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NIST Atomic Spectra Database
Ionization Energies Data

He (all spectra)
2 Data Rows Found 
Example of how to reference these results:
Kramida, A., Ralchenko, Yu., Reader, J., and NIST ASD Team (2023). NIST Atomic Spectra Database (ver. 5.11), [Online]. Available: https://physics.nist.gov/asd [2024, October 11]. 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   Ground  Level   Ionization  Energy 
 (eV) 		 Uncertainty
 (eV) 		  References 
2  Helium  He  1s2   1S0    24.587389011                  0.000000025    L17714 
2  Helium  H  1s   2S1/2    (54.4177655282)                0.0000000010   L19200 

If you did not find the data you need, please inform the ASD Team.

[ASD Home][Lines Query][Levels Query][List of Spectra][Ground States and Ionization Energies][Bibliography][Help] NIST Physical Measurement Laboratory