4 research outputs found
Electronic-structure-induced deformations of liquid metal clusters
Ab initio molecular dynamics is used to study deformations of sodium clusters
at temperatures K. Open-shell Na cluster has two shape
isomers, prolate and oblate, in the liquid state. The deformation is stabilized
by opening a gap at the Fermi level. The closed-shell Na remains magic also
at the liquid state.Comment: REVTex, 11 pages, no figures, figures (2) available upon request
(e-mail to hakkinen at jyfl.jyu.fi), submitted to Phys. Rev.
Thermodynamics of Na_8 and Na_{20} clusters studied with ab-initio electronic structure methods
We study the thermodynamics of Na_8 and Na_{20} clusters using
multiple-histogram methods and an ab initio treatment of the valence electrons
within density functional theory. We consider the influence of various electron
kinetic-energy functionals and pseudopotentials on the canonical ionic specific
heats. The results for all models we consider show qualitative similarities,
but also significant temperature shifts from model to model of peaks and other
features in the specific-heat curves. The use of phenomenological
pseudopotentials shifts the melting peak substantially (~ 50--100 K) when
compared to ab-initio results. It is argued that the choice of a good
pseudopotential and use of better electronic kinetic-energy functionals has the
potential for performing large time scale and large sized thermodynamical
simulations on clusters.Comment: LaTeX file and EPS figures. 24 pages, 13 figures. Submitted to Phys.
Rev.