Hafnium energy level diagram

Energy levels and transitions of neutral hafnium (Hf I): the 74 strongest classified lines below 2 µm from the NIST Atomic Spectra Database and the 34 levels they connect, each line with its vacuum wavelength, frequency and, for 70 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 hafnium

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).

¹⁷⁹Hf hyperfine structure (I = 9/2)

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

Isotope shifts

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

Listed Hf 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.

Hf energy levels

Hf⁺ ionisation limit 55047.90 cm⁻¹ = 6.82507 eV (181.660 nm)

Sources

• Büttgenbach, Dicke, Gebauer, Phys. Lett. A 62, 307 (1977); Boos et al., Phys. Rev. Lett. …
• Malcheva, Yoca, Mayo, Ortiz, Engström, Lundberg, Nilsson, Biémont, Blagoev, MNRAS 396, 22…
• NIST ASD
• NIST ASD level energies

Frequencies are c x observed centre-of-gravity wavenumbers (isotope key 'natural': natural-abundance Hf assumed, i.e. an isotope and hyperfine blend, not a single-isotope frequency; the pipeline may ignore them). Lifetimes flagged 'derived upper bound' are computed from NIST A values and are not printed measurements; the two z 3D° lifetimes (Malcheva et al. 2009) are direct measurements. 179Hf hyperfine constants are second-hand and rounded. Isotope shift sign: nu(180) - nu(178), convention inferred (see note on each entry). No laser-cooling transition is known for Hf. Lifetimes computed as 1/sum(A) from NIST rates are kept under "lifetime_derived_from_nist_rates" and are not shown on the site as measured lifetimes.

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