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[Anglade Pierre-Matthieu <anglade@gmail.com>]

Hi,

I wonder if this problem could be solved by enforcing "nsym 1" in your system 
?

regards

PMA


On Fri, Feb 27, 2009 at 11:18 AM, Quan Phung Manh <manhquank9@gmail.com> 
wrote:
> I'm learning CO on TiO2 surface using Molecular dynamics. This is the input
> file
>
> #Definition of the k-point grids
> kptopt 1
> nshiftk 2
> shiftk  0.5 0.0 0.0
>         0.0 0.5 0.0
> ngkpt  2 2 1
>
> #Definition of the unit cell
> acell 5.5045254737E+00  1.2085958617E+01  3.9054040855E+01
>
> #Definition of the atom types
> ntypat 5
> znucl 22 8 1 6 8
>
> #Definition of the atoms
> natom 27
> typat 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 3 3 4 5
> xangst
> 0.000000000     3.433979661     1.702548614
> 0.000000000    -0.030909893     4.965652343
> 0.000000000     3.183736244     8.301964739
> 0.000000000    -0.007453315    11.238648984
> 1.456434713     0.249962141     1.826819536
> 1.456434713     3.160658047     4.997001953
> 1.456434713    -0.015133698     8.106539672
> 1.456434713     3.191007391    11.602913960
> 0.000000000     3.134088248     3.712077931
> 0.000000000    -0.036979110     6.917159950
> 0.000000000     3.187105620    10.148049014
> 0.000000000     0.085095967     3.023282974
> 0.000000000     3.185355376     6.258969546
> 0.000000000    -0.016913131     9.441795449
> 0.000000000     3.189623132    12.679519266
> 1.456434713     4.628213937     1.641901518
> 1.456434713     1.210599710     5.011844303
> 1.456434713     4.461364915     8.201911335
> 1.456434713     1.198244350    11.547258895
> 1.456434713     2.045849552     1.627326844
> 1.456434713     5.122602774     4.938437347
> 1.456434713     1.894988115     8.197087652
> 1.456434713     5.182999613    11.552484499
> 0.000000000     3.197805952     0.000000000
> 2.912869425     0.000000000     0.700956091
> 0.000000000    -0.007453315    13.738648984
> 0.000000000    -0.007453315    14.866648984
>
> natfix 25
> iatfix 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25
>
> #Definition of the planewave basis set
> ecut  40.0
>
> #Definition of the SCF procedure
> nstep 200              # Maximal number of SCF cycles
> tolmxf  5.0d-4
> toldff  5.0d-5
>
> #Optimization of the lattice parameters
> ionmov  9              # Langevin molecular dynamics
> ntime  20
> mditemp 100
> iprcel 45
>
> occopt 3
> tsmear 9.5d-5
>
> And I have many warnings in MOLDYN STEP NUMBER    1. For example
>  symatm : WARNING -
>   Trouble finding symmetrically equivalent atoms
>   Applying inv of symm number  2 to atom number   1  of typat  1
>   gives tratom= -1.0111E-03  5.3775E-01  8.2374E-02.
>   This is further away from every atom in crystal than the allowed
> tolerance.
>   The inverse symmetry matrix is -1  0  0
>                                   0  1  0
>                                   0  0  1
>   and the nonsymmorphic transl. tnons =    0.0000000    0.0000000
> 0.0000000
>   The nearest coordinate differs by -2.022E-03  0.000E+00  0.000E+00
>   for indsym(nearest atom)=    1
>
>   This indicates that when symatm attempts to find atoms symmetrically
>   related to a given atom, the nearest candidate is further away than some
>   tolerance.  Should check atomic coordinates and symmetry group input data.
>
> and an error
>  symatm : ERROR -
>   Largest error (above) is so large that either input  atomic coordinates
> (xred)
>   are wrong or space group symmetry data is wrong.
>   Action : correct your input file.
>
>  leave_new : decision taken to exit ...
>
> I choose ionmov = 1 and have no error.
>
> Is there anything wrong with the input file?
>
> Best regards
> --
> Quan Phung Manh
> Khoa Hoá học - ĐH Khoa học tự nhiên - 19 Lê Thánh Tông Hà Nội
> ĐT: 01663 922 302
>



-- 
Pierre-Matthieu Anglade