S. Demuynck, S.N. Mishra, A.A. Tulapurkar, S. Cottenier, J. Meersschaut, M. Rots Physica B: Condensed Matter 293, 3-4, 376-3812001A1Published while none of the authors were employed at the CMMDOI http://dx.doi.org/10.1016/S0921-4526(00)00546-9