发表机构
Univ Rennes, CNRS, ISCR (Institut des Sciences Chimiques de Rennes); ICI-RECENT AIR（雷恩大学; ICI-RECENT AIR）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本文介绍NewMag程序的大规模更新，用于从相对论和多组态计算中提取f元素体系的Stevens晶体场参数，支持扩展活性空间和二阶相关方法，并讨论其与现有代码的差异及应用价值。
AI 中文摘要
我们报道了NewMag程序的大规模更新，该程序能够在相对论和多组态计算后提取Stevens晶体场参数（CFPs）。该代码现在可以后处理ORCA和OpenMolcas的输出，这些输出包含具有最小或扩展活性空间的状态平均完全活性空间自洽场（SA-CASSCF）计算、二阶NEVPT2或CASPT2计算以及自旋轨道组态相互作用（SOCI）计算。Stevens参数按照原始Stevens约定以所谓的“扩展”参数提取。在应用参数值校正以确保归一化后，还计算旋转不变指示符，遵循Rudowicz方法。在SOCI水平，自旋轨道耦合（SOC）常数也在SOC算符的球近似下提取。对于所有参考计算水平，重建模型谱，允许直接评估其质量。所报告的实现成功适用于具有非空、非半填充/空或非全填充f壳层的f元素体系，即对于f^n组态，其中n不等于0、7和14。讨论了与SINGLE_ANISO和AILFT代码的异同。通过选定的例子，我们展示了在f元素体系中确定CFPs对于理解其磁性和光学性质的一般意义，更具体地说明了NewMag的附加价值。最后，讨论了该方法在d元素体系中的应用，以揭示其何时能直接成功应用以及何时可能无法令人满意地再现从头算能量。
英文摘要
We report a massive update of the NewMag program, which enables to extract Stevens crystal-field parameters (CFPs) after relativistic and multiconfigurational calculations are performed. The code can now post-treat ORCA and OpenMolcas outputs that contain state-average complete active space self-consistend field (SA-CASSCF) calculations with minimal or extended active spaces, second-order NEVPT2 or CASPT2 calculations, and spin-orbit configuration interaction (SOCI) calculations. Stevens parameters are extracted following the original Stevens convention with the so-called "extended" parameters. Rotation invariant indicators are also computed, after applying a correction of the parameter values to ensure normalization, following Rudowicz. At the SOCI level, the spin-orbit coupling (SOC) constant is also extracted within a spherical approximation of the SOC operator. For all the reference calculation levels, the model spectrum is reconstructed, allowing a direct assessment of its quality. The reported implementation is successfully applicable to f-element systems with a non-void, non-half-filled/empty or non-full f shell, that is for f^n configurations with n != 0, != 7 and != 14. Similarities and differences with the SINGLE_ANISO and AILFT codes are discussed. With selected examples, we showcase the interest of determining CFPs in f-element systems to understand their magnetic and optical properties in general, and more specifically the added value of NewMag. Finally, application of this approach to d-element systems is discussed, to reveal when it readily and successfully applies and when it may fail in reproducing satisfactorily the ab initio energies.
