The formation of superexcited organic species in field ionization sources

Abstract

Collisionally produced superexcited states of organic molecules have been observed in a quadrupole mass spectrometer employing a field ionization source. The production and detection of these superexcited molecules is unique to the experimental arrangement and, therefore, escaped earlier observation in other spectrometers. The mechanism of formation of the superexcited molecules involves the collision of highly energetic ions with a solid surface. These species are ionizable in a time-dependent field. A lower limit on the lifetime of the excited isolated molecules is found to be ≈ 10 −6 s.