Photochemical Synthesis and Spectroscopy of Covalent PAH Dimers.

Laser photochemistry of pressed-pellet samples of polycyclic aromatic hydrocarbons (PAHs) produces covalently bonded dimers and some higher polymers. This chemistry was discovered initially via laser desorption time-of-flight mass spectrometry experiments, which produced masses (/) of 2M-2 and 2M-4 (where M is the monomer parent mass). Dimers are believed to be formed from photochemical dehydrogenation and radical polymerization chemistry in the desorption plume.