An electron (from an atom with several electrons) has a resonance frequency. If this atom loses an electron, how the resonance frequency of the electron (remaining on the atom) changes? It becomes higher or lower? Please send me references. Thanks!
If you are talking about light this question is trivial, it depends on the energy levels and the ion has different energy levels than atoms. And usually, except with some exception, due to spin-orbit or spin-spin coupling, the resonance frequency should increase.
But maybe you are talking about something different.
Thanks Gianpiero. Yes, with light. Yes you are right. But I got both of them depending on the materials. It seems that spin and molecular orbitals cannot give an analytical solution with this complexity. Do you know any reference (book or article) that studies it deeply? Maybe numerically? Thank you.