Advancement in Comprehending the Evolution of Nanooxides in Flames using Laser Irradiation

Time and wavelength-resolved laser-induced incandescence (LII) study is performed in a titania nanoparticle-generating flame under different laser fluences. Measurements of the flame light emission are performed during the laser pulse and at short delay times. The results cannot be explained within the traditional description of heat exchange mechanisms between particles and the environment. The paper suggests to distinguish electron and phonon temperatures in the nanoparticles in order to reconcile observations. The fundamental phenomenon responsible for a possibility of that temperature difference and its implication to pyrometry measurements in flames is discussed and justified in the paper.