To use to atoms with more than one electron, the Rydberg formula may be modified by changing Z with Z − b or n with n − b where b is regular symbolizing a screening effect mainly because of the inner-shell and various electrons (see Electron shell plus the afterwards https://gandula.de/2024/08/01/ein-leitfaden-fur-anfanger-zum-verstandnis-der-funktionsweise-von-bohrmaschinen/