Photoinduced evaporation of benzene cluster ions

Photofragmentation of benzene cluster ions, (C6H6)n+ with n = 5–8, is studied in a wide photon energy range of 0.5-3.0 eV. Apparent evaporation energies for n = 5–8 are determined to be 0.55-0.52 eV. These are approximately 0.2 eV larger than the binding energies for one neutral monomer to the cluster ions. The average translational energies of 50–75 meV for ejected neutral monomers are obtained in the photon energy range of 1.1–2.0 eV. The remainders of nearly 0.2 eV cannot be explained only in terms of the translational energies of the photofragments. This result indicates that a part of the imparted energy is partitioned into photofragments as internal energies.