Quantum-mechanical-based computational design of molecular catalysts requires accurate and fast electronic structure calculations to determine and predict properties of transition-metal complexes. For Zr-based molecular complexes related to polyethylene catalysis, previous evaluation of density functional theory (DFT) and wavefunction methods only examined oxides and halides or select reaction barrier heights. In this work, we evaluate the performance of DFT against experimental redox potentials and bond dissociation enthalpies (BDEs) for zirconocene complexes directly relevant to ethylene polymerization catalysis. We also examined the ability of DFT to compute the fourth atomic ionization potential of zirconium and the effect the basis set selection has on the ionization potential computed with CCSD(T). Generally, the atomic ionization potential and redox potentials are very well reproduced by DFT, but we discovered relatively large deviations of DFT-calculated BDEs compared to experiment. However, evaluation of BDEs with CCSD(T) suggests that experimental values should be revisited, and our CCSD(T) values should be taken as most accurate.

中文翻译：

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与茂锆聚合催化剂相关的电离势、氧化还原势和键能的密度泛函理论和 CCSD(T) 评估

基于量子力学的分子催化剂计算设计需要准确快速的电子结构计算来确定和预测过渡金属配合物的性质。对于与聚乙烯催化相关的 Zr 基分子配合物，先前的密度泛函理论 (DFT) 和波函数方法评估仅检查氧化物和卤化物或选择反应势垒高度。在这项工作中，我们针对与乙烯聚合催化直接相关的茂锆络合物的实验氧化还原电位和键解离焓 (BDE) 评估了 DFT 的性能。我们还研究了 DFT 计算锆的第四原子电离势的能力，以及基组选择对使用 CCSD(T) 计算的电离势的影响。一般来说，DFT 很好地再现了原子电离势和氧化还原势，但我们发现与实验相比，DFT 计算的 BDE 存在相对较大的偏差。然而，用 CCSD(T) 评估 BDE 表明应该重新审视实验值，我们的 CCSD(T) 值应该被认为是最准确的。