Mackay overlayer

More precisely, if ,c = 0, the polymer forms a non-icosahedral structure, e.g., it is decahedral or fcc-like ,c = 1 indicates icosahedral geometry with Mackay overlayer or a complete icosahedron which might possess a few monomers bound in anti-Mackay type. Finally, for n,c > 2, the monomers form an icosahedral core with a considerably extended anti-Mackay overlayer. The probabilities(7) for the different values of njc as a function of temperature provide the necessary information to reveal structural transitions. 

The exceptional case of the 38-mer shows a significantly different behavior. A single icosahedral core forms and in the interval 0.08 < 7 <0.19 icosahedra with Mackay overlayer are dominant. Although the energetic fluctuations are weak, near T 0.08, a surprisingly strong structural crossover to non-icosahedral stmctures occurs the formation of a maximally compact fee truncated octahedron. 

The magic 55-mer exhibits a very pronounced transition from unstmetured globules to icosahedral conformations with complete Mackay overlayer at a comparatively high temperature T 0.33). Below this temperature, the ground-state structure has already formed and is sufficiently robust to resist the thermal fluctuations. 

Figure 1.5 provides confirmation that the complete Mackay icosahedra are particularly stable. Between these magic numbers, the stability of the clusters first decreases as atoms are added to the surface of the icosahedron, and then increase as the overlayer nears completion. When especially stable... 

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