Consecutive Metastable Peaks in Mass Spectra

The observation of consecutive metastable peaks in mass spectra has prompted a calculation for the abundance of these species. Expressions for fractional abundance as a function of primary and secondary rates and residence times are derived for all species of normal and metastable ions. Primary and secondary rates for a toluene consecutive dissociation were calculated using the method of Vestal, Wahrhaftig, and Johnston, and the breakdown curves were determined. By assuming a constant energy-transfer function the normalized areas of the calculated curves are found to compare very favorably with the mass spectrum obtained in this laboratory with a double-focusing mass spectrometer.