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

Excited states in the odd-odd nucleus At-212 have been studied using gamma- ray and electron spectroscopy following the Pb-208(Li-7,3n) reaction. Level s were identified to spins of 25h and to excitation energies of about 4.8 M eV. New isomeric states which decay by enhanced E3 transitions have been es tablished at spins 18(+), 22(-) and 25(-). Shell model calculations reprodu ce well the main features of the level scheme and show the configuration de pendence of certain empirical residual interaction matrix elements. (C) 199 9 Published by Elsevier Science B.V.