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    <div class="moz-cite-prefix">Hello Mohammad,<br>
      <br>
      For pure non-periodic clusters you may be able to try calculating
      optical properties in Gaussian. I'm not sure any kind of periodic
      code would be able to provide you with confinement, because
      confinement requires constrained dimensions which you are
      effectively removing by infinitely repeating your unit cell.<br>
      <br>
      I am of course not sure whether you are studying colloidal quantum
      dots (nanocrystals) or the embedded kind in a semiconductor. I
      assume in theory you can represent some kind of quantum dot array
      in giant cells but once again it will become very heavy to
      calculate and I fear I'm not quite sure how you would get useful
      properties out of it. If you did that, maybe by studying the
      average potential variations throughout the cell you can study
      confinement, but I have no experience in this. If the confinement
      does not have to be 3-dimensional you can of course create an
      epitaxial structure in programs such as wien.<br>
      <br>
      I myself use VASP and wien for my calculations but i only look at
      surface adsorption so I approximate them by infinite surfaces.
      Another program that may be useful for semi-periodic structures is
      Crystal09 which seems to also be able to do 1D and 2D&nbsp; structures,
      avoiding any artefacts you get from for instance repeating a
      surface slab in its surface direction.<br>
      <br>
      You will most likely know best how your system looks like and what
      specific properties you need to extract useful data though.<br>
      <br>
      <br>
      Regards,<br>
      <br>
      Michael Sluydts<br>
      <br>
      Op 16/05/2013 10:38, Lawal Mohammed schreef:<br>
    </div>
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      cite="mid:1368693516.33416.YahooMailNeo@web125706.mail.ne1.yahoo.com"
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        <div><span>Hello Michael and Co,<br>
          </span></div>
        <div style="color: rgb(0, 0, 0); font-size: 16px; font-family:
          times new roman,new york,times,serif; background-color:
          transparent; font-style: normal;"><span>Can you please suggest
            any periodic code for quantum confinement effect? And </span>how
          can confinement and surface effects be neglected, in such case
          what will be implication. please elaborate.<br>
        </div>
        <div>With kind regards</div>
        <div>Mohammed<br>
        </div>
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          serif; font-size: 12pt;">
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              <hr size="1"> <font face="Arial" size="2"> <b><span
                    style="font-weight:bold;">From:</span></b> Michael
                Sluydts <a class="moz-txt-link-rfc2396E" href="mailto:Michael.Sluydts@UGent.be">&lt;Michael.Sluydts@UGent.be&gt;</a><br>
                <b><span style="font-weight: bold;">To:</span></b> A
                Mailing list for WIEN2k users
                <a class="moz-txt-link-rfc2396E" href="mailto:wien@zeus.theochem.tuwien.ac.at">&lt;wien@zeus.theochem.tuwien.ac.at&gt;</a> <br>
                <b><span style="font-weight: bold;">Sent:</span></b>
                Wednesday, May 15, 2013 3:49 PM<br>
                <b><span style="font-weight: bold;">Subject:</span></b>
                Re: [Wien] Need assistance<br>
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                  <div class="yiv6592978983moz-cite-prefix">Hello
                    Mohammad,<br>
                    <br>
                    It all depends what you want to do. Wien2k is
                    optimal for calculating properties of periodic
                    structures, so it is mostly recommended for bulk.<br>
                    <br>
                    For confinement effects aperiodic code is
                    recommended. However it is unlikely you will ever be
                    able to calculate optical properties of anything
                    larger than a small cluster aperiodically
                    (extrapolation is of course a useful tool).<br>
                    <br>
                    I myself do use periodic DFT to estimate surface
                    adsorption on colloidal quantum dots, so you'll have
                    to pick the right tool for whatever you are
                    interested in.<br>
                    <br>
                    <br>
                    Regards,<br>
                    <br>
                    Michael Sluydts<br>
                    <br>
                    <br>
                    Op 15/05/2013 9:37, Lawal Mohammed schreef:<br>
                  </div>
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                    <div
                      style="color:#000;background-color:#fff;font-family:times
                      new roman, new york, times, serif;font-size:12pt;">
                      <div>Dear Wien2k Community,</div>
                      <div>I am a new user of Wien2k code. I want to
                        know if it is possible to do simulation study of
                        quantum dots using Wien2k. Actually, I am about
                        to start a research on quantum dots based
                        materials for intermediate band solar cells.
                        Therefore, I really need to know the potential
                        of Wien2k package. Could you please help me?</div>
                      <div>With kind regards</div>
                      <div>Mohammed Lawal<br>
                      </div>
                      <div> <br>
                      </div>
                    </div>
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