2-甲基甘油酸-硫酸/甲磺酸团簇的大气物化特性研究

气溶胶通过散射或吸收长波和短波辐射影响着地球的气候系统。 2-甲基甘油酸是一种气溶胶示踪剂, 在 大气观测和成核实验中被多次观测到。而硫酸和甲磺酸作为非常重要的气溶胶前体物, 也受到广泛的关注。基于 DF-MP2-F12/VDZ-F12 结合 M06-2X/6-311++G(3df,3pd) 理论方法对 2-甲基甘油酸-硫酸/甲磺酸团簇进行了计算模拟, 分析了其在大气中的物理化学性质。结果表明 2-甲基甘油酸-硫酸团簇和 2-甲基甘油酸-甲磺酸团簇的吉布斯自由能 具有相同的温度依赖性。 2-甲基甘油酸-硫酸/甲磺酸团簇会优先蒸发 2-甲基甘油酸分子而不是硫酸/甲磺酸分子, 且随 着尺寸增加, 2-甲基甘油酸分子的蒸发速率迅速增加。此外, 还计算了 2-甲基甘油酸-硫酸/甲磺酸团簇的瑞利散射强 度和极化率, 有助于理解此类团簇对大气光辐射的影响。

Atmospheric physicochemical properties of 2-methylglyceric acid-sulfuric acid/methanesulfonic acid clusters

Atmospheric aerosols can affect the climate system of the earth by scattering or absorbing long-wave and short-wave radiation. As one of the aerosol tracers, 2-Methylglyceric acid has been observed frequently in atmospheric observations and nucleation experiments. Sulfuric acid and methanesulfonic acid, as very important aerosol precursors, have also received extensive attention and been widely studied. Therefore, 2-methylglyceric acid-sulfuric acid/methanesulfonic acid clusters were simulated based on the theory level of DF-MP2-F12/VDZ-F12 combined with M06-2X/6-311G(3df,3pd), and their physicochemical properties in the atmosphere were analyzed. The results show that 2-methylglyceric acid-sulfuric acid cluster and 2-methylglyceric acid-methanesulfonic acid cluster have the same Gibbs free energy temperature dependence. 2-Methylglyceric acid-sulfuric acid/methanesulfonic acid clusters will preferentially evaporate 2-methylglyceric acid molecules rather than sulfuric acid/methanesulfonic acid molecules, and the evaporation rate of 2-methylglyceric acid molecules increases rapidly with the increase of the cluster size. In addition, the Rayleigh scattering intensity and polarizability of 2-methylglyceric acid-sulfuric acid/methanesulfonic acid clusters are calculated, which is helpful to understand the influence of the clusters on atmospheric radiation.