Assessment of Density Functional Theory in Predicting Structures and Free Energies of Reaction of Atmospheric Prenucleation Clusters

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• 作者：Jonas Elm ; Merete Bilde ; Kurt V. Mikkelsen
• 刊名：Journal of Chemical Theory and Computation
• 出版年：2012
• 出版时间：June 12, 2012
• 年：2012
• 卷：8
• 期：6
• 页码：2071-2077
• 全文大小：256K
• 年卷期：v.8,no.6(June 12, 2012)
• ISSN：1549-9626

文摘

This work assesses different computational strategies for predicting structures and Gibb鈥檚 free energies of reaction of atmospheric prenucleation clusters. The performance of 22 Density Functional Theory functionals in predicting equilibrium structures of molecules and water prenucleation clusters of atmospheric relevance is evaluated against experimental data using a test set of eight molecules and prenucleation clusters: SO₂, H₂SO₄, CO₂路H₂O, CS₂路H₂O, OCS路H₂O, SO₂路H₂O, SO₃路H₂O, and H₂SO₄路H₂O. Furthermore, the functionals are tested and compared for their ability to predict the free energy of reaction for the formation of five benchmark atmospheric prenucleation clusters: H₂SO₄路H₂O, H₂SO₄路(H₂O)₂, H₂SO₄路NH₃, HSO₄^{鈥?/sup>路H₂O, and HSO₄鈥?/sup>路(H₂O)₂. The performance is evaluated against experimental data, coupled cluster, and complete basis set extrapolation procedure methods. Our investigation shows that the utilization of the M06-2X functional with the 6-311++G(3df,3pd) basis set represents an improved approach compared to the conventionally used PW91 functional, yielding mean absolute errors of 0.48 kcal/mol and maximum errors of 0.67 kcal/mol compared to experimental results.}