title: Nucleation of Mixed Nitric Acid-Water Ice Nanoparticles in Molecular Beams that Starts with a HNO3 Molecule.
abstract: Mixed (HNO3)m(H2O)n clusters generated in supersonic expansion of nitric acid vapor are investigated in two different experiments, (1) time-of-flight mass spectrometry after electron ionization and (2) Na doping and photoionization. This combination of complementary methods reveals that only clusters containing at least one acid molecule are generated, that is, the acid molecule serves as the nucleation center in the expansion. The experiments also suggest that at least four water molecules are needed for HNO3 acidic dissociation. The clusters are undoubtedly generated, as proved by electron ionization; however, they are not detected by the Na doping due to a fast charge-transfer reaction between the Na atom and HNO3. This points to limitations of the Na doping recently advocated as a general method for atmospheric aerosol detection. On the other hand, the combination of the two methods introduces a tool for detecting molecules with sizable electron affinity in clusters.
authors: †J. Heyrovský Institute of Physical Chemistry, v.v.i., Academy of Sciences of the Czech Republic, Dolejškova 3, 182 23 Prague 8, Czech Republic.
authors: Jozef
authors: J
authors: Lengyel
authors: †J. Heyrovský Institute of Physical Chemistry, v.v.i., Academy of Sciences of the Czech Republic, Dolejškova 3, 182 23 Prague 8, Czech Republic.
authors: Andriy
authors: A
authors: Pysanenko
authors: †J. Heyrovský Institute of Physical Chemistry, v.v.i., Academy of Sciences of the Czech Republic, Dolejškova 3, 182 23 Prague 8, Czech Republic.
authors: Jaroslav
authors: J
authors: Kočišek
authors: †J. Heyrovský Institute of Physical Chemistry, v.v.i., Academy of Sciences of the Czech Republic, Dolejškova 3, 182 23 Prague 8, Czech Republic.
authors: Viktoriya
authors: V
authors: Poterya
authors: ‡Institut für Physikalische Chemie, Universität Göttingen, Tammannstrasse 6, D-37077 Göttingen, Germany.
authors: Christoph C
authors: CC
authors: Pradzynski
authors: ‡Institut für Physikalische Chemie, Universität Göttingen, Tammannstrasse 6, D-37077 Göttingen, Germany.
authors: Thomas
authors: T
authors: Zeuch
authors: †J. Heyrovský Institute of Physical Chemistry, v.v.i., Academy of Sciences of the Czech Republic, Dolejškova 3, 182 23 Prague 8, Czech Republic.
authors: Petr
authors: P
authors: Slavíček
authors: †J. Heyrovský Institute of Physical Chemistry, v.v.i., Academy of Sciences of the Czech Republic, Dolejškova 3, 182 23 Prague 8, Czech Republic.
authors: Michal
authors: M
authors: Fárník
keywords: acidic dissociation; aerosol; charge transfer; polar stratospheric clouds; sodium doping; solvated electron