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Formation and decay of doubly charged ions from polycyclic aromatic hydrocarbons and related compounds
Author(s) -
Hagan D. A.,
Eland J. H. D.
Publication year - 1991
Publication title -
rapid communications in mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.528
H-Index - 136
eISSN - 1097-0231
pISSN - 0951-4198
DOI - 10.1002/rcm.1290051106
Subject(s) - chemistry , photoionization , ion , double ionization , dissociation (chemistry) , perylene , ionization , benzene , ionization energy , chemical ionization , photochemistry , analytical chemistry (journal) , organic chemistry , molecule
Coincidence techniques have been used to investigate double photoionization and subsequent decay of a series of polycyclic aromatic hydrocarbons (PAHs) from benzene to perylene. At fixed photon energy (40.8eV) the total yield of double ionization relative to single photoionization for both PAHs and for aliphatic compounds increases asthe same function of the excess energy above the double ionization energy. The ratio of double to single ionization for a given compound at different photon energies varies linearly with the excess energy. The fraction of dissociative double photoionization falls with increasing size in the PAH series; the ejection of characteristic neutral species (H˙, H 2 and C 2 H 2 ) is the main dissociation pathway in the larger PAHs while charge separation is important for smaller species. Partial hydrogenation or aliphatic substitution results in decreasing stability of the doubly charged ions and increasing dissociation.