Key Laboratory for Macromolecular Science of Shaanxi Province, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an 710119, China.
Key Laboratory for Macromolecular Science of Shaanxi Province, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an 710119, China.
J Environ Sci (China). 2020 Mar;89:125-135. doi: 10.1016/j.jes.2019.10.009. Epub 2019 Nov 9.
Glycine (Gly) is ubiquitous in the atmosphere and plays a vital role in new particle formation (NPF). However, the potential mechanism of its on sulfuric acid (SA) - ammonia (A) clusters formation under various atmospheric conditions is still ambiguous. Herein, a (Gly)·(SA)·(A) (z ≤ x + y ≤ 3) multicomponent system was investigated by using density functional theory (DFT) combined with Atmospheric Cluster Dynamics Code (ACDC) at different temperatures and precursor concentrations. The results show that Gly, with one carboxyl (-COOH) and one amine (-NH) group, can interact strongly with SA and A in two directions through hydrogen bonds or proton transfer. Within the relevant range of atmospheric concentrations, Gly can enhance the formation rate of SA-A-based clusters, especially at low temperature, low [SA], and median [A]. The enhancement (R) of Gly on NPF can be up to 340 at T = 218.15 K, [SA] = 10, [A] = 10, and [Gly] = 10 molecules/cm. In addition, the main growth paths of clusters show that Gly molecules participate into cluster formation in the initial stage and eventually leave the cluster by evaporation in subsequent cluster growth at low [Gly], it acts as an important "transporter" to connect the smaller and larger cluster. With the increase of [Gly], it acts as a "participator" directly participating in NPF.
甘氨酸（Gly）在大气中无处不在，在新粒子形成（NPF）中起着至关重要的作用。然而，其在各种大气条件下与硫酸（SA）-氨（A）簇形成的潜在机制仍不清楚。在此，通过使用密度泛函理论（DFT）结合大气团簇动力学代码（ACDC），在不同温度和前体浓度下，研究了（Gly）·（SA）·（A）（z≤x+y≤3）多组分体系。结果表明，甘氨酸（Gly）具有一个羧基（-COOH）和一个氨基（-NH）基团，可通过氢键或质子转移以两种方式与 SA 和 A 强烈相互作用。在相关的大气浓度范围内，甘氨酸（Gly）可以增强 SA-A 基簇的形成速率，特别是在低温、低[SA]和中值[A]下。在 T=218.15 K、[SA]=10、[A]=10 和 [Gly]=10 分子/cm 时，甘氨酸（Gly）对 NPF 的增强（R）可达 340。此外，簇的主要生长途径表明，在低[Gly]下，甘氨酸（Gly）分子在簇形成的初始阶段参与簇形成，最终通过蒸发离开簇，在随后的簇生长中，它充当重要的“转运器”，连接较小和较大的簇。随着[Gly]的增加，它作为一个直接参与 NPF 的“参与者”发挥作用。
