Theoretical description of potential energy curves (PECs) of molecular ions is essential for interpretation and prediction of coupled electron-nuclear dynamics following ionization of parent molecule. However, an accurate representation of these PECs for core or inner valence ionized state is nontrivial, especially at stretched geometries for double- or triple-bonded systems. In this work, we report PECs of singly and doubly ionized states of molecular nitrogen using state-of-the-art quantum chemical methods. The valence, inner valence, and core ionized states have been computed. A double-loop optimization scheme that separates the treatment of the core and the valence orbitals during the orbital optimization step of the multiconfiguration self-consistent field method has been implemented. This technique allows the energy to be converged to any desired ionized state with any number of core or inner-shell holes. The present work also compares the PECs obtained using both delocalized and localized sets of orbitals for the core hole states. The PECs of a number of singly and doubly ionized valence states have also been computed and compared with previous studies. The computed PECs reported here are expected to be of importance for future studies to understand the interplay between photoionization and Auger spectra during the breakup of molecular nitrogen when interacting with intense free electron lasers.

中文翻译：

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具有核和价孔的单电离态和双电离态分子氮的势能曲线

分子离子势能曲线 (PEC) 的理论描述对于解释和预测母体分子电离后的耦合电子-核动力学至关重要。然而，核心或内价电离态的这些 PEC 的准确表示是非常重要的，尤其是在双键或三键系统的拉伸几何形状时。在这项工作中，我们使用最先进的量子化学方法报告了分子氮的单电离态和双电离态的 PEC。已经计算了价态、内价态和核心电离态。已经实施了双环优化方案，该方案在多配置自洽场方法的轨道优化步骤中将核心和价轨道的处理分开。这种技术允许能量通过任意数量的核或内壳孔集中到任何所需的电离状态。目前的工作还比较了使用离域和局部轨道集获得的核空穴状态的 PEC。还计算了许多单和双电离价态的 PEC 并与以前的研究进行了比较。预计这里报告的计算出的 PEC 对未来的研究具有重要意义，以了解与强自由电子激光器相互作用时分子氮分解过程中光电离和俄歇光谱之间的相互作用。还计算了许多单和双电离价态的 PEC 并与以前的研究进行了比较。预计这里报告的计算出的 PEC 对未来的研究具有重要意义，以了解与强自由电子激光器相互作用时分子氮分解过程中光电离和俄歇光谱之间的相互作用。还计算了许多单和双电离价态的 PEC 并与以前的研究进行了比较。预计这里报告的计算出的 PEC 对未来的研究具有重要意义，以了解与强自由电子激光器相互作用时分子氮分解过程中光电离和俄歇光谱之间的相互作用。