# How do nuclear properties influence the atomic properties and vice versa?

I was wondering how the nucleus can influence the atomic properties (chemical and physical). I found that the mass number influences the boiling, melting and density of an atom. Also the electron wave functions depend on the number of protons. But are there also other properties of the nucleus like electric or magnetic spin which influence the atomic properties? Or do some atomic properties influence the nuclear properties?

• The first that comes to mind is the hyperfine structure of the atom, that says that the energy levels of the electrons shift when taking into account the interaction between the nucleus and the electrons. – user137661 Jun 6 '19 at 21:44
• @SV There is even more than this, for example isotope shift (en.wikipedia.org/wiki/Isotopic_shift) in the spectral lines due to mass and volume difference of the nucleus. – eranreches Jun 6 '19 at 22:45
• @eranreches That looks very interesting, do you know if there is a book or article that shows how it is derived? – user137661 Jun 7 '19 at 1:23
• @SV You can consult "Atomic Physics" by C. J. Foot, section $6.2$. – eranreches Jun 7 '19 at 1:28

The OP is basically searching for hyperfine interaction. Nuclei may have magnetic dipole ($$I \geq) 1/2$$, electric quadrupole ($$I \geq) 1$$) and higher moments. These moments interact with the electrons and may cause hyperfine splitting of electronic energy levels. A famous example is the 21 cm line resonance due to the hyperfine interaction of the proton (S=1/2) and electron (S=1/2) spins in neutral hydrogen atoms.