[QE-users] Raman spectra error

[Premkumar Thirumalaisamy]

Hello,

I have calculated Raman and IR spectra for a single molecule using
ph.x and extracted the output using dyxmat.x. Raman spectral intensities
which i am getting is linearly increasing with wave number, but
experimentally it has some vibrational modes. Here, i have attached the
ph.x input file and dynmat.x output file. I will be happy, if I get some
valuable suggestions and corrections.

Thank you very much..!

-- 
Regards,
Premkumar T.


Curc.dm.out
Description: Binary data


Curc.ph.in
Description: Binary data
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Re: [QE-users] Some questions about regterg

[Stefano de Gironcoli]

g_psi multiplies the correction vector by an approximation of the 
inverse of (H-eS), typically just the inverse of the diagonal .


regterg is the real version of the routine: that is appropriate the one 
for k==Gamma


in this case psi is real in real space which means that the Fourier 
components at G and -G are complex conjugate of each other.


the normalization is as usual

1 = \sum_G psi(G)^* psi(G)   when summing over all G

but only half of them (the "positive" G) are stored and the 
normalization is computed as


1 = psi(0)* psi(0) + 2.0 \sum_G/=0 psi(G)* psi(G)   or rather

1 = 2.0 \sum_G psi(G)* psi(G)   -  psi(0)* psi(0)

the processor with gstart==2 is the one for which the first component is G=0

HTH

stefano

On 29/07/19 15:59, carlossiero siero wrote:

Dear Users,

I have been digging in the regterg.f90 subroutine and I was wondering 
if somebody could tell me what the calling to g_psi (line 286) is doing?


| CALL g_psi( npwx, npw, notcnv, 1, psi(1,nb1), 
ew(nb1) )


I thought the correction vectors, |psi> = (H - e*S) |psi>, were 
already stored in psi, so there is no need to do any inversion or 
anything else.


Also, running a 1processor calculation, the normalization goes through 
line 299:


|      IF ( gstart == 2 ) ew(n) = ew(n) - psi(1,nbn) * 
psi(1,nbn)


What is the purpose of substrating the psi product of the first 
element on each of the new vectors?


Thanks so much for your help!

Carlos

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[QE-users] Some questions about regterg

[carlossiero siero]

Dear Users, 

I have been digging in the regterg.f90 subroutine and I was wondering if 
somebody could tell me what the calling to g_psi (line 286) is doing?

| CALL g_psi( npwx, npw, notcnv, 1, psi(1,nb1), ew(nb1) ) 

I thought the correction vectors, |psi> = (H - e*S) |psi>, were already stored 
in psi, so there is no need to do any inversion or anything else. 

Also, running a 1processor calculation, the normalization goes through line 299:
 
|      IF ( gstart == 2 ) ew(n) = ew(n) - psi(1,nbn) * 
psi(1,nbn)

What is the purpose of substrating the psi product of the first element on each 
of the new vectors?

Thanks so much for your help! 

Carlos ___
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Re: [QE-users] Problem about requirement on computing powers

[Pietro Davide Delugas]

Hi

- to facilitate the convergence with SrTiO3 one has usually to either 
increase the number of bands used or use   randomly generated starting 
wave functions. Try to use occupations = smearing it could help  the scf 
cycle in the first iterations.
- you are using noncollinear + spinorbit coupling, to make these 
calculation converge usually one needs to specify a starting 
magnetization in your case, if SrTiO_3 is insulating, you should try to 
initialize Ti with starting magnetization ( put it as first species and 
then put starting_magnetization = 0.1)  even if the Ti d states should 
be empty so no final magnetization should be there. Again spin orbit 
should only affect very weakly Ti d states which are empty why you do 
you need to use spin orbit to compute phono dispersion ?

- try to use occup

-   last but just because I spotted it only now the pseudopotential for 
Ti isTl.rel-pbe-dn-rrkjus_psl.1.0.0.UPF check that you are not using a 
pseudo fot Tallium instead o pseudo for Titanium


hope it helps
regards
Pietro

On 7/29/19 9:07 AM, Che Min Wu wrote:

Dear users,
I am trying to calculate phonon dispersion on SrTiO3 supercell and 
SrTiO3 slab with Quantum Espresso and thermo_pw package. However, it 
took hours to converge in each iteration of Self-consistent 
calculation, some times it even aborted because it used up 100% of CPU.


 This is my fist time calculating structure larger than an unit cell, 
I am running on a server with 16 intel I5 cpu core and 320GB of RAM. I 
ran it with command
mpirun -np 4 $BIN_DIR/thermo_pw.x < srtio3_slab.in 
 > srtio3_slab.out
I wonder if it is me doing things wrong, or is it simply impossible to 
do these calculation with my computing power.

I have attached my input file , thanks for any reply or suggestion.

Thanks and Regards
Che Min Wu

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Re: [QE-users] Relaxation of Fe2O3

[Matteo Cococcioni]

Dear Anuja,

I don't have experience with this system and don't know how big the total
energy is. however, your convergence threshold for electrons (1.d-6) looks
a bit loose. that might result in not so accurate forces and, as a result,
ionic/cell steps are taken in the wrong direction. Try to tighten this
threshold. Also you may want to try to reduce the trust radius of the ionic
steps so the initial updates of ionic positions are not too big.
I assume you have studied the convergence wrt all the other parameters. Are
you sure, though, that a 888 k-point mesh is enough with such a small
Fermi-Dirac smearing of the distribution function? is the system metallic
in this phase?

Best regards,

Matteo



Il giorno dom 28 lug 2019 alle ore 18:08 Anuja Chanana <
anujachanan...@gmail.com> ha scritto:

> Dear users,
> I am trying to relax the bulk structure of alpha-Fe2O3 in the rhombohedral
> crystal structure. The ground state is +--+. However, the crystal lattice
> doesn't relax and the total energy values keep fluctuating rather than
> showing any convergence. The following is the input file
>
> 
> calculation = 'vc-relax',
> restart_mode = 'from_scratch',
> title = 'Fe2O3',
> prefix = 'Fe2O3',
> outdir = './tmp_Fe2O3_rhom_scf_1',
> pseudo_dir = '.',
> forc_conv_thr = 1.0D-5,
> tprnfor = .true.,
> tstress = .true.
> verbosity = 'high'
> wf_collect = .true.,
> nstep = 1000,
> /
>
> 
>   ibrav=5,
>   celldm(1)=10.2528224724d0, celldm(4)=0.5694631780d0,
>   nat=10,
>   ntyp=5,
>   ecutwfc = 80,
>   ecutrho = 640,
>   occupations='smearing'
>   smearing='fd'
>   degauss= 0.005,
>   nspin=2,
>   starting_magnetization(1)= 0.0,
>   starting_magnetization(2) =  1.0,
>  starting_magnetization(3) =  -1.0,
>  starting_magnetization(4) =  -1.0,
>  starting_magnetization(5) =   1.0,
>   lda_plus_u = .true.
>   Hubbard_U(2) = 3.8
>   Hubbard_U(3) = 3.8
>   Hubbard_U(4) = 3.8
>   Hubbard_U(5) = 3.8
> /
>
> 
> mixing_beta = 0.2,
> conv_thr = 1.0D-6,
> electron_maxstep=1000,
> /
>  
>  /
>
>  
> /
>
> ATOMIC_SPECIES
>   O 15.999400d0 O.pw91-n-rrkjus_psl.1.0.0.UPF
>   Fe1 55.845000d0 Fe.pw91-spn-rrkjus_psl.1.0.0.UPF
>   Fe2 55.845000d0 Fe.pw91-spn-rrkjus_psl.1.0.0.UPF
>   Fe3 55.845000d0 Fe.pw91-spn-rrkjus_psl.1.0.0.UPF
>   Fe4 55.845000d0 Fe.pw91-spn-rrkjus_psl.1.0.0.UPF
>
> ATOMIC_POSITIONS {crystal}
>O   0.9444650930d0   0.5556659533d0   0.2500659533d0
>O   0.2500650930d0   0.9444659533d0   0.5556659533d0
>O   0.0557952789d0   0.4445978598d0   0.7501978598d0
>O   0.4445952789d0   0.7501978598d0   0.0557978598d0
>O   0.5556650930d0   0.2500659533d0   0.9444659533d0
>O   0.7501952789d0   0.0557978598d0   0.4445978598d0
>   Fe1   0.1446976654d0   0.1446981632d0   0.1446981632d0
>   Fe2   0.6448278513d0   0.6448300697d0   0.6448300697d0
>   Fe3   0.3554325205d0   0.3554337433d0   0.3554337433d0
>   Fe4   0.8555627065d0   0.8555656499d0   0.8555656499d0
>
> K_POINTS {automatic}
>   8 8 8 0 0 0
>
>
> Has anyone ever tried relaxing the structure before and faced a similar
> situation?
> What is the best possible solution if the system doesn't show a smooth
> convergence.
> Looking forward to a reply.
>
> Thanks and Regards
> Anuja Chanana
>
>
>
> [image: Mailtrack]
> 
>  Sender
> notified by
> Mailtrack
> 
>  07/28/19,
> 09:35:20 PM
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[QE-users] Problem about requirement on computing powers

[Che Min Wu]

Dear users,
I am trying to calculate phonon dispersion on SrTiO3 supercell and SrTiO3
slab with Quantum Espresso and thermo_pw package. However, it took hours to
converge in each iteration of Self-consistent calculation, some times it
even aborted because it used up 100% of CPU.

 This is my fist time calculating structure larger than an unit cell, I am
running on a server with 16 intel I5 cpu core and 320GB of RAM. I ran it
with command
mpirun -np 4 $BIN_DIR/thermo_pw.x < srtio3_slab.in > srtio3_slab.out
I wonder if it is me doing things wrong, or is it simply impossible to do
these calculation with my computing power.
I have attached my input file , thanks for any reply or suggestion.

Thanks and Regards
Che Min Wu


srtio3_slab.in
Description: Binary data


srtio3_supercell.in
Description: Binary data
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