Cycles Research Institute
Home
Cycles
CYCLE SUBJECTS / ASTRONOMY / LADMA ->
Vladimir Ladma

Magic numbers

Shell model

The nucleouses with so called "magic number" of nucleons have an extreme stability, i.e. the highest binding energy.

Shell model assumes this sequence of numbers:

      (1)(2)(3)(4) (5) (6)
--------------------------
       2  2  2  2   2   2
          6  6  6   6   6
            12 12  12  12
               30  30  30
                   32  32
                       44
--------------------------
total  2  8 20 50  82 126

Let us rewrite the previous scheme another way:

     (1)(2)(3)(4)(5)(6) (7)
--------------------------------------
 2    2  x  2  2  2  2   2    Helium
 6       6  x  6  6  6   6    Carbon
12         12  x 12 12  12    Magnesium
20            20  x 20  20    Calcium
30               30  x  30    Zinc
42                  42   x    Molybdenum
56                      56    Barium
--------------------------------------
total 2  6 14 28 50 82 126

Missing numbers 8 and 20 can be writen: 8=2+6 and 20=2+6+12 (similarly 40= 2+6+12+20, 38= 6+12+20, 64= 2+12+20+30).

Here is an inverse of the previous diagram:

     (1)(2)(3)(4)(5)(6)(7)
--------------------------------------
 2    *  2  *  *  *  *  *     Helium
 6       *  6  *  *  *  *     Carbon
12          * 12  *  *  *     Magnesium
20             * 20  *  *     Calcium
30                * 30  *     Zinc
42                   * 42     Molybdenum
56                      *     Barium
--------------------------------------
total 2  6 14 28 50 82 126

Sequence M(s)

Let number s be a shell number. We define number M(s):

M(s) = m1(s)-m2(s) = 1/3 s(s+1)(s+2) - s(s-1)

 s       0   1   2   3   4   5   6   7   8   9  10
---------------------------------------------------
 m1(s)   0   2   8  20  40  70 112 168 240 330 440
 m2(s)   0   0   2   6  12  20  30  42  56  72  90
---------------------------------------------------
 M(s)    0   2   6  14  28  50  82 126 184 258 350

Numbers M(s) makes arithmetic progression of the 3-th degree.

  0   2   6  14  28  50  82 126 184
     2   4   8  14  22  32  44  58
        2   4   6   8  10  12  14
          2   2   2   2   2   2

Nuclear and electron shells

Structure of periodic table is not definitive yet. (Even it is not known if it has finite or infinite number of elements.)

Sequence of electron shells:

    0,2,8,18,32, .. i.e.   2*n^2

Sequence of nuclear shells:

    0,2,6,12,20,30,42, .. i.e.   n*(n+1)= n^2+n

In the following diagram are the both sequences,
the first one: totals in vertical direction,
the second one: values in horizontal direction.

--+----------------------------------
 0|  1-1
 2|  1+1 4-2
 6|      4+2 9-3
12|          9+3 16-4
20|              16+4 25-5
30|                   25+5 36-6
42|                        36+6 49-7
56|                             49+7
--+----------------------------------
      2   8   18  32   50    72   98

Equivalence classes

Periodic table reminds mathematical structures (groups of equivalence classes,...)

Also e.g. the begining of table of stable izotopes is simple and well structured:

 00         0
 01 H       1     2
 02 He      3     4
 03 Li      6     7
--------------------
 04 Be      9
 05 B      10    11
 06 C      12    13
 07 N      14    15
-------------------------
 08 O      16    17    18
 09 F      19
 10 Ne     20    21    22
 11 Na     23
-------------------------
 12 Mg     24    25    26
 13 Al     27
 14 Si     28    29    30
 15 P      31
--------------------------