The decay of the 13 2⁺ isomeric state and the structure of the low-lying states in ¹⁹⁹Hg

The decay modes of the 13 2⁺ isomeric state (532 keV, T _{1 2} = 43 min) of ¹⁹⁹Hg to the 5 2^- state at 158 keV and to the 5 2^- state at 413 keV were determined from the relative intensities of the 374 keV ( 13 2⁺ → 5 2^-) and 413 keV ( 5 2^-′ → 1 2^-) γ-rays as observed in. The data obtained from the present experiment regarding the M4 transition rates, together with the E2 and M1 rates determined from previous Coulomb excitation experiments on ¹⁹⁹Hg, are analysed in terms of a modified core-excitation model. The four lowest excited states in ¹⁹⁹Hg are described in this model as a p _{1 2} neutron coupled to the 2⁺ and 2^+' states of the doubly even Hg neighboring nuclei with some small extra single-particle contributions.