Stability of two-component alkali clusters formed on helium nanodroplets G. Droppelmann, M. Mudrich, C. P. Schulz and F. Stienkemeier Eur. Phys. J. D, 52 1-3 (2009) 67-70 Published online: 06 March 2009 DOI: 10.1140/epjd/e2009-00071-3