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The NMR chemical shifts and indirect spin-spin coupling constants of 12 molecules containing 29 Si, 73 Ge, 119 Sn, and 207 Pb [X (CCMe) 4, Me 2 X (CCMe) 2, and Me 3 XCCH] are presented. The results are obtained from non-relativistic as well as two-and four-component relativistic density functional theory (DFT) calculations. The scalar and spin–orbit relativistic contributions as well as the total relativistic corrections are determined. The main relativistic effect in these molecules is not due to spin–orbit coupling but rather to the scalar relativistic contraction of the s-shells. The correlation between the calculated and experimental indirect spin–spin coupling constants showed that the four-component relativistic density functional theory (DFT) approach using the Perdew’s hybrid scheme exchange-correlation functional (PBE0; using the Perdew-Burke-Ernzerhof exchange and correlation functionals) gives results in …