Interstitial Hydrogen in Fe/V Superstructures: Lattice Site Location and Thermal Vibration.

We report real space location of hydrogen in single crystalline Fe/V superstructures. Anisotropic strain is quantified versus hydrogen concentration by using the yield of backscattered primary 2 MeV ^{4}He ions for incidence in different crystallographic directions. From a comparison of ion channeling in combination with ^{1}H(^{15}N,αγ)^{12}C nuclear reaction analysis and Monte Carlo simulations we show that hydrogen is located in octahedral z sites and quantify its vibrational amplitude of 0.2 A.