Mechanism of wedge effect in splitting of chemical bond by impact of X2-(C02)n onto silicon surface (X=Br, I)

Uwe Kalmbach, Hisato Yasumatsu, Shin'ichi Koizumi, Akira Terasaki, Tamotsu Kondow

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12 Citations (Scopus)


Dissociation of Br2- (into Br and Br-) in a cluster anion, Br2-(CO2)n, by impact of Br2- (CO2)n on a silicon surface was investigated as a function of the number of CO2 molecules, n, at a collision energy per Br2- of 30-50 eV. The branching fraction of the Br2- dissociation used as a propensity of the Br2- dissociation rate showed a marked n-dependence similar to that observed in the collisional dissociation of 12-(CO2)n, on a silicon surface. The result is explained in terms of wedge effect in which a CO2 molecule at a midpoint of Br2- splits the Br2- bond as a wedge vs. cage effect in which the bond splitting of Br2- in the CO2 solvent cage is suppressed. The agreement of the n-dependence between the Br2-(CO2)n and I2-(CO2)n collisions lends a further support for the validity of the bond splitting by the wedge action. A molecular dynamics simulation reproduces the wedge effect in the Br2-(CO2)n collision, as well. The cage effect appearing in the vicinity of n=12 corresponds to the complettion of the first CO2 solvent shell as is the case of the I2-(CO2)n collision.

Original languageEnglish
Pages (from-to)7443-7448
Number of pages6
JournalJournal of Chemical Physics
Issue number15
Publication statusPublished - Apr 15 1999
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • General Physics and Astronomy
  • Physical and Theoretical Chemistry


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