Reference lines in the optogalvanic spectra of uranium and thorium over the wavelength range 694–755 nm

Abstract

The optogalvanic spectra of uranium and thorium are convenient sources of lines with which to calibrate wavemeters for high-resolution laser spectroscopy. We used hollow-cathode lamps for both uranium and thorium to observe the spectra, using a single-frequency cw dye laser operating over the wavelength range 694-755 nm. Eight uranium and seven thorium lines were measured with an accuracy of a few parts in 10 8 with our Fabry-Perot wavemeter. The estimated uncertainty of the measurements is 0.0002 cm Ϫ1 for both species. The results were compared with several previous measurements of these lines and were found to be in good agreement with values determined by Fourier-transform spectroscopy.

The Spectrum of Th‐Ar Hollow Cathode Lamps in the 691–5804 nm region: Establishing Wavelength Standards for the Calibration of Infrared Spectrographs

“…The solid circles represent data where the uncertainty in the NIST measurements is less than 5 parts in 10 8 . The weighted mean is (À2:75 AE 0:10) ; 10 À8 , in good agreement with the difference of (À2:4 AE 0:4) ; 10 À8 found from seven lines by DeGraffenreid & Sansonetti (2002). Figure 8 shows a comparison of our Ar i lines with those of Whaling et al (2002).…”

THE SPECTRUM OF THORIUM FROM 250 nm TO 5500 nm: RITZ WAVELENGTHS AND OPTIMIZED ENERGY LEVELS

“…Since then, the wavenumbers of several thorium lines have been measured via laser spectroscopy by Sansonetti & Weber (1984;fifteen lines), DeGraffenreid & Sansonetti (2002;seven lines), and DeGraffenreid et al (2012;eight lines). also compiled thousands of neon lines, some of which are recommended as standards.…”

“…The thorium spectrum was also measured in the near-infrared (NIR) through 5500 nm (1800 cm −1 ) at a lamp current of 320 mA by Engleman et al (Nave et al 1997) from 691 nm to 5804 nm with a hollow cathode lamp running at 20 mA by Kerber et al (2008, hereafter KNS08). Also since 1983, a number of thorium lines have been measured with high accuracy by laser spectroscopy (Sansonetti & Weber 1984;DeGraffenreid & Sansonetti 2002;DeGraffenreid et al 2012, collectively referred to hereafter as LS3). These lines can be used to recalibrate the results of PE83, reducing the systematic contribution to their uncertainties.…”

Relativistic all-order calculations of Th,Th+, andTh2+atomic properties

“…Recently, Redman et al [12] presented results of precise observations of a thorium-argon hollow cathode lamp emission spectrum in the region between 3500 nm and 1175 nm using a high-resolution Fourier transform spectrometer. Their measurements were combined with results from previously published thorium line lists [24][25][26][27][28][29] to re-optimize the energy levels of neutral, singly, and doubly ionized thorium (Th, Th + , and Th 2+ ). A systematic analysis of previous measurements in light of these new results enabled [Redman et al [12]] to identify and propose corrections for systematic errors and typographical errors and incorrect classifications in previous identifications.…”