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The significance of field ionisation kinetics to ion structure: Isomerisation and decompostition of [C 4 H 8 ] + · radical ions
Author(s) -
Morgan Roger P.,
Derrick Peter J.
Publication year - 1975
Publication title -
organic mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.475
H-Index - 121
eISSN - 1096-9888
pISSN - 0030-493X
DOI - 10.1002/oms.1210100802
Subject(s) - microsecond , picosecond , nanosecond , ion , chemistry , isomerization , kinetics , cyclobutane , ionization , decomposition , laser , physics , catalysis , optics , organic chemistry , ring (chemistry) , quantum mechanics
Abstract The kinetics of formation of [C 3 H 5 ] + [M CH 3 ] + , [C 3 H 4 ] + ·[M CH 4 ] + · and [C 2 H 4 ] + ·[M C 2 H 4 ] + · from but‐1‐ene, cis‐ and trans‐but‐2‐ene, 2‐methylpropene, cyclobutane and methylcyclopropance following field ionisation have been determined as a function of time 20 (or 30) picoseconds to 1 nanosecond and at two points in the microsecond time‐frame. The results are consistent with the supposition that at the shortest accessible times (20 to 30 picoseconds) the structure of the [C 4 H 8 ] + · molecular ion qualitatively resembles that of its neutral precursor, but suggest that prior to decomposition within nanoseconds the various molecular ions (excepting cyclobutane where the processes are slower) attain a common structure or mixture of structures. Reaction pathways of the presumed known ion structures are delineated from the nature of decompostion at the shortest times.