High-spin states, yrast isomers and residual interactions in the odd-odd nucleus 212at

Excited states in the odd-odd nucleus At have been studied using γ-ray and electron spectroscopy following the Pb(Li,3n) reaction. Levels were identified to spins of 25ℏ and to excitation energies of about 4.8 MeV. New isomeric states which decay by enhanced E3 transitions have been established at spins 18, 22 and 25. Shell model calculations reproduce well the main features of the level scheme and show the configuration dependence of certain empirical residual interaction matrix elements