title: Clustering of Uracil Molecules on Ice Nanoparticles.
abstract: We generate a molecular beam of ice nanoparticles (H2O)N, 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)mH+and (BrU)mH+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 Um·(H2O)nH+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.
authors.affiliation: J. Heyrovský Institute of Physical Chemistry, The Czech Academy of Sciences , Dolejškova 3, 182 23 Prague, Czech Republic.
authors.forename: Andriy
authors.initials: A
authors.lastname: Pysanenko
authors.affiliation: J. Heyrovský Institute of Physical Chemistry, The Czech Academy of Sciences , Dolejškova 3, 182 23 Prague, Czech Republic.
authors.forename: Jaroslav
authors.initials: J
authors.lastname: Kočišek
authors.affiliation: Institute of Organic Chemistry and Biochemistry v.v.i., The Czech Academy of Sciences , Flemingovo nám. 2, 160610 Prague 6, Czech Republic.
authors.forename: Dana
authors.initials: D
authors.lastname: Nachtigallová
authors.affiliation: J. Heyrovský Institute of Physical Chemistry, The Czech Academy of Sciences , Dolejškova 3, 182 23 Prague, Czech Republic.
authors.forename: Viktoriya
authors.initials: V
authors.lastname: Poterya
authors.affiliation: J. Heyrovský Institute of Physical Chemistry, The Czech Academy of Sciences , Dolejškova 3, 182 23 Prague, Czech Republic.
authors.forename: Michal
authors.identifier: http://orcid.org/0000-0002-7106-0719
authors.initials: M
authors.lastname: Fárník