The identification of soft X-ray lines

For soft X-rays, in the range 100⩽hν⩽700 eV, new data of the relative intensities of L and M lines are presented which differ from those given in the popular tables prepared by E.W. White and G.G. Johnson by up to two orders of magnitude. The new data may be helpful in identifying soft X-ray lines correctly. Finally, some selected cases of severe overlaps between principal lines are discussed.