Relativistic effects on nuclear magnetic shielding of group-11 metal halides

ALEJANDRO MALDONADO; GUSTAVO A. AUCAR; JUAN I MELO

Turin

Congreso; CHITEL 2015; 2015

Chitel

Results of the calculation of the nuclear magnetic shielding, σ, of group-11 metal halides, MX (M = Cu, Ag, Au; X = H, F, Cl, Br, I) within both, relativistic and non relativistic frameworks are shown. We applied two different methods, polarization propagators at random phase level of approach (PPA-RPA), and DFT (with B3LYP and PBE0 functionals). The linear response elimination of small component (LRESC) formalism was used to analyze relativistic effects.1The performance of different DFT functionals is first analyzed. DFT results are not so close to the RelPPA-RPA ones, which is in agreement with previous works on heavy-atom containing molecules.2 The SO contribution is only important for MF molecules (M = Cu, Ag, Au). For the others such contribution is not so large. On the other hand, the LRESC formalism allow us to analyze the electronic mechanisms responsible for such relativistic effects. We split them in terms of core- and ligand-dependent. The LRESC analysis of relativistic effects shows that the most important contributions arise from core-dependent mechanisms. The ligand-dependent ones (mostly of SO type) are only important for MF molecules (M = Cu, Ag, Au).An unexpected very high value of σ(Cu) in AuF was previously reported. Using the LRESC formalism we found that such high value is an artifact of calculations and arise due to a quasi-instability problem.3 To overcome it one should introduce higher or lower electron correlation in calculations. The consistent value of the shielding should be close to 15000 ppm.