RIKEN Nuclear Physics Seminar
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Lecturer: Vitali Yu. Denisov (GSI, Germany)

Title:  Formation of superheavy elements in fusion reactions.
	Interaction potential well between very heavy ions.

Date:   11/16/2001 (Fri.) 13:45 -

Place:  RIKEN Main Bldg. 2F Seminar Room

                           The seminar will be given in English.

Abstract:
The process of the synthesis of  superheavy elements (SHEs) is not yet
understood completely. We make an attempt to describe the cold fusion
reactions of the type X + (Pb,Bi) $\rightarrow$ SHE + 1n at subbarrier
and near barrier energies. The process of the formation of SHEs is
subdivided intothree steps: 1. The capture of two spherical nuclei and
the formation of a common shape of the two touching nuclei.
Low-energy surface vibrations and transferof few nucleons are taken into
account in the first step of the reaction. 2. The formation of a spherical
or near spherical compound nucleus. 3. The surviving of the excited
compound nucleus due to evaporation of neutrons and gamma-ray emission 
in competition with fission. The presented model describes well the 
available experimental cross-section data for elements with Z=104-112 
and allows for predicting cross-section values for the synthesis of so 
far unknown heavier elements. The interaction potential between heavy 
ions around the touching point is calculated for various Skyrme forces 
in the extended Thomas-Fermi approximation by using the frozen 
Hartree-Fock-Bogoliubov densities of the individual. The potential pockets 
in collisions leading to SHEs are discussed systematically for different 
projectile-target combinations.
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        Contact persons of Nuclear Physics Seminar
        Y. Fukuyama, Y. Nishi, and T. Wakui (RI Beam Science Lab.)
        (email) seminar@rarfaxp.riken.go.jp 
	(FAX)   048-462-4689
        (WWW)   http://rarfaxp.riken.go.jp/~seminar/    
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