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Displaying 1 - 25 of 125

Mercury in the HgMn Stars X Lupi and HR 7775

October 12, 2021
Author(s)
C R. Proffitt, T Brage, D S. Leckrone, G Wahlgren, J C. Brandt, Craig J. Sansonetti, Joseph Reader, S Johansson
Observations of mercury lines in the HgMn stars chi Lupi and HR 7775 made with the Hubble Space Telescope's Goddard High Resolution Spectrograph are presented and analyzed. In chi Lupi we find that all observed lines are consistent with the same isotopic

Comprehensive atomic wavelengths, energy levels and hyperfine structure for singly-ionized iron-group elements

January 23, 2017
Author(s)
Gillian Nave, Craig J. Sansonetti, Keeley I. Townley-Smith, J C. Pickering, Florence Liggins, Anne P. Thorne, Christian Clear
We summarize recent work at the National Institute of Standards and Technology and Imperial College London on wavelengths, hyperfi ne structure, energy levels, and analysis of singly-ionized iron-group elements of astrophysical interest.

Extended Analysis of the Spectrum of Singly Ionized Chromium (Cr II)

July 23, 2014
Author(s)
Craig J. Sansonetti, Gillian Nave
We have made new observations of the spectrum of singly-ionized chromium (Cr II) in the region 2850 Angstrom to 37900 Angstrom with the National Institute of Standards and Technology 2 m Fourier transform spectrometer. These data extend our previously

Atomic Data for Iron-group Elements of Astrophysical Interest

July 11, 2013
Author(s)
Gillian Nave, Craig J. Sansonetti, J C. Pickering, Matthew Ruffoni, Anne P. Thorne, Florence Liggins
The joint project between NIST and Imperial College London to measure spectra of singly-ionized iron-group elements using Fourier transform and high-resolution grating spectroscopy is described.

Light polarization and quantum interference effects in unresolvable atomic lines: application to a precise measurement of the 6,7Li D2 lines.

March 7, 2013
Author(s)
Roger C. Brown, Saijun Wu, James V. Porto, Craig J. Sansonetti, Clayton Simien, Samuel M. Brewer, Joseph N. Tan, John D. Gillaspy
We characterize the effect of quantum interference of light scattering on the line shapes and measured line positions in atomic spectra. These effects occur when the excited state splittings are of order the excited state line widths, and represent an

Absolute transition frequencies and quantum interference in a frequency comb based measurement of the 6,7Li D lines

July 6, 2011
Author(s)
Craig J. Sansonetti, Clayton Simien, John D. Gillaspy, Joseph N. Tan, Samuel M. Brewer, Roger C. Brown, Saijun Wu, James V. Porto
Optical frequencies of the D lines of 6,7Li were measured with a relative accuracy of 5x10-11 using an optical comb synthesizer. Quantum interference in the laser induced fluorescence for the partially-resolved D2 lines was found to produce polarization

Use of Phosphor Image Plates for Measuring Intensities in Vacuum Ultraviolet Spectra

January 28, 2011
Author(s)
Gillian Nave, Craig J. Sansonetti, Csilla Szabo, John J. Curry, Darren Smillie
We describe the use of phosphor image plates for recording spectra in the vacuum ultraviolet (VUV) and for determining accurate relative and absolute intensities. We investigated the spatial uniformity, noise level, linearity of the response to VUV light

Progress at NIST in measuring the D-lines of Li isotopes using an optical frequency comb

December 20, 2010
Author(s)
Clayton Simien, Samuel M. Brewer, Joseph N. Tan, John D. Gillaspy, Craig J. Sansonetti
Precise spectroscopic experiments with light atoms can provide information about nuclear properties that are very difficult to obtain in electron scattering experiments. For example, relative nuclear radii of low-Z isotopes can be determined accurately

An optical frequency comb for infrared spectrograph calibration

November 17, 2010
Author(s)
Gabriel G. Ycas, Franklyn J. Quinlan, Steve Osterman, Gillian Nave, Craig J. Sansonetti, Scott A. Diddams
Detection of extrasolar planets by measurement of the stellar radial velocity shift requires high resolution spectroscopy with long term stability. Presently, the primary wavelength standards in the NIR are NePt and ThAr lamps and absorption cells. These

Atomic Data for Lighting Applications

October 16, 2008
Author(s)
Gillian Nave, Craig J. Sansonetti, Joseph Reader
A major objective of our research program is the observation of spectra of rare earth elements in support of our program of atomic data measurements for lighting applications. Three years ago, NIST acquired a high-resolution Fourier transform spectrometer

Infrared Spectrum and Revised Energy Levels for Neutral Krypton

October 16, 2008
Author(s)
Craig J. Sansonetti, Marion Greene
We observed the spectrum of neutral krypton (Kr I) in its naturally occurring isotopic mixture as emitted by a microwave-excited electrodeless discharge lamp with the National Institute of Standards and Technology 2-m Fourier transform spectrometer. The

Precise Wavelengths for Fe, Ge and Pt in the Region Near 1935

October 16, 2008
Author(s)
Gillian Nave, Craig J. Sansonetti
Wavelengths of seven spectral lines of Fe I, Ge I and Pt I between 1932 and 1938 have been measured with uncertainties of less than 1x10 -4 (5 parts in 10 8) using Fourier transform spectroscopy. These lines provide accurate standards for wavelength

Spectrum of Singly-Ionized Cesium (Cs II)

October 16, 2008
Author(s)
Craig J. Sansonetti, K L. Andrew
We measured the spectrum of cesium emitted by a pulsed radio-frequency discharge in the region 1550 to 40 000 using concave grating spectrographs, Fabry-Perot interferometry, and Fourier transform spectroscopy. By varying the operating parameters of the

X-Ray Induced Fluorescence Measurement of Segregation in a DyI3 Metal-Halide Lamp

April 19, 2007
Author(s)
T Nimalisuriya, John J. Curry, Craig J. Sansonetti, E J. Ridderhof, S Shastri, A J. Flikweert, W W. Stoffels, M Haverlag, J J. van der Mullen
X-ray induced fluorescence measurements, using high energy synchrotron radiation generated on the Sector 1 Insertion Device beamline at the Advanced Photon Source, were performed on a metal-halide lamp containing Hg and DyI$_3}$. Density distributions of