Neptunium energy level diagram

Energy levels and transitions of neutral neptunium (Np I): 77 levels and 90 classified lines below 2 µm taken from the cited literature, each line with its vacuum wavelength and frequency. The NIST Atomic Spectra Database lists only the ground level and the ionisation limit of neptunium, so the level energies on this page are those of the literature sources named below.

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

Key transitions of neptunium

λ, ν from the level energies of the cited literature (NIST lists no excited levels) unless a measured frequency for this isotope is available. A: measured value or NIST. Γ/2π: natural linewidth of the upper level, 1/(2πτ).

²³⁷Np hyperfine structure (I = 5/2)

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

Isotope shifts

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

Closed and nearly closed transitions of neptunium

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 Np 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.

Np energy levels

Np⁺ ionisation limit 50535.54 cm⁻¹ = 6.26561 eV (197.881 nm)

Sources

• Blaise & Wyart, 'Selected Constants: Energy Levels and Atomic Spectra of Actinides' (Tabl…
• Blaise & Wyart, 'Selected Constants: Energy Levels and Atomic Spectra of Actinides' (Tabl…
• Blaise & Wyart, 'Selected Constants: Energy Levels and Atomic Spectra of Actinides' (Tabl…
• Blaise & Wyart, 'Selected Constants: Energy Levels and Atomic Spectra of Actinides' (Tabl…
• Blaise & Wyart, 'Selected Constants: Energy Levels and Atomic Spectra of Actinides' (Tabl…
• Kaja, Studer, Berg, Berndt, et al., 'Resonant laser ionization of neptunium: investigatio…
• Kaja, Urquiza-Gonzalez, Berg, Reich, Stemmler, Studer, et al., 'High-resolution laser spe…

Levels and classifications: archived online version (2002 captures) of the Blaise & Wyart actinide tables (Laboratoire Aime Cotton); energies refer to 237Np (hyperfine centre of gravity). In that level table the column headed 'J' after the energy is the Lande g factor. Hyperfine A and B of the table are printed in 10^-3 cm^-1 and were converted to MHz (1 x 10^-3 cm^-1 = 29.979 MHz; marked derived). Kaja et al. quote the first-step levels as 25075.15, 25277.64, 25342.48 and 25551.93 cm^-1; the three-decimal energies of the level table are used as identifiers. 'relative_intensity' is the emission intensity printed in the selected-wavelength table (300, 1000, 3000 or 10000) and only ranks lines. Isotope shifts are nu(239Np) - nu(237Np). Configurations are stored without parent terms (full printed string in each level note); terms printed in parentheses (leading component 25-50 %) are stored without the parentheses.

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