Premium
Electron‐Driven Self‐Assembly of Salt Nanocrystals in Liquid Helium
Author(s) -
Daxner Matthias,
Denifl Stephan,
Scheier Paul,
Ellis Andrew M.
Publication year - 2014
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201409465
Subject(s) - metastability , chemistry , ion , excited state , mass spectrum , nanocrystal , liquid helium , cationic polymerization , molecule , electron transfer , helium , spectral line , salt (chemistry) , crystallography , photochemistry , atomic physics , materials science , nanotechnology , organic chemistry , physics , astronomy
Abstract The self‐assembly of salt nanocrystals from chemical reactions inside liquid helium is reported for the first time. Reaction is initiated by an electron impacting a helium nanodroplet containing sodium atoms and SF 6 molecules, leading to preferential production of energetically favorable structures based on the unit cell of crystalline NaF. These favorable structures are observed as magic number ions (anomalously intense peaks) in mass spectra and are seen in both cationic and anionic channels in mass spectra, for example, (NaF) n Na + and (NaF) n F − . In the case of anions the self‐assembly is not directly initiated by electrons: the dominant process involves resonant electron‐induced production of metastable electronically excited He − anions, which then initiate anionic chemistry by electron transfer.