Electron impact dissociation of cyanobenzene radical cations by ion cyclotron resonance spectroscopy

Trapped ion cyclotron resonance spectroscopy has been used for the first time to study the electron impact dissociation of ions. Fragmentation of C₆H₅CH⁺ to produce C₆H⁺₄ and HCN is observed to occur at low electron energies (3–9 eV). The extent of dissociation is observed to be linear in emission current, rising from a threshold at 3.0 ± 0.5 eV to a maximum cross section estimated to be 6A² at 7.5 ± 0.5 eV. The implications of these results are discussed.