Quantum Diffusion of Deuterium in Sodium.

Area of Science:

• Materials Science
• Nuclear Physics
• Physical Chemistry

Background:

• Deuterium diffusion in metals is crucial for understanding hydrogen isotope behavior in materials.
• Previous studies on quantum diffusion were limited to protium (lightest hydrogen isotope) in specific metals like niobium and tantalum.
• Experimental data on hydrogen isotope diffusion in alkali metals were scarce.

Purpose of the Study:

• To investigate the temperature dependence of deuterium diffusion coefficients in sodium.
• To observe and analyze quantum diffusion mechanisms of deuterium in a metal lattice.
• To establish conditions necessary for quantum diffusion of hydrogen isotopes in metals.

Main Methods:

• Utilized the online nuclear reaction analysis technique.
• Studied deuterium diffusion in sodium across a temperature range of 110 K to 240 K.
• Analyzed diffusion behavior at cryogenic temperatures (below 160 K) and above.

Main Results:

• Observed quantum tunneling of deuterium atoms in the sodium lattice below 160 K.
• Identified classical overbarrier atomic jumps as the diffusion mechanism above 160 K.
• Obtained the first experimental results on quantum diffusion of deuterium in a metal and hydrogen isotope diffusion in an alkali metal.
• Determined that a low Debye temperature (below 200 K) is a necessary condition for quantum deuterium migration.

Conclusions:

• Quantum diffusion of deuterium in sodium has been experimentally confirmed for the first time.
• This research expands the understanding of quantum diffusion phenomena to heavier hydrogen isotopes and alkali metals.
• Low Debye temperature is a critical factor enabling quantum diffusion mechanisms in metallic systems.