The calculation of elastic and bulk moduli

Calculation is one of the simplest ways to determine the bulk modulus, as experiments are difficult to perform. At the heart of the calculation is an analytical expression for the potential energy of a crystal in terms of interatomic distances and bond angles. The Born-Meyer function. Equation (2.9), is a simple example of such a function. The potential energy is calculated as a function of interatomic distance, bond angles and other parameters included in the potential energy equation. The interatomic 

The principals can be explained by using a simple potential energy function. Take an equation such as Equation (2.6) as the starting point, but to make matters clearer, write it as  

In terms of this simple model. Young s modulus depends sensitively on the interatomic distance in the solid. 

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