Unimolecular Dissociation Kinetics of Benzene Cluster Ions

Kazuhiko Ohashi, Kei Adachi, Nobuyuki Nishi

Research output: Contribution to journalArticle

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Abstract

The "unimolecular" dissociation processes of benzene cluster ions prepared by resonant 2-photon ionization (R2PI) of neutral clusters were investigated by using a time-of-flight mass spectrometer equipped with a reflection. The dissociation rates were determined for fast-decay processes (kfast) in the acceleration region and slow dissociations (kslow) in the drift region of the spectrometer. The ejection of one neutral molecule was a dominant dissociation channel of small (C6H6)n+ in the drift region; in addition, the ejection of two molecules was observed for n - 2≥14. These size-specific dissociation channels and the size dependence of the kslow values imply a closing of the first shell of (C6H6)n+ at n = 14. The magnitude of both kfast and kslow was found to be independent of the excess energy upon R2PI, suggesting rapid cooling of the nascent hot ions by prompt dissociation within the laser focus. For slow dissociation within a well-defined time window, the measured values of kslow were compared with those calculated according to a statistical theory of unimolecular reaction. The comparison deduced the average internal energies of (C6H6)n+ at ca. 1 μs after preparation.

Original languageEnglish
Pages (from-to)915-924
Number of pages10
JournalBulletin of the Chemical Society of Japan
Volume69
Issue number4
DOIs
Publication statusPublished - Jan 1 1996

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Benzene
Ions
Kinetics
Ionization
Photons
Molecules
Mass spectrometers
Spectrometers
Cooling
Lasers

All Science Journal Classification (ASJC) codes

  • Chemistry(all)

Cite this

Unimolecular Dissociation Kinetics of Benzene Cluster Ions. / Ohashi, Kazuhiko; Adachi, Kei; Nishi, Nobuyuki.

In: Bulletin of the Chemical Society of Japan, Vol. 69, No. 4, 01.01.1996, p. 915-924.

Research output: Contribution to journalArticle

Ohashi, Kazuhiko ; Adachi, Kei ; Nishi, Nobuyuki. / Unimolecular Dissociation Kinetics of Benzene Cluster Ions. In: Bulletin of the Chemical Society of Japan. 1996 ; Vol. 69, No. 4. pp. 915-924.
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