Competition between two forms of ordering in finite Coulomb clusters.
The lowest-energy state of spherical clusters made up of single-species charged particles in a three-dimensional confining potential is investigated by molecular dynamics simulations for a system size of 5 x 10(3) to 1.2 x 10(5). The energy per particle is compared between shell-structured clusters and spherical finite-bcc lattices with relaxed surfaces. The shell structure in the interior is the lowest-energy configuration for ion numbers lower than about 10(4), while for higher ion numbers, an interior with bcc ordering surrounded by a few shells on the outside has lower energy. The formation of a small bcc lattice (nucleation) in the shell-structured cluster of 2 x 10(4) ions is observed.
Totsuji
Hiroo
H
Graduate School of Natural Science and Technology and Faculty of Engineering, Okayama University, Tsushimanaka 3-1-1, Okayama 700-8530, Japan. totsuji@elec.okayama-u.ac.jp
Kishimoto
Tokunari
T
Totsuji
Chieko
C
Tsuruta
Kenji
K