Hydrogen and deuterium trapping at nitrogen in tantalum studied by PAC

PAC experiments using¹⁸¹Hf as probe atom were performed in Ta samples containing 1.1 at% of N and loaded with 0.2 at% of H or of 1.6 at% of D. At room temperature only the known frequency due to N is present. Below 100K or 140K, for H and D respectively, the amplitude of this interaction decreases and two new interaction frequencies characterized by V₀=240MHz, η=0.80 and V₀=250 MHz, η=0.40 appear. These frequencies are attributed to H(D) trapped by N in the vicinity of the probe atom¹⁸¹Hf. The disappearance of these interactions at 100K and 140K is interpreted as a release of H (D) from Hf but not from N. From the data the jump rates of H(D) around N in Ta are derived.