[Pw_forum] About electron-phonon calculation on one point with version 3.1.1
Yingli Niu
niuyingli at gmail.com
Wed Nov 8 03:03:40 CET 2006
Dear all
I have read example07/run_example in espresso-3.1.1.
It is convenient to calculate the q-points for a full dispersion with
ldisp=.true. .
But before el-ph calculation, it is better to make a convergence test
on one or several q-points.
Then I have to use the script example07/run_example in espresso-3.0.
Because there is no example showing how to calculate el-ph on one
q-point in espresso-3.1.1.
I try to use example07/run_example in espresso-3.1.1 to calculate
el-ph on one q-point:
1. make a scf calculation on dense k-mesh for el-ph calculation
(case.scf.fit.in with la2F = .true.)
2. make a scf calculation for phonon calculation(case.scf.in)
3. make el-ph calculation:
cat > li.elph.in_ecut << EOF
Electron-phonon coefficients for Li
&inputph
reduce_io = .true.
tr2_ph = 1.0d-14
prefix = 'li'
fildyn = 'li.dyn'
fildvscf = 'li.dv'
amass(1) = 6.941
outdir = '$TMP_DIR/'
elph = .true.
trans = .true.
lnscf = .true.
ldisp = .false.
/
0.00 -0.25 0.25
EOF
I thought that it would calculate phonons on q-point(0.00 -0.25
0.25)because of "trans=.true." and "lnscf=.true.".
But I failed.
I make a calculation as in espresso-3.0
1. make a scf calculation on dense k-mesh for el-ph calculation
(case.scf.in without la2F = .true.)
2. make a nscf calculation for phonon calculation (case.nscf1.in,
calculation='phonon')
3. make a phonon calculation ( with elph=.flase. , trans=.true. ,
ldisp=.false.)
4. make a nscf calculation for elph calculation (case.nscf1.in,
calculation='phonon')
5. make a el-ph calculation (with elph=.true. , trans=.true. ,
ldisp=.false.)
I got the results!
My question is:
1. Must we calculate one q-point el-ph using run_example in espresso-3.0?
That is to say the method which I test (scf.fit, scf, el-ph) is wrong!
2. If we got error result for el-ph calculation on some q-point with
ldisp=.true., when should we
set restart_mode = 'restart'? In case.scf.fit.in or case.scf.in
in espresso-3.1.1?
3. What's wrong with my script ?
It should have calculated phonon and el-ph because it set
trans=.true. ,elph=.true. to calculate
on 0.00 -0.25 0.25?
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