Dissociative Electron Attachment during the Laser Desorption of Anthracene Picrate

Steven M. Hankin, Phillip John

Research output: Contribution to journalArticlepeer-review


The laser desorption of the charge-transfer complex anthracene-picrate has been studied by post-ionization time-of-flight (L2ToF) mass spectrometry. Mass spectra recorded after post-ionization of the desorbed plume exhibited negative-ion signals exclusively associated with picric acid. Furthermore, these negative ions were observed only as the focus of the ionization laser beam was moved to within 150 µm of the point of desorption. Negative ions were not present in the L2ToF mass spectra of picric acid alone but were observed only in the presence of anthracene. While the charge-transfer complex is not expected to remain intact following laser desorption into the gas phase, the generation of negative ions upon laser irradiation of the desorbed plume occurs through interaction of the neutral picric acid molecules with electrons produced by in-situ photoionization of the anthracene component. Acceleration of the primary electrons through the high-density plume induces electron attachment and subsequent fragmentation of picric acid. The spatial profile of the ions created in the plume arising from the laser desorption of anthracene picrate supports a PAH-mediated electron attachment phenomenon leading to the formation of negatively charged ions.

Original languageEnglish
Pages (from-to)6887–6890
Number of pages4
JournalJournal of Physical Chemistry A
Issue number35
Publication statusPublished - 1 Sept 1999


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