No subject

The value remain the same when calculate by same number of CPUs and pools. There would 
be  only a little different for different number of CPUs and pools, less than 0.01% in energy.

     K-point  mesh      Pseudopotentials  Cutoff  / Ry      Anatase  lattice parameters      time        a=b      c      Energy  / Ry      CPU      Wall        experiment*      x      3.78216      9.50465      x      x      x        CASTEP      400 eV      3.7987      9.6934      -730.11745                      gamma  (1X1X1)      30,240      3.39021      11.77804      -725.08174      4m18.70s      18m 9.12s        2X2X1      30£¬240      3.8683      9.0275      -725.48834      8m 4.25s       32m33.56s        4X4X2      25,200      3.7500      9.3829      -725.41398      9m58.82s      17m46.87s        30,240      3.7899      9.6203      -725.49520      3m41.55s      7m50.32s        40,320      3.7850      9.5716      -725.54336      8m54.73s      34m  1.43s        50,400      3.7926      9.6366      -725.59434      10m14.46s      41m  3.22s        7X7X3      30,240      3.7919      9.6058      -725.49443      31m59.60s      46m37.77s        10X10X4      30,240      3.7916      9.6067      -725.49451      31m32.94s      44m  4.11s   
The input file as follows,
 
 &CONTROL
                       title = 'Anatase lattice' ,
                 calculation = 'vc-relax' ,
                restart_mode = 'from_scratch' ,
                      outdir = '/home/vega/espresso-4.0/tmp/' ,
                      wfcdir = '/tmp/' ,
                  pseudo_dir = '/home/vega/espresso-4.0/pseudo/' ,
                      prefix = 'Anatase lattice default' ,
                     disk_io = 'none' ,
               etot_conv_thr = 0.0005 ,
               forc_conv_thr = 0.0011668141375 ,
                       nstep = 1000 ,
 /
 &SYSTEM
                       ibrav = 6,
                   celldm(1) = 7.1356,
                   celldm(3) = 2.5122,
                         nat = 12,
                        ntyp = 2,
                     ecutwfc = 30 ,
                     ecutrho = 240 ,
 /
 &ELECTRONS
                    conv_thr = 7.3D-8 ,
 /
 &IONS
                ion_dynamics = 'bfgs' ,
 /
 &CELL
               cell_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      0.000000000    0.000000000    0.000000000
   Ti      0.500000000    0.500000000    0.500000000
   Ti      0.000000000    0.500000000    0.250000000
   Ti      0.500000000    0.000000000    0.750000000
    O      0.000000000    0.500000000    0.042000000
    O      0.000000000    0.000000000    0.208000000
    O      0.500000000    0.500000000    0.292000000
    O      0.000000000    0.500000000    0.458000000
    O      0.500000000    0.000000000    0.542000000
    O      0.500000000    0.500000000    0.708000000
    O      0.000000000    0.000000000    0.792000000
    O      0.500000000    1.000000000    0.958000000
K_POINTS automatic
2 2 1  1 1 1

But it is especially strange that the total energy was -730.11745 Ry, rather different than the PWscf's results. 
Also PWscf's results seems to be a litter lager than experimental data. Is it because the pseudopotential Ti.pw91-sp-van_ak.UPF underbinding for TiO2?


Vega Lew
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
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