Anomalous size dependence in the melting temperatures of free sodium clusters:: An explanation for the calorimetry experiments -: art. no. 233401

The meltinglike transition in unsupported Na-N clusters (N=55, 92, 147, 181, 189, 215, 249, 271, 281 and 299) is studied by first-principles isokinetic molecular dynamics simulations. The irregular size dependence of the melting temperatures T-m observed in the calorimetry experiments of Schmidt et al. [Nature (London) 393, 238 (1998)] is quantitatively reproduced. We demonstrate that structural effects alone can explain all broad features of experimental observations. Specifically, maxima in T-m(N) correlate with high surface stability and with structural features such as a high compactness degree.