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<font color="#FF0000">Dear Dr. Blaha</font>
<p>Peter Blaha wrote:
<blockquote TYPE=CITE><i>I guess we don"t understand each other.</i><i></i>
<p><i>I can see that the energy is decreasing. But I still don"t know for
wich</i>
<br><i>calculation it occurs.</i>
<br><i>From your first struct file, I saw CXZ lattice with monoclinic angle.</i>
<br><i>First of all only an angle gamma (not alpha) is allowed.</i>
<br><i>Secondly, the calculations may simply be wrong because of the well
known</i>
<br><i>CXZ bug with monoclinic angle.</i></blockquote>
<font color="#FF0000">As I mentioned before the CXZ was not correct file
please ignore of that file.</font>
<br><font color="#FF0000">every detail that I sent was belong to P lattice
with non rectangular cell.</font>
<blockquote TYPE=CITE><i>Now if the problem comes from a rectangular P
calculation, my next</i>
<br><i>suggestion was:</i>
<br><i>a) You did not converge with -fc (but -cc or -ec) and thus your
forces</i>
<br><i>are not correct. Of course in such a case when you minimize the
wrong</i>
<br><i>forces, E-tot will rise.</i></blockquote>
<font color="#FF0000">I used of mini program with following command in
order to minimized force.</font>
<br><b><font color="#FF0000"> min_lapw -I -j 'runsp_lapw
-it -p -i 99 -fc 1.5'</font></b>
<br>
<blockquote TYPE=CITE>
<br><i>b) Forces can be "wrong", when R0 for a heavier element (Mn) is
too large.</i>
<br><i>While the R0 for Si might be ok, for Mn it might be not.</i></blockquote>
<font color="#FF0000">Be sure I will check for smaller R0 but you should
consider I used of this value in rectangular cell and it has not such a
big influence.</font>
<blockquote TYPE=CITE>
<br><i>c) Could it be that you have broken the symmetry by some wrong movements</i>
<br><i>of some atoms ? Also in such a case the forces might be wrong.</i>
<br><i>(I'm surprised that right at the beginning you have such a low symmetry.
I</i>
<br><i>thought this is fcc-Si and one Mn is substituting one Si? It should
not</i>
<br><i>have forces, but some higher symmetry???</i></blockquote>
<font color="#FF0000">This is not bulk calculation, this is a surface and
I have 2 symmetry operation (inversion and identity symmetry). this is
Si surface with Si-dimer on top most layer + Mn as an adsorbate atom on
this surface.</font>
<blockquote TYPE=CITE><i></i>
<br><i>d) Why would you fix both, Mn and some (distant) Si atoms ?</i></blockquote>
<font color="#FF0000">We performed this calculation in order to find Potential
Energy Surface for adsorbate atom then we should fix the position of adatom,
also we treat The atoms in middle layer as a bulk for this reason,
atom 14-17 are fixed.</font>
<blockquote TYPE=CITE>
<p>I hope I could explaine what I want to do and what is my problem.</blockquote>
thank you for your attention,
<br>Mahbube.
<br>--
<br>---------------------------------------------------------------------------
<br>Mahbube Hortamani
<p>Fritz-Haber-Institut
<br>der Max-Planck-Gesellschaft
<br>Abteilung Theorie
<br>Faradayweg 4-6
<br>D-14 195 Berlin-Dahlem / Germany
<p>Phone : ++49-30-8413 4820
<br>Fax : ++49-30-8413 4701
<br>E-mail : hortaman@fhi-berlin.mpg.de
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