For metals having the same crystal structure (e.g., FCC, BCC), the activation energy for self-diffusion increases with increasing metal melting temperature. How do you explain this phenomenon? Both the phenomena of diffusion and melting involve the of interatomic bonds. For diffusion bonds must be when an atom migrates from one lattice position to an adjacent vacancy, and the activation energy for diffusion is indicative of the ease with which atomic motion occurs; that is, the greater the strength of the interatomic bonds, the the value of Qd. On the other hand, the melting of a metal is a result of the of atomic bonds as a result of relatively large atomic vibrations; the these bonds the higher the melting temperature. Therefore, metals that have high melting temperatures also have activation energies for self-diffusion