Comment on `Formation of a Dodecagonal Quasicrystalline Phase in a Simple Monatomic Liquid'

In a recent paper M. Dzugutov, Phys. Rev. Lett. 70 2924 (1993), describes a molecular dynamics cooling simulation where he obtained a large monatomic dodecagonal quasicrystal from a melt. The structure was stabilized by a special potential [Phys. Rev. A46 R2984 (1992)] designed to prevent the nucleation of simple dense crystal structures. In this comment we will give evidence that the ground state structure for Dzugutov's potential is an ordinary bcc crystal

The favoured cluster structures of model glass formers

We examine the favoured cluster structures for two new potentials, which both behave as monatomic model glass-formers in bulk. We find that the oscillations in the interatomic potential lead to global minima that are non-compact arrangements of linked 13-atom icosahedra. We find that the structural properties of the clusters correlate with the glass-forming propensities of the potentials, and with the fragilities of the corresponding supercooled liquids.Comment: 9 pages, 7 figures; new section added and error in potential parameters correcte

Comment on `Universal relation between the Kolmogorov-Sinai entropy and the thermodynamic entropy in simple liquids'

The intriguing relations between Kolmogorov-Sinai entropy and self diffusion coefficients and the excess (thermodynamic) entropy found by Dzugutov and collaborators do not appear to hold for hard sphere and hard disks systems.Comment: 1 page revte