StaR-LIF: State-resolved laser-induced fluorescence modeling for diatomic molecules

Abstract

This study introduced a new model for quantitative analysis of the state-resolved laser-induced fluorescence signal of diatomic molecules, namely StaR-LIF. This model is built upon a master equation of the collisional-radiative transfer processes, which incorporated the latest data on the collisional energy transfer rates between individual spin- and parity-resolved rovibronic quantum levels, together with the most recent updates on the energy levels, line strengths and broadening/shift parameters of the relevant absorption and fluorescence transitions. To facilitate the use of this model, a web-based graphic user interface has been developed and made available at https://starlif.pku.edu.cn. Example applications of the current model have been demonstrated for NO, OH and CH, including parametric studies on the effects of variable pulse width and saturating excitation, as well as the temporal evolution of fluorescence spectrum during collisional transfer. The StaR-LIF model can provide quantitative modeling and analysis capabilities over a wide range of gasdynamic and excitation conditions, and promises to be useful in future LIF studies of complex reacting flows.