You can select data on a particular isotope, for example 17O
by entering 17O in the quick search box. Then check off the first box
labelled "ADOPTED LEVELS, GAMMAS". On the bottom of the page click on
the HTML button as below.
Get selected ENSDF datasets:
At the top of the page there may be various graphical displays for the level
schemes: JPEG PDF PS. You can select one of these to see the
If you scroll down the page you will also see text data giving you the
energies of the states, the spin and parity, the life time of the
state, references, the isospin T=(N-Z)/2, and the magnetic moment in
nuclear magnetons. From the table or the graphical level schemes you
can see that the ground state spin of 5/2+ is consistent with the shell
model predictions. The first excited state is 1/2+, which is also
consistent with the shell model expectations. The 2nd excited state is
1/2-, which no longer follows the simple shell model scheme so the
nucleons have rearranged themselves in a different fashion. There
should be a large component in the wave function for the 1/2- state of
a neutron moving up to the d5/2 level where it couples with another
neutron to produce a combined spin 0. This leaves a hole in the 1p1/2
state which would give the right spin and parity for the state.
Shell Model Check the following nuclei 3He, 3H,15O, 41Ca,43Ca,45Ca,47Ca,49Ca,51Ca,
67As, 69As, 71As.
Make a table for them listing the spin-parity combination, the magnetic
moment in nuclear magnetons, and the quadrupole moment in barns.
a) Does the shell model give the expected spin-parities for these
b) What is the orbital angular momentum for the Ca and As isotopes?
c) Does the magnetic moment for the Ca and As isotopes follow the
expected trend predicted by the shell model? Give the evidence from the
data to support your conclusion.
3) Collective Models
i) Vibrational nuclei a) Make a table for the following nuclei:
spin-parity, energy 1st excited
spin-parity, energy 2nd excited
spin-parity, energy 3rd excited
spin-parity, energy 4th excited
Eavg = (E2
+ E3 + E4 )/3
ratio = Eavg / E1
b) Describe qualitatively and quantitatively if the ratios in the above
table are consistent with what one expects from the vibrational model.
Support your conclusions.
ii) Rotational nuclei Search on 238 Pu and at the top of the page there may be various
graphic styles for the Band drawings, Select Bands:.
Using the diagram on the left for spins 0+, 2+, ...,26+ do the
a) Make a good quality plot of energy of the excited state on the y
axis vs J(J+1) on the x axis.
b) Make the best linear fit of an equation of the form y= a + bx
, and determine the moment of inertia of 238 Pu.
c) Can you make a better fit going to second order? That is try y = a +
bx + cx2 .
d) From these data do you conclude that 238 Pu is a rigid
rotor over this span of angular momenta?