Thank you very much for the help! Last question: are these advices valid to do adsorbed-NO on TiO2 surfaces calculations?
Best regards, Francesco Moriggi Il 20/11/2017 21:18, Nicola Marzari ha scritto: > > > Dear Francesco, > > > to follow up on Paolo's advice, I would do this: > > 1) freeze the molecule - i.e. do not relax it. > > 2) tighten the 2 thresholds a lot - conv_thr > and tr2_ph (i.e. make them smaller by one order of magnitude, two, > etc...). > > 3) use sssp pseudos: http://materialscloud.org/sssp/ > > The tables show exactly what is the convergence of the phonons with > cutoff (for molecular solids in the case of N and O), > using the scripts from > > http://materialscloud.org/sssp/downloads.html > > where you can find all the parameters we used > > 4) once you feel you are in control on the cutoffs and tolerance > thresholds, you can start relaxing the molecule. In order to get > very accurate results there, you need to have a very tight criterion on > the relaxation, as well. > > nicola > > > > On 16/11/2017 10:09, Francesco Moriggi wrote: >> Hello, i'm Francesco Moriggi, a master student at the Milan >> University, i have a problem with ph.x. I am calculating NO frequency >> and i'm not reaching a convergence in values compared to cutoff >> energy, using norm conserving and ultrasoft pseudopotentials. Values >> i get are (i've put an image too in the email): >> >> *Cutoff freq Norm freq US* >> >> ** >> >> *75 1879.0 1844.4* >> >> ** >> >> *80 1875.5 1858.2* >> >> ** >> >> *85 1890.6 1907.1* >> >> ** >> >> *90 1923.5 1895.2* >> >> ** >> >> *100 1889.6 1909.3* >> >> ** >> >> *110 1914.2 1893.1* >> >> ** >> >> *120 1890.5 1900.4* >> >> ** >> >> *130 1890.7 1901.0* >> >> ** >> >> *140 1914.7 1890.9* >> >> ** >> >> *150 1886.9 ////* >> >> With Gaussian (aug-cc-pv5Z) i've got *1889.21* cm-1. >> >> An example of the input of geometry optimization is: >> >> *&CONTROL** >> ** calculation = "relax",** >> ** prefix = "NO",** >> ** pseudo_dir = >> "/galileo/home/userexternal/fmoriggi/QE/NO/pseudoNO/ultrasoft",** >> ** outdir = "./out",** >> **/** >> **&SYSTEM** >> ** ibrav = 1,** >> ** a = 20,** >> ** nat = 2,** >> ** ntyp = 2,** >> ** nspin = 2,** >> ** ecutwfc = 150.D0,** >> ** ecutrho = 1200.D0,** >> ** occupations = 'smearing', smearing = 'gauss', degauss=0.02,** >> ** starting_magnetization(1)=-0.9,** >> ** starting_magnetization(2)=1.5,** >> **/** >> **&ELECTRONS** >> ** electron_maxstep = 500,** >> ** conv_thr = 1.D-7,** >> ** mixing_beta = 0.7D0,** >> **/** >> **&IONS** >> **/** >> **ATOMIC_SPECIES** >> **O 16.00 O.pbe-van_ak.UPF** >> **N 14.00 N.pbe-van_ak.UPF** >> **ATOMIC_POSITIONS {angstrom}** >> **N 1.16 0.0 0.0** >> **O 0.000 0.0 0.0 0 0 0** >> **K_POINTS** >> **1** >> **0.0 0.0 0.0 1.0* >> >> Later i've done an scf with a better conv_thr. This is the input. >> >> *&CONTROL** >> ** calculation = "scf",** >> ** prefix = "150",** >> ** pseudo_dir = >> "/galileo/home/userexternal/fmoriggi/QE/NO/pseudoNO/ultrasoft",** >> ** outdir = "./out150",** >> **/** >> **&SYSTEM** >> ** ibrav = 1,** >> ** a = 20,** >> ** nat = 2,** >> ** ntyp = 2,** >> ** nspin = 2,** >> ** ecutwfc = 150.D0,** >> ** ecutrho = 1200.D0,** >> ** occupations = 'smearing', smearing = 'gauss', degauss=0.02,** >> ** starting_magnetization(1)=-0.9,** >> ** starting_magnetization(2)=1.5,** >> **/** >> **&ELECTRONS** >> ** electron_maxstep = 500,** >> ** conv_thr = 1.D-9,** >> ** mixing_beta = 0.7D0,** >> **/** >> **&IONS** >> **/** >> **ATOMIC_SPECIES** >> **O 16.00 O.pbe-van_ak.UPF** >> **N 14.00 N.pbe-van_ak.UPF** >> **ATOMIC_POSITIONS {angstrom}** >> **N 1.166278 0.0 0.0** >> **O 0.000 0.0 0.0 0 0 0** >> **K_POINTS** >> **1** >> **0.0 0.0 0.0 1.0* >> >> And then i run the ph.x with this input: >> >> *phonon calculation - NO** >> ** &inputph** >> ** tr2_ph=4.0d-12,** >> ** prefix='150'** >> ** amass(1)=14.007,** >> ** amass(2)=15.9994,** >> ** >> outdir='/galileo/home/userexternal/fmoriggi/QE/NO/relax/ultra/out150'** >> ** /** >> ** 0.0 0.0 0.0* >> >> If you can help me it would be very useful to my future TiO2 based >> calculations. >> >> >> Best regards, >> >> Francesco Moriggi >> >> Webpage: http://users.unimi.it/ceotto/about_FrancescoMoriggi.html >> >> >> >> _______________________________________________ >> Pw_forum mailing list >> [email protected] >> http://pwscf.org/mailman/listinfo/pw_forum >> > > _______________________________________________ Pw_forum mailing list [email protected] http://pwscf.org/mailman/listinfo/pw_forum
