Experimental evidence for quasimelting in small particles.

We present experimental evidence which demonstrates for the first time that small particles on substrates sit in deep potential-energy wells and, once floated out of these, can quasimelt between various local minima on shallow morphological free-energy surfaces. The energy needed to nucleate the quasimolten state is found to be orders of magnitude larger than that needed to sustain the state. The particles retain the unstable state for long intervals of time until they find another well on the substrate in which they can form a stable Wulff' polyhedron shape.