Energy Levels in the Nucleus
The spectrum produced by an element as a result of electron transitions between energy levels is unique to the element. Observation of the spectrum allows us to identify the atom, because lines or gaps in the spectrum correspond to transitions between energy levels. The energy levels are characteristic of the atom, hence so are the differences of the energy levels. These energy levels arise basically because electrons form standing waves around the nucleus.
We can describe electrons in terms of waves. We can also describe neutrons and protons in terms of waves. In the nucleus, neutrons and protons also form standing waves that correspond to certain energies – energy in the nucleus is quantized in the same way as electron energies are quantized in electron shells. In the same way that an electron may move between two energy levels with emission or absorption of a photon with energy equal to the difference between the energies of those energy levels, so may a nucleon (proton or neutron) absorb or emit a photon and move between energy levels in the nucleus.
This is always true. The analogy is obvious if decay results in the emission of a
ray, but when nuclear decay results in the emission of an
particle for example, the energy levels may be less obvious because energy is often shared between different particles, some of them hard to observe.particles are observed to have a continuous range of energies, even though the decay that produces it is described by the equation
In this equation the neutron and proton have closely defined energy, hence the difference in their energies is closely defined. The energy carried away by theparticle (the electron
in the equation above) is not equal to this difference but may have a range of energies. The discrepancy in the energy (and momentum) is resolved by including the antineutrino
This particle also has energy and momentum and inclusion of this allows conservation of both energy and momentum.