### Atomic Data for Argon (Ar)

### Atomic Number = 18

### Atomic Weight = 39.948

### Reference = E95

    Isotope   Mass       Abundance Spin Mag Moment

    36Ar      35.967545  0.337%    0
    38Ar      37.962732  0.063%    0
    40Ar      39.962384  99.600%   0

    Ar I  Ground State 1s22s22p63s23p6  1S0
          Ionization energy  127109.842 cm-1 (15.759610 eV)   Ref. VHU99

    Ar II Ground State 1s22s22p63s23p5  2P°3/2
          Ionization energy  222848.3 cm-1 (27.62966 eV)   Ref. M60b