Photoinduced processes of solid aromatic compounds by mid-IR free electron laser

Effects of the irradiation of a mid-infrared (MIR) free electron laser on solid-state aromatic compounds were investigated for anthracene, tetracene, and perylene by time-of-flight mass spectroscopy, time-resolved optical emission spectroscopy, and X-ray absorption spectroscopy. The irradiation induced vaporization and chemical reactions on the sample surfaces, resulting in the formation of graphite-like species, which absorbed IR photons more efficiently than the intact molecules. Successive irradiation on the reformed surfaces induced plasma, which caused the molecular decomposition and ionization.