Atoms of a certain kind interact via a Lennard-Jones pair potential of the form Up==[(@"-09] [)() 4€ where r is the distance between particles, and e = 3.2 meV and o = 2.8 Å are parameters of the potential. Assume that the stable arrangement of the atoms in the solid state is simple cubic. The molar mass of the material is 20.2 g/mol.
Tension is applied to the crystal along the (100) direction until it breaks, forming new surfaces along (100) planes. Determine the stress (force per area) that must be applied to fracture the crystal. Determine the surface free energy y of the new surfaces, again considering only nearest neighbour interactions and assuming the lattice parameter is unchanged. Consider a tube of inside diameter 0.1 mm dipped into the liquid state of this material, held in a container. If there is perfect wetting of the liquid in the tube (contact angle 0 = 0 degrees), give the distance h above the liquid surface that liquid will rise into the tube. You may assume that the surface energy and density are identical in the liquid and solid states.
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