Garvey-Kelson Mass Relations and n-p Interaction

Two Garvey-Kelson mass relations are found to be directly related to the n-p interaction. In the case of the same nuclear core, the neutron-proton interaction energy between two neutrons and one proton ε_2n-1p is experimentally found to be close to that between one neutron and two protons ε_1n-2p, which is equivalent to the first Garvey-Kelson mass relation. The sum of ε_2n-1p and ε_1n-2p is close to the n-p interaction energy between two neutrons and two protons ε_2n-2p, which leads to the second Garvey-Kelson mass relation. An explanation about these two n-p interaction relations is presented. It is shown that both of these mass relations hold more accurately when the core is an even-even one.