Accurate ab initio anharmonic force field and heat of formation for silane |
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Authors: | JAN M. L. MARTIN KIM K. BALDRIDGE TIMOTHY J. LEE |
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Affiliation: | 1. Department of Organic Chemistry , Weizmann Institute of Science , Kimmelman Building, Room 262, Rehovot, 76100, Israel;2. MS230-3, NASA Ames Research Center , Moffett Field, CA, 94035-1000, USA |
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Abstract: | 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?1, which includes an anharmonic zero-point energy (19.59 kcal mol?1), inner-shell correlation (—0.36 kcal mol?1), scalar relativistic corrections (— 0.70 kcal mol?1) and atomic spin-orbit corrections (—0.43 kcal mol?1). In combination with the recently revised ΔH o f, o[Si(g)], we obtain ΔH o f.o[SiH4(g)] = 9.9 ± 0.4 kcal mol?1 in between the two established experimental values. |
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