<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
<style type="text/css" style="display:none;"> P {margin-top:0;margin-bottom:0;} </style>
</head>
<body dir="ltr">
<div style="font-family: Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
Dear all,</div>
<div style="font-family: Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
<br>
</div>
<div style="font-family: Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
I have asked this question a week ago but did not get an answer. I am asking it again ; maybe it got missed.</div>
<div style="font-family: Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
<br>
</div>
<div style="font-family: Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
<pre>I am working on Carbon quantum dots (CQD) systems. As is well known, these are
0D systems, that is the motion of the electrons are confined in the three
directions. In my understanding, they are confined to a single point the k=0
(Gamma point).</pre>
<pre> 1. How do we simulate CQD in QE? I have formed the system and put vacuum in
all three directions (23 angstroms). Regarding the K_POINTS, i have only
included the Gamma point. is that correct?
2. How to calculate the optical properties via let us say the epsilon.x
toolset? Would we just run an scf calculation at the single Gamma point and
then run epsilon.x ?<br><br></pre>
<pre><div><span>3. I tried vc-relaxing the system I have got, but the structure was destroyed. Any advice on what parameters should be set to treat</span></div><ol><li style="display:block"><span>quantum dots. I have even used the option assume_isolated='martyna-tuckerman'.</span></li></ol><div><br></div><div>Any help would be highly appreciated.<br></div></pre>
<br>
</div>
<div style="font-family: Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
<br>
</div>
<div style="font-family: Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
<br>
</div>
</body>
</html>