  From large basis set coupled cluster calculations and a minor empirical
adjustment, an anharmonic force field for silane has been derived that is
consistently of spectroscopic quality ($\pm 1 cm^{-1}$ on vibrational
fundamentals) for all isotopomers of silane studied. Inner-shell polarization
functions have an appreciable effect on computed properties and even on
anharmonic corrections. From large basis set coupled cluster calculations and
extrapolations to the infinite-basis set limit, we obtain TAE_0=303.80 \pm 0.18
kcal/mol, which includes an anharmonic zero-point energy (19.59 kcal/mol),
inner-shell correlation (-0.36 kcal/mol), scalar relativistic corrections
(-0.70 kcal/mol), and atomic spin-orbit corrections (-0.43 kcal/mol). In
combination with the recently revised \HVSI{0}, we obtain $\Delta
H^{\circ}_{f,0}[SiH_4(g)]=9.9 \pm 0.4 kcal/mol$, in between the two established
experimental values.
