Theory of the implementation of the fundamental parameter method for the X-ray fluorescence determination of low-atomic-number elements

The theory of X-ray fluorescence generation in elements with a low atomic number Z is extended to the case of host matrices with high Z. The total contribution of the selective excitation effects is estimated with regard to the cascade K-L transitions. The influence of the elemental composition of the matrix and the excitation conditions on the X-ray fluorescence intensity of the elements in study is assessed. The accuracy of the model of X-ray fluorescence generation in the low-atomic-number elements is confirmed by the agreement of the experimental and calculated intensities of carbon in various carbon-containing compounds.