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D.R.E.A.M.

__D__atabase on __R__are __E__arths __A__t __M__ons University

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Maintained by the Atomic Physics and Astrophysics Group at Mons University, Belgium

Biémont E., Palmeri P., Quinet P., Astrophys. Space Sci. __269-270__, 635-637 (1999)

Biémont E., Quinet P., Palmeri P., J. Electr. Spectrosc. Rel. Phen. __144-147__, 23-25 (2005)

Quinet P., Palmeri P., Atoms __8(2)__, 18 (2020)

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1. __General introduction and presentation of the tables__

Despite their low cosmic abundance, the lanthanides (Z=57-71) become
increasingly important in astrophysics because they are observed on the
high resolution spectra of some stars now currently available via
ground-based or satellite observations. The main purpose of D.R.E.A.M.
(Database on Rare-Earths At Mons University) is to provide the
astrophysicists, but also the physicists, with an updated information
concerning the wavelengths, the oscillator strengths, the transition
probabilities and the radiative lifetimes of neutral, singly or
multiply ionized lanthanides.
In our compilation, the spectra are classified in order of increasing
Z-values and, for a given Z, according to the ionization degree.
For each line in a particular spectrum,
the tables show, respectively:

- the wavelength (in A) deduced from the experimental energy levels.
These wavelengths are given in air above 2000 A and in vacuum below that limit;

- the lower level of the transition represented by its experimental
value (in cm
^{-1}), its parity ((e) for even and (o) for odd)
and its J-value. Level energies are taken from the NIST compilation
(W.C. Martin, R. Zalubas and L. Hagan, Atomic Energy Levels - The
Rare-Earth Elements, NBS-NSRDS 60, 1978) except when otherwise
indicated;

- the upper level of the transition presented in the same way as for
the lower level;

- the calculated oscillator strength, log gf, where g=2J+1 is
the statistical weight of the lower level of the transition.
More details about the computational procedure are given in the
different publications listed below. Only transitions
for which log gf > -4.0 are reported in the tables.
For some ions, experimental oscillator strengths or normalized oscillator
strengths using measured lifetimes are given. In these
cases, "EXPT" or "NORM" appears in the last column of the tables;

- the calculated transition probability, gA in s
^{-1}, where
g=2J+1 is the statistical weight of the upper level of the transition.
For some ions, experimental gA-values or normalized gA-values using
measured lifetimes are given. In these cases, "EXPT" or "NORM"
appears in the last column of the tables;

- the cancellation factor, CF, as defined by Cowan (1981). Small values
of this factor (typically CF < 0.01) indicate transitions affected by
severe cancellation effects.

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2. __Database__

The different tables are accessible directly
by clicking on the ion considered in the following list.

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Lanthanum (Z = 57)........
La I,
La III

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Cerium (Z = 58)...............
Ce II,
Ce III

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Promethium (Z = 61).......

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Samarium (Z = 62)..........
Sm II,
Sm III

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Europium (Z = 63)...........
Eu III

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Gadolinium (Z = 64)........
Gd III

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Terbium (Z = 65).............
Tb III

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Dysprosium (Z = 66)........
Dy III

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Holmium (Z = 67)............
Ho III

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Erbium (Z = 68)...............
Er II,
Er III

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Thulium (Z = 69).............
Tm II,
Tm III,
Tm IV

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Lutetium (Z = 71)...........
Lu I,
Lu II,
Lu III

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3. __References__

The list of references is available here.

... to the AGIF center main page

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