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<DIV><FONT face=Arial size=2>Dear all,</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Now I'm suffering the convergence problems about my
system.</FONT></DIV>
<DIV><FONT face=Arial size=2>My system is the surface of TiO2 and noble metal
atoms. First I relaxed surface of TiO2 with a slab
geometry.</FONT></DIV>
<DIV><FONT face=Arial size=2>Most of parameter of the calculations was set
to default. </FONT><FONT face=Arial size=2>The convergence of SCF and BFGS a bit
slower but </FONT></DIV>
<DIV><FONT face=Arial size=2>they both converged finally. When I add
the noble metals </FONT><FONT face=Arial size=2>on the surface, the
convergence of SCF can't converge any more. </FONT></DIV>
<DIV><FONT face=Arial size=2>Then I checked the output of the not converged
systems. I found the self-consistency error fluctuated, some </FONT></DIV>
<DIV><FONT face=Arial size=2>thing like the manual describing, 'A typical sign
of such behavior is that the self-consistency error goes down, </FONT></DIV>
<DIV><FONT face=Arial size=2>down, down, than all of a sudden up again, and so
on'. So I think maybe I should increase the empty bands to </FONT></DIV>
<DIV><FONT face=Arial size=2>the system because of the adding of noble
metal atoms. Then I add about 20% more empty bands to the system.</FONT></DIV>
<DIV><FONT face=Arial size=2>I want to know whether the accuracy will be
affected by doing this? Do you think adding more empty bands to the
</FONT></DIV>
<DIV><FONT face=Arial size=2>system will significantly affect the results of
relax calculation for TiO2 and noble metals?</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>And I also found another suggestions to using
mixing mode=¡¯local-TF¡¯ for slab systems, and Reduce mixing beta.</FONT></DIV>
<DIV><FONT face=Arial size=2>Do you think there will be a big difference between
the relax calculation using default setting and adjusted settings</FONT></DIV>
<DIV><FONT face=Arial size=2>to improve the SCF convergence?</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>thank you for reading.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>any hints will be appreciated.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>vega</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial
size=2>=================================================================================<BR>Vega
Lew (weijia liu)<BR>PH.D Candidate in Chemical Engineering<BR>State Key
Laboratory of Materials-oriented Chemical Engineering<BR>College of Chemistry
and Chemical Engineering<BR>Nanjing University of Technology, 210009, Nanjing,
Jiangsu, China</FONT></DIV></BODY></HTML>