Bidirectional Interaction of Alanine with Sulfuric Acid in the Presence of Water and the Atmospheric Implication

详细信息    查看全文

• 作者：Chun-Yu Wang ; Yan Ma ; Jiao Chen ; Shuai Jiang ; Yi-Rong Liu ; Hui Wen ; Ya-Juan Feng ; Yu Hong ; Teng Huang ; Wei Huang
• 刊名：Journal of Physical Chemistry A
• 出版年：2016
• 出版时间：April 21, 2016
• 年：2016
• 卷：120
• 期：15
• 页码：2357-2371
• 全文大小：907K
• 年卷期：0
• ISSN：1520-5215

文摘

Amino acids are recognized as important components of atmospheric aerosols, which impact on the Earth’s climate directly and indirectly. However, much remains unknown about the initial events of nucleation. In this work, the interaction of alanine [NH₂CH(CH₃)COOH or Ala], one of the most abundant amino acids in the atmosphere, with sulfuric acid (SA) and water (W) has been investigated at the M06-2X/6-311++G(3df, 3pd) level of theory. We have studied thermodynamics of the hydrated (Ala)(SA) core system with up to four water molecules. We found that Ala, with one amino group and one carboxyl group, can interact with H₂SO₄ and H₂O in two directions and that it has a high cluster stabilizing effect similar to that of ammonia, which is one of the key nucleation precursor. The corresponding Gibbs free energies of the (Ala)(SA)(W)_n (n = 0–4) clusters formation at 298.15 K predicted that Ala can contribute to the stabilization of small binary clusters. Our results showed that the hydrate distribution is temperature-dependent and that a higher humidity and temperature can contribute to the formation of hydrated clusters.