TDPAC study of the ZrCo-hydrogen system

The properties of the ZrCo-hydrogen system as a function of composition rat io H/ZrCo were investigated by combining TDPAC and X-ray diffraction techni ques with the full potential linearized augmented plane wave (LAPW) band st ructure calculations. It was found that during hydrogenation ZrCo transferr ed directly into ZrCoH3 and no transition phase existed. The z component V- zz of the efg and the asymmetry parameter eta at the Zr and Co sites were c alculated for ZrCoH3 by using the structure parameters of Zr and Co, obtain ed in the present work, combined with the hydrogen structure parameters obt ained from neutron diffraction on ZrNiH3. The calculations are in good agre ement with the measured values for V-zz and eta. This agreement is consiste nt with the proposed 4c and 8f interstitial sites occupancy of the hydrogen atoms in ZrCoH3.