Borromean halo, Tango halo, and halo isomers in atomic nuclei

Structure of the ground and excited states in halo-like nuclei is discussed. Both the Borromean and tango halo types can be observed for n-pconfigurations of atomic nuclei. Structure of the halo may be different for the different levels and resonances in atomic nuclei. Isobar analog, double isobar analog, configuration, and double configuration states can simultaneously have n-n, n-p, and p-p halo components in their wave functions. When the halo structure of the excited state differs from that of the ground state, or the ground state has non-halo structure, the gamma-transition from the excited state to the ground state can be essentially hindered, i.e. the formation of a specific type of isomers (halo isomers) becomes possible. B(MQ lambda) and B(E lambda) values for gamma-transitions in Li-6,Li-7,Li-8, Be-8,Be-9,Be-10, B-8,B-10,B-11, C-10,C-11,C-12,C-13,C-14, N-13,N-14,N-15,N-16,N-17, O-15,O-16,O-17,O-19, and F-17 are analyzed. Special attention is given to nuclei which ground state does not exhibit halo structure but the excited state (halo isomer) may have one.