Influence of the molecular environment on the hyperfine interaction of 111Cd ions in gaseous radioactive indium halides Original Research Article

Systematic investigations of the radioactive decay of 111In in different gaseous indium halides have revealed a significant influence of the molecular density of the indium halide gas. The experiments were performed with the perturbed angular correlation (PAC) of the γ-photons which are emitted when the nucleus decays to 111Cd, a well-established method in nuclear physics. We present here the result of recent measurements on indium(III)-bromide. The attenuation coefficient was determined for molecular densities between 1014 and 1020 cm−3 and from boiling temperature to 830°C. The temperature dependence first discovered with indium(III)-iodide was observed here as well and confirms our theory based on the average charge of the 111Cd ion which is different for monomeric or dimeric halides. This measurement together with previous experiments on indium chlorides and -iodides allow us to give a complete qualitative interpretation of the observed phenomena.