## Abstract

Photodissociation of (C_{6}H_{6})_{2} ^{+} is studied with photon energies between 1.29 and 2.81 eV. Massselected ion beam of (C_{6}H_{6})_{2} ^{+} is photodissociated by a pulsed laser beam in the field-free region of a reflectron-type time-of-flight mass spectrometer. The average relative translational energy, 〈ε_{t}〉, and the angular distributions of the photofragments (C_{6}H_{6} ^{+} and C_{6}H _{6}) are measured as a function of photon energy. With a photon energy of 2.81 eV, the (C_{6}H_{6})_{2} ^{+} ions are promoted to a bound upper state correlated to C_{6}H_{6} ^{+}(ππ) + C_{6}H_{6}(X). Only a small fraction (≈3%) of the available energy is partitioned into the translational energy of the fragments and the product angular distribution is isotropic. Absorption of a photon in the range of 1.29-2.14 eV induces a charge resonance transition to a repulsive upper state which correlates to C_{6}H_{6} ^{+}(X) + C_{6}H_{6}(X). The observed values for 〈ε_{t}〉 are at most 10% of the available energy, although the statistical phase space calculation shows that the complete randomization of the available energy is not achieved. As the photoexcited (C _{6}H_{6})_{2} ^{+} moves apart on the dissociative potential surface, ≈90% of the available energy flows into the intramolecular modes of the fragments. The energy partitioning becomes almost statistical regardless of the photoexcitation to a dissociative state.

Original language | English |
---|---|

Pages (from-to) | 390-398 |

Number of pages | 9 |

Journal | The Journal of Chemical Physics |

Volume | 98 |

Issue number | 1 |

DOIs | |

Publication status | Published - 1993 |

## All Science Journal Classification (ASJC) codes

- Physics and Astronomy(all)
- Physical and Theoretical Chemistry