On the stability of dissociated dislocations

The change in energy related to the dissociation of a 1/2 〈1l0〉 screw dislocation into two Shockley partials or of an edge dislocation into the Lomer-Cottrell configuration has been recalculated. It is shown that the exact value, and even the sign, of this change cannot be found using linear isotropic elasticity when the splitting distance is too small.