Hi Jiqiang, Thank you very much for your help!
I tried using only gamma point, but I got an error message when I calculated phonon saying "can't start from gamma tricks...". Besides, I need to calculate the raman frequencies after phonon calculation, so I think it's better if I use more k points. Have you tried Raman calculation? Could you give me more advice? Best, Xiaolin On Wed, Oct 28, 2015 at 10:21 PM, Xiaolin Xu <[email protected]> wrote: > Hi Jiqiang, > > Thank you very much for your help! > > I tried using only gamma point, but I got an error message when I > calculated phonon saying "can't start from gamma tricks...". Besides, I > need to calculate the raman frequencies after phonon calculation, so I > think it's better if I use more k points. > > Have you tried Raman calculation? Could you give me more advice? > > Best, > > Xiaolin > > On Wed, Oct 28, 2015 at 6:20 PM, jqli14 <[email protected]> wrote: > >> (1)employ k_points gamma instead of k_pionts automatic 1 1 1 0 0 0, >> although both give the same result, but the later does not call the gamma >> point specific algorithm to speed the calculation. >> (2)if it can not converge within handreds of electronic steps, reduce the >> value of mixing_beta or change the mixing_mode. >> >> Jiqiang Li >> >> >> 在 2015-10-29 07:57:58，"Xiaolin Xu" <[email protected]> 写道： >> >> >Dear all, >> > >> > >> >I was doing phonon dispersion calculations for lithium iron phosphate. >> However, the calculation speed is really slow and it does not converge. Is >> this because my system is too big? There are 28 atoms in the unit cell. My >> input file is like this: >> >(1) >> > >> > >> > >> >&CONTROL >> > >> >calculation = "scf", >> > >> >pseudo_dir = "/home/xiaolin/pseudo", >> > >> >outdir = "/home/xiaolin/test2", >> > >> >tstress=.true., >> > >> >tprnfor=.true., >> > >> >nstep=100, >> > >> >/ >> > >> >&SYSTEM >> > >> >ibrav = 8, >> > >> >celldm(1) = 19.749526 >> > >> >celldm(2) = 0.582432, >> > >> >celldm(3) = 0.454693, >> > >> >nat = 28, >> > >> >ntyp = 4, >> > >> >ecutwfc = 80.D0, >> > >> >/ >> > >> >&ELECTRONS >> > >> >mixing_beta = 0.7, >> > >> >/ >> > >> >&IONS >> > >> >/ >> > >> >ATOMIC_SPECIES >> > >> >Li 6.941 Li.pbe-s-hgh.UPF >> > >> >Fe 55.845 Fe.pbe-sp-hgh.UPF >> > >> >P 30.97376 P.pbe-hgh.UPF >> > >> >O 15.9994 O.pbe-hgh.UPF >> > >> >ATOMIC_POSITIONS (alat) >> > >> >Li 0 0 0 >> > >> >... >> > >> >K_POINTS (automatic) >> > >> >1 1 1 0 0 0 >> > >> > >> > >> > >> >(2) >> > >> > >> > >> > >> >Normal modes for lifepo4 >> > >> >&inputph >> > >> >tr2_ph=1.5d-5, >> > >> >amass(1)=6.941, >> > >> >amass(2)=55.845, >> > >> >amass(3)=30.97376, >> > >> >amass(4)=15.9994, >> > >> >outdir = '/home/xiaolin/test2', >> > >> >trans=.true., >> > >> >asr=.true., >> > >> >nogg=.true., >> > >> >fildyn='dmat.lifepo4' >> > >> >/ >> > >> >0.0 0.0 0.0 >> > >> > >> > >> > >> > >> > >> > >> >Thank you in advance! >> > >> > >> > >> > >> >Lin >> >> >> >> >> >> >> _______________________________________________ >> Pw_forum mailing list >> [email protected] >> http://pwscf.org/mailman/listinfo/pw_forum > > >
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