Accurate computational determination of the binding energyof the S O 3 ∙ H 2 O complex

• Published in: The Journal of chemical physics 2006-08, Vol.125 (5), p.054312-054312-7
• Main Authors: Fliegl, Heike, Glöß, Andreas, Welz, Oliver, Olzmann, Matthias, Klopper, Wim
• Format: Article
• ISSN: 0021-9606; 1089-7690
• DOI: 10.1063/1.2234372

Reliable thermochemical data for the reaction S O 3 + H 2 O ⇔ S O 3 ∙ H 2 O are of crucial importance for an adequate modeling of the homogeneous H 2 S O 4 formation in the atmosphere. We report on high-level quantum chemical calculations to predict the binding energy of the S O 3 ∙ H 2 O complex. The electronic binding energy is accurately computed to D e = 40.9 ± 1.0 kJ ∕ mol = 9.8 ± 0.2 kcal ∕ mol . By using harmonic frequencies from density functional theory calculations (B3LYP/cc-pVTZ and TPSS/def2-TZVP), zero-point and thermal energies were calculated. From these data, we estimate D 0 = − Δ H 1 a 0 ( 0 K ) = 7.7 ± 0.5 kcal ∕ mol and Δ H 1 a 0 ( 298 K ) = − 8.3 ± 1.0 kcal ∕ mol .