Atomic configuration of a ½ 〈111〉 screw dislocation in pure Mo and in Mo containing He interstitials

The atomic configuration around a screw dislocation with ½ 〈111〉 Burgers vector is calculated using two different sets of interatomic potentials for Mo. The boundary conditions are given by anisotropic elasticity theory. A narrow dislocation without a distinct stacking fault region results. Two different molybdenum‐helium potentials are used to calculate the positions with maximum energy gain for helium atoms near the ½ 〈111〉 screw dislocation in Mo. The strongest binding energy of the helium atom of ≈ 1.6 eV is found for the dilatational sink close to the dislocation line. The present calculations confirm earlier results on the interaction between a helium atom and a ½ 〈111〉 {110} edge dislocation that elasticity theory gives a reasonable description far away from the dislocation core but fails in the neighbourhood of the core region.