In the article "tunnel ionization of complex atoms and of atomic ions in an alternating electromagnetic field" (ADK ionization model) it is written: "...to derive an equation for the probability of tunnel ionization of complex atoms or atomic ions, and in arbitrary states... it is necessary ... to obtain the sought-for equation, in which the states of the complex atoms are characterized by effective principal and orbital quantum numbers n* and l* that take into account the quantum effects "
I'll appreciate it if someone can explain to me what is the physical meaning of these effective quantum numbers and what's the meaning by the "quantum effect" ?
Thanks in advance