The photoluminescence excitation spectra of multicomponent media

With no restrictions on the value of optical density, we derive an equation that describes the photoluminescence excitation spectra of separate components with overlapping absorption bands in a multicomponent medium. Based on the equation obtained, we propose methods for measuring the ratios of absorption optical densities of the components and quantum yields of their luminescence. The applicability of the proposed methods is demonstrated by measuring the characteristics of coumarin and porphyrin dissolved in different proportions in ethanol. We have also measured the quantum yield and luminescence decay time of the radiationinduced color centers F 3 + in the lithium fluoride crystal and calculated probabilities of radiative and nonradiative transitions from the first excited singlet state of these centers.