Vibrational resonances below 5 MeV in the fission of 240Pu

Using the 239Pu(d,pf) reaction, the next lower Ksup(π) = 0+ vibrational resonance below 5 MeV in the deformed potential of 240Pu was located at 4.55 MeV. The resultant spacing of fission vibrations near 5 MeV in the second minimum is 500 keV. A resonance at 4.70 MeV is interpreted as the Ksup(π) = 0- vibration coupled to the 4.55 MeV Ksup(π) = 0+ state, which yields E(Ksup(π) = 0-) = 150 keV relative to the ground state of the second minimum. (Auth.)