[Pw_forum] (no subject)

Pallavi Bothra pallavi.bothra43 at gmail.com
Fri Dec 27 11:33:53 CET 2013


Dear PWSCF users,
                                  I am trying to find out activation energy
barrier using the following input file:

BEGIN
BEGIN_PATH_INPUT
&PATH
  restart_mode      = 'from_scratch'
  string_method     = 'neb',
  nstep_path        = 20,
  ds                = 2.D0,
  opt_scheme        = "broyden",
  num_of_images     = 13,
  k_max             = 0.3D0,
  k_min             = 0.2D0,
  path_thr          = 0.1D0,
  CI_scheme         = "auto",
/
END_PATH_INPUT
BEGIN_ENGINE_INPUT
&CONTROL
                      outdir = './temp' ,
                  pseudo_dir = '/lustre/home/pati/dibyajyoti/pseudo' ,
                      prefix = 'Pt' ,


/
&SYSTEM
                          ibrav = 0,
                         celldm(1) = 1.8903
                         nat = 10,
                        ntyp = 3,
                     ecutwfc = 30 ,
                     ecutrho = 300 ,
                 occupations = 'smearing' ,
                    smearing = 'marzari-vanderbilt' ,
                    degauss = 0.01
                     nspin = 2
                   starting_magnetization = 0.5
                   nbnd = 43

/
 &ELECTRONS
              electron_maxstep = 1000 ,
                 conv_thr = 1.0d-10
                 mixing_beta = 0.2 ,
                mixing_ndim = 10
               mixing_mode = 'local-TF',

/
 &IONS
               upscale = 100 ,

/
ATOMIC_SPECIES
Pt   195.084  Pt.pbe-n-rrkjus.UPF
C     12.0107  C.pbe-rrkjus.UPF
O     15.9994  O.pbe-rrkjus.UPF
BEGIN_POSITIONS
FIRST_IMAGE
ATOMIC_POSITIONS angstrom
Pt       1.850700972   1.443626858   0.453046673
Pt       0.943102964  -0.609627043   1.659354547
Pt      -0.798952486  -1.224214284  -0.100158908
Pt      -2.211088061   0.532477856  -1.210633206
Pt      0.270075228   0.834135105  -1.601571936
Pt       1.835978831  -0.859969770  -0.656743659
Pt      -0.639803936   1.200085717   0.697528230
C       -1.060512280  -2.400253027   1.556970754
O       -0.145487591  -2.112102579   2.495594831
O       -1.947109262  -3.229564672   1.624429613
LAST_IMAGE
ATOMIC_POSITIONS angstrom
Pt       2.264303115   1.248048227  -0.373892267
Pt      1.233936451   0.429684066   1.664068322
Pt     -0.599847604  -1.184402943   0.479361678
Pt      -2.264784842   0.422857144  -0.859094096
Pt      0.154170583   0.511311728  -1.355526205
Pt      1.788026807  -1.237306598  -0.282147524
Pt     -1.090091750   1.304671686   1.067520981
C       -1.183511240  -2.839811696   1.082397758
O       -0.053539990   1.362720752   2.762505051
O       -1.560582512  -3.882441918   1.450309452

END_POSITIONS
K_POINTS gamma

CELL_PARAMETERS
15.00  0.000  0.000
0.000   15.000  0.000
0.000  0.000  15.0000
END_ENGINE_INPUT
END

Here I have optimized the initial and final configuration using the same
above-mentioned parameters.

Now my output file is as follows:
            tcpu =      0.5    self-consistency for image   1
     tcpu =    241.7    self-consistency for image   2
     tcpu =    488.9    self-consistency for image   3
     tcpu =   1528.9    self-consistency for image   4
     tcpu =   1946.8    self-consistency for image   5
     tcpu =   2173.8    self-consistency for image   6
     tcpu =   2394.8    self-consistency for image   7
     tcpu =   2606.1    self-consistency for image   8
     tcpu =   2818.9    self-consistency for image   9
     tcpu =   3035.4    self-consistency for image  10
     tcpu =   3240.4    self-consistency for image  11
     tcpu =   3451.0    self-consistency for image  12
     tcpu =   3652.6    self-consistency for image  13

     activation energy (->) =   3.653530 eV
     activation energy (<-) =   4.304438 eV

     image        energy (eV)        error (eV/A)        frozen

         1      -6602.5486692            0.022305            T
         2      -6602.0377242            1.565266            F
         3      -6601.0045584            3.796768            F
         4      -6600.1369964            6.450495            F
         5      -6599.5968046            9.161897            F
         6      -6599.1340788           12.357714            F
         7      -6598.8951396           15.478612            F
         8      -6599.1668824           15.915268            F
         9      -6600.0106926           13.371867            F
        10      -6601.1786031            9.108378            F
        11      -6602.2646119            4.906636            F
        12      -6602.9623766            2.160567            F
        13      -6603.1995776            0.022152            T

     climbing image =  7

     path length          =  7.695 bohr
     inter-image distance =  0.641 bohr

     ------------------------------ iteration   2
------------------------------

     tcpu =   3850.9    self-consistency for image   2
     tcpu =   4044.8    self-consistency for image   3
     tcpu =   4238.3    self-consistency for image   4
     tcpu =   4683.9    self-consistency for image   5
     tcpu =   4895.3    self-consistency for image   6
     tcpu =   5105.9    self-consistency for image   7
     tcpu =   5408.6    self-consistency for image   8
     tcpu =   5620.6    self-consistency for image   9
     tcpu =   5849.9    self-consistency for image  10
     tcpu =   6057.8    self-consistency for image  11
     tcpu =   6230.2    self-consistency for image  12

     activation energy (->) =   2.062313 eV
     activation energy (<-) =   2.713222 eV


-----------------------------------------
------------------------------------------

GOING ON

----------------------------------------------
--------------------------------------------------
   ------------------------------ iteration   7
------------------------------

     tcpu =  18797.0    self-consistency for image   2
     tcpu =  18990.2    self-consistency for image   3
     tcpu =  19167.7    self-consistency for image   4
     tcpu =  19373.5    self-consistency for image   5
     tcpu =  19550.3    self-consistency for image   6
     tcpu =  19735.4    self-consistency for image   7
     tcpu =  19928.9    self-consistency for image   8
     tcpu =  20208.5    self-consistency for image   9
     tcpu =  20414.3    self-consistency for image  10
     tcpu =  20601.5    self-consistency for image  11
     tcpu =  20797.3    self-consistency for image  12

     activation energy (->) =   0.870973 eV
     activation energy (<-) =   1.521881 eV

     image        energy (eV)        error (eV/A)        frozen

         1      -6602.5486692            0.022305            T
         2      -6602.3736900            0.418040            F
         3      -6602.0387523            0.866756            F
         4      -6602.4903013            1.278867            F
         5      -6602.6203749            1.591716            F
         6      -6602.4366766            1.877891            F
         7      -6602.0438039            6.617516            F
         8      -6601.6776962            9.883500            F
         9      -6602.1051387            9.603478            F
        10      -6602.5765272            7.925611            F
        11      -6602.9662496            4.279627            F
        12      -6603.1521927            1.394729            F
        13      -6603.1995776            0.022152            T

     climbing image =  8

     path length          =  8.676 bohr
     inter-image distance =  0.723 bohr

     ------------------------------ iteration   8
------------------------------

     tcpu =  20970.9    self-consistency for image   2
     tcpu =  21179.9    self-consistency for image   3
     tcpu =  21361.6    self-consistency for image   4
     tcpu =  21610.7    self-consistency for image   5
     tcpu =  21795.2    self-consistency for image   6
     tcpu =  21975.4    self-consistency for image   7
     tcpu =  22174.0    self-consistency for image   8
     tcpu =  22394.2    self-consistency for image   9
     tcpu =  22588.3    self-consistency for image  10
      tcpu =  22790.2    self-consistency for image  11
     tcpu =  22963.6    self-consistency for image  12

     activation energy (->) =   0.428213 eV
     activation energy (<-) =   1.079121 eV

     image        energy (eV)        error (eV/A)        frozen

         1      -6602.5486692            0.022305            T
         2      -6602.3935880            0.506242            F
         3      -6602.1204563            1.078653            F
         4      -6602.7001074            1.279534            F
         5      -6602.8317653            1.500866            F
         6      -6602.6432007            0.976795            F
         7      -6602.4268968            1.081261            F
         8      -6602.2149366            2.153274            F
         9      -6602.6011231            1.898303            F
        10      -6602.9175545            1.150728            F
        11      -6603.0816841            0.278682            F
        12      -6603.1673752            0.239983            F
        13      -6603.1995776            0.022152            T

     climbing image =  3

     path length          =  9.060 bohr
     inter-image distance =  0.755 bohr

     So, here in the last iteration it is found that image 4, 5 and 6 are
lower in energy than the initial one.
But how is it possible?
What is the wrong in the procedure?

Thank you very much

Regards
 Pallavi Bothra
Graduate student
JNCASR, Bangalore
India
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