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Diffusion
Geometric Jump Factor

· The geometric jump factor α is defined as:
α = (Fraction of Atoms that can Jump) x 
(Number of Equivalent Paths)
· For the illustrated interstitial impurity diffusion mechanism in a simple cubic lattice:
* The atoms in the body centered location can jump to the next cell, and there is one such atom per cell on the starting plane: Jumping fraction = 1
* Only One Path couples the equivalent body centered sites in adjacent cells: Number of Paths = 1. The geometric jump factor α = 1.
· The temperature independent diffusion coefficient for this structure is: 
D0 = νa2