Metastable Transitions Observed in a Time-of-Flight Mass Spectrometer

A time-of-flight mass spectrometer has been employed in the investigation of metastable transitions by using a retarding potential technique. Expressions have been developed which permit a simple, nearly quantitative determination of the masses of the daughter ions arising from these transitions. In addition equations are derived which permit the identification of charge exchange reactions, An++B→Ap++B(n—p)+. Most of the metastable transitions observed using magnetic instruments have either been determined or accounted for by this method in n-butane, ethyl acetate, trimethyl phosphate, and dimethylmethylphosphonate. In addition, this approach has the unique feature of permitting the observation of new metastable transitions not observed in magnetic instruments. The limitations of the method are recognized and discussed.