Coulomb interaction in the supermultiplet basis

The approximate expression for matrix elements of Coulomb interaction in the supermultiplet basis, taking into account the orbitally non-symmetric terms, is obtained. The quantum numbers for the orbital part of the interaction are not specified. The expression can be used in nuclear models employing the supermultiplet scheme. The obtained expression have been used to calculate the Coulomb energy of light (4 ≤ A ≤ 40) and heavy (158 ≤ A ≤ 196) nuclei in the framework of strictly restricted dynamics model. The results are in sufficient agreement with the experimental data for light mirror nuclei and with the results of semi-empirical calculations for heavy nuclei. The contribution of the orbitally non-symmetric part to the full Coulomb energy matrix element has been estimated to be less than 5%. (author)