of symmetric fission-barrier heights and compared it to the results obtained using the expansion of the nuclear surface in spherical harmonics. The agreement with experiment was better with the TKS parametrization using 3 parameters $\alpha_2$, $\alpha_4$, $\alpha_6$ than with the later including deformation parameters up to $\beta_{14}$, thus showing the fast convergence of the TKS parametrization.

Fission dynamics and Langevin equation
--------------------------------------

Fission dynamics is investigated through the resolution of the Langevin equation which for the generalized coordinates $q_i$ is given by

$$\begin{aligned}
  && \!\!\!\!\!\!\!\! 
     {dq_i\over dt} = \sum_{j} \; [M^{-1}(\vec q)]_{i\, j} \; p_j  
                                                          \nonumber\\[ -1.0ex]
  &&                                                \label{eqn:rho}\\[ -1.0ex]
  && \!\!\!\!\!\!\!\! 
     {dp_i\over dt} =  - {1\over 2} \sum_{j,k} \,
                             {d[M^{-1}(\vec q)]_{jk} \over dq_i} \; p_j \; p_k 
                    - {dV(\vec q)\over dq_i} 
              - \sum_{j,k} \gamma_{ij}(\vec q) \; [M^{-1}(\vec q)]_{jk} \; p_k 
%              - \sum_{j,k}  [\gamma(\vec q)]_{ij} \; [M^{-1}(\vec q)]_{jk} \; p_k 
                    + F_i(t)                                     \nonumber\end{aligned}$$

${}$\
where $p_i$ are the canonical momenta associated with the coordinates $q_i$. $[M(\vec q)]$ represents the tensor of inertia determined in our approach in the irrotational incompressible fluid approximation of Werner-Wheeler as developed by Davies, Sierk and Nix [@Da76] and $[\gamma(\vec q)]$ corresponds to the friction tensor calculated in the framework of the so-called [*wall and 