"Theoretical prediction and interpretation of NMR and EPR parameters"

   

   Vladimir G. Malkin and Olga L. Malkina

   Institute of Inorganic Chemistry, Slovak Academy of Sciences,

   Dubravska cesta 9, SK-84236 Bratislava, Slovakia

   

   Nowadays quantum chemical calculations of NMR parameters (chemical shift tensors, indirect
   nuclear spin-spin couplings, electric field gradients and contact and pseudo-contact shifts)
   become increasingly popular. Most of such calculations are performed using Density Functional
   Theory (DFT). Being a relatively inexpensive approach (in comparison with post-Hartree-Fock
   approaches), DFT however leads to quite accurate results due to (implicit) inclusion of
   electron correlation effects.

   During the lecture, different computational aspects affecting the accuracy of the calculated
   results will be addressed. Examples demonstrating a typical accuracy in calculations of NMR
   and EPR parameters will be shown. Inclusion of environmental effects (solvent effects,
   interactions in crystals and similar) will be also considered.

   Relativistic effects play an important role in chemistry and, especially, in the field of NMR
   and EPR spectroscopy. We will give a short excursion in the field of relativistic calculations
   of NMR and EPR parameters. Relativistic effects and paramagnetic NMR are two very closely
   related (from a theoretical point of view) issues. A short introduction to calculations of
   PNMR shifts will be included in the lecture.

   While quantum-chemical calculations can often provide NMR parameters with useful accuracy,
   there is much more than just the numbers that can be gained from calculations. We will discuss
   a few approaches to interpretation of chemical shifts and spin-spin couplings with a stress on
   our recent development: visualization of indirect spin-spin coupling pathways and chemical
   shifts using a real space functions.