It is shown that the isovector np-pair number operator can be realized in the O(5) quasi-spin basis. The computation of the isovector np-pair number is demonstrated for even-even and odd-odd ds-shell nuclei described by the charge-independent mean field plus isovector pairing model restricted within the O(5) seniority-zero subspace, thereby binding energies and low-lying excited states of these ds-shell nuclei are fit, along with estimates for the isovector neutron-proton pairing contributions. For reasonable neutron-proton pairing strengths the isovector np-pairing energy contribution to the total binding energy in odd-odd N=Z nuclei is systematically larger than that in the even-even nuclei. In sum, the results suggest that the isovector np-pairing mode is favored in odd-odd N=Z nuclei; and additionally, a decrease in the double binding-energy difference for odd-odd nuclei is primarily due to the symmetry and Wigner energy contributions to the binding energy.

结果表明，等矢量np对数算子可以在O（5）准自旋的基础上实现。通过用电荷独立的平均场加上限制在O（5）资历为零的子空间内的等矢量配对模型描述的偶数和奇数个ds - shell核，证明了等矢量ds-p对数的计算，从而限制了能量拟合了这些ds壳核的低位和激发态，以及对等矢量中子-质子配对贡献的估计。对于合理的中子-质子配对强度，等矢量Np对能量对奇数N = Z的总结合能的贡献系统核比偶数核系统地大。总之，结果表明，等奇数N = Z核倾向于采用等位向量np配对模式。另外，奇数核的双重结合能差的减小主要是由于对称能和维格纳能对结合能的贡献。