[Pw_forum] Anatase lattice parameters testing results
vega lew
vegalew at hotmail.com
Sun Jul 6 20:58:27 CEST 2008
Dear all,
There is someting wrong with last mail, so I send it again.
Now I have tested Anatase lattice parameters using new BFGS file of PWscf. The new BFGS filesseem to be perfect. The data in following table is calculated by PWscf except for the first two lines.The first line is the experimental data at 15K of J. Am. Chem. SOC. 1987, 109, 3639-3646.The second line is the average value calculated by CASTEP. But the value is not stable, it'swould be changed a bit of different run.From the third line to the bottom is the data calculated by PWscf. The value is quite stable.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.UPFATOMIC_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 0.958000000K_POINTS automatic2 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 LewPH.D Candidate in Chemical EngineeringState Key Laboratory of Materials-oriented Chemical EngineeringCollege of Chemistry and Chemical EngineeringNanjing University of Technology, 210009, Nanjing, Jiangsu, ChinaVega LewPH.D Candidate in Chemical EngineeringState Key Laboratory of Materials-oriented Chemical EngineeringCollege of Chemistry and Chemical EngineeringNanjing University of Technology, 210009, Nanjing, Jiangsu, China
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