Kinetic Energy Release Distribution in the Dissociation of Toluene Molecular Ion. The Tropylium vs Benzylium Story Continues

Production of C 7 H 7 + from toluene molecular ion (TOL •+ ) was studied using mass-analyzed ion kinetic energy spectrometry. The kinetic energy release distribution (KERD) was determined, which showed that both benzylium (Bz + ) and tropylium (Tr + ) ions were produced from TOL •+ . The interconversion between the molecular ions of toluene and cycloheptatriene prior to the dissociations was confirmed. Ab initio calculations at the HF/6-31G** and G2(MP2,SVP) levels were carried out for some important chemical species. The KERD in the Bz + channel was calculated using the statistical phase space theory, while classical trajectory calculations were done to obtain the theoretical KERD in the Tr + channel. The Tr + /Bz + branching ratio determined by analyzing the experimental KERD was much larger than reported previously.