Theoretical investigation of ionic dissociations of fluorosulfonic acid in microsolvated clusters

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• 作者：Shujin Li ; Kevin H. Weber ; Fu-Ming Tao and Renao Gu
• 关键词：Fluorosulfonic acid ; Molecular cluster ; Microsolvation ; Acid dissociation ; Superacid ; Hydrogen bonded clusters
• 刊名：Chemical Physics
• 出版年：2006
• 出版时间：21 April 2006
• 年：2006
• 卷：323
• 期：2-3
• 页码：397-406
• 全文大小：214 K

文摘

Ionization or ionic dissociation of fluorosulfonic acid (HSO₃F) in the clusters HSO₃F–(H₂O)_n (n = 1–3) and HSO₃F–NH₃–(H₂O)_n (n = 0, 1) is investigated by density functional theory and ab initio molecular orbital theory. The equilibrium structures, binding energies, and harmonic frequencies are calculated using the hybrid density functional (B3LYP) method with the 6-311++G** basis set and the second-order Møller–Plesset approximation (MP2) method with the 6-311++G** basis set. Harmonic frequencies are obtained from the B3LYP/6-311++G** calculations. Fluorosulfonic acid is found to require a minimum of three water molecules for ionization to occur and at least one water molecule to protonate ammonia. The corresponding clusters with fewer water molecules are found to be strongly hydrogen-bonded. The acid strength and related properties of fluorosulfonic acid are discussed and compared to those of perchloric acid and sulfuric acid in the context of clusters with ammonia and water.