Kozioł Karol, Aucar I Agustín, Gaul Konstantin, Berger Robert, Aucar Gustavo A
Narodowe Centrum Badań Jadrowych (NCBJ), Andrzeja Sołtana 7, 05-400 Otwock-Świerk, Poland.
Instituto de Modelado e Innovación Tecnológica (UNNE-CONICET), Facultad de Ciencias Exactas y Naturales y Agrimensura, Universidad Nacional del Nordeste, Avda. Libertad, 5460 Corrientes, Argentina.
J Chem Phys. 2024 Aug 14;161(6). doi: 10.1063/5.0213653.
The results of relativistic calculations of nuclear magnetic resonance shielding tensors (σ) for the thallium monocation (Tl+), thallium hydride (TlH), and thallium halides (TlF, TlCl, TlBr, TlI, and TlAt) are presented as obtained within a four-component polarization propagator formalism and a two-component linear response approach within the zeroth-order regular approximation. In addition to a detailed analysis of relativistic effects performed in this work, some quantum electrodynamical (QED) effects on those nuclear magnetic resonance shieldings and other small contributions are estimated. A strong dependence of σ(Tl) on the bonding partner is found, together with a very weak dependence of QED effects with them. In order to explain the trends observed, the excitation patterns associated with relativistic ee (or paramagnetic-like) and pp (or diamagnetic-like) contributions to σ are analyzed. For this purpose, the electronic spin-free and spin-dependent contributions are separated within the two-component zeroth-order regular approximation, and the influence of spin-orbit coupling on involved molecular orbitals is studied, which allows for a thorough understanding of the underlying mechanisms.
本文给出了利用四分量极化传播子形式体系和零阶正则近似下的二分量线性响应方法，对铊正离子（Tl⁺）、氢化铊（TlH）以及卤化铊（TlF、TlCl、TlBr、TlI和TlAt）的核磁共振屏蔽张量（σ）进行相对论计算的结果。除了对本工作中相对论效应进行详细分析外，还估算了一些量子电动力学（QED）效应以及对那些核磁共振屏蔽的其他小贡献。发现σ(Tl)对键合配体有强烈依赖性，而QED效应与之的依赖性非常弱。为了解释所观察到的趋势，分析了与相对论ee（或类顺磁）和pp（或类抗磁）对σ的贡献相关的激发模式。为此，在二分量零阶正则近似下分离出电子的无自旋和自旋相关贡献，并研究了自旋 - 轨道耦合对所涉及分子轨道的影响，从而能够深入理解其潜在机制。
