The correlation between some structural properties of IV materials with compression stress

Lattice constant, density, total energy, cohesive energy, bulk modulus, microhardness, Young modulus, speed of sound, energy of acoustic phonons, plasmon energy and vibrational energy, for diamond, silicon, germanium, and gray tin, all have been calculated and studied when compression stress is exerted. It is found that most of them increase with pressure except the lattice constant which decreases and the vibrational energy behaves in different ways depending upon the matter. The bulk modulus is suggested to correlate to the lattice constant in every change with pressure and it had been regarded in all other properties' calculations. This correlation is used as simple formula as well as new simple formula had been suggested for plasmonpressure relation.