| Abstract
| - The distribution of deuterium (hydrogen) between the surface and the bulk of palladium deuteride(hydride) within the interval of temperatures 78−160 K was studied by simultaneously measuring thework function changes and D2 (H2) pressure in the process of thin PdDy (0.005 < y< 0.855) and PdHx (0.005< x< 0.900) film formation. It has been found that at 78 K the concentration of the positively polarized,atomic deuterium (hydrogen) adspecies on the outer surface of palladium deuteride (hydride) approaches1.9 (1.5), while the atomic ratio D/Pd (H/Pd) in the bulk does not exceed 1. The work function stronglydecreases (by ∼2400 mV for PdD0.785). Surface segregation of deuterium predominates that of hydrogen.Above 120 K an increase of the work function is observed in the process of PdDy (PdHx) formation. Thisis interpreted as deuterium (hydrogen) positioning below the surface image plane within the first layerof Pd atoms. Under these conditions the surface concentration of deuterium (hydrogen) adatoms does notdiffer significantly from that in the bulk, approaching 1.
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