[CP2K-user] EXTERNAL_PRESSURE and PRESSURE_TOLERANCE settings in cell optimisations for crystals

Huaiyang Sun shyf... at gmail.com
Wed Nov 25 15:49:59 UTC 2020


Thank you, Matt. I've found a TZVP-MOLOPT-SR-GTH-q11basis set for Y in 
BASIS_MOLOPT_UCL.

Sincerely,
Huaiyang Sun



On Wednesday, November 25, 2020 at 10:48:55 PM UTC+8 Matt W wrote:

> You can find some good quality basis sets in in BASIS_MOLOPT_UCL:
>
> https://github.com/cp2k/cp2k/blob/master/data/BASIS_MOLOPT_UCL
>
> there are also some alternative Lanthanide basis sets available in other 
> files.
>
> Matt
>
> On Wednesday, November 25, 2020 at 2:44:47 PM UTC sh... at gmail.com wrote:
>
>> Dear Fabian,
>> Thanks for the explanation! I've noticed the CELL_REF and OT issues of 
>> the input file. The CP2K output file also hints about the OT algorithm.   
>> The reason I use DZV-GTH-PADE basis for Y is that I cannot find GTH-PBE 
>> basis set for it in the cp2k/data directory. Maybe I should find the 
>> corresponding basis set in somewhere else.
>> Anyway, thanks for your help and suggestions!
>>
>> Best regards.
>> Huaiyang Sun
>>
>> On Wednesday, November 25, 2020 at 3:26:58 PM UTC+8 fa... at gmail.com 
>> wrote:
>>
>>> Dear Huaiyang Sun,
>>>
>>> Many solids have a bulk modulus in the range of 1 to 100 GPa. A material 
>>> with a bulk modulus of 10 GPa changes its volume by 1% when subjected to a 
>>> pressure of 1000 bar. In this case a PRESSURE_TOLERANCE of 100 bar is 
>>> already accurate to within 0.1% of the volume.
>>>
>>> The input file has some issues:
>>> use CELL_REF for a cell optimization
>>> you cannot use OT together with k-points, use DIAGONALIZATION instead
>>> I would recomment to not mix different basis sets, especially not using 
>>> PADE ones for PBE calculations
>>>
>>> Cheers,
>>> Fabian
>>> On Wednesday, 25 November 2020 at 04:09:02 UTC+1 sh... at gmail.com 
>>> wrote:
>>>
>>>>
>>>> Deal all,
>>>>
>>>> I'm doing a cell optimisation run of a YAG (Y3Al5O12) crystal. I wonder 
>>>> about the meaning of the tags EXTERNAL_PRESSURE and PRESSURE_TOLERANCE in 
>>>> the CELL_OPT section of the input. The default values are both 100 bar. 
>>>> Here are the few points I don't understand,
>>>>
>>>> 1. If the cell optimisation run is targeted at the input 
>>>> EXTERNAL_PRESSURE, shouldn't the default PRESSURE_TOLERANCE be given a much 
>>>> smaller value, like 5.0 or 1.0 bar?
>>>>
>>>> 2. Why 100 bar? 1 atm = 1.013 bar sounds more reasonable.
>>>>
>>>> 3. My simple understanding of cell optimisation is to find the minimum 
>>>> point of the energy-volume (E-V) curve. Then what's the role of external 
>>>> pressure?
>>>>
>>>> Here is my input file.
>>>>
>>>> &GLOBAL
>>>>   project  pristine-opt
>>>>   run_type CELL_OPT
>>>>   print_level MEDIUM
>>>> &END GLOBAL
>>>>
>>>> &FORCE_EVAL
>>>>   METHOD QS
>>>>
>>>>   &SUBSYS
>>>>     &CELL 
>>>>       ABC  12.0003 12.0003 12.0003  
>>>>       PERIODIC XYZ 
>>>>       MULTIPLE_UNIT_CELL  1   1   1
>>>>       SYMMETRY CUBIC 
>>>>     &END CELL
>>>>
>>>>     &TOPOLOGY
>>>>       MULTIPLE_UNIT_CELL  1   1   1
>>>>       COORD_FILE_FORMAT XYZ
>>>>       COORD_FILE_NAME yag_from_cif_conven_unit.xyz 
>>>>     &END TOPOLOGY
>>>>
>>>>     &KIND Y
>>>>       ELEMENT Y
>>>>       BASIS_SET DZV-GTH-PADE
>>>>       POTENTIAL GTH-PBE-q11
>>>>     &END KIND 
>>>>
>>>>
>>>>     &KIND Al
>>>>       ELEMENT Al
>>>>       BASIS_SET DZVP-MOLOPT-SR-GTH 
>>>>       POTENTIAL GTH-PBE-q3
>>>>     &END KIND 
>>>>
>>>>     &KIND O
>>>>       ELEMENT O
>>>>       BASIS_SET DZVP-GTH-PBE
>>>>       POTENTIAL GTH-PBE-q6
>>>>     &END KIND
>>>>
>>>>     &KIND Ce
>>>>       ELEMENT Ce
>>>>       BASIS_SET DZVP-MOLOPT-SR-GTH-q12
>>>>       POTENTIAL GTH-PBE-q12
>>>>     &END KIND
>>>>
>>>>     &KIND Yb
>>>>       ELEMENT Yb
>>>>       BASIS_SET DZVP-MOLOPT-SR-GTH-q24
>>>>       POTENTIAL GTH-PBE-q24
>>>>     &END KIND
>>>>
>>>>   &END SUBSYS
>>>>
>>>>   &DFT
>>>>     BASIS_SET_FILE_NAME BASIS_SET_YAG
>>>>     POTENTIAL_FILE_NAME POTENTIAL_YAG
>>>>
>>>>     &MGRID
>>>>       NGRIDS 4
>>>>       CUTOFF 600
>>>>       REL_CUTOFF 60
>>>>     &END MGRID
>>>>
>>>>     &QS
>>>>       EPS_DEFAULT 1.0E-12
>>>>     &END QS
>>>>
>>>>     &POISSON
>>>>       PERIODIC XYZ
>>>>     &END POISSON
>>>>
>>>>     &SCF
>>>>       SCF_GUESS ATOMIC
>>>>       EPS_SCF 5.0E-7
>>>>       MAX_SCF 200 
>>>>
>>>>       CHOLESKY INVERSE 
>>>>
>>>>       &OT ON
>>>>         MINIMIZER DIIS
>>>>       &END OT
>>>>       #&DIAGONALIZATION 
>>>>       #  ALGORITHM STANDARD
>>>>       #&END DIAGONALIZATION 
>>>>
>>>>       # ADDED_MOS 30
>>>>       #
>>>>       # &SMEAR ON
>>>>       # METHOD FERMI_DIRAC
>>>>       # ELECTRONIC_TEMPERATURE [K] 300
>>>>       #&END SMEAR 
>>>>
>>>>       # &MIXING
>>>>       #  METHOD BROYDEN_MIXING
>>>>       #  ALPHA 0.4
>>>>       #  BETA 0.5
>>>>       #  NBROYDEN 8
>>>>       # &END MIXING 
>>>>     &END SCF
>>>>
>>>>     &XC
>>>>       &XC_FUNCTIONAL PBE
>>>>       &END XC_FUNCTIONAL 
>>>>     &END XC
>>>>
>>>>     &KPOINTS
>>>>       EPS_GEO 1.0E-5
>>>>       SCHEME MONKHORST 3 3 3
>>>>     &END KPOINTS
>>>>   &END DFT
>>>>
>>>>   &PRINT
>>>>     &TOTAL_NUMBERS ON
>>>>     &END TOTAL_NUMBERS
>>>>   &END PRINT
>>>>   
>>>>   STRESS_TENSOR ANALYTICAL 
>>>> &END FORCE_EVAL
>>>>
>>>> &MOTION
>>>>   &GEO_OPT
>>>>     OPTIMIZER LBFGS
>>>>     TYPE MINIMIZATION
>>>>     MAX_DR   5.0E-4
>>>>     MAX_FORCE 5.0E-4
>>>>     RMS_DR  5.0E-4
>>>>     RMS_FORCE 5.0E-4
>>>>     MAX_ITER 500
>>>>   &END GEO_OPT
>>>>
>>>>   &CELL_OPT
>>>>     TYPE DIRECT_CELL_OPT
>>>>     OPTIMIZER LBFGS
>>>>     KEEP_SYMMETRY
>>>>     MAX_DR 5.0E-4
>>>>     MAX_FORCE 1.0E-4
>>>>     RMS_DR 5.0E-4
>>>>     RMS_FORCE 5.0E-4
>>>>     # defaults for p and delta p [bar]
>>>>     EXTERNAL_PRESSURE   100.0 0.0 0.0    0.0 100.0 0.0   0.0 0.0 100.0
>>>>     PRESSURE_TOLERANCE  100.0
>>>>   &END CELL_OPT
>>>> &END MOTION 
>>>>
>>>>
>>>>
>>>>
>>>> Thank you,
>>>> Huaiyang Sun
>>>>
>>>>
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