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<DIV><FONT face=Verdana color=#000080 size=2>Thanks fro your quick 
reply!</FONT></DIV>
<DIV><FONT color=#000080></FONT>&nbsp;</DIV>
<DIV><FONT color=#000080>In my understanding, dipole correction is electrostatic 
interaction between slabs.</FONT></DIV>
<DIV><FONT color=#000080>After set dipfield=.true. and other settings remain 
unchanged, self-consistent calculation has trouble to converge.</FONT></DIV>
<DIV><FONT color=#000080>In each self-consistent calculation step, there are 
several "c_bands: * eigenvalues not converged" warning messages. And, after 
several self-consistent steps, usually 3 steps, program stops with error 
message: "too many eigenvalues not converged".</FONT></DIV>
<DIV><FONT color=#000080>Could you give me some advice about this error? 
Where&nbsp;may be&nbsp;the error in my input file? number of k-points ? My input 
file for pw.x is like this:</FONT></DIV>
<DIV><FONT color=#000080></FONT>&nbsp;</DIV>
<DIV>
<DIV>&amp;control</DIV>
<DIV>calculation&nbsp;=&nbsp;'relax',</DIV>
<DIV>nstep=200,</DIV>
<DIV>tprnfor&nbsp;=&nbsp;.TRUE.,</DIV>
<DIV>tefield&nbsp;=&nbsp;.TRUE.,</DIV>
<DIV>dipfield = .TRUE.,</DIV>
<DIV>prefix&nbsp;=&nbsp;'relax',</DIV>
<DIV>pseudo_dir&nbsp;=&nbsp;'/home/ypwang/espresso/pseudo/',</DIV>
<DIV>outdir&nbsp;=&nbsp;'./out',</DIV>
<DIV>/</DIV>
<DIV></DIV>
<DIV>&amp;system</DIV>
<DIV>ibrav&nbsp;=&nbsp;6,&nbsp;celldm(1)&nbsp;=&nbsp;7.35,&nbsp;celldm(3)&nbsp;=&nbsp;8,&nbsp;nat&nbsp;=&nbsp;20,&nbsp;ntyp&nbsp;=&nbsp;5,</DIV>
<DIV>ecutwfc&nbsp;=&nbsp;40.0,&nbsp;ecutrho&nbsp;=&nbsp;480,</DIV>
<DIV>occupations&nbsp;=&nbsp;'smearing',&nbsp;degauss&nbsp;=&nbsp;0.005,&nbsp;smearing&nbsp;=&nbsp;'mv',</DIV>
<DIV>edir&nbsp;=3,</DIV>
<DIV>emaxpos&nbsp;=&nbsp;0.9,</DIV>
<DIV>eopreg&nbsp;=&nbsp;0.1,</DIV>
<DIV>eamp&nbsp;=&nbsp;0.00</DIV>
<DIV>/</DIV>
<DIV></DIV>
<DIV>&amp;electrons</DIV>
<DIV>diagonalization&nbsp;=&nbsp;'cg'</DIV>
<DIV>mixing_mode&nbsp;=&nbsp;'local-TF'</DIV>
<DIV>mixing_beta&nbsp;=&nbsp;0.3</DIV>
<DIV>conv_thr&nbsp;=&nbsp;1.0d-8</DIV>
<DIV>/</DIV>
<DIV></DIV>
<DIV>&amp;IONS</DIV>
<DIV>bfgs_ndim&nbsp;=&nbsp;7</DIV>
<DIV>/</DIV>
<DIV></DIV>
<DIV>ATOMIC_SPECIES</DIV>
<DIV>...</DIV>
<DIV>&nbsp;</DIV>
<DIV></DIV>
<DIV></DIV>
<DIV>K_POINTS&nbsp;automatic</DIV>
<DIV>4&nbsp;4&nbsp;2&nbsp;1&nbsp;1&nbsp;1</DIV></DIV>
<DIV><FONT color=#000080></FONT>&nbsp;</DIV>
<DIV><FONT color=#000080>Thanks in advance!</FONT></DIV>
<DIV><FONT face=Verdana color=#000080 size=2></FONT>&nbsp;</DIV>
<DIV><FONT face=Verdana color=#000080 size=2></FONT>&nbsp;</DIV>
<DIV><FONT face=Verdana color=#c0c0c0 size=2>2009-10-10 </FONT></DIV><FONT 
face=Verdana color=#000080 size=2>
<HR style="WIDTH: 100px" align=left color=#b5c4df SIZE=1>
</FONT>
<DIV><FONT face=Verdana color=#c0c0c0 size=2><SPAN>shypirate</SPAN> 
</FONT></DIV>
<HR color=#b5c4df SIZE=1>

<DIV><FONT face=Verdana size=2><STRONG>发件人:</STRONG> Paolo Giannozzi 
</FONT></DIV>
<DIV><FONT face=Verdana size=2><STRONG>发送时间:</STRONG> 2009-10-10&nbsp; 21:21:47 
</FONT></DIV>
<DIV><FONT face=Verdana size=2><STRONG>收件人:</STRONG> PWSCF Forum </FONT></DIV>
<DIV><FONT face=Verdana size=2><STRONG>抄送:</STRONG> </FONT></DIV>
<DIV><FONT face=Verdana size=2><STRONG>主题:</STRONG> Re: [Pw_forum] What is the 
meaning of dipfield=.true. ? </FONT></DIV>
<DIV><FONT face=Verdana size=2></FONT> </DIV>
<DIV><FONT face=Verdana size=2>
<DIV>On&nbsp;Oct&nbsp;10,&nbsp;2009,&nbsp;at&nbsp;14:07&nbsp;,&nbsp;shypirate&nbsp;wrote:</DIV>
<DIV></DIV>
<DIV>&gt;&nbsp;But&nbsp;my&nbsp;question&nbsp;is,&nbsp;what&nbsp;is&nbsp;the&nbsp;meaning&nbsp;if&nbsp;I&nbsp;set&nbsp;dipfield=.true.&nbsp;?</DIV>
<DIV></DIV>
<DIV>did&nbsp;you&nbsp;read&nbsp;the&nbsp;documentation&nbsp;for&nbsp;variable&nbsp;dipfield?</DIV>
<DIV></DIV>
<DIV>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;If&nbsp;.TRUE.&nbsp;and&nbsp;tefield=.TRUE.&nbsp;a&nbsp;dipole&nbsp;correction&nbsp;is&nbsp;&nbsp;</DIV>
<DIV>also</DIV>
<DIV>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;added&nbsp;to&nbsp;the&nbsp;bare&nbsp;ionic&nbsp;potential&nbsp;-&nbsp;implements&nbsp;the&nbsp;&nbsp;</DIV>
<DIV>recipe</DIV>
<DIV>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;of&nbsp;L.&nbsp;Bengtsson,&nbsp;PRB&nbsp;59,&nbsp;12301&nbsp;(1999).&nbsp;See&nbsp;variables&nbsp;&nbsp;</DIV>
<DIV>edir,</DIV>
<DIV>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;emaxpos,&nbsp;eopreg&nbsp;for&nbsp;the&nbsp;form&nbsp;of&nbsp;the&nbsp;correction,&nbsp;that&nbsp;&nbsp;</DIV>
<DIV>must</DIV>
<DIV>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;be&nbsp;used&nbsp;only&nbsp;in&nbsp;a&nbsp;slab&nbsp;geometry,&nbsp;for&nbsp;surface&nbsp;&nbsp;</DIV>
<DIV>calculations,</DIV>
<DIV>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;with&nbsp;the&nbsp;discontinuity&nbsp;in&nbsp;the&nbsp;empty&nbsp;space.</DIV>
<DIV></DIV>
<DIV>&gt;&nbsp;If&nbsp;I&nbsp;use&nbsp;dipfield=.false.,&nbsp;all&nbsp;results&nbsp;are&nbsp;wrong,&nbsp;is&nbsp;not&nbsp;it?</DIV>
<DIV></DIV>
<DIV>if&nbsp;you&nbsp;use&nbsp;options&nbsp;without&nbsp;knowing&nbsp;what&nbsp;they&nbsp;do,&nbsp;there&nbsp;are&nbsp;good</DIV>
<DIV>changes&nbsp;that&nbsp;all&nbsp;your&nbsp;results&nbsp;are&nbsp;wrong</DIV>
<DIV></DIV>
<DIV>P.</DIV>
<DIV>--</DIV>
<DIV>Paolo&nbsp;Giannozzi,&nbsp;Dept&nbsp;of&nbsp;Physics,&nbsp;University&nbsp;of&nbsp;Udine</DIV>
<DIV>via&nbsp;delle&nbsp;Scienze&nbsp;208,&nbsp;33100&nbsp;Udine,&nbsp;Italy</DIV>
<DIV>Phone&nbsp;+39-0432-558216,&nbsp;fax&nbsp;+39-0432-558222</DIV>
<DIV></DIV>
<DIV></DIV>
<DIV></DIV>
<DIV>_______________________________________________</DIV>
<DIV>Pw_forum&nbsp;mailing&nbsp;list</DIV>
<DIV>Pw_forum@pwscf.org</DIV>
<DIV>http://www.democritos.it/mailman/listinfo/pw_forum</DIV></FONT></DIV></BODY></HTML>