Selenium energy level diagram

Energy levels and transitions of neutral selenium (Se I): the 16 strongest classified lines below 2 µm from the NIST Atomic Spectra Database and the 11 levels they connect, each line with its vacuum wavelength, frequency and, for 10 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.

Hover a line or a level to isolate it, click to keep it selected. Scroll to zoom, drag to move.

Download: diagram (PDF) diagram (SVG) transitions (CSV) levels (CSV) source code

Key transitions of selenium

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).

Listed Se 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, this site's own Cowan-code calculation with the parameters fitted to the NIST energies (HFR fit; inputs and fit report in the repository folder cowan/; used only where nothing else gives a rate; strong lines typically within a factor 2, weak lines worse), or a model calculation.

Se energy levels

Se⁺ ionisation limit 78658.15 cm⁻¹ = 9.75237 eV (127.132 nm)

Sources

• Bengtsson, Berzinsh, Larsson, Svanberg, Z. Phys. D 23, 29 (1992) (short-pulse laser excit…
• Bengtsson, Berzinsh, Larsson, Svanberg, Zerne, J. Phys. II France 2, 773 (1992) (time-res…
• D. C. Morton, Astrophys. J. Suppl. 130, 403 (2000), as listed (A_ki ref. M00) in the NIST…
• NIST ASD level energies
• R. H. Garstang, J. Res. Natl. Bur. Stand. 68A, 61 (1964), Table 25 (intermediate-coupling…
• R. H. Garstang, J. Res. Natl. Bur. Stand. 68A, 61 (1964), Table 25. Note: derived: 1/sum …
• R. H. Garstang, J. Res. Natl. Bur. Stand. 68A, 61 (1964), Table 25. Note: derived: 1/sum …
• R. H. Garstang, J. Res. Natl. Bur. Stand. 68A, 61 (1964), Table 25. Note: derived: 1/sum …
• R. H. Garstang, J. Res. Natl. Bur. Stand. 68A, 61 (1964), Table 25. Note: derived: 1/sum …
• This site: Cowan-code HFR calculation of Se I with the parameters fitted to the NIST ener…
• Ubelis and Berzinsh, Phys. Scr. 34, 805 (1986) (emission branching; values read in the ab…

NIST ASD has Se I level energies but no classified lines; the E1 transitions here are the classified persistent lines of the NIST Handbook of Basic Atomic Spectroscopic Data, re-expressed with the NIST ASD level energies of data/nist/Se_I_levels.tsv (identification by configuration, term and J). The 'wavelength_nm' field gives the observed wavelength as listed (vacuum below 200 nm, air above) with its 'medium'; the wavelength in each label is the vacuum Ritz value from the NIST ASD energies. A values of the six 5s-4p4 lines are those of Morton 2000 as listed by NIST (compilation: Bengtsson et al. laser lifetimes x Ubelis and Berzinsh branching); rme_J_ea0 is derived from them (convention of SCHEMA.md). Branching fractions of the 3S°1 level are derived from the four Ubelis and Berzinsh A values; those of 5S°2 from the two Morton A values. Lifetimes of the 4p4 metastable levels and all forbidden-line rates are 1964 THEORY (Garstang); A_s of a forbidden line is the sum of the calculated M1 and E2 parts given in its note. Natural selenium is 92 % even isotopes (I = 0) and 7.6 % 77Se (I = 1/2). Second pass 2026-10-01: Bengtsson et al., Z. Phys. D 23, 29 (1992) was read directly (first two pages): tau(3S°1) = 2.9(5) ns and f_abs(196.0 nm) = 0.074(16) are confirmed. Roederer & Lawler 2012 (Table 5) recommend the Morton A values with uncertainties 213(37), 98(17), 33(6) and 1.70(10) x 10^6 s^-1 (stored as alternatives) and note that isotope shifts are small and the 77Se hyperfine str

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