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<DIV>Dear all<BR> I made some test about the relaxed crystal
structure and calculate<BR>the phonon frequencies of the Brillouin zone
center. some outputs<BR>followed as that:<BR> tr2_ph=1.0d-10,
-5.4966,-5.4355,-5.4200,487.0055,487.2547,488.6275 ....
(c<BR>m-1)<BR> tr2_ph=1.0d-12,
-2.6613,-2.6554,-2.6540,474.2230,474.4394,477.5642 ....
(c<BR>m-1)<BR> tr2_ph=1.0d-14, -0.08, -0.08, -0.07, 476.39,
476.46, 479.27 ....
(c<BR>m-1)<BR> tr2_ph=1.0d-16, ??? ???
......<BR><BR>I want to ask whether I can adjust the parameter of threshold
<BR>for selfconsistency to find no negative <BR>frequency at the Brillouin
zone center (G point) of the relaxed<BR>crystal structure. maybe I can
succeed in doing it,(no negative <BR>frequencies at G point) Can I trust
the results with so high precision<BR>of the threshold for selfconsistency?
(such as tr2_ph=1.0d-18)<BR><BR>PS:I found the computer (cluster)<BR>will
break out if I adjust tr2_ph > 1.0d-13 in espresso-2.1.5 code for
<BR>unkown reason but there is no problem in the espresso-3.0.<BR>thank
you!<BR> <BR>Best regards<BR><BR>Xiangfeng Zhou<BR><BR>National
Laboratory of Solid State Microstructures and Department of Physics,
<BR><BR>Nanjing University<BR></DIV></FONT></div><br clear=all><hr>使用 <a
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