Performance of DFT for 29Si NMR chemical shifts of silanes

The predictive power of DFT, HF, and MP2 Si-29 NMR chemical shift calculations for silane molecules, including fluoro- and methylsilanes (SinH2n+2 (n = 1, ..., 5), SinF2n+2 (n = 1 ,..., 3), and SiHmX4-m (X = F, CH3)) is compared. A systematic accumulation of error proportional to the number of hydrogen neighbors to silicon sites is observed for DFT for all applied exchange-correlation functionals, whereas MP2 is not affected by this problem. A proposed empirical correction scheme for DFT provides excellent agreement with experiment with any exchange-correlation functional employed in this study.