Electron ionization and gas-phase ion molecule reactions of methylcyclohexane

▶ Electron ionization of C7H14 generates the main product ions C7H14+, C6H11+ and C4H7+. ▶ Total ionization cross section of C7H14 reaches a soft maximum of 18 × 10−16 cm2 at ∼65 eV. ▶ Ab initio calculations agree well with a predicted maximum of 21 × 10−16 cm2 at 70 eV. ▶ Subsequent ion-molecule reactions between C7H14 and fragment ions are also studied.