Luminescence of Aromatic Compounds During Ultrasonic Treatment of Tb2(SO4)3 Suspension in Commercial Gasoline

Abstract

The spectral-luminescent properties of a suspension of terbium sulfate in commercial gasoline under sonication are studied. The following emitters are identified from the luminescence spectrum: *Tb3+ ions in crystals, electronically excited molecules of arenes (benzene, toluene, and xylenes), and polycyclic aromatic hydrocarbons (PAHs) in the liquid phase of the suspension. The study of sonotriboluminescence in gasoline–heptane and heptane–xylene–PAH synthetic mixtures shows for the first time that there is an effective luminescence activator in gasoline, that is, terphenyl molecules. It has been established that these molecules have the highest luminescence yield among all sonotriboluminescence emitters found. This is provided by the transfer of the excitation energy from monocyclic arene molecules primarily excited during the sonication. In this case, the primary excitation of aromatic hydrocarbon molecules in commercial gasoline during the ultrasonic treatment of suspensions occurs under the impact of charged particles/electrons generated during electrical discharges initiated by collision and destruction of microcrystals. This process is similar to radioluminescence excitation in liquid scintillators which can be considered commercial gasoline. The formation of *Tb3+ is due to separation and recombination processes of charges that populate the excited states of luminescence centers in microcrystals electrified during tribodestruction under sonication of the suspension.