Effect of nanopore on hydration of hafnium investigated by TDPAC as a hyperfine tool

Abstract

The Time Differential Perturbed γ-γ Angular Correlation (TDPAC) measurement has been carried out with the hydrolysis product of Hafnium(Hf)-IV ion at pH1 both in bulk and under nano confinement using 181Hf/Ta as PAC probe. The experiment was performed at two different temperatures, viz., 300 K and 280 K. Three different probe sites could be identified for the bulk complex while it is four in case the complex is inside the nanopore, at both the measuring temperatures. The major site, in case of bulk complex, has a quadrupole frequency ωQ ~ 105 Mrad/s and η ~ 0.6. However, the major site, in case the complex is inside nanopore having an average pore size of 6 nm, has ωQ ~ 210 Mrad/s and η ~ 0.3. Two different values of PAC parameters corresponding to the major probe sites for the bulk and nano-confined complex, indicate completely different hydration chemistry in the present two cases.