### Atomic Data for Protactinium (Pa)

### Atomic Number = 91

### Atomic Weight = 231.03588

### Reference = E95

    Isotope    Mass        Abundance Spin Mag Moment

    231Pa      231.035880  Trace     3/2  +2.01
    234Pa      234.043303  Trace     4

    Pa I  Ground State 1s22s22p63s23p63d104s24p64d104f145s25p65d106s26p65f26d7s2  4K11/2
          Ionization energy  47500 cm-1 (5.89 eV)   Ref. S74

    Pa II Ground State 1s22s22p63s23p63d104s24p64d104f145s25p65d106s26p65f27s2  3H4