Test of Computational Approaches for Gold-Thiolate Clusters Calculation

Abstract

High-level procedures (MP2, CCSD, CCSD(T)) and reliable experimental data have been used to assess the performance of a variety of exchange-correlation functionals for the calculation of structures and energies of small models of thiolate-protected gold clusters. Clusters represent rather complicated objects for examination, therefore the simple models including Au2, AuS were considered to find an appropriate method to calculate Au-Au and Au-S interactions in protected clusters. The mean unsigned errors of the quantum chemical methods were evaluated via reliable experimental bond distances and dissociation energies of Au2 and AuS. Based on the calculation, the SVWN5, TPSS+D3, PBE96+D3, and PBE0+D3 were found to give the most reliable results and can be recommended for calculation of the structure and properties of thiolate-protected gold clusters. The influence of the relativistic corrections calculated in Dirac-Coulomb-Breit framework and inclusion of dispersion corrections on the structure and energy of thiolate-protected gold clusters have been analyzed.