A full relativistic formalism that gives new insight into magnetic molecular properties

GUSTAVO A. AUCAR, ALEJANDRO F. MALDONADO Y CARLOS A. GIMENEZ

Santiago de Compostela

Conferencia; 9th triennial Congress of the World Association of Theoretical and Computational Chemist WATOC; 2011

WATOC

Recent developments of full relativistic formalisms and its implementation in computational codes gives now the opportunity to calculate and analyse the electronic origin of magnetic molecular properties of heavy-atom containing molecules, and improve our understanding of such properties.   When four-component methods are applied for studying the electronic behaviour of molecular systems new physical insights do arise naturally. In fact new mechanisms and new phenomena should be expected. Dirac-like operators replace its non relativistic counterparts and so what we are used to treat within NR quantum chemistry are not any longer what they were.   In this talk we will show new physical insight that makes more beautiful the understanding of NMR spectroscopic parameters when worked out within the full relativistic formalism from the outset. It will be based on polarization propagators, which are powerful theoretical tools as all propagator methods are. We will focus on the origin of diamagnetic contributions (virtual creation and annihilation of electron-positron pairs), spin and time reversal symmetry, gauge dependence and covariance; and the analysis of results of calculations of both spectroscopic parameters when the finite size of nuclei is considered and their values for molecules which contain more than three heavy atoms, like SnBrnI4-n.