ON WIGNER SUPERMULTIPLET SCHEME

Calculation of Wigner and Racah coefficients for the group SU(4) ⊃ [SU(2) x SU(2)] make it possible to perform the spin-isospin sums in the cfp (fractional parentage coefficients) expansion of the matrix elements of one- and two-body operators in the Wigner supermultiplet scheme. The SU(4) coefficients needed to evaluate one- and two-particle cfp's, the matrix elements of one-body operators, and the diagonal matrix elements of two-body operators are calculated in general algebraic form for many-particle states characterized by the SU(4) irreducible representations [yy0], [y y - 1 0], [yy1], [y11], [y y - 1 y -1], [y10], [yy y - 1], [y00], and [yyy], whose states are specified completely by the spin and isospin quantum numbers (y = arbitrary integer). Applications are made to the calculation of the matrix elements of the complete space-scalar part of the Coulomb interaction and the space-scalar part of the particle-hole interaction for nucleons in different major oscillator shells.