Lifetimes of quasideuteron configurations in the odd-odd N=Z nucleus 2550Mn25

Lifetimes and gammagamma coincidences for low-spin states of the odd-odd nucleus Mn-50 were measured in the Ca-40(C-12,np)Mn-50 fusion-evaporation reaction at 27 MeV beam energy at the ESTU-tandem accelerator at Yale. The excitation energy of the J(pi) = 5(+) isomer is established for the first time from high-resolution gamma-ray spectroscopy. Comparison to simulations of the Doppler-shift attenuation processes as functions of the level lifetimes enables us to extract lifetime information for five states. The measurement of B(M1) values agrees with the previous assignments of quasideuteron configurations in Mn-50 done on the basis of E2/M1-multipole mixing ratios and gamma-branching ratios. The observations verify the predictions of an earlier full pf-shell model calculation for Mn-50.