[Pw_forum] [pw-forum]: Celldm(4) Celldm(5) Celldm(6)

[Francesco Pelizza]

Hi dear Users and Developers,

I really need a full explanation on how to get Celldm(4) Celldm(5) 
Celldm(6) from a VC-relaxation.

The optimized structure of a system with angles between a-lat b-lat a 
c-lat not equals to 90° is given to me in some systems I am studying,

But I can not find a way of putting this in a new input file.

If I masure with xcrysden the inclination between periodic images, I got 
an angle that if i translate in the cosine value and put it into the 
input file, it does not give me the right angle when I open again the 
input file with xcrysden.
Also a SCF calculation does not give a value identical or not even 
slightly different from the VC-rel calculation itself.

So, How can I find out exactly Celldm(4) Celldm(5) Celldm(6) from this 
piece of output file?

How do I put this in an input file being sure that quantum espresso will 
consider this value for building the lattice and doing the calculation 
properly ??

Thank you very much for your time and patience

Francesco Pelizza - PhD
Strathclyde University (Glasgow)

HERE you can find an output file as example


Begin final coordinates
      new unit-cell volume =   3435.21521 a.u.^3 (   509.04637 Ang^3 )

CELL_PARAMETERS (alat=  9.35454172)
    1.031703302  -0.002607611   0.034483284
   -0.004621093   2.150980697   0.080635052
   -0.031624028   0.077886584   1.892891072

ATOMIC_POSITIONS (angstrom)
H        2.323443642   3.458500775   8.048639166
H        2.246157109   6.259499847   5.493082766
H        2.238584163   4.257844190   0.859706518
H        3.682576551   4.461248011   7.513953456
H        3.660946840   5.289309420   5.076217107
H        2.349858362   7.288089944   3.177035899
H        3.698019711   6.240499825   2.728594264
H        3.699705365   5.164845115   0.461710112
F        2.578959296   7.555136884   0.769673740
F        0.723629375   6.423372715   1.255939854
F        2.384732674   3.966152941   3.106747236
F        0.653462109   5.273905894   3.651911386
F        2.644696706   2.964473519   5.656123191
F        0.735387849   4.041727492   6.056045010
F        0.629819356   5.581707632   8.226678603
F        2.449175259   6.758487891   7.688004312
F        4.791542403   2.350295723   2.918699000
F        5.145230100   1.372558160   5.464114891
H        3.794899005   0.874565766   1.033564982
H        3.767987315   0.169480940   8.124815255
F        1.620809549   1.343881537   2.353960638
H        0.055376396   1.880995718   0.351068538
F        1.746935882   0.059135078   4.717276882
H        0.118749183   1.089942064   7.543474278
H        0.038360119   8.721213695   5.604899727
H        0.156416543   9.733931543   3.301761239
F        1.606381831   9.555176644   7.542110410
F        1.724803088  10.423382736   0.580085061
H        3.762597275   9.742742557   6.180086748
H        3.818806059  10.647160213   3.895291475
F        4.834332727   8.431554403   8.190079715
F        5.022683471   9.219462377   1.286641665
C        4.861902815   0.149655116   8.161361938
C        4.884761682   0.947642455   1.045408665
C        0.337188869   0.143176054   4.742567438
C        0.232687916   1.146022481   2.332101032
C        2.593624135   4.380706568   7.522390456
C        2.129082034   4.198114186   6.068998645
C        2.035262317   5.577048626   8.307268734
C        2.567916441   5.297168460   5.092510941
C        2.062790705   5.205690370   3.651450062
C        2.607997073   5.181809062   0.410338732
C        2.124256003   6.343778231   1.286849130
C        2.609613700   6.314467444   2.746950137
C        0.204140831   9.649137133   7.505914552
C        0.317897336  10.413912382   0.493174549
C        4.910634377  10.672243764   3.875929892
C        4.854146045   9.672373698   6.207264609
End final coordinates