The blackbody infrared radiation induced dissociation of methyl benzoate (C8H8O_2~(+·)) radical cation was investigated by using a Fourier transfer ion cyclotron resonance mass spectrometer equipped with a resistively heated (wire temperatures of 400—1070 K) wire ion guide. We observed product ion branching ratios that are strongly dependent upon wire temperature. At low temperatures (670—890 K) the major product ion C7H_8~(+·) (m/z 92), which is formed by loss of CO2, and at higher temperatures (above 900 K), loss of methoxy radical (~·OCH3) competes with loss of CO2. The energies of the various reactant ions and transition states for product ion formation were estimated by using density functional theory molecular orbital calculations, and a proposed mechanism for the dissociation chemistry of C8H8O_2~(+·) involving a multistep rearrangement reaction is tested using the Master Equation formalism.
展开▼
