Electronic Structures and Quantum Size Effect of Nanometer-sized Silver Clusters

The electronic structures and optical spectra of nanometer-sized silver clusters Agn（n=2 to 15） have been determined in the framework of self-consistent-field local density theory SCC-DV-Xα. The results show that there is a quantum size effect in Agn clusters which can be observed as a red shift in the absorption threshould and semiconductor-conductor transition with increasing n. Based on the highst occupied molecular orbital energy we studied the microscopical mechanism of the transition from low efficiency to high efficiency and the ion step prior to electron step in latent image growth. The results also show that there is an electron defect on the surface silver atoms of Agn clusters which is favourable for the latent image particles to adsorb developer anion in development.