Elastic energy of dislocation. A perfect dislocation in a cubic crystal with lattice parameter equal to a dissociates to two partial dislocation according to the following reaction based on the Burgers vector of the partial dislocations: a/2 [-101] =a/6 [-211] + a/6 [-1-12]

Compute the ratio of the elastic energy of one of the partial dislocations to that of the perfect dislocation (the partial dislocations will both have the same elastic strain energy per unit length). Will the energy of the system increase or decrease after the dissociation occurs? What is the magnitude of the burgers vector of the partial dislocation in terms of a?