NetNews Usenet Archive 1992 #18/NN_1992_18.iso/spool/sci/physics/fusion/2012

Internet Message Format | 1992-08-13 | 3.6 KB

Path: sparky!uunet!gatech!mailer.cc.fsu.edu!sun13!ds8.scri.fsu.edu!jac
From: [e-mail] (Jim Carr)
Newsgroups: sci.physics.fusion
Subject: Re: Press Release
Summary: Periodic Table of the Nuclides
Message-ID: <[e-mail]>
Date: 13 Aug 92 14:51:47 GMT
References: <[e-mail]> <[e-mail]> <[e-mail]>
Sender: [e-mail]
Reply-To: [e-mail] (Jim Carr)
Organization: SCRI, Florida State University
Lines: 54

In article <[e-mail]> [e-mail] (Keith Mancus) writes:
>
>|> In article <[e-mail]>, Jed
>|> Rothwell <[e-mail]> writes:
>|>
>|> > ... NCM Periodic Table of the Beta Stable Nuclides, and the complete
>|> > explanations for thermal neutron fission characteristics, presents
>|> > incontrovertible support for CSC's Nucleon Cluster Model.
>
>  Could someone refer me to a readable source of the mainstream nucleon
>model?  Specifically, what I want is a "Periodic Table of the Nuclides,
>Orthodox Style."  I have never seen anything like this anywhere, whereas
>chemical periodic tables appear even in high school texts.

These are two different questions, in my view.

Nuclear physicists use a "Chart of the Nuclides" to keep track of such
matters.  You do not see it in texts because it is rather large: even
with boxes 12mm on a side, the thing is about 29" by 50" and hangs on a
wall.  A booklet version exists, but is not as convenient.  (available
from General Electric Company, Nuclear Energy Operations, 175 Curtner
Avenue M/C 684, San Jose CA 95125, USA)

In principle, one could build a periodic table, but it would have to be
3-dimensional and would have to accomodate somehow the fact that "similar"
regions grow in size as one moves up the chart ... and the fact that the
additional degree of freedom (neutrons) complicates the physics enough
that there are few rules to rely on.  For example, N=Z closed shell
nuclei are very stable at the low end (He-4, O-16, Ca-40) but Sn-100
has yet to be seen and, if it even exists, it is at the very edge of
the valley.  The existing chart uses color to encode information on
stability and lifetime and, because of the use by reactor people,
neutron absorption cross sections and major fission branches.

The global pattern -- where closed shells occur and where deformation is
maximal -- can be seen in graphs of separation energies or quadrupole
moments as a function of N and Z in most introductory texts.  Sorry,
I cannot recommend one, but Enge is pretty basic and I think it has
all the requisite pictures.  Preston and Bhaduri has lots of stuff,
but you have to start looking in chapters 6 (fig. 6-3 and 6-4) and
9 (fig. 9-1 and 9-4) since they do not start with phenomenology.
Marmier and Sheldon (two volume set) cover the experimental situation
somewhat better.  See what you can find in your library.

The most reliable source on the mainstream model would be deShalit
and Feshbach "Theoretical Nuclear Physics, Volume 1: Nuclear Structure".
This is pretty serious stuff; however, they do introduce some key
experimental results early on, before proceeding to derive all of them.

--
J. A. Carr                                    |  "The New Frontier of which I
[e-mail]                           |  speak is not a set of promises
Florida State University  B-186               |  -- it is a set of challenges."
Supercomputer Computations Research Institute |   John F. Kennedy (15 July 60)