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Dear Arnaud,<br>
<br>
We have done such calculations few years ago in the case of LiMoS2 material
(space group : P-1). The main problem in such optimization of the unit cell
is to optimized independently quantities that are dependent from each others.
<br>
One way to proceed is to optimize the cell parameters in an iterative way,
as well the cell parameter lengths as the angle values. Such calculations
can take many times because for each minimum value of each parameter you
need to check the other parameters.<br>
Depending of your structure, such calculations can be very time consuming.
In our case, the structure had a 2D character. Thus it was easier to find
a global minimum.<br>
<br>
In a general point of view, the more efficient way to proceed is to evaluate
the stress tensor of the cell. Such feature is available in other codes such
as abinit (that is free - gnu license). Today, I'm using such pseudopotential
code for the geometry optimization and Wien2k for the chemical bond analysis
and the properties simulations. The use of this two complementary tools is
very powerful in terms of cpu time. Moreover, if you calculate the atomic
force in the wien code using the pseudopotential optimized structure, the
agreement is usually very good.<br>
<br>
With my best regards<br>
<br>
Xavier<br>
<br>
Xavier Rocquefelte<br>
Institut des Matériaux Jean Rouxel<br>
Nantes, France<br>
<br>
<br>
<br>
<a class="moz-txt-link-abbreviated" href="mailto:arnaud.vaseur@laposte.net">arnaud.vaseur@laposte.net</a> a écrit:<br>
<blockquote type="cite"
cite="midHK7WOW$58384E1707D44E659F987BAB298F907F@laposte.net">
<p class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span lang="EN-GB"
style=""><font size="3"><font face="Times New Roman">Dear WIEN2K users,
I have question about optimization of an monoclinic structure, so to do that
have I to optimize c/a, v, b/a, v, ...., c/a, v, b/a, v, in SCF manner until
convergence of the structure or can I perform just one <span style=""> </span>c/a,
b/a, v optimization ? How can I to optimize i.e. beta angel? <span
style=""> </span>Any comments are welcome. <o:p></o:p></font></font></span></p>
<p class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span lang="EN-GB"
style=""><o:p><font face="Times New Roman" size="3"> </font></o:p></span></p>
<p class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span lang="EN-GB"
style=""><font size="3"><font face="Times New Roman">Thank you in advance
<span style=""> </span><span style=""> </span><span style=""> </span><o:p></o:p></font></font></span></p>
<p class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span lang="EN-GB"
style=""><o:p><font face="Times New Roman" size="3"> </font></o:p></span></p>
<p class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span lang="EN-GB"
style=""><font size="3"><font face="Times New Roman">Arnaud <o:p></o:p></font></font></span></p>
<br>
<br>
Accédez au courrier électronique de La Poste : <a class="moz-txt-link-abbreviated" href="http://www.laposte.net">www.laposte.net</a> ; <br>
3615 LAPOSTENET (0,34€/mn) ; tél : 08 92 68 13 50 (0,34€/mn) </blockquote>
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