<html><body><div style="color:#000; background-color:#fff; font-family:Arabic Transparent, Arial;font-size:12pt"><div dir="ltr">Dear all</div><div dir="ltr"><br></div><div style="color: rgb(0, 0, 0); font-size: 16px; font-family: Arabic Transparent,Arial; background-color: transparent; font-style: normal;" dir="ltr">I want to calculate phonon frequency. I did a relax for my system(carbon nanotube) and saw that the stress (Kbar) for this system is around (-40Kbar). How can i decrease the stress on my system, and for an acceptable magnitude of ferquencey, how much be the stress on system.?</div></div></body></html>