odd-even effect

The "odd-even effect" in physics refers to the influence of the parity of proton and neutron numbers on nuclear stability and binding energy. Nuclei with an even number of protons and an even number of neutrons (even-even nuclei) are generally more stable and have greater binding energy compared to nuclei with an odd number of protons or neutrons (odd-odd nuclei). This phenomenon is partly explained by the pairing energy term in nuclear models, which favors nuclei with paired nucleons. This effect influences the ease with which nuclear transformations, such as fission, can be induced. For instance, isotopes with an odd number of neutrons are often fissionable with slow neutrons, while those with an even number may require faster neutrons.123