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The crystallography of the Pd-Dx system has been studied by in situ neutron powder diffraction at 309 °C, in the supercritical region, and, after quenching in the pure β phase to 50 °C, in the two-phase region at 50 °C. Rietveld profile analysis of the supercritical diffraction patterns showed that 14% of D interstitials were occupying tetrahedral interstices, in sharp contrast to previous studies at lower temperatures. Tetrahedral occupancy was maintained through the two-phase region at 50 °C. These results are discussed in the light of first-principles total-energy calculations of hydrogen states in palladium.

Transmission electron microscopy (TEM) has been used to characterize NaAlH4 doped with Ti, after H cycling. NaAlH4 was shown to be highly unstable under the electron beam, and 'knock on' damage lead to a decomposition of NaAlH4 with Na and H evaporating from the sample. All Ti containing phases were stable under the electron beam. After H cycling, the Ti was present as a mixture of amorphous and crystalline Al1-xTix.