Melting in large sodium clusters: An orbital-free molecular dynamics study

of all the atoms across the cluster. For an icosahedral isomer those two steps are found to be much closer in temperature (at ≈ 240 K and 270 K, respectively). For the case of Na92, the icosahedral isomer again melts in two well defined steps, surface melting at ≈ 130 K and homogeneous melting at ≈ 240 K, whereas an amorphous isomer shows an extremely broad, featureless melting transition. In the case of Na55, only an icosahedral isomer was investigated, which melted in a single stage at ≈ 190 K. Our results on homogeneous melting for Na142 and Na92 are in excellent agreement with recent experimental determinations of melting temperatures and latent heats. However, the