Effects of diabaticity on fusion of heavy nuclei in the dinuclear model ...

More detailed investigations are required to clarify these points. In the calculations, we do not
consider thermal effects in the values <strong>of</strong> Γ α.
The adiabatic potential energy V adiab is calculated using the expression (3.2), but taking
into account the dependence <strong>of</strong> the shell correction and the pairing correction on the excitation
energy E ∗ (λ). Shell effects are damped exponentially δU shell = δU shell(E ∗ = 0) exp(−ζE ∗ )
if the system is excited with the excitation energy E ∗ . The parameter ζ is chosen as ζ −1 =
5.48A 1
/(1+ 1.3A− 1
3 ) MeV [110]. The pairing corrections are taken as follows δUpair = 0
3
for E ∗ ≥ E c and δU pair=δU pair(E ∗ = 0)[1 − E ∗ /E c] 2 for E ∗ < E c [78] with E c =10MeV.
We neglect the dependence <strong>of</strong> potential energy on the angular momentum in the reactions
considered [18, 20, 22, 34, 38] because in fusion reactions with heavy nuclei only low angular
momenta (< 20 − 30 ¯h) contribute [78, 111].
The potential energy <strong>of</strong> the DNS in the touching configuration <strong>of</strong> the nuclei was calculated
as a function <strong>of</strong> the mass asymmetry η within the adiabatic TCSM because the diabatic effects
are very small near this configuration [35]. The diabatic potential practically coincides with the
adiabatic one in the touching configuration <strong>of</strong> the nuclei. Therefore, the values <strong>of</strong> the fusion
barrier in the η-channel and the quasi-fission barrier are practically independent <strong>of</strong> time. Indeed,
the motion in η proceeds with nucleon exchanges between the levels near the Fermi surfaces <strong>of</strong>
the DNS nuclei. For smaller elongations (λ