THE TRANSPORT COEFFICIENTS FOR LARGE SCALE NUCLEAR COLLECTIVE MOTION

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THE TRANSPORT COEFFICIENTS FOR LARGE SCALE
NUCLEAR COLLECTIVE MOTION
F. A. Ivaniuk, Institute for Nuclear Research,
Kiev, Ukraine
COLLABORATORS
H.H.Hofmann, TU, Munich V.V.Pashkevich, JINR,
Dubna S.Yamaji, RIKEN, Tokyo G.I.Kosenko,
OmskUniversity, Omsk
The Langevin approach for fusion-fission
reactions Transport coefficients within locally
harmonic approximation effective Hamiltonian
response functions equation of motion for
the shape parameters transport coefficients
numerical results Influence of pairing Effect
of the rotation (Still) existing problems Summary
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Shape parameterization
Langevin equations Y.Abe et al, Phys.Rep. 275
(1996) 49
V.V.Pashkevich, Nucl.Phys. A 169 (1971) 275
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Dynamics in Locally Harmonic Approximation
Causal response function
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Residual interaction
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Transport coefficients
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Self-consistent response function
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Self-consistent transport coefficients(transport
coefficients at finite frequency)
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Lorentzian fit
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Numerical results
F. A. Ivanyuk, H. Hofmann, V. V. Pashkevich and
S. Yamaji, Phys. Rev. C 55 (1997) 1730
D.Hilsher, I.I.Gonchar and H.Rossner, Phys. At.
Nucl. 57 (1994) 1187
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Effects of pairing
F. A. Ivanyuk and H. Hofmann, Nucl. Phys. A 657
(1999) 19
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Pair.transp.coeff
208Pb16O--gt224Th Onset of dissipation D.J.
Hofman, B.B. Back and P.Paul, Rapid increase in
pre-scission giant- dipole-resonance g-ray
emission with bombarding energy, Phys. Rev. C
51 (1995) 2597
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Spurious contributions
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Frequency of collective vibrations
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Rotation. Quasi-static properties
I0
I60h
Two-center shell model, z0 distance between
centers of oscillator potentials
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Rotation. Response function
T1, 2, 3 MeV
F. A. Ivanyuk and S. Yamaji, Nucl. Phys. A 694
(2001) 295
I0
I60h
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ee-mass and friction parameters, T0.5 MeV
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-mass and friction parameters, T0.5 MeV
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Deformation energy
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18O 208Pb
G.I.Kosenko, F.A.Ivanyuk and V.V.Pashkevich,
Journ. Nucl. Rad. Sci. 3 (2002) 71
yield,
Elab78 MeV

Vpot , MeV
Elab 90 MeV
The two stage approach to the description
of Fusion/fission reactions is suggested. On each
stage (fusion or fission) the three-dimensional
Langevin Equation for the shape variables is
solved. The distri- butions obtained on first
stage are used as initial con- ditions for the
description of fission dynamics. It turned out
possible to describe in this way both fusion and
fission cross sections, the energy and mass
distributions of fission fragments, the
probability of evaporation residue formation, the
dependence of pre-fission neutron multiplicities
on the fragment mass number
fragment mass
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Problem(s) levels repulsion
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Summary
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NPAE08
--Collective processes in atomic nuclei

• ---Collective processes in atomic nuclei
• -Nuclear reactions at low and high energies
• -Nuclear structure and decay data
• -Rare nuclear processes, nuclear astrophysics
• -Neutron and reactor physics
• -Nuclear data and data evaluation
• -Problems of atomic energies
• -Applied nuclear physics in medicine and industry
• -Experimental facilities and detection techniques

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