Protactinium - 91Pa: properties of free atoms
Protactinium atoms have 91 electrons and the shell structure is 2.8.18.32.20.9.2.
The ground state electron configuration of ground state gaseous neutral protactinium is [Rn].5f2.6d1.7s2 and the term symbol is 4K11/2.
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
Atomic spectrum
A representation of the atomic spectrum of protactinium.
Ionisation Energies and electron affinity
The electron affinity of protactinium is (no data) kJ mol‑1. The ionisation energies of protactinium are given below.
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Effective Nuclear Charges
The following are "Clementi-Raimondi" effective nuclear charges, Zeff. Follow the hyperlinks for more details and for graphs in various formats.
1s | (no data) | ||||||
---|---|---|---|---|---|---|---|
2s | (no data) | 2p | (no data) | ||||
3s | (no data) | 3p | (no data) | 3d | (no data) | ||
4s | (no data) | 4p | (no data) | 4d | (no data) | 4f | (no data) |
5s | (no data) | 5p | (no data) | 5d | (no data) | ||
6s | (no data) | 6p | (no data) | ||||
7s |
References
These effective nuclear charges, Zeff, are adapted from the following references:
- E. Clementi and D.L.Raimondi, J. Chem. Phys. 1963, 38, 2686.
- E. Clementi, D.L.Raimondi, and W.P. Reinhardt, J. Chem. Phys. 1967, 47, 1300.
Electron binding energies
Label | Orbital | eV [literature reference] |
---|---|---|
K | 1s | 112601 [1] |
L I | 2s | 21105 [1] |
L II | 2p1/2 | 20314 [1] |
L III | 2p3/2 | 16733 [1] |
M I | 3s | 5367 [1] |
M II | 3p1/2 | 5001 [1] |
M III | 3p3/2 | 4174 [1] |
M IV | 3d3/2 | 3611 [1] |
M V | 3d5/2 | 3442 [1] |
N I | 4s | 1387 [2] |
N II | 4p1/2 | 1224 [2] |
N III | 4p3/2 | 1007 [2] |
N IV | 4d3/2 | 743 [2] |
N V | 4d5/2 | 708 [2] |
N VI | 4f5/2 | 371 [2] |
N VII | 4f7/2 | 360 [2] |
O I | 5s | 310 [2] |
O II | 5p1/2 | 232 [2] |
O III | 5p3/2 | 232 [2] |
O IV | 5d3/2 | 94 [2] |
O V | 5d5/2 | 94 [2] |
P I | 6s | - |
P II | 6p1/2 | - |
P III | 6p3/2 | - |
Notes
I am grateful to Gwyn Williams (Jefferson Laboratory, Virginia, USA) who provided the electron binding energy data. The data are adapted from references 1-3. They are tabulated elsewhere on the WWW (reference 4) and in paper form (reference 5).
References
- J. A. Bearden and A. F. Burr, "Reevaluation of X-Ray Atomic Energy Levels," Rev. Mod. Phys., 1967, 39, 125.
- M. Cardona and L. Ley, Eds., Photoemission in Solids I: General Principles (Springer-Verlag, Berlin) with additional corrections, 1978.
- Gwyn Williams WWW table of values
- D.R. Lide, (Ed.) in Chemical Rubber Company handbook of chemistry and physics, CRC Press, Boca Raton, Florida, USA, 81st edition, 2000.
- J. C. Fuggle and N. Mårtensson, "Core-Level Binding Energies in Metals," J. Electron Spectrosc. Relat. Phenom., 1980, 21, 275.