Neutron diffraction study of the location of deuterium in the deuterium-stabilized ZrTi2D3.83 phase

Hydrogen jump motion in Laves-phase hydrides: Two frequency scales

“…The ratio of the g-g distances as a function of R A /R B for a number of C15-type deuterides AB 2 D x . The values of r 2 /r 1 are derived from the neutron diffraction data for TaV 2 D x [10], ZrTi 2 D x [24], ZrMo 2 D x [25], [22] and YMn 2 D x [23]. [28] on YMn 2 H x (R A /R B = 1.425, x = 0.4, 0.65 and 1.26) are consistent with these expectations.…”

Deuterium site energy difference in ZrTi2D4.3 as studied by high-temperature neutron diffraction

“…A closely similar situation was also found for the hafnium analogue HfTi 2 D 4 [7]. However, attempts to derive hydrogen (deuterium) site energy differences from the temperature dependent deuterium atom redistributions between ZrTi 3 -and Zr 2 Ti 2 -type interstices failed [6], at least if based on data below room temperature. The aim of the present work was to study the hydrogen atom redistribution in -ZrTi 2 H ∼4 above room temperature.…”

“…However, later quasi-elastic [4] and incoherent inelastic neutron scattering experiments [5] suggested the presence of hydrogen also in tetrahedral Zr 2 Ti 2 -type interstices (site 96g). This was subsequently confirmed by highresolution neutron powder diffraction experiments on the deuteride ZrTi 2 D 3.83 at and below room temperature [6]. At room temperature the 32e (ZrTi 3 ) and 96g (Zr 2 Ti 2 ) sites were occupied by ∼81% and ∼6% deuterium, respectively, while the 8b sites (Ti 4 -type interstices) remained empty.…”

“…The structure model used was that reported by Skripov et al [6], i.e. Zr on site 8a, Ti on site 16d, and D on sites 32e and 96g of space group Fd3 m. The neutron scattering amplitudes used were 7.160 fm for Zr, −3.438 fm for Ti and 6.671 fm for D. In contrast to previous structure refinements the metal substructure was allowed to be partially disordered.…”

“…Consequently, these parameters were refined separately in consecutive cycles up to convergence. The positional parameters as taken from [6] were fixed during all refinements while the isotropic thermal displacement parameters were fixed at the values of Skripov et al [6] only for the refinement on the 300 K data. The latter were scaled up to higher temperature by using the Debye approximation and then fixed.…”