Accurate ab initio anharmonic force field and heat of formation for silane

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 (±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 TAE0=303.80±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 ∆H◦ f,0[Si(g)], we obtain ∆H ◦ f,0[SiH4(g)]=9.9±0.4 kcal/mol, in ∗Corresponding author. Email: [email protected] †Permanent address: San Diego Supercomputer Center MC0505, University of California, San Diego, 9500 Gilman Drive, Building 109, La Jolla, CA 92093-0505, USA