11 research outputs found
Time Differential Perturbed Angular γγ-Correlation Studies of Diethylenetriaminepentaacetic Acid Complexes with In and Cd
Static and dynamic electric quadrupole interactions of Cd in complexes with diethylenetriaminepentaacetic acid were studied by the time differential perturbed angular γγ-correlation technique using two parent isotopes, In(EC)Cd and Cd. The measurements were carried out using neutral aqueous solutions of the diethylenetriaminepentaacetic- acid-complexes with initial isotopes at 293 K and 77 K. It was shown that the Cd-diethylenetriaminepentaacetic-acid-complex in aqueous solutions at pH = 7.0 is characterised by the re-orientational correlation time of 7.7×10 s and an electric field gradient V=6.7(2)×10 V/m with an asymmetry parameter η=0.75(5). A direct comparison of the electric quadrupole interaction parameters for diethylenetriaminepentaacetic- acid-complexes with In and Cd confirmed the proposal about the fragmentation of the complexes caused by the after-effects of electron capture in In. An observed difference in the electric quadrupole interaction parameters obtained for the solutions with In and Cd complexes reflects a process of a chemical rearrangement of the complex structure after the In decay into C
Pd-vacancy complex in Si identified with the perturbed angular correlation technique
A Pd-vacancy (Pd-V-) complex in Si has been identified with the perturbed angular correlation technique using the radioactive Pd-100 probe produced by recoil implantation. The fraction of Pd probes in the complex has been determined as a function of dopant type (B, P, As, and Sb), dopant concentration (10(15)-6x10(19) cm(-3)) and annealing temperature (21-500 degrees C). The Pd-V- complex, with a unique interaction frequency of 13.1(2) MHz, was observed only in n(+)-Si with a maximum relative fraction of similar to 52% achieved between 200-300 degrees C while a broad distribution of interaction frequencies was apparent in n-, p-, and p(+)-Si. Annealing beyond 300 degrees C yielded a reduction in the Pd-V- fraction with a dissociation energy of 2.5(7) eV. Density functional theory calculations of the electric field gradient for the given defect configuration were consistent with a measured value of 3.58x10(21) V/m(2)