Hi Lijun Zhang. I would say it is a phonon instability (like the one occurring in ferroelectricity). An elastic instability would be signaled by a sound velocity going to zero. SB
On Feb 5, 2006, at 11:53 AM, Lijun Zhang wrote: > Dear all, > I am doing some calculations on pressure-induced phase transitions. > With increasing pressures, It is found that a mode softens exactly > at Gamma > point.(higher pressure, more negative value) Does it represent a > phonon instability or an elastic instability? > Thank you in advance. > > Lijun Zhang > > __________________________________________________ > ??????????????? > http://cn.mail.yahoo.com --- Stefano Baroni - SISSA & DEMOCRITOS National Simulation Center - Trieste [+39] 040 3787 406 (tel) -528 (fax) / stefanobaroni (skype) Please, if possible, don't send me MS Word or PowerPoint attachments Why? See: http://www.gnu.org/philosophy/no-word-attachments.html -------------- next part -------------- An HTML attachment was scrubbed... URL: /pipermail/attachments/20060206/08372091/attachment.htm
