Vibrational states of atomic hydrogen in bulk and nanocrystalline palladium studied by neutron spectroscopy

Article

关键词: AB-INITIO CALCULATIONS;    STORAGE PROPERTIES;    LATTICE-DYNAMICS;    PD NANOCRYSTALS;    SINGLE-CRYSTAL;    SCATTERING;    DIFFRACTION;    TRANSITION;    METALS;    NANODENDRITES;   

DOI  :  10.1103/PhysRevB.96.054304

来源: SCIE

【 摘 要 】

The vibrational states of hydrogen atoms in bulk and nanocrystalline palladium were examined in a wide energy region 0 <= h omega <= 300 meV using neutron spectroscopy. In bulk PdH0.73, the vibrational excitations of H atoms were roughly reproduced by the quantum harmonic oscillator (QHO) model. In PdH0.42 nanocrystals with a diameter of 8 nm, however, additional vibrational excitations were found at energies above 80 meV. The energies and intensities of the additional states were not explained by the QHO but reasonably described as vibrations in a highly anharmonic trumpetlike potential. The additional excitations are attributed to the vibrations of H atoms at tetrahedral sites in the subsurface region stabilized by surface effects. Thus, this is an experimental work which clearly detects hydrogen vibration inside metal nanoparticles.

【 授权许可】

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