, HD, HT, and DT) in both the ground and excited electronic states. We apply the adiabatic-nuclei

Complete collision data set for electrons scattering on molecular hydrogen and its isotopologues: III. Vibrational excitation via electronic excitation and radiative decay.

August 10, 2022
Author(s)
Dmitry Fursa, Mark Zammit, Igor Bray, Liam Scarlett, Daniel Boyle, Yuri Ralchenko
We present cross sections for vibrational excitation via electronic excitation followed by radiative decay (ERD), for electrons scattering on all bound vibrational levels of the ground electronic state (X 1Σ+ g ) of molecular hydrogen and its isotopologues

Atomic Physics and Spectroscopy During the First 50 Years of JPCRD

March 9, 2022
Author(s)
Yuri Ralchenko
Atomic spectroscopy and atomic physics papers represent a significant part of publications in Journal of Physical and Chemical Reference Data (JPCRD). Critically compilations of spectroscopic data, accurate calculations of collisional parameters

Spectroscopic analysis of M- and N-intrashell transitions in Co-like to Na-like Yb ions

December 19, 2021
Author(s)
Yuri Ralchenko, Dipti Goyal, Roshani Silwal, Endre Takacs, Joan Dreiling, Samuel Sanders, Amy Gall, Hemalatha Rudramadevi, John Gillaspy
The M-intrashell spectra from Co-like Yb$^43+}$ through Na-like Yb$^59+}$ ions produced in an electron beam ion trap (EBIT) at the National Institute of Standards and Technology have been studied in the extreme ultraviolet (EUV) range. A few N-intrashell

Identifications of extreme ultraviolet spectra of Br-like to Ni-like neodymium ions using an electronbeam ion trap

April 30, 2021
Author(s)
C. Suzuki, Dipti Goyal, Y. Yang, A. Gall, Roshani Silwal, S. Sanders, Aung S. Naing, Joseph N. Tan, Endre A. Takacs, Yuri Ralchenko
Charge-resolved extreme ultraviolet spectra of open N-shell neodymium (Nd) ions have been recorded in an electron beam ion trap facility at the National Institute of Standards and Technology. The measurements have been performed for nominal electron beam

Complete collision data set for electrons scattering on molecular hydrogen and itsisotopologues: I. Fully vibrationally-resolved electronic excitation of H 2 (X 1 ? g + ).

January 1, 2021
Author(s)
Liam H. Scarlett, D Fursa, Mark C. Zammit, I Bray, Yuri Ralchenko, Kayla D. Davie
We present a comprehensive set of vibrationally-resolved cross sections for electron-impact electronic excitation of molecular hydrogen suitable for implementation in collisional-radiative models. The adiabatic-nuclei molecular convergent close-coupling

Development of NIST Atomic Databases and OnlineTools

September 5, 2020
Author(s)
Yuri Ralchenko, Alexander Kramida
Over the last 25 years, the atomic standard reference databases and online tools developed at the National Institute of Standards and Technology (NIST) provide users around the world with the highest-quality data on various atomic parameters (e.g., level

Measurement of the 2P1/2-2P3/2 fine structure splitting in fluorine-like Kr, W, Re, Os and Ir

September 2, 2020
Author(s)
Galen O'Neil, Samuel C. Sanders, Paul Szypryt, Dipti Goyal, Amy Gall, Yang Yang, Samuel M. Brewer, W.Bertrand (Randy) Doriese, Joseph Fowler, Daniel Swetz, Joseph N. Tan, Joel Ullom, Andrey V. Volotka, Endre Takacs, Yuri Ralchenko
Quantum electrodynamics (QED) is currently considered to be one of the most accurate theories of fundamental interactions. As its extraordinary precision offers unique scientific opportunities, e.g., search for new physics, stringent experimental tests of

Measurements of the Linear Polarization of Satellite Transitions from Li- and Be- like Ar Ions

June 18, 2020
Author(s)
Amy Gall, Dipti Goyal, Sean W. Buechele, Samuel C. Sanders, Roshani Silwal, Csilla Szabo-Foster, N Brickhouse, Yuri Ralchenko, Endre A. Takacs
Non-thermal electron distributions, such as beams of electrons, are found in many laboratory and astrophysical plasma sources and can produce anisotropic and polarized emission. Theories used to model the emission require sublevel specific analysis, which

Complete collision data set for electrons scattering on molecular hydrogen and its isotopologues: I. Fully vibrationally-resolved electronic excitation of H2(X 1O+g ).

June 16, 2020
Author(s)
Liam H. Scarlett, D Fursa, Mark C. Zammit, Igor Bray, Yuri Ralchenko, Kayla D. Davie
We present a comprehensive set of vibrationally-resolved cross sections for electron-impact electronic excitation of molecular hydrogen suitable for implementation in collisional-radiative models. The adiabatic-nuclei molecular convergent close-coupling

Determination of the isotopic change in nuclear charge radius from extreme-ultraviolet spectroscopy of highly charged ions of Xe

June 16, 2020
Author(s)
Yuri Ralchenko, Roshani Silwal, A. Lapierre, John Gillaspy, Joan M. Dreiling, S A. Blundell, Dipti Goyal, A. Borovik, Jr., G Gwinner, A.C.C. Villari, Endre Takacs
The electron beam ion trap (EBIT) at the National Institute of Standards and Technology was employed to measure the isotopic shift of the Na-like D 3s 2S1=2 3p 2P1=2;3=2, Mg-like 3s2 1S0 3s3p 1P1, Mg-like 3s2 1S0 3s3p 3P1, Al-like 3s23p 2P1=2 3s23p 2P3=2

Spectroscopic analysis of N-intrashell transitions in Rb-like to Ni-like Yb ions

June 9, 2020
Author(s)
Dipti Goyal, R. Silwal, Joan M. Dreiling, Samuel C. Sanders, Endre A. Takacs, Yuri Ralchenko
Extreme ultraviolet spectra of highly-charged ytterbium ions produced in an electron beam ion trap at National Institute of Standards and Technology were observed with a at- eld grazing incidence spectrometer in the wavelength region of about 4 nm to 20 nm

Linear Polarization of Anisotropically Excited X-ray Lines from the n=2 Complex in He-like Ar16+

May 13, 2020
Author(s)
Dipti Goyal, Sean W. Buechele, Amy C. Gall, Samuel C. Sanders, Csilla I. Szabo-Foster, Roshani Silwal, Endre A. Takacs, Yuri Ralchenko
High-resolution x-ray spectra were recorded at the National Institute of Standards and Technology (NIST) electron beam ion trap (EBIT) using two Johann-type crystal spectrometers, with their dispersion planes oriented parallel and perpendicular to the beam