Online time-differential perturbed angular correlation study with an 19O beam – Residence sites of oxygen atoms in highly oriented pyrolytic graphite

Abstract: The online time-differential perturbed angular correlation (TDPAC) method was applied to a study of the physical states of a probe 19F, the β− decay product of 19O (t 1/2 =26.9s), implanted in highly oriented pyrolytic graphite. The observed magnitude of the electric field gradient at the probe nucleus, ∣V zz ∣=2.91(17)×1022 Vm−2, suggests that the incident 19O atoms are stabilized at an interlayer position with point group C 3v . Exhibiting observed TDPAC spectra having a clear sample-to-detector configuration dependence, we demonstrate the applicability of the present online method with a short-lived radioactive 19O beam. [Copyright &y& Elsevier]