### Atomic Data for Helium (He)

### Atomic Number = 2

### Atomic Weight = 4.002602

### Reference = E95

    Isotope  Mass     Abundance  Spin Mag Moment

    3He      3.01603  0.000138%  1/2  -2.12762
    4He      4.00260  99.999862  0

Notes:
The spectroscopic data below are for the isotope 4He.

    He I  Ground State 1s2  1S0
          Ionization energy  198310.669 cm-1 (24.587387 eV)   Ref. M02

    He II Ground State 1s  2S1/2
          Ionization energy  438908.8789 cm-1 (54.417760 eV)   Ref. MK00b