Laser-induced fluorescence studies of polyaromatic hydrocarbons (PAH) vapors at high temperatures
A study on how temperature changes affect the fluorescence properties of PAH, such as fluorescence intensity, bandwidth, etc., was carried out using an instrumental system. Light from a nitrogen laser, 337 nm, was utilized to excite anthracene and pyrene. The fluorescence spectra at gas-phase anthracene and pyrene were measured at various temperatures using different carrying gases (argon or nitrogen). Fluorescence bandwidths of vapor pyrene and anthracene became very broad with increasing sample temperature, which was ascribed to thermal vibrational sequence congestion and other linewidth broadening effect, such as Doppler effects. The fluorescence intensity of pyrene increased with increasing sample temperature, which was attributed to the increase of pyrene absorption cross-section at 337 nm. The results of fluorescence measurements of gas-phase PAH for the first time are important to many applications of fluorescence studies of PAH in combustion diagnostics and environmental monitoring. Original is an abstract.