Abstract
One of the fundamental eigenmodes of finite interacting systems is the mode of uniform radial expansion and contraction—the breathing mode (BM). Here we show in a general way that this mode exists only under special conditions: (i) for harmonically trapped systems with interaction potentials of the form () or , or (ii) for some systems with special symmetry such as single-shell systems forming platonic bodies. Deviations from the BM are demonstrated for two examples: clusters interacting with a Lennard-Jones potential and parabolically trapped systems with Yukawa repulsion. We also show that vanishing of the BM leads to the occurrence of multiple monopole oscillations which is of importance for experiments.
- Received 31 March 2008
DOI:https://doi.org/10.1103/PhysRevLett.101.045002
©2008 American Physical Society