Abstract: Effect of lanthanum on silver nanoparticles prepared by vacuum deposition has been investigated by transmission electron microscope (TEM) and scanning electron microscope (SEM) .Experimental results show that lanthanum decreases the size of the silver particles.The reason is that,with the effect of lanthanum,the atomic coherent energy of the substrate increases,the combined nanoparticles of lanthanum and silver are confined to fixed positions,thus coalesce is reduced.

Key words: Rare earth, Lanthanum, Nanoparticles, Size