ISIS Neutron and Muon Source Data Journal

Does hydrogen occupy the tetrahedral site in ?-PdH? Comparison to bulk PdH

Abstract: Palladium hydride was the first hydrogen-in-metal system to be discovered (by Graham in 1868 [1]). Ignoring imperfections, in a face centred cubic (fcc) metal such as Pd, there are two possible sites for hydrogen to occupy: octahedral and tetrahedral. In bulk PdH, the longer Pd?H distance of the octahedral site means that this is the preferred site. Two groups have recently proposed that there is a significant occupation of the tetrahedral sites, in nanoparticulate Pd, particularly near room temperature. In our previous proposal, RB222028, we used a Pd(20%)/C sample with a low hydrogen content carbon [7], to test whether hydrogen migrates from tetrahedral to octahedral sites as the temperature is lowered. On cooling there is a reduction in the peak width of the beta-PdH mode and it becomes more asymmetric. This is consistent with high energy tetrahedral H moving to the lower energy octahedral sites. Unfortunately, this attractive picture is complicated by convolution with the temperature dependent Debye-Waller factor. To address this, we propose to repeat the measurements using Pd-black, which approximates bulk Pd.

Experimenter: Dr Peter Albers
Local Contact: Professor Stewart Parker

DOI: 10.5286/ISIS.E.RB2410655

ISIS Experiment Number: RB2410655

Publisher: STFC ISIS Neutron and Muon Source

Data format: RAW/Nexus
Select the data format above to find out more about it.

Data Citation

The recommended format for citing this dataset in a research publication is as:
[author], [date], [title], [publisher], [doi]

For Example:
Dr Peter Albers et al; (2026): Does hydrogen occupy the tetrahedral site in ?-PdH? Comparison to bulk PdH, STFC ISIS Neutron and Muon Source, https://doi.org/10.5286/ISIS.E.RB2410655

Data is released under the CC-BY-4.0 license.