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Title: Bond-rearrangement and ionization mechanisms in the photo-double-ionization of simple hydrocarbons (C2H4, C2H3F, and 1,1-C2H2F2) near and above threshold

We have investigated bond-rearrangement driven by photo-double-ionization (PDI) near and above the double ionization threshold in a sequence of carbon-carbon double bonded hydrocarbon molecules: ethylene, fluoroethylene, and 1,1-difluoroethylene. We employ the kinematically complete cold target recoil ion momentum spectroscopy (COLTRIMS) method to resolve all photo-double-ionization events leading to two-ionic fragments. We observe changes in the branching ratios of different dissociative ionization channels depending on the presence of none, one, or two fluorine atoms. The role of the fluorine atom in the bond-rearrangement channels is intriguing as evident by the re-ordering of the threshold energies of the PDI in the fluorinated molecules. These effects offer a compelling argument that the electronegativity of the fluorine (or the polarity of the molecule) strongly influences the potential energy surfaces of the molcules and drives bond-rearrangement during the dissociation process. The energy sharing and the relative angle between the 3D-momentum vectors of the two electrons provide clear evidence of direct and indirect PDI processes.
Authors:
 [1] ;  [1] ;  [2] ;  [2] ;  [3] ;  [3] ;  [4] ;  [5] ;  [5] ;  [4] ;  [1] ;  [1]
  1. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
  2. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Goethe Univ., Frankfurt (Germany)
  3. Goethe Univ., Frankfurt (Germany)
  4. Auburn Univ., AL (United States)
  5. Kansas State Univ., Manhattan, KS (United States)
Publication Date:
OSTI Identifier:
1339563
Report Number(s):
LBNL-1005182
Journal ID: ISSN 2469-9926; ir:1005182
Grant/Contract Number:
AC02-05CH11231
Type:
Accepted Manuscript
Journal Name:
Physical Review A
Additional Journal Information:
Journal Volume: 94; Journal ID: ISSN 2469-9926
Publisher:
American Physical Society (APS)
Research Org:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
74 ATOMIC AND MOLECULAR PHYSICS