SHAPE ISOMERISM OF SODIUM CLUSTERS WITH QUADRUPOLE, OCTUPOLE, AND HEXADECAPOLE DEFORMATIONS IN THE STRUCTURE-AVERAGED JELLIUM MODEL

Abstract

Multidimensional deformation energy surfaces of singly charged sodium clusters with 8≤ Z ≤50 valence electrons have been calculated including quadrupole, octupole, and hexadecapole shapes for the ionic background. We solve the Kohn-Sham equations in the local-density approximation with preserved axial symmetry on a two-dimensional lattice. In addition to the diffusivity of the jellium surface, the structure-averaged jellium model (SAJM) which yields the empirical bulk properties and surface tension of sodium is successfully applied to deformed systems. Discussing the systematics of shape transitions, we find good agreement with recent experimental dipole resonance splittings found in the photoabsorption cross sections and confirm the oblate shape of the first neighboring clusters above the closed 2p shell ( Z =40) provided that left-right asymmetry is enabled.