Fig. 9
Self-diffusivity of hydrogen in YH2 using mean square displacements (MSD) and velocity autocorrelation (VAC) from AIMD simulations (solid symbols). Error bars for MSD and VACF are based on the standard error of the mean across 300 and 2,400 time origins, respectively. The error bars for diffusivity from MSD are less the symbol size. The open square symbols are experimental data on YH1.97 using neutron spectroscopy (NS)8 while the open circles represent data from pulsed field gradient nuclear magnetic resonance spectroscopy (PFG–NMR)13 with YH1.91. A crossover can be noted in the NS data at ~ 870 K.
