<html xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:m="http://schemas.microsoft.com/office/2004/12/omml" xmlns="http://www.w3.org/TR/REC-html40"><head><meta http-equiv=Content-Type content="text/html; charset=us-ascii"><meta name=Generator content="Microsoft Word 15 (filtered medium)"><style><!--
/* Font Definitions */
@font-face
{font-family:SimSun;
panose-1:2 1 6 0 3 1 1 1 1 1;}
@font-face
{font-family:PMingLiU;
panose-1:2 2 5 0 0 0 0 0 0 0;}
@font-face
{font-family:PMingLiU;
panose-1:2 2 5 0 0 0 0 0 0 0;}
@font-face
{font-family:Calibri;
panose-1:2 15 5 2 2 2 4 3 2 4;}
@font-face
{font-family:"\@PMingLiU";
panose-1:2 2 5 0 0 0 0 0 0 0;}
@font-face
{font-family:SimSun;
panose-1:2 1 6 0 3 1 1 1 1 1;}
/* Style Definitions */
p.MsoNormal, li.MsoNormal, div.MsoNormal
{margin:0cm;
margin-bottom:.0001pt;
font-size:11.0pt;
font-family:"Calibri","sans-serif";}
a:link, span.MsoHyperlink
{mso-style-priority:99;
color:#0563C1;
text-decoration:underline;}
a:visited, span.MsoHyperlinkFollowed
{mso-style-priority:99;
color:#954F72;
text-decoration:underline;}
span.EmailStyle17
{mso-style-type:personal-compose;
font-family:"Calibri","sans-serif";
color:windowtext;}
.MsoChpDefault
{mso-style-type:export-only;
font-family:"Calibri","sans-serif";}
@page WordSection1
{size:612.0pt 792.0pt;
margin:72.0pt 90.0pt 72.0pt 90.0pt;}
div.WordSection1
{page:WordSection1;}
--></style><!--[if gte mso 9]><xml>
<o:shapedefaults v:ext="edit" spidmax="1026" />
</xml><![endif]--><!--[if gte mso 9]><xml>
<o:shapelayout v:ext="edit">
<o:idmap v:ext="edit" data="1" />
</o:shapelayout></xml><![endif]--></head><body lang=EN-GB link="#0563C1" vlink="#954F72"><div class=WordSection1><p class=MsoNormal>Dear users,<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>I was trying to produce a plot the imaginary part of dielectric constant against the frequency (eV).<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>I performed the SCF and then EPSILON calculation on a wurtzite bulk ZnO (after relaxation). <o:p></o:p></p><p class=MsoNormal>The calculated bandgap for GGA-PBE is around 0.5-1.0eV so I would expect the threshold of the graph should be around that value.<o:p></o:p></p><p class=MsoNormal>However, the threshold is found starting at zero. Something is not right here.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>I enclose my input and output files. Could you shed some light?<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Best,<o:p></o:p></p><p class=MsoNormal>Geoffrey<o:p></o:p></p><p class=MsoNormal><span style='font-size:14.0pt;color:black'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:8.0pt;color:black'>+--------------------------------</span><span style='font-size:8.0pt;color:black'>---------------------------------------------</span><span style='font-size:8.0pt;color:black'><o:p></o:p></span></p><p class=MsoNormal><span style='font-size:8.0pt'>H.Y Geoffrey Tse, Postdoctoral, <o:p></o:p></span></p><p class=MsoNormal><span style='font-size:8.0pt'>Room N202, Physics Building<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:8.0pt'>Peking University<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:8.0pt'>Haidian District<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:8.0pt'>Beijing 100871<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:8.0pt'>P.R China<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:8.0pt'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:8.0pt'>Tel: (+86) 18811792348<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:8.0pt'>Email: geoffrey.tse@pku.edu.cn<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:8.0pt;color:black'>+--------------------------------</span><span style='font-size:8.0pt;color:black'>---------------------------------------------</span><span style='font-size:8.0pt;color:black'><o:p></o:p></span></p><p class=MsoNormal><o:p> </o:p></p></div></body></html>