Pysanenko Andriy, Kočišek Jaroslav, Nachtigallová Dana, Poterya Viktoriya, Fárník Michal
J. Heyrovský Institute of Physical Chemistry, The Czech Academy of Sciences , Dolejškova 3, 182 23 Prague, Czech Republic.
Institute of Organic Chemistry and Biochemistry v.v.i., The Czech Academy of Sciences , Flemingovo nám. 2, 160610 Prague 6, Czech Republic.
J Phys Chem A. 2017 Feb 9;121(5):1069-1077. doi: 10.1021/acs.jpca.6b12594. Epub 2017 Jan 26.
We generate a molecular beam of ice nanoparticles (HO), N̅ ≈ 130-220, which picks up several individual gas phase uracil (U) or 5-bromouracil (BrU) molecules. The mass spectra of the doped nanoparticles prove that the uracil and bromouracil molecules coagulate to clusters on the ice nanoparticles. Calculations of U and BrU monomers and dimers on the ice nanoparticles provide theoretical support for the cluster formation. The (U)H and (BrU)H intensity dependencies on m extracted from the mass spectra suggest a smaller tendency of BrU to coagulate compared to U, which is substantiated by a lower mobility of bromouracil on the ice surface. The hydrated U·(HO)H series are also reported and discussed. On the basis of comparison with the previous experiments, we suggest that the observed propensity for aggregation on ice nanoparticles is a more general trend for biomolecules forming strong hydrogen bonds. This, together with their mobility, leads to their coagulation on ice nanoparticles which is an important aspect for astrochemistry.
我们生成了冰纳米颗粒（HO）的分子束，N̅ ≈ 130 - 220，它会捕获几个单独的气相尿嘧啶（U）或5-溴尿嘧啶（BrU）分子。掺杂纳米颗粒的质谱证明尿嘧啶和溴尿嘧啶分子在冰纳米颗粒上凝聚成簇。对冰纳米颗粒上U和BrU单体及二聚体的计算为簇的形成提供了理论支持。从质谱中提取的（U）H和（BrU）H强度对m的依赖性表明，与U相比，BrU凝聚的趋势较小，这一点可由溴尿嘧啶在冰表面较低的迁移率得到证实。还报道并讨论了水合U·(HO)H系列。在与先前实验比较的基础上，我们认为观察到的在冰纳米颗粒上聚集的倾向是形成强氢键的生物分子更普遍的趋势。这一点，连同它们的迁移率，导致它们在冰纳米颗粒上凝聚，这对天体化学来说是一个重要方面。
