Neutron-particle and proton-hole excitations in the N=128 isotones ²⁰⁸Hg and ²⁰⁹Tl from spectroscopy following ²⁰⁸Pb+²³⁸U deep-inelastic reactions

Gamma rays in the π^-2ν² nucleus ²⁰⁸Hg and π^-1ν² nucleus ²⁰⁹Tl have been studied at Gammasphere using deep-inelastic reactions induced by a 1360 MeV²⁰⁸ Pb beam on a thick ²³⁸U target. Previously unknown yrast γ-ray cascades above the 8⁺ and 17/2⁺ nanosecond isomers in ²⁰⁸Hg and ²⁰⁹Tl, respectively, were identified in coincidence with known γ rays deexciting the isomers. Yrast levels up to spin 13^- in ²⁰⁸Hg have been located, and they are interpreted in light of the structure of the ²¹⁰Pb isotone and with the help of shell model calculations. Shell model calculations by using the V_low-k realistic interaction have been performed for ²¹⁰Pb and ²⁰⁸Hg, and compared with experiment. The V _low-k effective Hamiltonian seems to account well for the properties of these neutron-rich shell model nuclei.