M sub-shell fluorescence and Coster-Kronig yield data generation for elements, 57≤Z≤90 (computer code 'MFCKYLD')

•Generation of M sub-shell fluorescence yield and Coster-Kronig yield values.•Interpolation of non-relativistic and relativistic data in 57-90 and 67-90 Z-ranges.•Agreement between generated and actual values supported the adopted procedure.•Code MFCKYLD gives both data values on terminal/file on entering Z with keyboard/file.•Precision, deviation of fitted from actual values, is far better than earlier work.

M subshell fluorescence yield (ωMi, i=1−5) and Coster-Kronig yield (fMij, i=1−4, j=2−5) values have been generated for elements with Z, 57≤Z≤90. Keeping in view the importance of ωMi and fMij for M X-ray productions in the region Z>56, the interpolation of non-relativistic data of McGuire [Phys. Rev. A 1972;5:1043-7] in the region Z=57-90 as well as relativistic data of Chen et al. [Phys. Rev. A 1980;21:449-53 and 1983;27:2989-94] in the region Z=67-90 was attempted. The agreement between the generated data and the actual ones supported the adopted procedure. Subsequently, a computer software code MFCKYLD was developed to generate the yield values on computer terminal or in file for both non-relativistic and relativistic data just by entering the atomic number Z of the element through keyboard or file. The precision of present procedure that relies on the deviation of fitted values from the actual ones was found far better than the earlier fitted data.