  In this paper formulate the hypothesis that in a molecule $D_2 O$ (in a
cluster of heavy water $(D_2 O)_N)$ when its specific energy is of the order of
150 eV one of the molecular bonds $O - D$ is changed into $O - D_{\mu}$ i.e. a
molecule $D_2 O$ transforms into a muonic molecule. This postulate is necessary
to explain the experiment which was carried out in Brookhaven National
Laboratory (USA).
