Pysanenko Andriy, Habartová Alena, Svrčková Pavla, Lengyel Jozef, Poterya Viktoriya, Roeselová Martina, Fedor Juraj, Fárník Michal
J Phys Chem A. 2015 Aug 27;119(34):8991-9. doi: 10.1021/acs.jpca.5b05368.
Multiple molecules adsorbed on the surface of nanosized ice particles can either remain isolated or form aggregates, depending on their mobility. Such (non)aggregation may subsequently drive the outcome of chemical reactions that play an important role in atmospheric chemistry or astrochemistry. We present a molecular beam experiment in which the controlled number of guest molecules is deposited on the water and argon nanoparticles in a pickup chamber and their aggregation is studied mass spectrometrically. The studied molecules (HCl, CH3Cl, CH3CH2CH2Cl, C6H5Cl, CH4, and C6H6) form large aggregates on argon nanoparticles. On the other hand, no aggregation is observed on ice nanoparticles. Molecular simulations confirm the experimental results; they reveal a high degree of aggregation on the argon nanoparticles and show that the molecules remain mostly isolated on the water ice surface. This finding will influence the efficiency of ice grain-mediated synthesis (e.g., in outer space) and is also important for the cluster science community because it shows some limitations of pickup experiments on water clusters.
吸附在纳米尺寸冰颗粒表面的多个分子，根据其迁移率，可能保持孤立状态，也可能形成聚集体。这种（非）聚集随后可能推动在大气化学或天体化学中起重要作用的化学反应的结果。我们展示了一个分子束实验，其中在收集室中，将可控数量的客体分子沉积在水和氩纳米颗粒上，并通过质谱法研究它们的聚集情况。所研究的分子（HCl、CH3Cl、CH3CH2CH2Cl、C6H5Cl、CH4和C6H6）在氩纳米颗粒上形成大的聚集体。另一方面，在冰纳米颗粒上未观察到聚集现象。分子模拟证实了实验结果；它们揭示了氩纳米颗粒上的高度聚集，并表明分子在水冰表面大多保持孤立状态。这一发现将影响冰粒介导的合成效率（例如在外层空间），并且对团簇科学界也很重要，因为它显示了水团簇拾取实验的一些局限性。
