The neutron-proton interaction energy of the valence nucleons

Abstract

Summary. -- A general mass formula is presented, which is based only on experimental data. It permits the visualization of the energetic structure of the nuclear valence shells. The neutron-proton interaction energy of the two unpaired valence nucleons, ~np differs from l In the valence shells of 4He, several fermion4 ~2n-2p" fermion, fermion-boson and boson-boson n-p interaction energies have been calculated. The 2n~-2p~ interaction energy is found greater than the total binding energy of the 4He core. The detachment energies ~x (x = p, 2p, n or 2n) have been calculated, or estimated; their variation as a function of the valence nucleon pair numbers suggests that the lpl/~ valence shell is filling before the lP3/2 valence shell in the ground state of the light nuclei. The properties of the 4He valence shell nuclei are marked by the negative value of the detachment energies from the core of an unpaired proton or neutron and of a proton pair; these negative values are probably responsible for the low abundance of the elements Li, Be and B. PACS 21.10 - General and average properties of nuclei; properties of nuclear energy levels.