Lattice location of I implanted into Fe single crystals

The channeling technique has been used to locate I atoms implanted at 140 keV into Fe single crystals with a dose of 5×${10}^{14}$ atoms ${\mathrm{cm}}^{-2\mathrm{}}$. Observations were made of the backscattering yield for 3.5-MeV ${}_{}{}^{14}{}_{}{}^{}\mathrm{N}$ ions in angular scans across the $〈111〉$, $〈110〉$ axial, and {110},{100}, and {211} planar channels. Shoulders are observed in the I yield for the {100} and $〈110〉$ scans and the width of these indicate that some I atoms occupy sites 0.35±0.03 Å from {100} planes and 0.67±0.10 Å from $〈110〉$ axes. These coordinates are consistent with the calculated location in the presence of a nearest-neighbor vacancy. A distribution between substitutional, random, and vacancy associated sites is considered and site occupancies are derived in a simultaneous fit to all five scans using an average potential model for channeling. The significance of these results in the light of previous hyperfine-field measurements is discussed.