Abstract

Multiphoton ionization spectroscopy provides the sensitivity needed to approach single molecule detection. Extremely high detection selectivity is required to utilize this sensitivity in practical applications. We are investigating the fundamental aspects of multiphoton ionization and fragmentation processes that influence selective detection of aromatic hydrocarbons. The objective is to be able to combine the ionization spectrum of the neutral molecule with fragmentation spectra of parent and daughter ions to improve selective detection. We have observed parent ion fragmentation spectra for aromatic molecules in room temperature environments and in cooled supersonic beams. Although the parent ion fragmentation spectra reveal strong transitions in red spectral regions, isolated from the neutral molecule UV transitions, the ion transitions are spectrally congested when observed in room temperature ionization cells. We report on our most recent observations of parent ion fragmentation spectra measured in a cooled supersonic beam environment.

© 1985 Optical Society of America