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Ionization Energies Data

Ca (all spectra)
20 Data Rows Found 
Example of how to reference these results:
Kramida, A., Ralchenko, Yu., Reader, J., and NIST ASD Team (2024). NIST Atomic Spectra Database (ver. 5.12), [Online]. Available: https://physics.nist.gov/asd [2025, March 19]. National Institute of Standards and Technology, Gaithersburg, MD. DOI: https://doi.org/10.18434/T4W30F
BibTex Citation (new window)
 

 At. Num.   El.  name   Isoel.  Seq.   Ground  Shells a   Ground  Level   Ionization  Energy 
 (eV) 		 Uncertainty
 (eV) 		  References 
20  Calcium  Ca  [Ar]4s2   1S0    6.1131549210                 0.0000000005   L22848 
20  Calcium  K  [Ar]4s   2S1/2    11.871719                     0.000004       L7185,L7323 
20  Calcium  Ar  [Ne]3s23p6   1S0    50.91316                      0.00025        L1405 
20  Calcium  Cl  [Ne]3s23p5   2P°3/2    [67.2732]                      0.0021         L11770 
20  Calcium  S  [Ne]3s23p4   3P2    [84.34]                        0.08           L11770 
20  Calcium  P  [Ne]3s23p3   4S°3/2    [108.78]                        0.25           L7185 
20  Calcium  Si  [Ne]3s23p2   3P0    [127.21]                        0.25           L7185 
20  Calcium  Al  [Ne]3s23p   2P°1/2    147.24                         0.12           L7185 
20  Calcium  Mg  [Ne]3s2   1S0    [188.54]                        0.06           L7185 
20  Calcium  Na  [Ne]3s   2S1/2    [211.275]                       0.004          L11770 
20  Calcium  Ne  1s22s22p6   1S0    [591.60]                        0.12           L11770 
20  Calcium  F  1s22s22p5   2P°3/2    [658.2]                         0.9            L11770 
20  Calcium  O  1s22s22p4   3P2    [728.6]                         1.1            L11770 
20  Calcium  N  1s22s22p3   4S°3/2    [817.2]                         0.6            L11770 
20  Calcium  C  1s22s22p2   3P0    [894.0]                         0.4            L11770 
20  Calcium  B  1s22s22p   2P°1/2    [973.7]                         0.3            L11770 
20  Calcium  Be  1s22s2   1S0    [1 086.8]                         0.4            L11770 
20  Calcium  Li  1s22s   2S1/2    (1 157.726)                       0.007          L16264c99 
20  Calcium  He  1s2   1S0    (5 128.8576)                      0.0003         L21139 
20  Calcium  H  1s   2S1/2    (5 469.86358)                     0.00006        L19200 
Notes:
a Designations used in the ground shell lists:
[Ne] = 1s22s22p6
[Ar] = 1s22s22p63s23p6

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