J/A+A/684/A149 Nd III spectrum and energy levels (Ding+, 2024)
Spectrum and energy levels of low-lying configurations of Nd III.
Ding M., Ryabtsev A.N., Kononov E.Y., Ryabchikova T.A., Clear C.P.,
Concepcion F., Pickering J.C.
<Astron. Astrophys. 684, A149 (2024)>
=2024A&A...684A.149D 2024A&A...684A.149D (SIMBAD/NED BibCode)
ADC_Keywords: Atomic physics
Keywords: atomic data - line: identification - methods: data analysis -
methods: laboratory: atomic - stars: abundances -
stars: chemically peculiar
Abstract:
Our goal is to accurately determine bound-to-bound transition
wavelengths and energy levels of the low-lying open-shell
configurations 4f4, 4f3 5d, 4f3 6s, and 4f3 6p of doubly
ionised neodymium (Nd III) through high-resolution spectroscopy and
semi-empirical calculations.
The emission spectra of neodymium (Nd, Z=60) were recorded using
Penning and hollow cathode discharge lamps in the region 11
500-54000cm-1 (8695-1852Å) by Fourier transform spectroscopy at
resolving powers up to 106. Wavenumber measurements were accurate to a
few 10-3cm-1. Grating spectroscopy of Nd vacuum sliding sparks and
stellar spectra were used to aid line and energy level identification.
For the analysis, new Nd III atomic structure and transition
probability calculations were carried out using the Cowan code
parameterised by newly established levels.
The classification of 432 transitions of Nd III from the Penning lamp
spectra resulted in the determination of 144 energy levels of the
4f4, 4f3 5d, 4f3 6s, and 4f3 6p configurations of Nd III, 105
of which were experimentally established for the first time. Of the 40
previously published Nd III levels, one was revised and 39 were
confirmed.
The results will not only benchmark and improve future semi-empirical
atomic structure calculations of Nd III, but also enable more reliable
astrophysical applications of Nd III, such as abundance analyses of
kilonovae and chemically peculiar stars, and studies of pulsational
wave propagation in these stars.
Description:
Supplemented by atomic structure calculations, Nd-Ar HCL FT spectra,
Nd VS grating spectra, and Nd-rich stellar spectra, 144 energy levels
of Nd III have been determined from the classification of 432 Nd III
transitions measured by FT spectroscopy of a Nd-Ar PDL between
11500-54000cm-1 (8695-1852Å), 39 previously published energy
levels were confirmed and 105 new levels of the 4f4, 4f35d,
4f36s, and 4f36p configurations are reported here for the first
time. These results are the most extensive and most accurate (to a few
10-3cm-1) Nd III energy level and transition wavenumber data to
date, which will support theoretical atomic structure investigations
of the lanthanides and enable wider and more reliable applications of
Nd III atomic data in astronomy.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 76 198 Parameters of the least squares fit of Nd III
energy levels in Cowan's codes
table5.dat 142 144 Energy levels experimentally established for the
4f4, 4f35d, 4f36s, and 4f36p
configurations of Nd III
table6.dat 171 432 Classified transitions of Nd III originating
from the 4f35d, 4f36s, and 4f36p
configurations in the Nd-Ar PDL FT spectra
table7.dat 118 191 Transitions of Nd III originating from the
4f36s and 4f36p configurations observed
only in the Nd VS grating spectra
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Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1 A1 --- Par [eo] Parity (e - even, o - odd)
3- 11 A9 --- Conf1 Configuration
13- 21 A9 --- Conf2 Configuration (1)
23- 38 A16 --- Param Parameter Name
40- 45 I6 cm-1 LSFval Least-Squares-Fitted Value
47- 49 I3 cm-1 e_LSFval ? Standard Deviation in LSF (2)
51- 55 A5 --- f_LSFval Flag on LSFval
57- 58 I2 --- Group ? Linked Group Number (3)
61- 66 I6 cm-1 HFRval Ab Initio HFR Value (4)
68- 76 F9.3 --- Ratio ? Ratio LSFval/HFRval (5)
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Note (1): The second configuration is nonblank only for configuration
interaction parameters.
Note (2): Standard deviation is computed only for parameters that were
varied in the LSF. The fixed parameters are indicated by 'fixed' in the
f_LSFval column
Note (3): Parameters in each numbered group were linked together with their
ratio fixed at the HFR level.
Note (4): The average energies are adjusted so that the energy of the ground
level 4f4 5I4 is zero in the HFR calculations with scaling of the
Slater and configuration interaction parameters respectively by 0.85 and
0.70 factors.
Note (5): Blank for parameters that are zero in HFR. The differences between
LSF and HFR parameters are given.
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Byte-by-byte Description of file: table5.dat
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Bytes Format Units Label Explanations
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1- 13 A13 --- (sub)conf Assigned configuration (1)
15- 25 A11 --- term Assigned term (2)
27- 28 I2 --- J J value
30- 38 F9.3 cm-1 E Excitation energy from the ground level
40- 44 F5.3 cm-1 e_E Uncertainty of excitation energy from the
ground level
46- 47 I2 --- N Number of lines of the level observed in the
Nd-Ar FT spectra
49 I1 --- N2 Number of lines which were either blended or
too weak and omitted from level energy
optimisation
52- 55 I4 cm-1 dE1 Difference from Cowan code calculations done
in this work
57- 61 I5 cm-1 dE2 Difference from calculations by Gaigalas
et al. (2019ApJS..240...29G 2019ApJS..240...29G)
63- 67 F5.3 --- g Lande g-factor calculated in this work
69- 70 I2 --- P1 Percentage of the first leading eigenvector
component
72- 80 A9 --- C1 (Sub)configuration of the first leading
eigenvector component (2)
82- 92 A11 --- T1 Term of the first leading eigenvector
component (1)
94- 95 I2 --- P2 ? Percentage of the second leading eigenvector
component
97-105 A9 --- C2 (Sub)configuration of the second leading
eigenvector component (2)
107-117 A11 --- T2 Term of the second leading eigenvector
component (1)
119-120 I2 --- P3 ? Percentage of the third leading
eigenvector component
122-130 A9 --- C3 (Sub)configuration of the third leading
eigenvector component (2)
132-142 A11 --- T3 Term of the third leading eigenvector
component (1)
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Note (1): The * symbol is used to indicate odd parity terms.
Trailing numbers after the terms of levels of the 4f^3
(sub)configuration are used to indicate recurrent terms of the
equivalent electrons.
Note (2): The * symbol is used to indicate odd parity terms.
Trailing numbers after the terms of levels of the 4f^4 configuration
are used to indicate recurrent terms of the equivalent electrons.
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Byte-by-byte Description of file: table6.dat
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Bytes Format Units Label Explanations
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1- 4 I4 --- snr Signal-to-noise ratio
6- 10 I5 --- int Relative intensity (1)
12- 18 E7.2 s-1 gA Transition probability weighted by
upper level statistical weight
20- 24 F5.2 --- log(gf) Log of absorption oscillator strength
weighted by lower level statistical weight
26- 30 F5.3 cm-1 FWHM Full width at half maximum
32- 41 F10.4 cm-1 wn Observed vacuum wavenumber (2)
43- 48 F6.4 cm-1 e_wn Observed vacuum wavenumber uncertainty (2)
50- 59 F10.4 cm-1 Ritz Vacuum Ritz wavenumber
61- 66 F6.4 cm-1 e_Ritz Vacuum Ritz wavenumber uncertainty
68- 74 F7.4 cm-1 obs-Ritz Difference between observed and Ritz
wavenumber
76- 84 F9.4 0.1nm lambdaAir Air Ritz wavelength (3)
86- 91 F6.4 0.1nm e_lambdaAir Air Ritz wavelength uncertainty
93-105 A13 --- lowerConfig Lower level (sub)configuration (4)
107-119 A13 --- lowerTermJ Lower level term and J value (4)
121-133 A13 --- upperConfig Upper level (sub)configuration (4)
135-147 A13 --- upperTermJ Upper level term and J value (4)
149-157 F9.3 cm-1 lowerE Lower level energy
159-167 F9.3 cm-1 upperE Upper level energy
169-171 A3 --- nbw Blend/weak line marker (5)
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Note (1): The relative intensities correspond to relative photon fluxes and are
recommended only as a rough guide.
Note (2): Observed vacuum wavenumbers and their uncertainties are presented at
the decimal point precision used for the inputs of LOPT,
Kramida (2011CoPhC.182..419K 2011CoPhC.182..419K), during level optimisation.
Note (3): Converted from Ritz vacuum wavenumber using the three-term dispersion
formula from Peck and Reeder (1972JOSA...62..958P 1972JOSA...62..958P).
Note (4): Trailing numbers after the terms of levels of the 4f^4 configuration
and 4f^3 (sub)configuration are used to indicate recurrent terms of
the equivalent electrons.
Note (5): Lines marked with B/W (blended or weak) likely have very uncertain
observed wavenumbers and relative intensities.
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Byte-by-byte Description of file: table7.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- int Relative intensity (1)
5- 8 I4 10+6/s gA Transition probability weighted by
upper level statistical weight
10- 14 F5.2 --- log(gf) Log of absorption oscillator strength
weighted by lower level statistical weight
16- 23 F8.3 0.1nm lambda Observed vacuum wavelength
25- 33 F9.4 0.1nm lambdaRitz Vacuum Ritz wavelength
35- 40 F6.4 0.1nm e_lambdaRitz Vacuum Ritz wavelength uncertainty
42- 50 F9.4 0.1nm lambdaAir Air Ritz wavelength (2)
52- 64 A13 --- lowerConfig Lower level (sub)configuration (3)
66- 78 A13 --- lowerTermJ Lower level term and J value
80- 92 A13 --- upperConfig Upper level (sub)configuration (3)
94- 98 A5 --- upperTermJ Upper level term and J value
100-108 F9.3 cm-1 lowerE Lower level energy
110-118 F9.3 cm-1 upperE Upper level energy
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Note (1): The relative intensities correspond to relative energy fluxes and are
recommended only as a very rough guide.
Note (2): Converted from Ritz wavelength using the three term dispersion
formula from Peck and Reeder (1972JOSA...62..958P 1972JOSA...62..958P).
Note (3): Trailing numbers after the terms of levels of the 4f^3
(sub)configuration are used to indicate recurrent terms of the
equivalent electrons.
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Acknowledgements:
Milan Ding, milan.ding15(at)imperial.ac.uk
(End) Patricia Vannier [CDS] 29-Jan-2024