Neodymium energy level diagram

Energy levels and transitions of neutral neodymium (Nd I): the 18 strongest classified lines below 2 µm from the NIST Atomic Spectra Database and the 22 levels they connect, each line with its vacuum wavelength, frequency and, for 9 of them, the reduced dipole matrix element derived from the NIST transition rate. Measured lifetimes, transition rates, hyperfine constants and isotope shifts from the literature are included, each with its citation.

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Key transitions of neodymium

λ, ν from NIST level energies unless a measured frequency for this isotope is available. A: measured value or NIST. Γ/2π: natural linewidth of the upper level, 1/(2πτ).

¹⁴³Nd hyperfine structure (I = 7/2)

Measured A, B constants; sources in the data file.

Isotope shifts

Shift = ν(first isotope) − ν(second isotope).

Listed Nd transitions below 2 µm

Reduced dipole matrix elements follow the convention A = ω³|d|²/(3πε₀ħc³(2J′+1)), with J′ the upper level. Tags show where a number comes from: measured, NIST compilation, high-accuracy theory, or a model calculation.

Nd energy levels

Nd⁺ ionisation limit 44560.11 cm⁻¹ = 5.52475 eV (224.416 nm)

Sources

• Biemont, Quinet, Svanberg, Xu, J. Phys. B 37, 1381 (2004), Table 2 (p. 1384), column "Thi…
• Blagoev & Komarovskii (1994), as adopted in C. A. Ryder, PhD thesis, Wayne State Universi…
• Den Hartog, Fittante, Lawler, J. Phys. B 44, 225001 (2011) (time-resolved laser-induced f…
• NIST ASD
• NIST ASD level energies
• Spalding, Proc. Phys. Soc. (London) 81, 156 (1963), abstract

Nd I lifetimes (second pass): 15 levels measured by Biemont et al. 2004 (opened, Lund University repository) and 84 lifetimes of Den Hartog, Fittante, Lawler 2011 read second-hand in two open theses (Ryder 2011 Table 5.2; Putnam 2014 Table 6.1) (method "compilation", no uncertainty printed; the original abstract quotes +/-5%). Where both exist the directly opened Biemont value is the entry and the Den Hartog value sits under the level key "alternatives" (each alternative names its quantity), except for 20300.875 cm^-1 where the Biemont value fails the tau x sum(A) check (see conflicts). Lifetimes were checked against the NIST A values: tau x sum(A) <= 0.96 for all drawn levels except those listed under conflicts. The branching-fraction paper (Stockett 2011) and the ground-term hyperfine paper (Childs & Goodman 1972) remain closed. Hyperfine A constants are for the even-parity metastable levels 7L5, 7L11, 7K4 (second-hand) and the ground level 5I4 of 143Nd (abstract of the original paper). Nuclear spins 7/2 for 143Nd and 145Nd from the IAEA/ENSDF ground-state table (https://nds.iaea.org/relnsd/v1/data?fields=ground_states&nuclides=143nd). Third pass (2026-10-02): added (a) 38 Nd I lifetimes read directly in Gorshkov et al., Astrophysics 17, 437 (1982), Table 1 (Springer free preview): 3 levels that had no lifetime get it as the entry (19590.241, 22229.000, 23562.766), 2 second-hand quotes of the same numbers are replaced by the direct reading with uncertainty (19700.856, 25478

Atoms with measured data

• Lithium-632 levels, 85 lines
• Lithium-732 levels, 85 lines
• Beryllium-917 levels, 26 lines
• Sodium-2336 levels, 106 lines
• Magnesium-2418 levels, 61 lines
• Magnesium-2518 levels, 61 lines
• Potassium-3934 levels, 84 lines
• Potassium-4034 levels, 84 lines
• Potassium-4134 levels, 84 lines
• Calcium-4035 levels, 61 lines
• Calcium-4335 levels, 61 lines
• Chromium-5256 levels, 87 lines
• Chromium-5356 levels, 87 lines
• Rubidium-8536 levels, 94 lines
• Rubidium-8736 levels, 94 lines
• Strontium-8440 levels, 70 lines
• Strontium-8640 levels, 70 lines
• Strontium-8740 levels, 70 lines
• Strontium-8840 levels, 70 lines
• Cadmium-11115 levels, 21 lines
• Cadmium-11315 levels, 21 lines
• Cadmium-11415 levels, 21 lines
• Caesium-13331 levels, 79 lines
• Barium-13744 levels, 89 lines
• Barium-13844 levels, 89 lines
• Dysprosium-16139 levels, 55 lines
• Dysprosium-16239 levels, 55 lines
• Dysprosium-16339 levels, 55 lines
• Dysprosium-16439 levels, 55 lines
• Erbium-16673 levels, 90 lines
• Erbium-16773 levels, 90 lines
• Erbium-16873 levels, 90 lines
• Thulium-16972 levels, 73 lines
• Ytterbium-17118 levels, 26 lines
• Ytterbium-17318 levels, 26 lines
• Ytterbium-17418 levels, 26 lines
• Mercury-19927 levels, 47 lines
• Mercury-20127 levels, 47 lines
• Mercury-20227 levels, 47 lines

All elements: periodic table