LOADING OF H(D) IN A Pd LATTICE

1 G. Preparata [1] has stressed that when x becomes larger than a critical threshold, deuterons enter in a coherent oscillatory state. Deuterons while in the -phase (x<0.7 at room temperature), are confined in deep and narrow wells at definite lattice sites; this occurs since the d-shell electrons of Pd through their coherent oscillations produce stationary potential wells at these sites . It has been discovered however, a long time ago , that at x ≈ 0.8 the number of conduction electrons per Pd atom as a function of x exhibits a sharp discontinuity of its slope (see fig. 1); in other words, when for x < 0.8 each Hydrogen or Deuterium entering in the Pd lattice contributes about 0.75 electrons to the conduction band, when x crosses 0.8 each new H (D) contributes more than five electrons to the conduction band ! This means that each new guest of the lattice donates its own electron and persuades four Pd electrons to shift to the conduction band, so the whole electron structure of the Pd-H(D) system gets rearranged; the d-shell electrons which help to keep H(D) nuclei confined become less numerous and then the potential wells become shallower and wider which allows to H(D) nuclei to perform oscillations that, according to their dynamics, described in the Chap. 5 of Ref. 1, are able to tune their phase and become coherent. The raising of some electrons from the d-band to the conduction band accounts for the endothermic character of the loading at high x and for the simultaneous increase of the electric conductivity induced by the larger number of carriers. We refer to this new phase of the Pd-H(D) system as the-phase.