Calculation of chemical-shift tensors of heavy nuclei: a DFT/ZORA investigation of Hg-199 chemical-shift tensors in solids, and the effects of cluster size and electronic-state approximations


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Alkan F. , Dybowski C.

PHYSICAL CHEMISTRY CHEMICAL PHYSICS, vol.16, no.27, pp.14298-14308, 2014 (Journal Indexed in SCI) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 16 Issue: 27
  • Publication Date: 2014
  • Doi Number: 10.1039/c4cp01682c
  • Title of Journal : PHYSICAL CHEMISTRY CHEMICAL PHYSICS
  • Page Numbers: pp.14298-14308

Abstract

Calculations 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 Hg-199 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.