[CP2K:4105] cell opt of TiO2, give a wrong result, anyone help

jjf_... at yahoo.com.cn jjf_... at yahoo.com.cn
Sun Oct 21 16:30:17 CEST 2012


Thanks, It worked.

在 2012年10月21日星期日UTC+8下午2时15分21秒,sandeep写道:
>
> Hi,
>     Few comments that might help you in getting right structure. 
>
> 1. Your cell parameters are very small. You need to take bigger cell and 
> repeat the calculations. 
>
> take at least  2 x 2 x 3  cell. (or better choice is 3 x 3 x 4)
>
> 2. Your cutoff value is less. Try increase to 280 Ry or above. or If you 
> are not sure about cut off value, pl. do set of single point calculations 
> by varying density cutoff. Check for energy convergence. 
>
>
> Wishes,
> Sandeep
>
>
> On Sun, Oct 21, 2012 at 9:52 AM, jjf... at yahoo.com.cn <javascript:> <
> jjf... at yahoo.com.cn <javascript:>> wrote:
>
>> Hi, energyone 
>>
>> I want use cp2k to optimzie the cell of TiO2, The following is the input 
>> file:
>>
>> &FORCE_EVAL
>>  STRESS_TENSOR ANALYTICAL
>>  METHOD Quickstep
>>  &DFT
>>    BASIS_SET_FILE_NAME /scratch/cp2k/BASIS_MOLOPT
>>    POTENTIAL_FILE_NAME /scratch/cp2k/GTH_POTENTIALS
>>    &MGRID
>>      CUTOFF 200
>>    &END MGRID
>>    &QS
>>      METHOD GPW
>>    &END QS
>>    &SCF
>>      EPS_SCF 5.E-7
>>      MAX_SCF 500
>>      &OT
>>        MINIMIZER CG
>>      &END
>>    &END SCF
>>    &XC
>>      &XC_FUNCTIONAL PBE
>>      &END XC_FUNCTIONAL
>>    &END XC
>>  &END DFT
>>  &SUBSYS
>>    &CELL
>>         ABC  4.594 4.594 2.959
>>         PERIODIC XYZ
>>    &END CELL
>>   &TOPOLOGY
>>    &END TOPOLOGY
>>  &COORD
>> Ti   -0.0000   -0.0000    0.0000
>> Ti    2.2970    2.2970    1.4795
>> O     1.4003    1.4003    0.0000
>> O     3.1937    3.1937    0.0000
>> O     0.8967    3.6973    1.4795
>> O     3.6973    0.8967    1.4795
>>    &END COORD
>>     &KIND TI
>>     BASIS_SET DZVP-MOLOPT-SR-GTH
>>     POTENTIAL GTH-PBE-q12
>>    &END KIND
>>    &KIND O
>>     BASIS_SET DZVP-MOLOPT-SR-GTH
>>     POTENTIAL GTH-PBE-q6
>>    &END KIND
>>  &END SUBSYS
>> &END FORCE_EVAL
>>  &MOTION
>>  &CELL_OPT
>>    KEEP_ANGLES .TRUE.
>>    OPTIMIZER CG
>>    &CG
>>     &LINE_SEARCH
>>      TYPE 2PNT
>>     &END LINE_SEARCH
>>    &END CG
>>  &END CELL_OPT
>>  &GEO_OPT
>>    OPTIMIZER BFGS
>>  &END GEO_OPT
>>  &END MOTION
>> &GLOBAL
>>  PROJECT TiO2
>>  RUN_TYPE CELL_OPT
>>  PRINT_LEVEL LOW
>> &END GLOBAL
>>
>>
>> When completing, It give the cell parameters:
>> 5.54 5.58 2.96
>> and the Coordinate:
>> Ti         0.4095385769        0.2898267710       -0.0352843895
>> Ti         3.1801930298        2.1516147238        1.4539613109
>>  O         1.9175831463        1.4494611116       -0.0449395166
>>  O         3.4936489849        3.0632060642       -0.0346941550
>>  O         0.7216799169        4.9591730884        1.4533505831
>>  O         4.6832547080        0.9868972431        1.4635018888
>>
>> The a and b is remarkable larger than exp. value. More importantly, Some 
>> Ti-O bond are broken, see the fig. below:
>>   
>> Anyone can give suggestion about how to do it?
>>
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>
>
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