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

U2 = 1
H ′ H − H0 = H − = α
U1 = −i¯h
n
2 m0(∇W ) 2 + m0
·
n∂/∂qn + q 1
| ψα >ɛα (q) ,
perturbation theory [60]. This can be immediately seen from the expression (2.1) for the jump
probability if the <strong>diabaticity</strong> parameter is rewritten as
|< χ2 ∆=2¯h | ∂/∂q | χ1 | · | >qc
·
| /π | H
′ q
12
|, (2.11)
where the dynamical coupling between the adiabatic states at the crossing point q = q c enters
into the numerator. Thus, the jump probability (2.1) cannot be expanded in powers <strong>of</strong> the
dynamical coupling matrix element. Because <strong>of</strong> this, the adiabatic basis is only convenient for
very small collective velocities so that the single-particle motion is purely adiabatic.
For larger velocities it is <strong>of</strong>ten more convenient to choose basis states ψ α which have smaller
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