Analysis of mixed nitric oxide - Water clusters by complementary ionization methods

0476041 - ÚFCH JH 2018 RIV NL eng J - Journal Article
Šmídová, Daniela - Lengyel, Jozef - Kočišek, Jaroslav - Pysanenko, Andriy - Fárník, Michal
Analysis of mixed nitric oxide - Water clusters by complementary ionization methods.
International Journal of Mass Spectrometry. Roč. 421, OCT 2017 (2017), s. 144-149. ISSN 1387-3806. E-ISSN 1873-2798
R&D Projects: GA ČR(CZ) GA17-04068S
Institutional support: RVO:61388955
Keywords : Cluster mass spectrometry * Atmospheric aerosols * Electron attachment
OECD category: Physical chemistry
Impact factor: 1.826, year: 2017

Mixed clusters of nitric oxide and water are investigated by mass spectrometry using different ionization methods, namely (1) the electron ionization at 70 eV (El), (2) the doping with sodium atoms and subsequent photoionization (NaPI), and (3) the low energy electron attachment (EA). All these methods applied to the same molecular beam generated by mixed NO-water expansion yield distinctly different mass spectra. The El spectra are dominated by the protonated water (H2O)(n)H+ ions, nevertheless, they show some evidence for the mixed NO-water clusters. The NaPI spectra exhibit only (H2O)(n).Na+ ions which originate from the pure water clusters (H2O)(N). The abundance of the pure water clusters generated in the mixed expansions is small compared to the abundance of the mixed species. The negative EA spectra clearly demonstrate the dominance of the mixed clusters, namely (H2O)(n).NO2- and (H2O)(n)center dot(NO)(m)(-), m =2, 3. None of the above mentioned methods alone can reveal the neutral cluster composition and size, however, based on their unique combination in our experiment, we can discuss the neutral clusters and ionization processes. In addition, we have investigated the negative ion intracluster chemistry by the theoretical calculations. Energetically favorable pathways from the (NO)(3)(-) ionic core to the NO2- in the presence of water are identified, justifying the generation of the (H2O)(n) center dot NO2- series. Further series in the negative ion spectra are discussed. (C) 2017 Elsevier B.V. All rights reserved.
Permanent Link: http://hdl.handle.net/11104/0272608