The structure and migration mechanisms of orientational defects were investigated by using molecular dynamics simulations. It was found that the defect structure was very different to that originally proposed by Bjerrum. Two basic structures were found for the D defect (with excess OH in the network), and a single predominant structure was found for the L defect (with a missing H bond). In general, one water molecule in the defect was displaced by about 1Å from the crystal lattice site. The defect jumps involved vibrational phase coincidence.

Structure and Dynamics of Orientational Defects in Ice. R.Podeszwa, V.Buch: Physical Review Letters, 1999, 83[22], 4570–3