The internal conversion electrons from M and N shells of the 14.4 keV transition of ^Fe diffused into Cr, Ni, Cu, Pt and Au substrates were measured using a high-resolution β-ray spectrometer. From relative intensities of conversion electrons analyzed using a deconvolution method, we deduced the contact charge density of 4s electrons ρ_(0) of ^Fe impurity atom in these host metals. The 4s contact charge density of ^Fe embedded in these host metals, as well as Fe and Co metals, is found to be nearly equal. This fact indicates that the 3s contact charge density ρ_(0) plays an important role in the variation of the isomer shift of ^Fe in these alloys
