A scaling formalism for the representation of rotational energy transfer in OH (A 2Σ+) in combustion experiments

Abstract

In order to predict spectra and temporal decays of the OH radical measured by Laser-Induced Fluorescence (LIF), the collisional energy transfer between different quantum states must be taken into account. At the elevated temperatures relevant for combustion studies, the large number of interacting quantum states and corresponding state-to-state energy transfer coefficients precludes the experimental measurement of all necessary information for the appropriate mixtures of colliders. Therefore, a scaling procedure has been devised which allows the representation of the matrix of Rotational Energy Transfer (RET) coefficients on the basis of measured data with four scaling coefficients. The scaling coefficients have been determined by comparison of the calculated RET rates with available measured data. The mathematical formalism for the scaling law - the ECS-EP law - is based on the Energy Corrected Sudden (ECS) law and includes an Exponential Power law (EP) for the representation of the basis coefficients.