MELTING AND OCTUPOLE DEFORMATION OF NA-40

The dynamics and electronic structure of the magic Na-40 cluster are s tudied as a function of temperature using an ab initio molecular dynam ics method. Na-40 is found to undergo a structural transition which ca n be identified as melting by traditional indicators. Melting transiti on was observed in the region 300-350 K with a latent heat of melting of 11 meV/atom, which is 42% of the bulk value. Octupole deformation i s the dominating type of multipole deformations in the temperature ran ge studied (150-550 K). The stability of the deformation type is indic ated by the persistently large HOMO-LUMO gap, both in the solid and li quid phases.