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FIZIKA B 16 (2007) 3, 113 - 128
 
CONTINUUM STATES IN NEUTRON-RICH CALCIUM AND NICKEL NUCLEI
M. BHATTACHARYA and G. GANGOPADHYAY
Department of Physics, University of Calcutta, 92, Acharya Prafulla Chandra
Road, Kolkata-700 009, India
Received 16 October 2006; Revised manuscript received 26 December 2007
Accepted 28 December 2007 Online 15 February 2008
The effect of the resonant continuum on Ca and Ni nuclei near the neutron
drip line has been investigated. The relativistic mean-field equations are
solved using scattering-like conditions for the positive energy states. Pairing
is implemented through a zero range interaction and the BCS equations are solved
including the resonant states. We find that our calculation can reproduce the
values for binding energy, radius, two-neutron separation energy, etc. in most
cases. The nuclei 70,72Ca show a sudden increase in the tail of the
density distribution as the 3s1/2 state, being very weakly bound and
having no centrifugal barrier, extends outside the nucleus radius to a large
distance creating a neutron halo. Ni isotopes do not show any neutron halo.
Appearance of new magic number and disappearance of the old ones in neutron-rich
isotopes lead to dramatic difference in the drip line for even- and odd-mass
nuclei in the two chains.
PACS numbers: 21.60.Jz,27.40.+z,27.50.+e,27.60.+j
UDC 539.142, 539.144, 539.17
Keywords: Ca and Ni nuclei, neutron rich isotopes, resonant continua,
relativistic mean-field equations, binding energy, radius, two-neutron
separation energy, neutron halo, new magic number
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