No subject


Wed Jul 6 14:13:09 CEST 2005


First of all only an angle gamma (not alpha) is allowed.
Secondly, the calculations may simply be wrong because of the well known
CXZ bug with monoclinic angle.

Now if the problem comes from a rectangular P calculation, my next
suggestion was:
a) You did not converge with -fc (but -cc or -ec) and thus your forces
are not correct. Of course in such a case when you minimize the wrong
forces, E-tot will rise.
b) Forces can be "wrong", when R0 for a heavier element (Mn) is too large.
While the R0 for Si might be ok, for Mn it might be not.
c) Could it be that you have broken the symmetry by some wrong movements
of some atoms ? Also in such a case the forces might be wrong.
(I'm surprised that right at the beginning you have such a low symmetry. I
thought this is fcc-Si and one Mn is substituting one Si? It should not
have  forces, but some higher symmetry???
d) Why would you fix both, Mn and some (distant) Si atoms ?

Please start over from an "ideal" structure with smaller R0. Just go on as
long E-tot decreases, but it is useless to continue for 20 or more
steps when E-tot rises.


>   Force for first and last two iterations from *.scf_mini file
>
>   :FGL001:   1.ATOM                        24.059        -16.881         -4.469
>   :FGL002:   2.ATOM                        -6.802          9.612         11.051
>   :FGL003:   3.ATOM                        -4.368          3.764          4.618
>   :FGL004:   4.ATOM                       -20.239         35.836         31.756
>   :FGL005:   5.ATOM                         3.157         13.709         12.698
>   :FGL006:   6.ATOM                         0.940         15.235         12.055
>   :FGL007:   7.ATOM                       -12.235         15.651         12.699
>   :FGL008:   8.ATOM                        -8.978         11.244         11.697
>   :FGL009:   9.ATOM                        -3.306         12.310          8.888
>   :FGL010:  10.ATOM                         1.628          2.925          0.406
>   :FGL011:  11.ATOM                        -4.995         13.456         18.024
>   :FGL012:  12.ATOM                        -5.050          7.108          6.447
>   :FGL013:  13.ATOM                        -1.347         -1.638         -1.134
>   :FGL014:  14.ATOM                       -26.940         44.450         37.416
>   :FGL015:  15.ATOM                       -35.284         47.530         38.351
>   :FGL016:  16.ATOM                       -11.786         49.034         40.891
>   :FGL017:  17.ATOM                       -40.286         43.123         33.653
>
>
> ********************************************************************************************
>
>   :FGL001:   1.ATOM                        24.123        -25.233        -18.147
>   :FGL002:   2.ATOM                        -0.173         -0.104         -0.386
>   :FGL003:   3.ATOM                         0.268          1.231          1.113
>   :FGL004:   4.ATOM                         0.019          0.425          0.158
>   :FGL005:   5.ATOM                         0.241          1.509          1.160
>   :FGL006:   6.ATOM                         0.553          2.056          2.128
>   :FGL007:   7.ATOM                        -0.231         -0.481         -0.416
>   :FGL008:   8.ATOM                         0.253          1.112          1.143
>   :FGL009:   9.ATOM                         0.212          0.789          1.032
>   :FGL010:  10.ATOM                         0.138          0.268          0.456
>   :FGL011:  11.ATOM                         0.046         -0.077          0.241
>   :FGL012:  12.ATOM                        -0.034          0.100          0.040
>   :FGL013:  13.ATOM                         0.054          0.239          0.435
>   :FGL014:  14.ATOM                       -26.826         46.568         42.144
>   :FGL015:  15.ATOM                       -37.760         58.469         46.499
>   :FGL016:  16.ATOM                       -14.238         57.585         50.945
>   :FGL017:  17.ATOM                       -42.535         46.324         36.899
>
>
> **********************************************************************************************
>
>   :FGL001:   1.ATOM                        24.118        -25.266        -18.214
>   :FGL002:   2.ATOM                        -0.154         -0.133         -0.394
>   :FGL003:   3.ATOM                         0.239          1.090          0.984
>   :FGL004:   4.ATOM                         0.026          0.395          0.156
>   :FGL005:   5.ATOM                         0.214          1.413          1.077
>   :FGL006:   6.ATOM                         0.485          1.857          1.915
>   :FGL007:   7.ATOM                        -0.213         -0.425         -0.354
>   :FGL008:   8.ATOM                         0.240          1.045          1.081
>   :FGL009:   9.ATOM                         0.187          0.712          0.931
>   :FGL010:  10.ATOM                         0.124          0.197          0.376
>   :FGL011:  11.ATOM                         0.059         -0.077          0.226
>   :FGL012:  12.ATOM                        -0.030          0.105          0.044
>   :FGL013:  13.ATOM                         0.039          0.202          0.389
>   :FGL014:  14.ATOM                       -26.793         46.586         42.160
>   :FGL015:  15.ATOM                       -37.740         58.490         46.507
>   :FGL016:  16.ATOM                       -14.240         57.598         50.960
>   :FGL017:  17.ATOM                       -42.525         46.336         36.912
>
>   Please keep in your mind that the positions of first atom and last four atoms are
> fixed. here you can see *.inM file.
>
>   NEWT 2.0           #(NOSE, NEWT, BFGS, MOLD, tolf (a4,f5.2))
>   0.0 0.0 0.0 0.0    # Atom1
>   0.5 0.5 0.5 0.5    # Atom2
>   0.5 0.5 0.5 0.5    # Atom3
>   0.5 0.5 0.5 0.5    # Atom4
>   0.5 0.5 0.5 0.5    # Atom5
>   0.5 0.5 0.5 0.5    # Atom6
>   0.5 0.5 0.5 0.5    # Atom7
>   0.5 0.5 0.5 0.5    # Atom8
>   0.5 0.5 0.5 0.5    # Atom9
>   0.5 0.5 0.5 0.5    # Atom10
>   0.5 0.5 0.5 0.5    # Atom11
>   0.5 0.5 0.5 0.5    # Atom12
>   0.5 0.5 0.5 0.5    # Atom13
>   0.0 0.0 0.0 0.0    # Atom14   (NOSE, MOLD:Masse, delta t, T, nose-frequency)
>   0.0 0.0 0.0 0.0    # Atom15   (NEWT: 1,2,3:delta, 4:eta(1=MOLD))
>   0.0 0.0 0.0 0.0    # Atom16   (BFGS, NEWT: [ 1 || 2 || 3 ] = 0 constraint)
>   0.0 0.0 0.0 0.0    # Atom17
>
>   thank you for your attention,
>   Mahbube.
>
>   Peter Blaha wrote:
>
>     I just noticed that your R0 for Mn is fairly large and not the WIEN2k
>     default. maybe this results in wrong forces, where zero force does not
>     correspond to E-min.
>     Another point: Mn as 3d element should have a larger sphere than Si
>     Just another silly check: Are you sure you converged with -fc and have the
>     valence forces in case.scf_mini.
>
>


                                      P.Blaha
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Peter BLAHA, Inst.f. Materials Chemistry, TU Vienna, A-1060 Vienna
Phone: +43-1-58801-15671             FAX: +43-1-58801-15698
Email: blaha at theochem.tuwien.ac.at    WWW: http://info.tuwien.ac.at/theochem/
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