Coupling of equivalent spins.

[K,N] = equivcouple(I,n)

The states due to n spins with quantum number I can be coupled to give a set of independent subspins. Their quantum numbers are returned in F, their respective abundance in N.

Five equivalent spins-1/2 can be coupled using

[F,N] = equivcouple(1/2,5)

F =
    2.5000    1.5000    0.5000
N =
     1     4     5

This means that the coupling of the five spins-1/2 gives 1 spin-5/2, 4 spins-3/2 and 5 spins-1.

The algorithm is very simple and is best illustrated by an example: 5 spins-1/2 give rise to a first-order splitting pattern [1 5 10 10 5 1] (see the function equivsplit). This splitting pattern can be decomposed into several subpatterns due to one spin-5/2, four spin-3/2 and five spin-1/2 according to

           5  5          5 spins-1/2
        4  4  4  4       4 spins-3/2
     1  1  1  1  1  1    1 spin-5/2
    ------------------
     1  5 10 10  5  1    sum

equivsplit, garlic