Probability of metastable states in Yukawa clusters

Finite strongly coupled systems of charged particles in external traps are of high interest in many fields. Here we analyze the occurrence probabilities of ground- and metastable states of spherical, three-dimensional Yukawa clusters by means of molecular dynamics and Monte Carlo simulations and an analytical method. We find that metastable states can occur with a higher probability than the ground state, thus confirming recent dusty plasma experiments with so-called Yukawa balls [1]. The analytical method [2], based on the harmonic approximation of the potential energy, allows for a very intuitive explanation of the probabilities when combined with the simulation results [3].\\ $[1]$ D. Block, S. K\"{a}ding, A. Melzer, A. Piel, H. Baumgartner, and M. Bonitz, Physics of Plasmas \textbf{15}, 040701 (2008)\\ $[2]$ F. Baletto and R. Ferrando, Reviews of Modern Physics \textbf{77}, 371 (2005)\\ $[3]$ H. K\"{a}hlert, P. Ludwig, H. Baumgartner, M. Bonitz, D. Block, S. K\"{a}ding, A. Melzer, and A. Piel, submitted for publication (2008)\\