17 Systematics and Their Implications
Ν ·Ν p
n
1
R. F. Casten
Institut für Kernphysik, University of Köln, Federal Republic of Germany A substantial simplification of the systematics in nuclear phase transition regions is obtained if the data are plotted against the product, Ν ·Ν , of the num ber of valence protons and neutrons instead of against Ν, Z, or A as is usually done. Such a scheme leads to a unified view of nuclear transition regions and to a simplified scheme for collective model calculations.
Downloaded by UNIV LAVAL on July 12, 2016 | http://pubs.acs.org Publication Date: November 14, 1986 | doi: 10.1021/bk-1986-0324.ch017
p
n
It i s g e n e r a l l y considered that the r e s i d u a l proton-neutron a c t i o n i s r e s p o n s i b l e f o r the onset of deformation nuclei.
Since
p - n strength should
the t o t a l
inter
[TAL62, FED77, CAS81] i n
be simply
related
[CAS85,
HAM65] to the number of i n t e r a c t i n g p a i r s of valence protons and neutrons, that one
i s , to the product
Νρ·Ν
η
(counted
as valence
holes
past
midshell),
might expect
nuclear systematics to be much simpler i f p l o t t e d against
such a parameter.
This i s indeed the case, as seen f o r the A-130 region i n
Fig.
1 (top).
To e x p l o i t
t h i s approach
when s i g n i f i c a n t
s h e l l or s u b s h e l l
closures are present requires c a r e f u l counting of valence p a r t i c l e s .
Thus,
f o r example, near A=150, the Z=64 gap i s assumed to be a c t i v e and thus the proton A-100
shell
i s Z=50-64 f o r N60.
Νρ·Ν
1-2.
[FED77] proton s h e l l
plots,
η
They r e v e a l
subject
Likewise,
i s Z-38-50 f o r N
