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Title: Ions colliding with clusters of fullerenes-Decay pathways and covalent bond formations

We report experimental results for the ionization and fragmentation of weakly bound van der Waals clusters of n C{sub 60} molecules following collisions with Ar{sup 2+}, He{sup 2+}, and Xe{sup 20+} at laboratory kinetic energies of 13 keV, 22.5 keV, and 300 keV, respectively. Intact singly charged C{sub 60} monomers are the dominant reaction products in all three cases and this is accounted for by means of Monte Carlo calculations of energy transfer processes and a simple Arrhenius-type [C{sub 60}]{sub n}{sup +}{yields}C{sub 60}{sup +}+(n-1)C{sub 60} evaporation model. Excitation energies in the range of only {approx}0.7 eV per C{sub 60} molecule in a [C{sub 60}]{sub 13}{sup +} cluster are sufficient for complete evaporation and such low energies correspond to ion trajectories far outside the clusters. Still we observe singly and even doubly charged intact cluster ions which stem from even more distant collisions. For penetrating collisions the clusters become multiply charged and some of the individual molecules may be promptly fragmented in direct knock-out processes leading to efficient formations of new covalent systems. For Ar{sup 2+} and He{sup 2+} collisions, we observe very efficient C{sub 119}{sup +} and C{sub 118}{sup +} formation and molecular dynamics simulations suggest that they are covalentmore » dumb-bell systems due to bonding between C{sub 59}{sup +} or C{sub 58}{sup +} and C{sub 60} during cluster fragmentation. In the Ar{sup 2+} case, it is possible to form even smaller C{sub 120-2m}{sup +} molecules (m= 2-7), while no molecular fusion reactions are observed for the present Xe{sup 20+} collisions.« less
Authors:
; ; ; ; ; ; ;  [1] ; ; ; ; ; ; ;  [2] ;  [3] ; ;  [4] ;  [5] ; more »; ;  [2] ; « less
  1. Department of Physics, Stockholm University, S-106 91 Stockholm (Sweden)
  2. CIMAP, UMR 6252, CEA/CNRS/ENSICAEN/Universite de Caen Basse-Normandie, bd Henri Becquerel, BP 5133, F-14070 Caen cedex 05 (France)
  3. (France)
  4. Departamento de Quimica, Modulo 13, Universidad Autonoma de Madrid, 28049 Madrid (Spain)
  5. (IMDEA-Nano), Cantoblanco, 28049 Madrid (Spain)
Publication Date:
OSTI Identifier:
22121677
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 139; Journal Issue: 3; Other Information: (c) 2013 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
74 ATOMIC AND MOLECULAR PHYSICS; 37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; ARGON; CATIONS; CHEMICAL BONDS; ENERGY TRANSFER; EVAPORATION MODEL; EXCITATION; EXCITED STATES; FRAGMENTATION; FULLERENES; HELIUM IONS; ION-MOLECULE COLLISIONS; KEV RANGE 100-1000; KEV RANGE 10-100; KINETIC ENERGY; MOLECULAR DYNAMICS METHOD; MONTE CARLO METHOD; NITROGEN IONS; THERMONUCLEAR REACTIONS; VAN DER WAALS FORCES; XENON