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<div class="">Let me share what I have found so far. I hope someone can at least verify if the following is correct:</div>
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<div class="">1. in plot_1d routine of chdens.f90, the plotted x-axis is deltax*dble(i-1).</div>
<div class="">2. deltax = m1 / (nx - 1)</div>
<div class="">3. and m1 = sqrt (e1 (1)**2 + e1 (2)**2 + e1 (3)**2)</div>
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<div class="">So in my case, m1, which is the modulus of e1=0.333 in alat units. That’s why the x-axis runs from 0 to ~0.33. However, the origin of the plot is (0,0,0) and not x0.</div>
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<div class="">Thank you,</div>
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<div class="">Vahid</div>
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<div class="">On Jun 20, 2017, at 4:12 PM, Vahid Askarpour <<a href="mailto:vh261281@dal.ca" class="">vh261281@dal.ca</a>> wrote:</div>
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<div class="">Just a correction to my pp.x input file:</div>
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<div class="">I actually used cartesian coordinates for the e1 and x0. So</div>
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<div class="">0.3571863 0.2721583 0.1838386 for x0 and</div>
<div class="">0.1171583 0.2721583 0.1535005 for e1.</div>
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<div class="">Vahid</div>
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<div class="PlainText">Dear QE Users,<br class="">
<br class="">
In order to calculate the total potential along one of the SnSe bonds (Se2-Sn4), I first performed a self-consistent run with the following lattice parameters.<br class="">
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ibrav=8, celldm(1)=21.34350847, celldm(2)=0.3628777, celldm(3)=0.38586894<br class="">
<br class="">
Sn 0.882841736 0.250000000 0.602195343<br class="">
Sn 0.617158264 0.750000000 0.102195343<br class="">
Sn 0.382841736 0.250000000 0.897804657<br class="">
Sn 0.117158264 0.750000000 0.397804657<br class="">
Se 0.142813748 0.250000000 0.976427467<br class="">
Se 0.357186252 0.750000000 0.476427467<br class="">
Se 0.642813748 0.250000000 0.523572533<br class="">
Se 0.857186252 0.750000000 0.023572533<br class="">
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I then ran pp.x with the following input:<br class="">
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&inputpp<br class="">
prefix = 'SnSe'<br class="">
filplot = 'potential.dat'<br class="">
plot_num= 1<br class="">
/<br class="">
&plot<br class="">
iflag=1<br class="">
output_format=0<br class="">
nfile = 1<br class="">
filepp(1) = 'potential.dat'<br class="">
e1(1)=0.117158264, e1(2)=0.750000000, e1(3)= 0.397804657,<br class="">
x0(1)=0.357186252, x0(2)= 0.750000000, x0(3)=0.476427467,<br class="">
nx=100, <br class="">
fileout= 'VSe2_Sn4.dat’<br class="">
/<br class="">
<br class="">
The bond length is 2.73A=5.16Bohr. Attached is the output of potential vs. distance. The x-axis runs from 0 to ~0.33. According to other links in the Forum, the x-axis is in atomic units. Two possibilities:<br class="">
<br class="">
1. The distance is in Bohr. So is the pp.x code plotting from 0 to 0.33 Bohr even though the bond length is 5.16Bohr as defined by the vectors x0 and e1?<br class="">
2. The distance is in alat. Then 0.33*alat=7.04Bohr. This is longer than the bond length.<br class="">
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So what is the unit of the x-axis?<br class="">
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Thank you,<br class="">
<br class="">
Vahid<br class="">
<br class="">
Vahid Askarpour<br class="">
Department of Physics and Atmospheric Science<br class="">
Dalhousie University,<br class="">
Halifax, NS, Canada<br class="">
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<span id="cid:7da36dd6-ba51-42c9-a450-cefd9690d036@namprd03.prod.outlook.com" class=""><SnSe_potential.pdf></span>_______________________________________________<br class="">
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