Variations of the decay rate of 64Cu in chemical compounds

The results of experimental studies of changes of the 64Cu (T1/2=12.70 h) radioactive decay probability λ in various chemical compounds (CuO, CuS, Cu2S, CuInS2, CuInTe2) have been presented. The maximum relative change Δλ/λ, which is equal to (2.3±0.5)x10-4, has been measured for the 64Cu nuclei in CuO relative to Cu2S. The technique of the investigations has been described. The possibility of determination of the experimental values of the changes of the electron density ρ=ρ(0) on the nuclei of copper atoms from the measured Δλ/λ values, and limitations of this technique when Δλ/λ are very small have been considered. The greatest change in Δρ for CuO relative to Cu2S is equal to (11.7 ± 2.6)a0-3, where a0 is Bohr radius