Fully Relativistic Calculations of NMR and EPR Parameters in the Framework of the Matrix Dirac-Kohn-Sham Equation

摘要

During the last two decades it has become clear that, when going down the periodical table, relativity affects NMR and EPR parameters much earlier than geometry of molecules. The reason lies in a well-known strong sensitivity of those parameters to the details of the electronic structure in the core area. While some systems and problems could be safely treated by more approximate relativistic approaches, there is still a need for fully relativistic calculations of NMR and EPR parameters. Surprisingly that, to the best of our knowledge till now there were no publications on four-component DFT calculations of NMR indirect nuclear spin-spin coupling constants [1] and EPR g-tensors. In this context, we would like to report here on a recent progress made in our group in fully relativistic Dirac-Kohn-Sham calculations of NMR and EPR parameters. In particular, we will show the results of calculations of g-tensor for [Wo(bdt)_2]~- (bdt=benzene-1,2-dithiolate) complex. Importance of variational treatment of spin-orbit operators in calculations of g-tensor for moderate-size transition metal complexes will be demonstrated. Then the concept of restricted magnetically balance (RMB), that is the cornerstone of our mDKS-RMB method, will be briefly described. A few calculations of NMR parameters - shielding tensor [3] and spin-spin coupling tensor [2] will be presented. Pilot calculations of chemical shifts using GIAO approach will be also shown.