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<p class=MsoNormal><font size=2 face="Times New Roman"><span style='font-size:
11.0pt'>Dear Wien2k users, <o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face="Times New Roman"><span style='font-size:
11.0pt'>I have been getting all negative dispersion curves for an orthorhombic
supercell (12 atom, 18 atom both, 24 atom) <o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face="Times New Roman"><span style='font-size:
11.0pt'>Now I have taken a 3x2x1 supercell (36 atoms) {since the z lattice
parameter is 8.2 A)<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face="Times New Roman"><span style='font-size:
11.0pt'>Although, this question is not directly related to Wien2k, I request
all users who are doing phonon calculations <o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face="Times New Roman"><span style='font-size:
11.0pt'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face="Times New Roman"><span style='font-size:
11.0pt'>In phonon software, we carry out the following for the creation of the
d45 file <o:p></o:p></span></font></p>
<ol style='margin-top:0in' start=1 type=1>
<li class=MsoNormal style='mso-list:l0 level1 lfo1'><font size=2
face="Times New Roman"><span style='font-size:11.0pt'>Define the lattice
parameters (optimized before by Wien2k) (I am using Pnma_51 space group)<o:p></o:p></span></font></li>
<li class=MsoNormal style='mso-list:l0 level1 lfo1'><font size=2
face="Times New Roman"><span style='font-size:11.0pt'>Define the number of
displacive particles(non-equivalent atoms etc.)<o:p></o:p></span></font></li>
<li class=MsoNormal style='mso-list:l0 level1 lfo1'><font size=2
face="Times New Roman"><span style='font-size:11.0pt'>Define the
coordinates of the displacive particles <o:p></o:p></span></font></li>
<li class=MsoNormal style='mso-list:l0 level1 lfo1'><font size=2
face="Times New Roman"><span style='font-size:11.0pt'>Then we have <o:p></o:p></span></font></li>
<ol style='margin-top:0in' start=1 type=a>
<li class=MsoNormal style='mso-list:l0 level2 lfo1'><st1:place w:st="on"><st1:PlaceName
w:st="on"><font size=2 face="Times New Roman"><span style='font-size:
11.0pt'>Interaction</span></font></st1:PlaceName><font size=2><span
style='font-size:11.0pt'> <st1:PlaceType w:st="on">Range-</st1:PlaceType></span></font></st1:place><font
size=2 face=Wingdings><span style='font-size:11.0pt;font-family:Wingdings'>à</span></font><font
size=2><span style='font-size:11.0pt'> Coordination Shell <o:p></o:p></span></font></li>
<li class=MsoNormal style='mso-list:l0 level2 lfo1'><font size=2
face="Times New Roman"><span style='font-size:11.0pt'>Interaction Range-</span></font><font
size=2 face=Wingdings><span style='font-size:11.0pt;font-family:Wingdings'>à</span></font><font
size=2><span style='font-size:11.0pt'> Supercell Size (Restore symmetry
or not, +/- displacements or not etc.)<o:p></o:p></span></font></li>
</ol>
</ol>
<p class=MsoNormal><font size=2 face="Times New Roman"><span style='font-size:
11.0pt'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face="Times New Roman"><span style='font-size:
11.0pt'>Now in (a), the default is 1. How do we choose this number. Does the
d45 file change if we change this number<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face="Times New Roman"><span style='font-size:
11.0pt'>With Pnma as space group and three in-equivalent atoms, what should I
put for a 3x2x1 supercell <o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face="Times New Roman"><span style='font-size:
11.0pt'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face="Times New Roman"><span style='font-size:
11.0pt'>Thanks in advance <o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face="Times New Roman"><span style='font-size:
11.0pt'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face="Times New Roman"><span style='font-size:
11.0pt'>Suddhasattwa <o:p></o:p></span></font></p>
<p class=MsoNormal style='margin-left:.25in'><font size=2 face="Times New Roman"><span
style='font-size:11.0pt'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face="Times New Roman"><span style='font-size:
11.0pt'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face="Times New Roman"><span style='font-size:
11.0pt'><o:p> </o:p></span></font></p>
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