  We found that in transition arrays of complex atomic spectra, the strengths
of electric-dipolar lines obey Benford's law, which means that their
significant digits follow a logarithmic distribution favoring the smallest
values. This indicates that atomic processes result from the superposition of
uncorrelated probability laws and that the occurrence of digits reflects the
constraints induced by the selection rules. Furthermore, Benford's law can be a
useful test of theoretical spectroscopic models. Its applicability to the
statistics of electric-dipolar lines can be understood in the framework of
random matrix theory and is consistent with the Porter-Thomas law.
