New empirical formulae for calculation of average M-shell fluorescence yields

•The collected average M-shell fluorescence yields cover the period from 1955 to 2005.•Three procedures are followed to deduce the average M-shell fluorescence yield.•The obtained results are compared with others works.•Reasonable agreement was typically obtained between our result and other works.

We have calculated and reviewed in a table form the average bulk M-shell fluorescence yield previously measured by different groups covering the period from 1955 to 2005. We have interpolated the weighted and unweighted mean values of the experimental data by using the analytical function (ω¯M/(1−ω¯M))1/4 as a function of the atomic number (Z) to deduce the empirical average M-shell fluorescence yield in the atomic range of 70≤Z≤92. Also, we used the famous formula ω¯M=A(Z−13)4 to generalize the average M-shell fluorescence yield for elements with 19≤Z≤100. The results have been compared with other theoretical, experimental and empirical values reported in the literature and a reasonable agreement has been obtained.