All-electron relativistic ab initio calculations have been performed to calculate the electronic structures of UNC and UCN. The spin-free electronic states have been calculated at multireference complete active space second-order perturbation (CASPT2) theory level. The spin-orbit states have been computed using Douglas-Kroll type of atomic mean-field integral approach. The ground state geometries and also a manifold of low-lying spin-free states (blow 1.8 eV) and spin-orbit states (below 2.1 eV) have been calculated for both the systems. The ground states of both UNC and UCN are found to be linear with a spectral term of ⁴H(Λ =5, 5fσ5fδ5fφ7s²) and ⁴I(Λ =6, 5fл5fδ5fφ7s²), respectively. The strong electron correlation and also the strong configuration mixing in case of spin-free and the spin-orbit states lead to the complicated electronic structures of the excited states in both the systems.

已经进行了全电子相对论的从头计算，以计算UNC和UCN的电子结构。在多参考完全有源空间二阶扰动（CASPT2）理论水平上计算了无自旋电子态。自旋轨道状态是使用Douglas-Kroll类型的原子平均场积分方法计算的。已经为这两个系统计算了基态几何形状以及低空无自旋状态（低于1.8 eV）和自旋轨道状态（低于2.1 eV）的多种形式。既UNC和UCN的基态被发现是线性同的光谱项⁴ H（Λ = 5，5fσ5fδ5fφ7s ²）和⁴ I（Λ = 6，5fл5fδ5fφ7s ²）， 分别。在无自旋和自旋轨道状态的情况下，强的电子相关性以及强烈的构型混合导致两个系统中激发态的复杂电子结构。