Transient behavior at deformations beyond saddle point and neutron multiplicity

The transient behavior of the fission rate at deformations beyond saddle point is studied and it is found that the ‘‘overshooting’’ disappears at these deformations. The neutron numbers and the neutron multiplicity in the decay chain are also calculated. The number of neutrons is found to decrease linearly as the atomic number decreases. The neutron multiplicity is found to be approximately proportional to the logarithm of the friction constant. From comparison with the measured neutron multiplicity of ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ ${+}^{142}$Nd${\to }^{158}$Er at 207 MeV, we deduce that the friction constant is about (3–6)×${10}^{21}$ ${\sec }^{\mathrm{-}1}$.