Formation of Molybdenum Deuteride at High Pressure: A Neutron Diffraction Study

Area of Science:

• Materials Science
• Solid-state Chemistry
• Crystallography

Background:

• Molybdenum deuterides are complex materials with potential applications.
• Understanding deuterium atom locations is crucial for predicting material properties.

Purpose of the Study:

• To determine the precise locations and occupancies of deuterium atoms in molybdenum deuteride.
• To investigate the structural changes under high pressure.

Main Methods:

• Time-of-flight neutron powder diffraction.
• High-pressure experiments up to ~6.2 GPa.

Main Results:

• Confirmed the P63/mmc space group for molybdenum deuteride.
• Determined an overstoichiometric deuterium content with a composition of MoD1.15.
• Identified deuterium atoms occupying both octahedral and tetrahedral interstitial sites.
• Observed short interatomic distances between deuterium and molybdenum atoms (1.49 and 1.90 Å).

Conclusions:

• Neutron diffraction is sensitive to deuterium positions and occupancies in molybdenum deuteride.
• The structure of MoD1.15 features deuterium atoms in both octahedral and tetrahedral sites.
• High pressure influences the deuterium distribution within the molybdenum lattice.