what does it mean for a nucleus to be in a higher energy state? is there any macro phenomenon that is related to it? when it drops back down, it gives off a gamma ray or something?
In some cases, one configuration of the nucleus is football-shaped, and there's an energy difference between that and the round shape. In other cases, a set of two protons and two neutrons will be jolted loose from the rest of the nucleus, and sort of orbit around it.