Studies of 1s electrons

Ionization of one 1s electron is treated in the same way as ionization of one valence electron. As discussed in Sec.H. 1. the ionization energy IP 1s α is therefore the difference of two total energies $$IP_{1s}^\alpha = E\left( {q_{1s}^\alpha - 1} \right) - E\left( {q_{1s}^\alpha } \right)$$ As an expression for the total energy E we use here the sum of the expressions (D.38) + (F.21) + (F.22).