<div dir="ltr"><div>Thanks Dr. Tran,</div><div><br></div><div><br></div><div><br></div><div class="gmail_extra">My mistake, the standard value is 0.25!!</div><div class="gmail_extra"><br></div><div class="gmail_extra">Yes, I saw the link you provided (response was on my own queries).</div><div class="gmail_extra"><br></div><div class="gmail_extra"><br></div><div class="gmail_extra">What is advised there is:</div><div class="gmail_extra"> <br></div><br><div>"What you get from the optic calculation (the case.epsilon) file is only the electronic part (and not even the whole electronic part) of the dielectric constant."</div><div><br></div><div>To get the ionic part of the static dielectric constant you would need to do the BERRYPI calculations to get Born effective charges tensors."</div><div><br></div><div><br></div><div><br></div><div>Do you have any previous experience on how much the properties may vary if we avoid the "ionic part of the dielectric constant'?</div><div> <br></div><br><div><br></div><div>Thanks and regards</div><div><br></div><div><br></div><div><br></div><div><br></div><div><br></div><div><br></div><div class="gmail_extra"><br></div><div class="gmail_extra"><br><div class="gmail_quote">On Sat, Aug 4, 2018 at 7:13 PM, <span dir="ltr"><<a href="mailto:tran@theochem.tuwien.ac.at" target="_blank">tran@theochem.tuwien.ac.at</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Hi,<br>
<br>
First, the standard value is 0.25 and not 0.025.<br>
<br>
For the dielectric constant, there was alreday some explanations here:<br>
<a href="https://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/msg14936.html" rel="noreferrer" target="_blank">https://www.mail-archive.com/w<wbr>ien@zeus.theochem.tuwien.ac.at<wbr>/msg14936.html</a><br>
<a href="https://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/msg14875.html" rel="noreferrer" target="_blank">https://www.mail-archive.com/w<wbr>ien@zeus.theochem.tuwien.ac.at<wbr>/msg14875.html</a><br>
<br>
alpha_opt at V=V_exp means that the dielectric function (and alpha_opt)<br>
is calculated only at V_exp and then used for all other volumes.<br>
See also this:<br>
<a href="https://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/msg15531.html" rel="noreferrer" target="_blank">https://www.mail-archive.com/w<wbr>ien@zeus.theochem.tuwien.ac.at<wbr>/msg15531.html</a><br>
<br>
No, it is not mandatory to do PBE calculation before YS-PBE0. Starting<br>
YS-PBE0 from PBE electron density (case.clmsum) may just help to reduce<br>
the number of SCF iterations with YS-PBE0.<br>
<br>
Of course it is possible to optimize lattice parameters with YS-PBE0.<br>
You just need to add the "-hf" option in the optimize.job file.<br>
What is not possible with YS-PBE0 is to optimize the position of<br>
atoms in the unit cell (because the forces are not implemented for<br>
YS-PBE0).<br>
<br>
FT<br>
<br>
<br>
On Saturday 2018-08-04 14:46, Dr. K. C. Bhamu wrote:<br>
<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
Date: Sat, 4 Aug 2018 14:46:02<br>
From: Dr. K. C. Bhamu <<a href="mailto:kcbhamu85@gmail.com" target="_blank">kcbhamu85@gmail.com</a>><br>
Reply-To: A Mailing list for WIEN2k users <<a href="mailto:wien@zeus.theochem.tuwien.ac.at" target="_blank">wien@zeus.theochem.tuwien.ac.<wbr>at</a>><br>
To: A Mailing list for WIEN2k users <<a href="mailto:Wien@zeus.theochem.tuwien.ac.at" target="_blank">Wien@zeus.theochem.tuwien.ac.<wbr>at</a>><br>
Subject: [Wien] regarding mixing parameter in hybrid calculations<br>
<br>
Dear Dr. Tran,<br>
<br>
In the recent past, I did some calculations using YS-PBE0 for MgO and results were well reproduced (wien2k Exercise).<br>
<br>
I just read your paper (J. Phys.: Condens. Matter 25 (2013)) and get to know that we can control the mixing parameter using various ways.<br>
<br>
1) Standard value (0.025)<br>
2) By fitting (alpa_opt)<br>
3) alpa_opt (V=V_exp)<br>
<br>
I have queries for option 2 and 3 alpa:<br>
<br>
2) If I am not wrong (after having a detailed search), the value of dielectric constant used to get alpa_opt is the value of dielectric constant from<br>
Rel(epsilon) at energy 0.013610 eV, right?<br>
<br>
3) How to get alpa_opt at V-V_exp?<br>
<br>
<br>
<br>
<br>
<br>
My next query is:<br>
<br>
It is reported in the Wien2k exercise that to do YS-PBE0 calculations we need to do a simple PBE scf. So if we really need to perform PBE calculations before<br>
going to YS-PBE0, I am wondering how to use YS-PBE0 to optimize the lattice parameters and to get structural properties?<br>
<br>
<br>
Could you please advice me on my concerns?<br>
<br>
* in above text "_" means an underscore.<br>
<br>
<br>
regards<br>
<br>
<br>
<br>
</blockquote>
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