Local volumetric rate of photon absorption

LVRPA local volumetric rate of photon absorption... 

It is rather atypical that a photochemical reaction will proceed in a single molecular pathway. Thus, several elementary steps are involved. Normally, the majority of them are dark (thermal) reactions while, ordinarily, one activation step is produced by radiation absorption by a reactant molecule or a catalyst. From the kinetics point of view, dark reactions do not require a different methodological approach than conventional thermal or thermal-catalytic reactions. Conversely, the activation step constitutes the main distinctive aspect between thermal and radiation activated reactions. The rate of the radiation activated step is proportional to the absorbed, useful energy through a property that has been defined as the local volumetric rate of photon absorption, LVRPA (Cassano et ak, 1995 Irazoqui et al., 1976) or the local superficial rate of photon absorption, LSRPA (Imoberdorf et al., 2005). The LVRPA represents the amount of photons that are absorbed per unit time and unit reaction volume and the LSRPA the amount of photons that are absorbed per unit time and unit reaction surface. The LVRPA is a property that must be used when radiation absorption strictly occurs in a well-defined three-dimensional (volumetrical) space. On the other hand, to... 

Three different but connected problems must be studied (i) the reaction kinetics model (ii) the development of the rate of electron-hole generation in a material particle of the solid suspension and (iii) the model for characterizing the radiation field to evaluate the local volumetric rate of photon absorption (LVRPA). Point (iii) has been already described in section 6.6.1 for quantum yield determinations. In the first part of this section, we will concentrate on problems (i) and (ii). 

Local volumetric rate of energy absorption (LVREA) is defined as the rate of the radiation-activated step in the photochemical reaction and depended on the photon distribution in the reaction space. 

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