On 07/19/2011 09:23 AM, Eric Germaneau wrote: > Hey Amin, > > The approach you proposed is ok but you should relax the cell as well. > By keeping the cell fix the system does not feel the pressure you wish > to apply.
Not so clear about the meaning of this sentence, could you please give some more explanations? ;-( > You can also change the volume, relax the positions only and compute the > pressure. > The best is to compute the free energy as function of pressure ans so > the QHA method is the best way to go. I think this method cann't do the job of structure-searching-and-finding for unknown phases when we changing the external pressure. Regards > Note that at first you can ignore the thermal effect and compute the > free energy from a regular phonon calculations. > I'm also very interested in such calculations but don't have experiences > doing this by mean of first principal calculations. > > I hope that helps, > Good luck, -- Hongsheng Zhao <zhaohscas at yahoo.com.cn> School of Physics and Electrical Information Science, Ningxia University, Yinchuan 750021, China