In Situ HREM observation of crystalline-to-gas transition in nanometer-sized Ag particles.

Sublimation of silver atoms from a nanometer-sized silver particle, namely, the crystalline-to-gas transition, has been directly observed by high resolution electron microscopy. Remarkable sublimation of silver atoms took place at 950 K from an approximately 9-nm-sized crystalline silver particle on the graphite substrate. The sublimation continued until the whole silver particle disappeared. No melting of the particle occurred during this process. The height-to-width ratio of a nanometer-sized silver particle on graphite at 950 K was about 0.65, and the ratio did not change so much during the sublimation-induced shrinkage of the particle.