Lattice vibrations and specific heat of zinc blende

The dispersion relations, frequency distribution function and specific heat of zinc blende have been calculated usingHouston's method on (1) A short range force (S. R.) model of the type employed in diamond bySmith and (2) A long range model assuming an effective charge Ze on the ions. Since the elastic constant data on ZnS are not in agreement with one another the following values were used in these calculations:

$$C_{11} = 10.78; C_{12} = 6.87 and C_{44} = 3.87 in 10^{11} dynes/cm^2 $$