External_pressure

[tao liu]

Dear ALL,

What I want to do at the moment is to optimize the cubic MgO structure 
(both cell parameter and atom position) at a certain pressure 10000 bar (T 
= 0 K, no MD) . I don't know why my calculation complete normally, but the 
stress tensor shows that the final Stress is about 595 bar. Could anyone 
suggest me what's wrong with the input file, Is it a correct input file for 
optimizing cell parameter and atom position at the same time?
Thanks.

Tao



*file.inp*
&GLOBAL
  PROJECT     CELL_pressure
  RUN_TYPE    CELL_OPT
  PRINT_LEVEL low
&END GLOBAL

&MOTION
  &PRINT
    &STRESS
    &END STRESS
  &END PRINT
  &CELL_OPT
    TYPE GEO_OPT
    OPTIMIZER LBFGS
    MAX_ITER 30
    EXTERNAL_PRESSURE [bar] 10000.0 0.0 0.0 0.0 1000.0 0.0 0.0 0.0 10000.0
    KEEP_ANGLES
    KEEP_SYMMETRY
  &END
  &GEO_OPT
    MAX_ITER 300
    MINIMIZER LBFGS
  &END
  &PRINT
    &END
  &END
&END


&FORCE_EVAL                                                                                                                                                                         

  
&PRINT                                                                                                                                                                            

    
&STRESS_TENSOR                                                                                                                                                                  

      NDIGITS 
4                                                                                                                                                                     

    &END 
STRESS_TENSOR                                                                                                                                                              

  &END 
PRINT                                                                                                                                                                        


  METHOD Quickstep
  &DFT            
    BASIS_SET_FILE_NAME GTH_BASIS_SETS
    POTENTIAL_FILE_NAME GTH_POTENTIALS
    &MGRID                                          
      CUTOFF 300                                    
    &END MGRID                                      
    &QS                                             
    &END QS                                         
    &SCF                                            
    &END SCF                                        
    &XC                                             
      &XC_FUNCTIONAL LDA                            
       &PADE .TRUE.                                 
       &END PADE                                    
      &END XC_FUNCTIONAL
    &END XC
  &END DFT
  &SUBSYS
    &CELL
      ABC 4.0 4.0 4.0
      SYMMETRY cubic
    &END CELL
    &COORD
    SCALED
Mg   0.000000000         0.000000000         0.000000000
Mg   0.000000000         0.500000000         0.500000000
Mg   0.500000000         0.000000000         0.500000000
Mg   0.500000000         0.500000000         0.000000000
O    0.500000000         0.500000000         0.500000000
O    0.500000000         0.000000000         0.000000000
O    0.000000000         0.500000000         0.000000000
O    0.000000000         0.000000000         0.500000000

    &END COORD
    &KIND Mg
      BASIS_SET SZV-GTH
      POTENTIAL GTH-lda-q2
    &END KIND

    &KIND O
      BASIS_SET SZV-GTH
      POTENTIAL GTH-lda-q6
    &END KIND

  &END SUBSYS
  STRESS_TENSOR ANALYTICAL
&END FORCE_EVAL


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