[en] The subbarrier fission probabilities of ²³⁴U, ²³⁶U, and ²⁴⁰Pu have been studied using the (d,pf) reaction, with improved statistics over previous measurements. A number of previously unidentified resonances have been found in ²³⁶U and ²⁴⁰Pu; in addition, a shelf or plateau from 4.0 to 4.5 MeV in the fission probability of ²³⁴U has been observed. The fission probabilities have been analyzed using the doorway-state model, and barrier parameters, transition state energies, and the energies of K/sup π/ = 0⁺ fission vibrations have been determined. The systematic behavior of transition state and K/sup π/ = 0⁺ resonance energies with varying N and Z is discussed