[Pw_forum] phonon calculation not converge

[Xiaolin Xu]

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
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