- Laser photodissociation of C7H7+ created through multiphoton ionization of para-chlorotoluene
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The nature of the C7H7+ ion created through resonant dissociative multiphotoionization of para-chlorotoluene by an ultraviolet (UV) laser was investigated thanks to its interaction with a second laser beam.The dissociation pattern corresponding to one or several photon absorption could be observed.Cross section for the one-photon absorption in the 265/530 nm range revealed the presence of the tropylium and benzyl isomers and suggested they possessed substantial internal energy.This was confirmed by the study of the C7H7+ + hν C5H5+ + C2H2 reaction, and more precisely of its rate and of the kinetic energy released.A ladder switch mechanism for the three-photon dissociative ionization of para-chlorotoluene leading to C7H7+ is shown to agree with our results.
- Lablanquie, Pascal,Ohashi, Kazuhiko,Nishi, Nobuyuki
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p. 399 - 408
(2007/10/02)
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- Ion-Molecule Reaction of CO2+ with Butane and Isobutane at Thermal Energy
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Rate constants and product ion distributions have been determined for thermal energy reactions of CO+2 with n-C4H10 and i-C4H10 by using an ion-beam apparatus.The total rate constants are (9.8+/-2.0)*10-10 and (1.0+/-0.2)*10-9 cm3 s-1 for n-C4H10 and i-C4H10, respectively.These values amount to about 75percent of the collision rate constants estimated from the Langevin theory.C4H+9, C3H+n (n=5-7), and C2H+n (n=3-5) are produced from n-C4H10 with branching ratios of 6, 56, and 38percent, while C4H+9 and C3H+n (n=5-7) are formed from i-C4H10 with branching ratios of 7 and 93percent, respectively.The lack of C2H+n fragments from i-C4H10 is attributed to a low probability of significant rearrangement of chemical bonds for the formation of the C2H+n fragments.The product ion distribution in the CO+2/n-C4H10 reaction is in good agreement with that predicted from the fragmentation pattern of n-C4H+10 at 13.78 eV, indicating that the CO+2/n-C4H10 reaction proceeds through a near-resonant charge transfer without momentum transfer.
- Tsuji, Masaharu,Matsumura, Ken-ichi,Funatsu, Tsuyoshi,Nishimura, Yukio,Obase, Hiroshi,et al.
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p. 2864 - 2870
(2007/10/02)
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