The moment of inertia at the saddle point of low energy fission of even-even nuclei

We use the molecular model of low energy fission, which describes the nucleus by two interacting fragments, to calculate the moment of inertia for U²³⁶ in the cranking approximation including BCS theory. We show that the moment of inertia at the saddle point: (1) depends almost linearly on the fragment distance. (2) is influenced only very weakly by the pairing constant and by the fragment deformations. (3) shows, as a function of the distribution of mass between the two fragments (A₁, A₂), a minimum near the magic configuration A₁=132, Z₁=50 and depends in this mass region strongly on the term structure near the Fermi energy. (4) is approximately that of a rigid body.