Basis set effects in ab initio studies of sulfur trioxide–water complexes

Gas phase dissociation of H2SO4: A computational study

“…[19]. For reaction (7) our data is in agreement with the published experimental upper limit [10,17] as well as all the other previous computational predictions [13,19,28,36]. Apparently for this reaction the ZPE and BSSE corrections seem to play an important role and cannot be neglected.…”

“…Indeed we obtained in agreement with the previous literature [19] that ZPE correction increases the reaction energy as well as the BSSE correction does. This last energy correction have been considered only by us and by Standard et al [36] and contribute to increase the reaction energy by 3.5 kJ mol À1 and 8 kJ mol À1 from our data and from Reference [36], respectively. Moreover, it is to be note that Meijer calculations [28], performed using plane wave DFT technique that are not affected by the BSSE inaccuracy, gave a value which is significantly smaller than the other DFT methods reported [19] and closer to our and Standard's MP4-ZPE-BSSE values.…”

Perspective: Water cluster mediated atmospheric chemistry

“…126,127 The structure and stability of water complexes of SO 3 and of H 2 SO 4 have been studied to better understand these reactions. 20,80,84,[128][129][130][131][132][133][134] Kinetic studies showed this reaction to be water catalyzed. 114-116, 135, 136 Ab initio results found that the barrier for SO 3 hydration is significantly lowered by one additional water molecule, 50 with further lowering of the reaction barrier with additional waters.…”

Investigating Atmospheric Sulfuric Acid–Water–Ammonia Particle Formation Using Quantum Chemistry

“…One of the key results of these investigations has been that the presence of additional water molecules significantly lowers the activation barrier of the SO 3 + H 2 O → H 2 SO 4 reaction. The studies also show that quantitatively accurate modeling of the formation and reactions of the SO 3 ·H 2 O complex require both high-level electronic energies (for example, the explicitly correlated RI-MP2-R12 calculations by Fliegl et al [81] or the QCISD calculations by Standard et al [80]) and, at least at lower temperatures, multidimensional tunneling corrections [42]. Especially the activation energies are sensitive to basis-set effects, as shown by Standard et al [80].…”

“…To our knowledge, no comprehensive and generally accepted explanation for the effect exists yet, though several studies have addressed issues related to the subject. For example, SO 3 ·H 2 O complexes have been studied by several groups, most recently by Morokuma and Muguruma [74], Meijer and Sprik [75], Larson et al [76,77], Loerting and Liedl [42,78], Ida et al [79], Standard et al [80] and Fliegl et al [81]. (Note that most of these studies do not explicitly focus on atmospheric nucleation mechanisms.)…”