https://doi.org/10.1140/epjd/e2005-00249-7
New FTS measurements, optimized energy levels and refined VUV standards in the Ne III spectrum*
National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
Corresponding author: a Alexander.Kramida@nist.gov
Received:
14
March
2005
Revised:
28
June
2005
Published online:
6
September
2005
All observed spectral lines of Ne III in the
range 204 Å to 36 
m (277 cm-1 to 490000 cm
have been
compiled and critically evaluated. 57 visible and ultraviolet lines of Ne
III have been precisely measured using Fourier transform spectroscopy. An
optimized level scheme has been derived from the total list of observed
lines. Relative positions of about 180 out of a total of 226 previously
known energy levels of Ne III have been determined with improved accuracy
compared to previous studies. Excitation energies of almost all excited
levels have been revised by (1.5–2.0) cm-1. 127 precise wavelength
standards in the region 210 Å to 2900 Å have been derived. Concepts
of error current and covariance matrix have been implemented in a computational algorithm that permits one
to derive the uncertainties of Ritz wavelength standards obtained from a set
of least-squares-optimized energy levels. Nine new energy levels have been
found, and 16 new transitions have been identified in the extreme
ultraviolet region. The ionization potential has been increased by
4.5 cm-1. The new value is
(
(
).
PACS: 32.10.Fn – Fine and hyperfine structure / 32.10.Hq – Ionization potentials, electron affinities / 32.30.Jc – Visible and ultraviolet spectra / 32.70.Cs – Oscillator strengths, lifetimes, transition moments / 31.15.Ct – Semi-empirical and empirical calculations (differential overlap, Hückel, PPP methods, etc.) / 95.30.Ky – Atomic and molecular data, spectra, and spectral parameters (opacities, rotation constants, line identification, oscillator strengths, gf values, transition probabilities, etc.)
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2005
