High pressure study of NaAlH4 by Raman spectroscopy up to 17 GPa

• A high-pressure Raman study was carried out on NaA1H(4) up to 17 GPa using the diamond anvil cell method. In the pressure region 2-5 GPa, several of the original modes split. Although this might be a sign of some structural change, the spectral changes do not allow us to claim the existence of a clear phase transition in this pressure range. The spectra revert to their ambient pressure forms on decreasing pressure below < 3.0-1.4 GPa. A phase transition to beta-NaA1H(4) was found at 14-16 GPa. This phase transition is also reversible with an unusually strong hysteresis: the beta-NaA1H(4) can be followed upon decompression down to 3.9 GPa. Analysis of Raman data shows that this phase transition is compatible with a theoretical prediction of a strong volume collapse.

Ämnesord

NATURVETENSKAP  -- Fysik -- Den kondenserade materiens fysik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences -- Condensed Matter Physics (hsv//eng)

Nyckelord

Hydrogen storage

hydrides

high pressure

phase transition

Raman scattering

NaAlH4

hysteresis

Condensed matter physics

Kondenserade materiens fysik

Publikations- och innehållstyp

ref (ämneskategori)

art (ämneskategori)