> [...] I displaced atoms in the cell according > to the eigen-displacements shown above,and got a cubic cell containg 8 > atoms. But I found the energy rised with the increase of atom > displacements, which was totally contrary to what I expected.
have you tried the same operation on a simpler system, such as e.g. GaAs? You should get the phonon frequencies. If you don't, you may have made a mistake Paolo -- Paolo Giannozzi, Democritos and University of Udine, Italy
