Variable temperature x-ray diffraction and differential scanning calorimetry experiments on the superlattice solids of alkanethiol protected silver nanoclusters show that the translational periodicity collapses around 398 K resulting in a liquid phase, which upon cooling, reverts into the parent crystalline phase. This reversibility is seen in a narrow temperature window of 400–448 K. If the heating is done above 473 K, the reversibility is lost, and the liquid in the cooling cycle freezes into a disordered phase. The stability of different phases, encountered in the experiments, is discussed in terms of a phenomenological free energy.

• Received 6 March 2000

DOI:https://doi.org/10.1103/PhysRevB.62.R739