vega lew wrote: > 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 files > seem 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's > would 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 I bet you did not check force convergence wrt ecutwfc, ecutrho, and MP grid. I would rather have a more systematic convergence test.
Another point is, anatase is in space group I41/amd or ibrav=7. Of course this will not make much difference as you use ibrav=6 > > 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/' , > &n! bsp; 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, > ! ; &nb sp; celldm(3) = 2.5122, > nat = 12, > ntyp = 2, > ecutwfc = 30 , > ecutrho = 240 , > / > &ELECTRONS > conv_thr = 7.3D-8 , > / > &IONS > ion_dynamics = 'bfgs' , > / > &CELL > &nbs! p; 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 > &n! bsp; O 0.500000000 &nbs p; 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 > 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 > > > ------------------------------------------------------------------------ > Explore the seven wonders of the world Learn more! > <http://search.msn.com/results.aspx?q=7+wonders+world&mkt=en-US&form=QBRE> > > ------------------------------------------------------------------------ > > Spam > <https://antispam.physics.unc.edu/b.php?c=s&i=10897626&m=fda2d6e69bfd> > Not spam > <https://antispam.physics.unc.edu/b.php?c=n&i=10897626&m=fda2d6e69bfd> > Forget previous vote > <https://antispam.physics.unc.edu/b.php?c=f&i=10897626&m=fda2d6e69bfd> > ------------------------------------------------------------------------ > > _______________________________________________ > Pw_forum mailing list > Pw_forum at pwscf.org > http://www.democritos.it/mailman/listinfo/pw_forum > -- NMRNMRNMRNMRNMRNMRNMRNMRNMRNMRNMRNMRNMRNMRNMRNMRNMRNMRNMRNMRNMR NMR Dr. Qiang "Charles" Chen NMR NMR Department of Physics and Astronomy NMR NMR University of North Carolina NMR NMR Phillips Hall, CB#3255 NMR NMR Chapel Hill, NC 27599-3255 NMR NMR Tel: 919-962-1571 (O) NMR NMRNMRNMRNMRNMRNMRNMRNMRNMRNMRNMRNMRNMRNMRNMRNMRNMRNMRNMRNMRNMR
