SPECTROSCOPY AND EXCITED-STATE DYNAMICS OF BENZENE-TRIMER ION

The photodissociation of (C6H6)3+ is studied in the range hν=0.9–3.0 eV. The electronic spectrum of (C6H6)3+ shows the main band at hν≈1.29 eV and a side band at ≈1.02 eV. The (C6H6)3+ ion retains spectroscopic features characteristic of (C6H6)2+, suggesting that the positive charge is carried by a dimer subunit in (C6H6)3+. The major fragment ion changes smoothly from (C6H6)2+ to C6H6+ with increasing photon energy from 0.9 to 1.8 eV. The product branching ratios and the kinetic energy of the C6H6+ fragment are consistent with a two-step model for the formation of C6H6+.