Diffusion and chemical interaction of hydroxyl generated from photodissociation of water vapor in the temperature range in 294 K–891 K in helium flow

Abstract

This paper summarizes the direct observation of tagged hydroxyl within 200 µs after its formation in the temperature range of 294 K–891 K. We estimate the time and temperature frame of the coexistence of chemical reactions and diffusion based on analysis of the behavior of the tagging fluorescence spot of photodissociation hydroxyl. The reasons for the existence of chemical reactions and interactions between chemical reactions and diffusion are then analyzed. Theoretical and experimental identification of this frame can be explored for non-contact spectral measurements based on hydroxyl in a general flow field.