Electronic factors in the volume isotope shift have been calculated in an ab initio way with the relativistic Dirac-Fock method for a number of different optical single/and
two-photon transitions in Au I. The agreement with a semi-empirical method is within
10% for the resonance transition. For this one and a few other transitions the effect of
core excitation has been analyzed with the Multi-configuration Dirac-Fock method as
well, and it was found to reduce the electronic factor in the order of 5 %.