A LOW-LYING 2- STATE IN 236U

A low-lying KIπ = 22- state of 236U, first characterized in measurements of 240Pu alpha decay, has been more thoroughly studied through the electron-capture decay of 236Np. The energy of the state is 687.70 ± 0.10 keV, its half-life is 4.4 ± 0.6 nsec, and it decays by M2 and E1 transitions to members of the ground state band. It is populated with an intensity of 1.5 ± 0.3% in the decay of 236Np, and (2.1 ± 0.4) × 10-5% in the decay of 240Pu, in the latter case presumably via an alpha transition to the unobserved spin-3 member of the band. Besides having the lowest energy of any known 2- state in an even nucleus, the state is characterized by fast M2 transitions and highly hindered El transitions. © 1969.