Evaluation of the elastic constants of diamond from its Raman frequencies

Summary

Expressions for the elastic constants of diamond have been derived in terms of the force constants calculated by Ramanathan which express the interaction of any atom with its 28 neighbours. The calculated values are: C₁₁=9·6×10¹²; C₁₂=3·9×10¹²; C₄₄=4·2×10¹² dynes/cm.² while the values experimentally determined by Bhagavantam and Bhimasenachar are:

$$C_{11} = 9 \cdot 5 \times 10^{12} ; C_{12} = 3 \cdot 9 \times 10^{12} ; C_{44} = 4 \cdot 3 \times 10^{12} dynes/cm.^2 $$