513.001 Molecular and Solid State Physics

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Lennard-Jones potential

The bond between two atoms can be described by a Lennard-Jones potential,

U(r) = 4ε((σ/r)12 - (σ/r)6).

If ε = 1.09E-21 J, and σ = 0.299 nm, what is the bond length r0 that minimizes the energy?

r0 = nm

For small deviations around r0, the force between the two atoms can be described by Hooke's law F = -k(r - r0). Here k is the effective spring constant. What is the spring constant for this bond?

k = N/m