# Binding energy per nucleon dependency

For a given isotope, does the nuclear binding energy per nucleon depend on the presence of electrons? For instance, if an electron was excited by an incoming photon and jumps to a different orbital, will the nuclear binding energy change?

• Yes, but very weakly. There are tiny chemical modulations of nuclear energies, so in theory nuclear decays and reactions are susceptible to chemical composition, temperature, pressure etc.. but the effects are so small that they can be neglected for all purposes as far as I know. May 25 '15 at 1:41
• Like what CuriousOne said, yes. Think of hydrogen. You've got one nucleon, a proton. You've also got an electron. The binding energy is -13.6keV. An incoming photon comes along, the electron jumps to a different orbital, and the binding energy has changed. May 25 '15 at 7:39
• Why would hydrogen have a binding energy? en.wikipedia.org/wiki/Hydrogen_atom Wikipedia says the binding energy of hydrogen is exactly 0? May 25 '15 at 7:41
• @JoshuaLin The nuclear binding energy of hydrogen is zero. The hydrogen atom in its ground state has a binding energy of 13.6 eV. It is bound because it has a binding energy. Can you be clearer in your question about what definition of binding energy you want to know about. May 25 '15 at 8:46
• Sorry, I meant the nuclear binding energy May 25 '15 at 8:48

In an answer to another question I made reasonable estimate of the amount of electron charge that's contained within the nucleus. (Actually for that question I used a volume somewhat larger than the nucleus, but the method is there.) To first approximation, all the electronic charge within the nuclear volume comes from the two $1s$ electrons. The distribution of a full $p$-wave or higher shell is spherically symmetric. By the shell theorem, a spherically symmetric shell of charge does not affect the energy levels of systems inside.