Lead energy level diagram

Energy levels and transitions of neutral lead (Pb I): the 31 strongest classified lines below 2 µm from the NIST Atomic Spectra Database and the 15 levels they connect, each line with its vacuum wavelength, frequency and, for 29 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 lead

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).

²⁰⁷Pb hyperfine structure (I = 1/2)

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

Isotope shifts

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

Closed and nearly closed transitions of lead

A transition is closed when its upper level can decay only to the level it was excited from, so the atom keeps scattering photons. “closed”: among the levels NIST lists, no other level below the upper level has the opposite parity and |ΔJ| ≤ 1, so no other electric-dipole decay exists. Otherwise the leak is the sum of the branching ratios of the other decay lines of the upper level (or 1 − branching ratio where that of the line itself has been measured), and the number of photons is 1 / leak. “≥” and “≤”: at least one possible decay path has no listed rate, so the leak is a lower limit. These numbers are derived from the branching ratios, lifetimes and rates of this page, not measured as such; the tag names the weakest of the inputs, * marks theory and ≈ a model or semi-empirical calculation. Listed: lines that start on the ground level or on a metastable level and leak at most 10 %, unless more than three possible decay paths have no listed rate. Fine-structure levels only: hyperfine and Zeeman dark states and forbidden decays without a listed rate are not considered. Select a line in the diagram for the full list of its leak channels.

Listed Pb 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.

Pb energy levels

Pb⁺ ionisation limit 59819.56 cm⁻¹ = 7.41668 eV (167.169 nm)

Sources

• Biémont, Garnir, Palmeri, Li, Svanberg, Mon. Not. R. Astron. Soc. 312, 116 (2000) (time-r…
• Bouazza, Gough, Hannaford, Lowe, Wilson, Phys. Rev. A 63, 012516 (2000) (Doppler-free sat…
• Lurio, Landman, J. Opt. Soc. Am. 60, 759 (1970), as quoted in Tables II and VI of Porsev …
• Maser, Hoenig, Wang, Rupasinghe, Porsev, Safronova, Majumder, "High-precision measurement…
• NIST ASD
• NIST ASD level energies
• Porsev, Kozlov, Safronova, Tupitsyn, Phys. Rev. A 93, 012501 (2016), arXiv:1510.06679, Ta…
• Wasowicz, Drozdowski, Kwela, Phys. Scr. 71, 274 (2005); 72, 200 (2005); Eur. Phys. J. Spe…
• Zheng, Wang, Verma, Wang, Langin, DeMille, "Simulated Laser Cooling and Magneto-Optical T…
• Zheng, Wang, Verma, Wang, Langin, DeMille, "Simulated Laser Cooling and Magneto-Optical T…

LS labels follow Porsev et al.; the NIST jj / J1K labels are given after the '=' sign (mapping checked against the energies in Porsev's Table V). Entries 'rme_J_ea0' are CALCULATED (CI+all-order) and marked theory; experiment-derived matrix elements quoted second-hand are kept under 'rme_J_ea0_reported' because they disagree with each other. Isotope shifts are nu(first) - nu(second); the 1.28 um M1 line shifts are positive as printed (opposite sign to the 283.3 nm line). The 405.78 nm shifts are derived from wavenumbers printed in a stellar-abundance paper that copied Bouazza's Table I, good to about 3 MHz. The three lifetimes of Biémont et al. were read on the publisher's HTML page by an automated reader (the paper's tables are images) and should be checked against the PDF. 'E2_rme_ea0sq' is an electric-quadrupole amplitude, not a dipole matrix element.

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