The potential energy, U, between two carbon atoms joined by a single covalent bond and separated by a distance, x, can be approximated byU = + where A = 9.010-39 Jm2 and B = 3.010-98 Jm8. Calculate the equilibrium separation of the atoms. If solid carbon had a simple cubic structure (primitive cubic lattice, with one atom per lattice point) estimate the Youngs modulus, E. For diamond, E is actually 1200 GPa, while for graphite it is 27GPa (averaged over all directions). Compare these values with the value you have estimated for the simple cubic structure, and discuss the reasons for any discrepancies.

The potential energy, U, between two carbon atoms joined by a single covalent bond and separated by a distance, x, can be approximated byU = + where A = 9.010-39 Jm2 and B = 3.010-98 Jm8. Calculate the equilibrium separation of the atoms. If solid carbon had a simple cubic structure (primitive cubic lattice, with one atom per lattice point) estimate the Youngs modulus, E. For diamond, E is actually 1200 GPa, while for graphite it is 27GPa (averaged over all directions). Compare these values with the value you have estimated for the simple cubic structure, and discuss the reasons for any discrepancies.

The potential energy, U, between two carbon atoms joined by a single covalent bond and separated by a distance, x, can be approximated byU = + where A = 9.010-39 Jm2 and B = 3.010-98 Jm8. Calculate the equilibrium separation of the atoms. If solid carbon had a simple cubic structure (primitive cubic lattice, with one atom per lattice point) estimate the Youngs modulus, E. For diamond, E is actually 1200 GPa, while for graphite it is 27GPa (averaged over all directions). Compare these values with the value you have estimated for the simple cubic structure, and discuss the reasons for any discrepancies.

Elastic deformation

1. Normal stress and normal strain

2. Shear stress and shear strain

3. Elastic moduli

4. Atomic picture of elasticity