Ponec Robert, Bučinský Lukáš, Gatti Carlo
Institute of Chemical Process Fundamentals, Academy of Sciences of the Czech Republic v.v.i., Prague 6, Suchdol 2, 165 02 Czech Republic, Institute of Physical Chemistry and Chemical Physics, Slovak University of Technology in Bratislava, Bratislava, Slovakia, and Istituto di Scienze e Tecnologie Molecolari del CNR (CNR-ISTM) e Dipartimento di Chimica Fisica ed Elettrochimica, Università di Milano, Via Golgi 19, I-20133, Milano, Italy.
J Chem Theory Comput. 2010 Oct 12;6(10):3113-21. doi: 10.1021/ct100338v.
This paper reports a systematic comparison of the performance of alternative methods of including relativistic effects on the nature of metal-metal bonding in the Re2Cl8(2-) anion. The comparison involved the description using a scalar relativistic Douglas-Kroll-Hess (DKH2) Hamiltonian with all-electron basis sets and the relativistic effective core potential (ECP) basis sets. The impact of the above methods on the picture of the bonding was analyzed using the so-called domain averaged Fermi holes (DAFH). Besides comparing the impact on the picture of the bonding of the two above methods, the focus was also put on the systematic comparison of the "exact" AIM generalized form of DAFH analysis with the approximate Mulliken-like approach used in an earlier DAFH study of ReRe bonding. It has been shown that in contrast to descriptions using ECP basis sets where the differences in the picture of the bonding emerging from the approximate and "exact" DAFH analysis are only marginal, the approximate DAFH approach has been found to dramatically fail in the case of all-electron basis sets required for the description in terms of the Douglas-Kroll-Hess (DKH2) Hamiltonian.
本文报道了对包含相对论效应的不同方法在Re2Cl8(2-)阴离子中金属-金属键本质方面的性能进行的系统比较。该比较涉及使用标量相对论性道格拉斯-克罗尔-赫斯（DKH2）哈密顿量与全电子基组以及相对论有效核势（ECP）基组的描述。使用所谓的域平均费米空穴（DAFH）分析了上述方法对键合图景的影响。除了比较上述两种方法对键合图景的影响外，还重点对DAFH分析的“精确”AIM广义形式与早期关于Re-Re键合的DAFH研究中使用的近似穆利肯类方法进行了系统比较。结果表明，与使用ECP基组的描述不同，在使用ECP基组时，近似和“精确”DAFH分析产生的键合图景差异仅为边际差异，而在使用道格拉斯-克罗尔-赫斯（DKH2）哈密顿量进行描述所需的全电子基组情况下，发现近似DAFH方法会显著失效。
