Synergistic Effect of Ammonia and Methylamine on Nucleation in the Earth's Atmosphere. A Theoretical Study
Synergistic Effect of Ammonia and Methylamine on Nucleation in the Earth's Atmosphere. A Theoretical Study
复制标题
氨和甲胺对地球大气成核的协同作用。
DOI：
10.1021/acs.jpca.8b00681
复制
发表时间：
2018
影响因子：
2.9
通讯作者：
Huang Wei
中科院分区：
文献类型：
--
作者：
Wang Chun Yu;Jiang Shuai;Liu Yi Rong;Wen Hui;Wang Zhong Quan;Han Ya Juan;Huang Teng;Huang Wei
Ammonia and amines are important common trace atmospheric species that can enhance new particle formation (NPF) in the Earth’s atmosphere. However, the synergistic effect of these two bases involving nucleation is still lacking. We studied the most stable geometric structures and thermodynamics of quaternary (NH3)(CH3NH2)(H2SO4)m(H2O)n(m= 1–3,n= 0–4) clusters at the PW91PW91/6-311++G(3df,3pd) level of theory for the first time. We find that the proton transfer from H2SO4molecule to CH3NH2molecule is easier than to NH3molecule in the free or hydrated H2SO4-base clusters, and thus leads to the stability. The energetically favorable formation of the (NH3)(CH3NH2)(H2SO4)m(H2O)n(n= 0–4) clusters, by hydration or attachment of base or substitution of ammonia by methylamine at 298.15 K, indicate that ammonia and methylamine together could enhance the stabilization of small binary clusters. At low RH and an ambient temperature of 298.15 K, the concentration of total hydrated (NH3)(CH3NH2)(H2SO4)2clusters could reach that of total hydrated (NH3)(H2SO4)2clusters, which is the most stable ammonia-containing cluster. These results indicate that the synergistic effect of NH3and CH3NH2might be important in forming the initial cluster with sulfuric acid and subsequently growth process. In addition, the evaporation rates of (NH3)(CH3NH2)(H2SO4)(H2O), (NH3)(CH3NH2)(H2SO4)2and (NH3)(CH3NH2)(H2SO4)3clusters, three relative abundant clusters in (NH3)(CH3NH2)(H2SO4)m(H2O)nsystem, were calculated. We find the stability increases with the increasing number of H2SO4molecules.
