Alkan, FahriDybowski, Cecil2016-03-162016-03-16Copyright2014-06-02Alkan, Fahri, and Cecil Dybowski. "Calculation of chemical-shift tensors of heavy nuclei: a DFT/ZORA investigation of 199 Hg chemical-shift tensors in solids, and the effects of cluster size and electronic-state approximations." Physical Chemistry Chemical Physics 16.27 (2014): 14298-14308.1463-9076 ; e- 1463-9084http://udspace.udel.edu/handle/19716/17508Publisher's PDFCalculations of the nuclear magnetic resonance chemical-shielding tensors of a suite of mercury-containing materials using various cluster models for the structures provide a stringent test of the procedures for forming models and for calculation with various methods. The inclusion of higher co-ordination shells in the molecular clusters permits quantum chemical calculations of 199Hg chemical-shielding tensor elements within 3% of the experimental values. We show that it is possible to reduce the size of computationally expensive molecular-cluster calculations with limited effect on calculated NMR parameters by carefully introducing the frozen core approximation. The importance of the relativistic Hamiltonian for accurate predictions of chemical-shielding values is demonstrated within the molecular cluster approach. The results demonstrate that careful design of a cluster to represent the solid-state structure, inclusion of relativistic components in the Hamiltonian at least at the spin–orbit level, and judicious use of approximations are essential to obtain good agreement with experimental results.en-USCC-BY 3.0 https://creativecommons.org/licenses/by-sa/3.0/us/ Authors retain copyright.ArticleDOI: 10.1039/C4CP01682C