MSPC

Assignment 1

 

Last date 27th sep, 2004

 

 

  1. a) Show that the attractive force between two atoms can be written as F=a1/r7

      b) Explain Born theory of Ionic Crystals

 

  1. Show how the incompleteness of 3d and 4f energy sublevels accounts for the characteristic properties of transitional elements and rare-earth elements.

 

  1. If the inter-atomic potential between atoms of a solid can be assumed as 

      V = a/r6 - b/r12,

calculate the constants a and b in terms of Elastic modulus E, and   poisson’s ratio n.

 

  1. If a solid has a FCC crystal structure and the inter-atomic potential as given in question 3 (in terms of E and n ). Calculate the elastic modulus along i) 001, ii) 111 directions. Assume the atoms interact only with its nearest neighbors.

 

  1. Derive the interaction forces between the two edge dislocations gliding on the parallel slip planes separated by a distance d0