Pulsed NMR studies of self-diffusion and defect structure in liquid and solid krypton

Abstract

Nuclear spin-spin relaxation and atomic self-diffusion have been studied for $^{83}\mathrm{Kr}$ in liquid and solid natural krypton. Transient NMR signals observed in the solid phase are separated into components governed by the effective quadrupolar and dipolar interactions. Interpretation of the quadrupolar component is aided by the analysis of observed quadrupole echoes. Fedders's calculations of quadrupolar effects for spin 9/2 are found to agree with $^{83}\mathrm{Kr}$ central transition relaxation rates observed in solid krypton. Analyses of motional narrowing indicate the coefficient of atomic self-diffusion in solid krypton to be $D={3.1}_{\ensuremath{-}2.1}^{+6.8}\mathrm{exp}[\ensuremath{-}\frac{(5010\ifmmode\pm\else\textpm\fi{}220)}{RT}]$ ${\mathrm{cm}}^{2}$/sec. In liquid krypton, direct external-gradient self-diffusion measurements yield $D\ensuremath{\rho}=(1.83\ifmmode\pm\else\textpm\fi{}0.25)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}3}\mathrm{exp}[\ensuremath{-}\frac{(180\ifmmode\pm\else\textpm\fi{}40)}{RT}]$ g/cm sec.