Performance of DFT for Si-29 NMR chemical shifts of silanes

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