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<DIV><FONT face=Arial size=2>Have you tested convergency against ecutwfc? I
remember that because of the pseudo </FONT></DIV>
<DIV><FONT face=Arial size=2>potential for oxigen you're using, ecutwfc can go
as high as 100 rye if your criterion for </FONT></DIV>
<DIV><FONT face=Arial size=2>convergency </FONT><FONT face=Arial size=2>of total
energy is 1 mRy. Although it sounds rediculous for USPP, you may</FONT></DIV>
<DIV><FONT face=Arial size=2>need</FONT><FONT face=Arial size=2> to see if the
ecutwfc influences the band gap.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Huiqun Zhou</FONT></DIV>
<DIV><FONT face=Arial size=2>@Nanjing University, China</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
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style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px">
<DIV style="FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV
style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: black"><B>From:</B>
<A title=bipulrr@gmail.com href="mailto:bipulrr@gmail.com">Bipul Rakshit</A>
</DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A title=pw_forum@pwscf.org
href="mailto:pw_forum@pwscf.org">PWSCF Forum</A> </DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Thursday, January 15, 2009 1:30
AM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> [Pw_forum] band gap
problem</DIV>
<DIV><BR></DIV>Dear Pwscf users,<BR>I am doing electronic calculation of SnO2
in rutile structure. I am using Sn.pw91-n-van.UPF and O.pw91-van_ak.UPF
<BR>PP. With this i am getting a band gap of 7.2 eV, while LDA calculations
(by other authors) shows band gap of 3.36 eV and experimental is 1.1
eV.<BR><BR>So is the PP which I am using gives this much band gap?<BR>or there
is some error in my cal.? I am sending the scf file. Please check it and
suggest me.<BR>thanks<BR><BR><BR><BR clear=all><BR>-- <BR>Bipul Rakshit<BR>PhD
Student, <BR>Barkatullah University,<BR>Bhopal 462026,<BR>MP, India<BR>
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