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binding energy than the second lightesto
The most remarkable feature in the abundance distribution of these raider
nuclides is, that, for wide ranges of mass numbers, their abundance values as a
function of A seem to follow a law of "smoothness" of their own-
In particular
the abundances of Sn^^, Sn^^, Te^°, Xe''^^, Xe^^, Ba^°, etc., show this behavior
in an impressive way-
The conclusion seems inevitable that in these mass ranges
a fraction of nuclear matter must have formed on the O^side of the energy valley
in the region of the tuistabls neutron-deficient nuclear species, in a way that
led to a "sBJOothed out" distribution of the stable species-
Possibly, awcondary
spallaticn processes may have led to the formation of these nuclides in the
required proporticnso
Magic nuEfeer effects in the higher mass i^gion
Elsasaer (1933, 193k) was the first physicist who noticed that the abundance
of nuclear species containing certain nujrfcers of neutrons or protons is excoptioneliy
lai^e-
Theae numbers, the so called "magic nurabers" ai^:
2, 8, 20, 28, 50, 82^ 126 »
They belong to two different arithmetical aeries:
(1) 2, 8, 20, UO, 70, 112 » - - - -
(2) 2, 6, lii, 28, 50, 82, 126 -
The first series is significant at lower mass nunbersj, whil©
the second
series prodoainatea at mass nuiribers greater than kOo
Magic number affects are
rum well understood in terms of a shell structure of the nucleuso
(Mayer and
Jensen, 1955)
A nagic nuiriber is signified by the sudden drop in the binding energy of the
next nucleono
Thti binding energy of the next nucleonj, however, is also a function