[skip navigation]
[ASD Home][Lines Query][Levels Query][List of Spectra][Ground States and Ionization Energies][Bibliography][Help] NIST Physical Measurement Laboratory
National Institute of Standards and Technology NIST Physical Measurement Laboratory
NIST Atomic Spectra Database Lines Data

He II: 13 Lines of Data Found
Z = 2, H isoelectronic sequence 

Example of how to reference these results:
Kramida, A., Ralchenko, Yu., Reader, J., and NIST ASD Team (2019). NIST Atomic Spectra Database (ver. 5.7.1), [Online]. Available: https://physics.nist.gov/asd [2020, September 22]. National Institute of Standards and Technology, Gaithersburg, MD. DOI: https://doi.org/10.18434/T4W30F
BibTex Citation (new window)
 
Wavelength range: 400 - 500 nm
Wavelength in: vacuum below 200 nm, air between 200 and 2000 nm, vacuum above 2000 nm
Some data for neutral and singly-charged ions are available in the Handbook of Basic Atomic Spectroscopic Data

Primary data sources
Query NIST Bibliographic Databases for
He II (new window)
Energy Levels:  Erickson 1977     The data refer to the isotope 4He. The energy level values were derived from Erickson's theoretical values of the total energies by scaling them to the current values of the fundamental constants, as given by Mohr et al. 2008 , and by applying an additional correction to the nS levels, as described by Kramida et al. 2008 . The ionization limit was obtained from the theoretical value given by Johnson and Soff 1985 by scaling it to the current values of the fundamental constants. Its uncertainty is estimated to be ±0.0002 cm-1. Uncertainties of differences of all energy level values from the ionization limit are estimated to be within 2 to 20 in the units of the last given decimal place. He II Energy Levels
Lines:  Erickson 1977     Wavelengths were calculated from the energy levels. He II Line Wavelengths and Classification
Transition Probabilities:  Wiese and Fuhr 2009     Transition probabilities, line strengths, and oscillator strengths were scaled from the corresponding data for hydrogen using the formulas given by Wiese and Fuhr 2009 . He II Transition Probabilities


 Observed 
 Wavelength 
 Air (nm) 
 Ritz 
 Wavelength 
 Air (nm) 
 Unc. 
 (nm) 
 Rel. 
 Int. 
(?)
 Aki
 (s-1
 Acc.   Ei 
 (cm-1
   Ek 
 (cm-1
 Lower Level 
 Conf., Term, J 
 Upper Level 
 Conf., Term, J 
 Type   TP
Ref.
 Line
Ref.
                                   
  468.5376849   0.0000024     9.3894e+07    AA (390 140.824628)    (411 477.853339)    3p   2P°   1/2   4d   2  3/2  T8637  
  468.5407225   0.0000023     4.9071e+07    AA (390 140.964175)    (411 477.8545580)   3s   2  1/2   4p   2P°   3/2  T8637  
  468.5524404   0.0000023     9.7947e+06    AA (390 140.824628)    (411 477.181412)    3p   2P°   1/2   4s   2  1/2  T8637  
  468.5568006   0.0000023     4.9070e+07    AA (390 140.964175)    (411 477.1224141)   3s   2  1/2   4p   2P°   1/2  T8637  
  468.5703849   0.0000023     2.0600e+08    AA (390 142.55723373)  (411 478.096926)    3d   2  3/2   4f   2F°   5/2  T8637  
                                   
  468.5704380   0.0000024     1.1266e+08    AA (390 142.5600890)   (411 478.097366)    3p   2P°   3/2   4d   2  5/2  T8637  
  468.5757080   0.0000023     5.5631e+05    AA (390 142.55723373)  (411 477.8545580)   3d   2  3/2   4p   2P°   3/2  T8637  
  468.5757974   0.0000024     1.8776e+07    AA (390 142.5600890)   (411 477.853339)    3p   2P°   3/2   4d   2  3/2  T8637  
  468.5804092   0.0000023     2.2070e+08    AA (390 143.13566549)  (411 478.218936)    3d   2  5/2   4f   2F°   7/2  T8637  
  468.5830890   0.0000023     1.4713e+07    AA (390 143.13566549)  (411 478.096926)    3d   2  5/2   4f   2F°   5/2  T8637  
                                   
  468.5884123   0.0000023     5.0067e+06    AA (390 143.13566549)  (411 477.8545580)   3d   2  5/2   4p   2P°   3/2  T8637  
  468.5905553   0.0000023     1.9588e+07    AA (390 142.5600890)   (411 477.181412)    3p   2P°   3/2   4s   2  1/2  T8637  
  468.5917884   0.0000023     5.5636e+06    AA (390 142.55723373)  (411 477.1224141)   3d   2  3/2   4p   2P°   1/2  T8637  

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