Excitation of X-ray fluorescence of thin-film samples by bremsstrahlung: Extension and analytical possibilities of the monochromatic model

Different approaches to the description of X-ray fluorescence excitation in thin films by bremsstrahlung within the monochromatic model are systematically expounded and compared. New analytical expressions are proposed for calculation of the wavelength of a virtual monochromatic excitation source. It is shown that some of them can be successfully used in quantitative X-ray fluorescence analysis of semiinfinite samples, including matrix effects, without a priori information on an analyte.