Diagonal $a^3{\mathrm{\Sigma }}_1^{+}-a^3{\mathrm{\Sigma }}_1^{+}$ and off–diagonal $X^1{\mathrm{\Sigma }}_{0^{+}}^{+}-a^3{\mathrm{\Sigma }}_{0^{-}}^{+}$ magnetic hyperfine structure (HFS) matrix elements were calculated ab initio for the LiRb and LiCs molecules in a wide range of internuclear distances using the multi–reference Fock space coupled clusters method with generalized relativistic effective core potentials to describe the four–component valence wavefunctions near the nuclei. At large distances, both HFS functions vary little, though they may fluctuate by as much as 12 to 24% in the intermediate range. The plateau exhibited by the $a^3{\mathrm{\Sigma }}_1^{+}-a^3{\mathrm{\Sigma }}_1^{+}$ HFS function at 4–5 Å, could be attributed to pronounced spin–orbit coupling of the intersecting $a^3{\mathrm{\Sigma }}^{+}$ and $b^3\mathrm{\Pi }$ states.

对角线 ${\mathrm{一种}}^3{\mathrm{\Sigma }}_{\mathrm{1个}}^{+}--{\mathrm{一种}}^3{\mathrm{\Sigma }}_{\mathrm{1个}}^{+}$ 和非对角线 $X^{\mathrm{1个}}{\mathrm{\Sigma }}_{0^{+}}^{+}--{\mathrm{一种}}^3{\mathrm{\Sigma }}_{0^{--}}^{+}$使用具有广义相对论有效核心电势的多参考Fock空间耦合聚类方法从头算出LiRb和LiCs分子在宽核间距内的磁性超精细结构（HFS）矩阵元素，以描述附近的四成分价波函数原子核。在较远的距离上，两个HFS功能变化不大，尽管它们在中间范围内可能波动12％至24％。高原展示的${\mathrm{一种}}^3{\mathrm{\Sigma }}_{\mathrm{1个}}^{+}--{\mathrm{一种}}^3{\mathrm{\Sigma }}_{\mathrm{1个}}^{+}$ HFS函数在4–5Å处，可以归因于相交的自旋轨道耦合 ${\mathrm{一种}}^3{\mathrm{\Sigma }}^{+}$ 和 $b^3\mathrm{\Pi }$ 状态。