Commutation Relations for Double Tensors of Two Equivalent D Electrons
We apply the Clebsch-Gordan and Racah coefficients to calculate the double tensors for two equivalent d electrons. We also obtain the commutation relations for these double tensors and choose certain quantum numbers, which produce a subgroup. From the root vectors of the commutation relations, we identify them with Lie algebra B2. Once we have the correct Lie algebra, it is feasible to use the Wigner-Eckart theorem to find matrix elements for transition states among atomic spectra or nuclear shell models.