Dechanneling cross-sections of α-particles by interstitial atoms in palladium

Abstract

Abstract The measured dechanneling cross-sections of α-particles by interstitial hydrogen atoms and carbon atoms in palladium are very close σ H/Pd = (5.7±2.6)×10 −3 A 2 and σ C/Pd = (4.6±1.0)×10 −3 A 2 . A model for dechanneling which takes into account only the scattering by the bare nucleus of the interstitial atom explains correctly the dechanneling by interstitial hydrogen ( σ H/Pd ≈ 4.6×10 −3 A 2 ), but greatly overestimates the dechanneling by interstitial carbon ( σ C/Pd ≈ 28×10 −3 A 2 ). We present here an a priori more realistic model which takes into account the screening effects by the remaining electrons around the nucleus of the interstitial and by the electrons of the palladium matrix. This last model gives (i) reasonable values for dechanneling by interstitial carbon ( σ C/Pd ≈ 5x10 −3 A 2 ) and allows one to determine that the more likely degree of ionization of interstitial carbon is small (ZC∗