[Pw_forum] (no subject)
Osmair Vital Osmair
osmairvital at gmail.com
Wed Sep 17 22:46:16 CEST 2014
Dear users,
I am trying to calculate critical temperature for Titanium. I used the
following
files:
Ti.scf.in
&control
calculation='scf'
restart_mode='from_scratch',
prefix='Ti',
pseudo_dir = './',
outdir='./'
/
&system
ibrav = 4,
celldm(1) = 5.576203,
celldm(3) = 1.587874,
nat = 1,
ntyp = 1,
occupations = 'smearing',
degauss = 0.03,
smearing = 'cold',
ecutwfc = 60.0,
la2F = .true.,
/
&electrons
mixing_beta = 0.7,
conv_thr = 1.0d-15,
diagonalization = 'cg',
/
ATOMIC_SPECIES
Ti 47.88 Ti.pbe-sp-hgh.UPF
ATOMIC_POSITIONS ANGSTROM
Ti 0.33333 0.66667 0.25000
K_POINTS {automatic}
8 8 8 0 0 0
Question 1) The calculation is finished without error, but in the output
file
has the message "No symmetry found
(note: 23 additional sym.ops. were found but ignored
their fractional translations are incommensurate with FFT grid)".
This is very interesting because I tested various inputs with different
elements with hexagonal structure (Zr, Tc, Re...) the same message appear.
So, is there any
problem or bug with the ibrav = 4 (hexagonal)?
In addiction, in the ph.x calculation using the input below, I found
negative frequencies, these frequencies can be attributed to this message?
Question 2)
After the scf calculation, I performed ph.x using the file:
&inputph
tr2_ph=1.0d-16,
prefix='Ti',
fildvscf='aldv',
amass(1)=47.88,
outdir='./',
fildyn='Ti.dyn',
electron_phonon='interpolated',
trans=.true.,
ldisp=.true.
nq1=4, nq2=4, nq3=4
/
In this calculation, the file Ti.dy0 has 36 points and it was generate
36 elph.* files. However, the kpoints.x generate 50 k-points:
bravais lattice >> 4
filout [mesh_k] >>
enter celldm(3) >> 1.587874
mesh: n1 n2 n3 >> 8 8 8
mesh: k1 k2 k3 (0 no shift, 1 shifted) >> 0 0 0
write all k? [f] >>
# of k-points == 50 of 512
If I use mesh: n1 n2 n3 >> 4 4 4, I have 12 k-points
So, I expected that the number o k-points generated by the kpoints.x is the
same of the obtained by the ph.x. Is this corrected and how can I improve
this?
Thanks in advance.
Osmair V. Oliveira
Brazil
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