Relativistic effects gold clusters

It came as a surprise, however, that Aug prefers a trigonal planar D3h structure in the gas phase [16] and is not octahedral as one might assume, suggesting that gold clusters do not follow the usual pattern of typical Lennard-Jones, Morse or Gupta systems, which all favor a maximum number of close atom-atom contacts. The preferred planarity of small gold cluster compounds is due to relativistic effects [17]. 

Wesendrup, R., Laerdahl, J.K and Schwerdtfeger, P. (1999) Relativistic Effects in Gold Chemistry. VI. Coupled Cluster Calculations for the Isoelectronic Series AuPt , Au2 and AuHg. Joumul of Chemical Physics, 110, 9457-9462. 

Rosch, N., Gorling, A., Ellis, D.E. and Schmidbaur, H. (1989) Aurophilicity as Concerted Effect Relativistic MO Calculations on Carbon-Centered Gold Clusters. Angewandte Chemie International Edition, 28, 1357-1359. 

On the other hand, Gold shows large relativistic effects (the Gold maximum — see eg. [21]). In fact, it has been explicitly demonstrated that for Au relativistic and arc-effects are nonadditive [22]. This is most obvious for its electron affinity While a nonrelativistic Cl-calculation [23] gives a value of 1.02 eV and a fully relativistic Coupled-Cluster calculation [22] yields 2.28 eV, the corresponding nonrelativistic and relativistic Hartree-Fock values are 0.10 eV [22] and 0.67 eV, respectively. Thus immediately the question arises to which extent the GGA s failure for metallic Au is due to the neglect of relativistic arc-contributions in Exc[n. ... 

Relativistic effects of the environment are included indirectly due to the solution of the KS-equations for the whole system. Special techniques have been developed for choosing the size and shape of the environment and of an initial electronic density on atomic centers. Application of this method to the calculations of interaction of Cu with Cu-clusters of different size shows good agreement with extended calculations of other workers (see [124] and references therein). The method is presently applied to the calculations of the interaction of the heaviest element 112 and its lighter homolog Hg with transition-metal clusters. First results are reported for those elements interacting with small gold clusters [125] (see Section 3.1). 

Gold is known to exhibit strong relativistic effects [3]. Hence, its diatomics were frequently chosen as test systems of various relativistic methods also complexes and cluster compounds of gold attracted considerable interest for studies of relativistic chemistry [16,144-148]. Whereas there are quite a few applications of pseudopotential and relativistic methods to gold complexes [16, 144,149], a direct determination of relativistic effects was done less frequently. 

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