<div dir="ltr">Dear Prof. Blaha,<br><br>Thank you so much for your help.<br>I think I have found the way to solve my problem.<br><br>Best Regards,<br>Zhiyong Zhu<br><br><div class="gmail_quote">On Tue, Jan 3, 2012 at 10:54 AM, Peter Blaha <span dir="ltr"><<a href="mailto:pblaha@theochem.tuwien.ac.at">pblaha@theochem.tuwien.ac.at</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="border-left:1px solid rgb(204,204,204);margin:0pt 0pt 0pt 0.8ex;padding-left:1ex"><div class="im"><blockquote class="gmail_quote" style="border-left:1px solid rgb(204,204,204);margin:0pt 0pt 0pt 0.8ex;padding-left:1ex">
Take a material, in which only one internal freedom x exists, as an example.<br>
If I do a series of total energy calculations with difference x and find a<br>
energy surface with respect to x, then I can obtain a force by taking a<br>
energy derivative with respect to x. Is the force obtained by this method<br>
meaningful (even in the presence of spin orbit coupling)?<br>
</blockquote>
<br></div>
Yes of course. (But once you have calculated the total energies, you can find the minimum<br>
and you don't "need" the forces).<div class="im"><br>
<br>
<blockquote class="gmail_quote" style="border-left:1px solid rgb(204,204,204);margin:0pt 0pt 0pt 0.8ex;padding-left:1ex">
> PS: As mentioned in UG, you can switch off SO for light atoms (eg. oxygens), and then the forces for<br>
> those atoms are still ok and meaningful.<br>
==============================<u></u>======================<br>
Does this mean that the spin-orbit term of Pulay correction for the<br>
investigated atom, eg. oxygen, comes from the oxygen itself only,<br>
and is irrelevant to those atoms around the oxygen?<br>
</blockquote>
<br></div>
Yes.<br><font color="#888888">
<br>
-- <br>
<br>
P.Blaha<br>
------------------------------<u></u>------------------------------<u></u>--------------<br>
Peter BLAHA, Inst.f. Materials Chemistry, TU Vienna, A-1060 Vienna<br>
Phone: +43-1-58801-165300 FAX: +43-1-58801-165982<br>
Email: <a href="mailto:blaha@theochem.tuwien.ac.at" target="_blank">blaha@theochem.tuwien.ac.at</a> WWW: <a href="http://info.tuwien.ac.at/theochem/" target="_blank">http://info.tuwien.ac.at/<u></u>theochem/</a><br>
------------------------------<u></u>------------------------------<u></u>--------------<br>
______________________________<u></u>_________________<br>
Wien mailing list<br>
<a href="mailto:Wien@zeus.theochem.tuwien.ac.at" target="_blank">Wien@zeus.theochem.tuwien.ac.<u></u>at</a><br>
<a href="http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien" target="_blank">http://zeus.theochem.tuwien.<u></u>ac.at/mailman/listinfo/wien</a><br>
</font></blockquote></div><br></div>