A comprehensive set of theoretical Coster-Kronig and fluorescence yields are presented for atomic numbers 18 less than or equal to Z less than or equal to 100. These quantities are based on ab initio relativistic calculations. Agreement with experimental values is fair for omega (1) and generally good for omega (2), omega (3) (Z greater than or equal to 54) . Therefore, atomic L shell fluorescence (omega (1), omega (2), omega (3)) and Auger yields (a(1), a(2) and a(3)) for some elements in the atomic number range 59 less than or equal to Z less than or equal to 85 were determined. These selected measured semi-empirical values were also fitted by least squares to polynomials in the Z of the form Sigma (n)a(n)Z(n) and compared with theoretical and with earlier fitted values. (C) 2000 Elsevier Science B.V. All rights reserved.