Cadmium-111 energy level diagram

Energy levels and transitions of neutral ¹¹¹Cd (Cd I, nuclear spin I = 1/2): the 21 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 19 of them, the reduced dipole matrix element. Level energies come from NIST and refer to the natural isotope mixture; transition rates are 16 NIST, 2 measured, 1 theory. Hyperfine constants and measured frequencies are those of this isotope.

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 ¹¹¹Cd

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).

¹¹¹Cd 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 ¹¹¹Cd

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 ¹¹¹Cd 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.

¹¹¹Cd energy levels

Cd⁺ ionisation limit 72540.05 cm⁻¹ = 8.99382 eV (137.855 nm)

Sources

• Gibble, 'Laser-cooling Cadmium Bosons and Fermions with Near Ultraviolet Triplet Excitati…
• Hofsaess, Padilla-Castillo, Wright, Kray, Thomas, Sartakov, Ohayon, Meijer, Truppe, 'High…
• NIST ASD
• NIST ASD level energies
• Robert, Manzoor, Chiarotti, Poli, 'Multipole transition amplitudes and radiative decay ra…
• Robert, Manzoor, Chiarotti, Poli, 'Multipole transition amplitudes and radiative decay ra…

Conventions. (1) Isotope-shift keys 'a-b' mean nu(a) - nu(b); all Cd shifts are relative to 114Cd as printed. Fermion shifts are hyperfine centres of gravity. (2) Hyperfine entries carry the measured interval (interval_MHz) and a derived A_MHz; I = 1/2 so B = 0. (3) Fields beyond SCHEMA.md: natural_linewidth_*, interval_MHz, photoionization, magic_wavelength_nm, bbr_shift_Hz, type 'M2', top-level 'rydberg' (ionization limit) and 'conflicts'. (4) rme_J_ea0 values are derived here from measured lifetimes with the schema convention (branching to the ground state taken as 1); they are not printed in the sources. (5) The clock (332 nm) and 314 nm isotope shifts are King-plot derived values of Ohayon et al., not direct measurements.

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-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