ni2.rcn

22 -9    2   10  1.0    5.E-06    1.E-09-2   130   1.0  0.65  0.0 0.50 0.0  0.70
   28     Ni2+ 3d8               2P06 3D08
   28     Ni2+ 2p5 3d9           2P05 3D09
   -1

The Atomic Number

   28     Ni2+ 3d8               2P06 3D08
00028

Positions 4 and 5 of each line indicate the atomic number of the element used in the calculation.
Together with the number of electrons this defines the valency.

RCN2 Label

   28     Ni2+ 3d8               2P06 3D08
      xxxxNi2+ 3d8xxxxxxxxxx

The text 'Ni2+ 3d8' is a label to be associated with the configuration.
A sensible choice which specifies the element, its oxidation state and the configuration is shown.

Shells and number of electrons

   28     Ni2+ 3d8               2P06 3D08
                                 c1xx c2xx c3xx c4xx c5xx c6xx c7xx c8xx

The final strings '2P06 3D08' specify the two shell configuration.
In principle up to 8 shells can be given.
c1 specifies the shell, 1s, 2p, 3d, etc, and
xx specifies the number of electrons in each shell.

A continuum electron is indicated with the main quantum number 99, i.e. '2P05 3D0899S01' can be used as a final state in 2p photoemission.

Note that the specification of the atomic number 28, implies a calculation for nickel. The configuration 2p6 3d8 implies that 26 electrons are assumed to be present: 1s2 2s2 2p6 3s2 3p6 = 18, plus 8 3d electrons.
Hence the valency is Ni2+.