[Pw_forum] converge problem in calculating the vacancy on TiO2 surfaces

vega lew quantumdft at gmail.com
Sun Mar 1 09:19:06 CET 2009


Dear all,

I am planning to calculate the Oxygen vacancy properties of TiO2 surfaces.
The calculation for the ideal surfaces are quite normal and the results are
in line with the one that literature reported.  But, when I tried to
calculate the anatase 101 surface with an Oxygen vacancy (O2c was removed
directly from the stoichiometric Anatase 101as described in J. Phys. Chem. C
2007, 111, 16397-16404, I encounter the problem of convergence for SCF
cycle. I tried to add 20% more  empty band to the system the problem still
laid in. How could I overcome the problem?

my input file was attached at the bottom of the mail

thank you for reading. Any hints will be appreciated.

vega



 &CONTROL

                       title = 'Anatase 101 1x3'
,
                 calculation = 'relax'
,
                restart_mode = 'from_scratch'
,
                      outdir = '/tmp/' ,
                      wfcdir = '/tmp/'
,
                  pseudo_dir = '/home/vega/espresso-4.0/pseudo/' ,
                      prefix = 'Anatase 101 1x3'
,
                     disk_io = 'none'
,
                       nstep = 1000
,
 /

 &SYSTEM

                       ibrav =
8,
                   celldm(1) =19.3269,
                   celldm(2) = 1.1094,
                   celldm(3) = 1.7450,
                         nat =
71,
                        ntyp =
2,
                       nosym = .true.
,
                   ecutwfc   =   30,
                   ecutrho   =  300,
 /

 &ELECTRONS



 /

 &IONS

                ion_dynamics = 'bfgs'
,
 /

ATOMIC_SPECIES

   Ti   47.86700
Ti.pw91-sp-van_ak.UPF
    O   15.99940
O.pw91-van_ak.UPF
ATOMIC_POSITIONS
crystal
Ti    0.79001   0.05515   0.04075      0   0   0
Ti    0.92677   0.05515   0.23765      1   1   1
Ti    0.29001   0.22181   0.04075      0   0   0
Ti    0.42677   0.22181   0.23765      1   1   1
Ti    0.57420   0.22181   0.08998      0   0   0
Ti    0.71096   0.22181   0.28687      1   1   1
Ti    0.07420   0.05515   0.08998      0   0   0
Ti    0.21096   0.05515   0.28687      1   1   1
O     0.61134   0.05515   0.08150      0   0   0
O     0.74810   0.05515   0.27840      1   1   1
O     0.11134   0.22181   0.08150      0   0   0
O     0.24810   0.22181   0.27840      1   1   1
O     0.39553   0.22181   0.13073      0   0   0
O     0.53229   0.22181   0.32763      1   1   1
O     0.89553   0.05515   0.13073      0   0   0
O     0.03229   0.05515   0.32763      1   1   1
O     0.25286   0.05515   0.04922      0   0   0
O     0.38962   0.05515   0.24612      1   1   1
O     0.75286   0.22181   0.04922      0   0   0
O     0.88962   0.22181   0.24612      1   1   1
O     0.46867   0.22181   0.00000      0   0   0
O     0.60543   0.22181   0.19690      1   1   1
O     0.96867   0.05515   0.00000      0   0   0
O     0.10543   0.05515   0.19690      1   1   1
Ti    0.79001   0.38848   0.04075      0   0   0
Ti    0.92677   0.38848   0.23765      1   1   1
Ti    0.29001   0.55515   0.04075      0   0   0
Ti    0.42677   0.55515   0.23765      1   1   1
Ti    0.57420   0.55515   0.08998      0   0   0
Ti    0.71096   0.55515   0.28687      1   1   1
Ti    0.07420   0.38848   0.08998      0   0   0
Ti    0.21096   0.38848   0.28687      1   1   1
O     0.61134   0.38848   0.08150      0   0   0
O     0.74810   0.38848   0.27840      1   1   1
O     0.11134   0.55515   0.08150      0   0   0
O     0.24810   0.55515   0.27840      1   1   1
O     0.39553   0.55515   0.13073      0   0   0
#O     0.53229   0.55515   0.32763      1   1   1
O     0.89553   0.38848   0.13073      0   0   0
O     0.03229   0.38848   0.32763      1   1   1
O     0.25286   0.38848   0.04922      0   0   0
O     0.38962   0.38848   0.24612      1   1   1
O     0.75286   0.55515   0.04922      0   0   0
O     0.88962   0.55515   0.24612      1   1   1
O     0.46867   0.55515   0.00000      0   0   0
O     0.60543   0.55515   0.19690      1   1   1
O     0.96867   0.38848   0.00000      0   0   0
O     0.10543   0.38848   0.19690      1   1   1
Ti    0.79001   0.72181   0.04075             0   0   0
Ti    0.92677   0.72181   0.23765      1   1   1
Ti    0.29001   0.88848   0.04075      0   0   0
Ti    0.42677   0.88848   0.23765      1   1   1
Ti    0.57420   0.88848   0.08998      0   0   0
Ti    0.71096   0.88848   0.28687      1   1   1
Ti    0.07420   0.72181   0.08998      0   0   0
Ti    0.21096   0.72181   0.28687      1   1   1
O     0.61134   0.72181   0.08150      0   0   0
O     0.74810   0.72181   0.27840      1   1   1
O     0.11134   0.88848   0.08150      0   0   0
O     0.24810   0.88848   0.27840      1   1   1
O     0.39553   0.88848   0.13073      0   0   0
O     0.53229   0.88848   0.32763      1   1   1
O     0.89553   0.72181   0.13073      0   0   0
O     0.03229   0.72181   0.32763      1   1   1
O     0.25286   0.72181   0.04922      0   0   0
O     0.38962   0.72181   0.24612      1   1   1
O     0.75286   0.88848   0.04922      0   0   0
O     0.88962   0.88848   0.24612      1   1   1
O     0.46867   0.88848   0.00000      0   0   0
O     0.60543   0.88848   0.19690      1   1   1
O     0.96867   0.72181   0.00000      0   0   0
O     0.10543   0.72181   0.19690      1   1   1
K_POINTS gamma

-- 
==================================================================================
Vega Lew ( weijia liu)
PH.D Candidate in Chemical Engineering
State Key Laboratory of Materials-oriented Chemical Engineering
College of Chemistry and Chemical Engineering
Nanjing University of Technology, 210009, Nanjing, Jiangsu, China
******************************************************************************************************************
Email: vegalew at gmail.com
Office: Room A705, Technical Innovation Building, Xinmofan Road 5#, Nanjing,
Jiangsu, China
******************************************************************************************************************
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