[Pw_forum] Gamma phonons in Si lattice

[Ezad Shojaee]

we have obtained exactly 4 times grater in energy and 4 times smaller in cell volume compared to the original FCC one. when the structure seems to be right in the energy calculation, what may cause the problem?
and beyond the converging prob, what do you expect of the frequencies to be, compared to the FCC one? like for example you expect the total energy to be 4 times grater? should there be any relation between the freq's in the SC and FCC one? which physical quantity should be the same?
Thanx
Ezad Shojaee - Tehran University
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