[QE-users] Reg- Absorption spectrum using TDDFPT (turbo_davidson.x, turbo_lanczos.x and epsilon.x)
Vivek Christhunathan
vivekppn at gmail.com
Tue Feb 18 15:33:02 CET 2020
Dear Iurii,
> G. Onida, L. Reining, A. Rubio, "Electronic excitations:
density-functional versus many-body Green's-function approaches", Rev. >
Mod. Phys. 74, 601 (2002).
Thanks a lot for providing the reference.
> Check this page for pseudos:
> https://www.materialscloud.org/discover/sssp/table/efficiency
I received an error message ' Error in routine lr_readin (1): Linear
response calculation not implemented for PAW' when I used the pseudos from
SSSP for the turbo_lanczos.x method. The SSSP contain Ultrasoft
pseudopotential information but it does not contain NC. We can do TDDFT
absorption calculation only by using NC, isn't it? The input files are
given below for your kind perusal.
# for scf calculation
&control
calculation = 'scf'
restart_mode = 'from_scratch'
prefix = 'TiO2'
tstress = .true.
tprnfor = .true.
pseudo_dir = './'
outdir = './outTiO2'
wf_collect=.true.
forc_conv_thr = 1d-4
!disk_io = 'none'
/
&system
ibrav = 0
celldm(1) = 14.35
nat = 24
ntyp = 2
ecutwfc = 60.0
ecutrho = 600.0
nbnd = 300
/
&electrons
mixing_beta = 0.3,
conv_thr = 1.0d-8
/
&IONS
/
&cell
cell_factor = 3.0d0
/
ATOMIC_SPECIES
Ti 47.867 Ti_pbe_v1.4.uspp.F.UPF
O 16.00 O.pbe-n-kjpaw_psl.0.1.UPF
CELL_PARAMETERS (alat)
1.017721118 0.000000000 0.000000000
0.000000000 0.508858021 0.000000000
0.000000000 0.000000000 1.298939229
ATOMIC_POSITIONS (crystal)
Ti 0.000000000 0.000000000 -0.000000846
Ti 0.500000000 0.000000000 -0.000000839
Ti 0.250000013 0.500000000 0.499999157
Ti 0.750000019 0.500000000 0.499999157
Ti 0.000000000 0.500000000 0.250000852
Ti 0.500000000 0.500000000 0.250000854
Ti 0.250000017 0.000000000 0.750000839
Ti 0.750000015 0.000000000 0.750000839
O 0.000000000 0.000000000 0.206573803
O 0.500000000 0.000000000 0.206573797
O 0.250000018 0.500000000 0.706573779
O 0.750000014 0.500000000 0.706573779
O 0.000000000 0.500000000 0.456574040
O 0.500000000 0.500000000 0.456574023
O 0.250000013 0.000000000 0.956574018
O 0.750000019 0.000000000 0.956574018
O 0.250000006 0.000000000 0.543426210
O 0.750000026 0.000000000 0.543426210
O 0.000000000 0.500000000 0.043426209
O 0.500000000 0.500000000 0.043426213
O 0.250000013 0.500000000 0.293425986
O 0.750000019 0.500000000 0.293425986
O 0.000000000 0.000000000 0.793425968
O 0.500000000 0.000000000 0.793425982
K_POINTS gamma
# for turbo_lanczos.x
&lr_input
prefix ='TiO2'
outdir ='./outTiO2'
restart_step = 100,
restart = .false.
/
&lr_control
itermax = 500
ipol = 4
d0psi_rs = .true.
/
Kind Regards,
Vivek C
__________________________________
Vivek Christhunathan
PhD researcher
Mechanical Engineering
College of Engineering and Informatics
Room 2053
Alice Perry Engineering Building
National University of Ireland Galway
Ireland
E-mail: v.christhunathan1 at nuigalway.ie
Phone: +353 899811181, +91 9600752742
On Mon, Feb 17, 2020 at 12:24 PM Timrov Iurii <iurii.timrov at epfl.ch> wrote:
> Dear Vivek,
>
>
> > Can you please provide any useful reference for the Bethe-Salpeter
> approach to obtain accurate absorption spectra for solids?
>
>
> You can start from this reference:
>
> G. Onida, L. Reining, A. Rubio, "Electronic excitations:
> density-functional versus many-body Green's-function approaches", Rev. Mod.
> Phys. 74, 601 (2002).
>
>
> Greetings,
>
> Iurii
>
>
> --
> Dr. Iurii Timrov
> Postdoctoral Researcher
> STI - IMX - THEOS and NCCR - MARVEL
> Swiss Federal Institute of Technology Lausanne (EPFL)
> CH-1015 Lausanne, Switzerland
> +41 21 69 34 881
> http://people.epfl.ch/265334
> ------------------------------
> *From:* users <users-bounces at lists.quantum-espresso.org> on behalf of
> Vivek Christhunathan <vivekppn at gmail.com>
> *Sent:* Monday, February 17, 2020 1:20:21 PM
> *To:* Quantum ESPRESSO users Forum
> *Subject:* Re: [QE-users] Reg- Absorption spectrum using TDDFPT
> (turbo_davidson.x, turbo_lanczos.x and epsilon.x)
>
> Dear Iurii,
>
> Many thanks for your prompt reply and for your clear explanation about the
> related questions.
>
> I will try my calculation as per your technical comments and I will let
> you know here.
>
> Can you please provide any useful reference for the Bethe-Salpeter
> approach to obtain accurate absorption spectra for solids?
>
> Kind Regards,
>
> Vivek C
>
>
> __________________________________
>
> Vivek Christhunathan
>
> PhD researcher
>
> Mechanical Engineering
>
> College of Engineering and Informatics
>
> Room 2053
>
> Alice Perry Engineering Building
>
> National University of Ireland Galway
>
> Ireland
> E-mail: v.christhunathan1 at nuigalway.ie
> Phone: +353 899811181, +91 9600752742
>
>
>
> On Fri, Feb 14, 2020 at 12:11 PM Timrov Iurii <iurii.timrov at epfl.ch>
> wrote:
>
>> Dear Vivek,
>>
>>
>> In order to obtain accurate absorption spectra for solids, the
>> Bethe-Salpeter approach is the right way to go. Nonetheless, please see my
>> comments below.
>>
>>
>> epsilon.x is based on DFT and it is the code to compute absorption
>> spectra in the independent-particle approximation, while turbo_lanczos.x
>> and turbo_davidson.x are based on time-dependent DFT (TDDFT) and include
>> interaction effects into account (it is possible to disable interactions
>> and obtain the same results as epsilon.x). Moreover, in epsilon.x the
>> intensities are not fully correct, because there is a missing term in the
>> commutator [V,r] (a contribution from the nonlocal part of the
>> pseudo-potential is missing, while in TDDFT codes above it is included).
>>
>>
>> Technical comments: you use a hybrid functional (input_dft = 'pbe0'),
>> therefore you should use d0psi_rs = .true. in turbo_lanczos.x and
>> turbo_davidson.x in order to have the correct intensities in the
>> absorption spectrum (this is true for molecules, while in solids it does
>> not help).
>>
>>
>> > ATOMIC_SPECIES
>> > Ti 47.867 Ti.upf
>> > O 16.00 O.upf
>>
>>
>> Check this page for pseudos:
>>
>> https://www.materialscloud.org/discover/sssp/table/efficiency
>>
>>
>> Greetings,
>>
>> Iurii
>>
>>
>> --
>> Dr. Iurii Timrov
>> Postdoctoral Researcher
>> STI - IMX - THEOS and NCCR - MARVEL
>> Swiss Federal Institute of Technology Lausanne (EPFL)
>> CH-1015 Lausanne, Switzerland
>> +41 21 69 34 881
>> http://people.epfl.ch/265334
>> ------------------------------
>> *From:* users <users-bounces at lists.quantum-espresso.org> on behalf of
>> Vivek Christhunathan <vivekppn at gmail.com>
>> *Sent:* Friday, February 14, 2020 12:24:25 PM
>> *To:* users at lists.quantum-espresso.org
>> *Subject:* [QE-users] Reg- Absorption spectrum using TDDFPT
>> (turbo_davidson.x, turbo_lanczos.x and epsilon.x)
>>
>> Dear QE users,
>>
>> Greetings!!!
>>
>> I am trying to find the absorption spectrum for the material 'TiO2'
>> supercell (2*1*1) which consists of 24 atoms. I tried a lot to find the
>> absorption spectrum by reading all the related threads from QE. I have
>> tried with all the methods such as turbo_davidson.x, turbo_lanczos.x and
>> epsilon.x. I can only succeed with the use of epsilon.x but I am unable to
>> get the same results for the turbo_davidson.x and turbo_lanczos.x. I would
>> like to know the reason behind this. And secondly to find an absorption
>> spectrum of the material does epsilon.x method gives accurate results when
>> compared with the other two?
>>
>> Thirdly I have tried it for the Zn doped TiO2 supercell. This time all
>> the methods did not give a hand for my calculation. The input files are
>> given below. I would be very grateful if you help me out in this regard.
>>
>> Please let me know if you need any further information. Looking forward
>> to hearing from you.
>>
>> Thanks in advance.
>>
>> # self-consistent calculation
>> &control
>> calculation = 'scf'
>> prefix = 'TiO2'
>> pseudo_dir = './'
>> outdir = './outTiO2'
>> !etot_conv_thr = 1e-5
>> forc_conv_thr = 1e-4
>> /
>> &system
>> ibrav = 0
>> celldm(1) = 14.113
>> nat = 24
>> ntyp = 2
>> ecutwfc = 80.0
>> ecutrho = 800
>> nbnd = 300
>> input_dft = 'pbe0'
>> /
>> &electrons
>> mixing_beta=0.3
>> conv_thr = 1.0d-8
>> diagonalization = 'david',
>> mixing_mode = 'plain',
>> /
>> &IONS
>> /
>> &cell
>> /
>> CELL_PARAMETERS (alat)
>> 1.000927809 0.000000000 0.000000000
>> 0.000000000 0.500440909 0.000000000
>> 0.000000000 0.000000000 1.235414320
>> ATOMIC_SPECIES
>> Ti 47.867 Ti.upf
>> O 16.00 O.upf
>> ATOMIC_POSITIONS (crystal)
>> Ti 0.000000000 0.000000000 -0.000006420
>> Ti 0.500000000 0.000000000 -0.000006418
>> Ti 0.250000017 0.500000000 0.499993602
>> Ti 0.750000015 0.500000000 0.499993602
>> Ti 0.000000000 0.500000000 0.250006398
>> Ti 0.500000000 0.500000000 0.250006394
>> Ti 0.250000016 0.000000000 0.750006426
>> Ti 0.750000016 0.000000000 0.750006426
>> O 0.000000000 0.000000000 0.212511476
>> O 0.500000000 0.000000000 0.212511476
>> O 0.250000011 0.500000000 0.712511501
>> O 0.750000021 0.500000000 0.712511501
>> O 0.000000000 0.500000000 0.462514694
>> O 0.500000000 0.500000000 0.462514705
>> O 0.250000019 0.000000000 0.962514709
>> O 0.750000013 0.000000000 0.962514709
>> O 0.250000008 0.000000000 0.537488518
>> O 0.750000024 0.000000000 0.537488518
>> O 0.000000000 0.500000000 0.037488489
>> O 0.500000000 0.500000000 0.037488487
>> O 0.250000019 0.500000000 0.287485309
>> O 0.750000013 0.500000000 0.287485309
>> O 0.000000000 0.000000000 0.787485317
>> O 0.500000000 0.000000000 0.787485307
>> K_POINTS gamma
>>
>> # turbo_lanczos.x calculation
>> &lr_input
>> prefix ='TiO2'
>> outdir ='./outTiO2'
>> !restart_step = 100,
>> !restart = .true.
>> /
>> &lr_control
>> itermax = 500
>> ipol = 1
>> !d0psi_rs = .true.
>> /
>> # turbo_spectrum.x calculation
>> &LR_INPUT
>> prefix = 'TiO2'
>> outdir = './outTiO2'
>> itermax0 = 500
>> itermax = 10000
>> extrapolation = 'osc'
>> epsil = 0.01
>> units = 1
>> start = 0.0
>> end = 4.0
>> increment = 0.01
>> ipol = 1
>> /
>> # turbo_davidson.x calculation
>> &lr_input
>> prefix = 'TiO2'
>> outdir = './outTiO2'
>> /
>> &lr_dav
>> !if_dft_spectrum = .false.
>> num_eign = 5
>> num_init = 10
>> num_basis_max = 90
>> residue_conv_thr = 1.0E-4
>> start = 0.0
>> finish = 3.50
>> step = 0.001
>> broadening = 0.004
>> reference = 0.3
>> /
>> # turbo_spectrum.x calculation
>> &lr_input
>> prefix = 'TiO2'
>> outdir = './outTiO2'
>> td = 'davidson'
>> epsil = 0.004
>> start = 0.0d0
>> end = 3.5d0
>> increment = 0.001d0
>> eign_file = 'TiO2.eigen'
>> /
>>
>> Kind Regards,
>>
>> Vivek C
>>
>>
>> __________________________________
>>
>> Vivek Christhunathan
>>
>> PhD researcher
>>
>> Mechanical Engineering
>>
>> College of Engineering and Informatics
>>
>> Room 2053
>>
>> Alice Perry Engineering Building
>>
>> National University of Ireland Galway
>>
>> Ireland
>> E-mail: v.christhunathan1 at nuigalway.ie
>> Phone: +353 899811181, +91 9600752742
>>
>> _______________________________________________
>> Quantum ESPRESSO is supported by MaX (www.max-centre.eu/quantum-espresso)
>> users mailing list users at lists.quantum-espresso.org
>> https://lists.quantum-espresso.org/mailman/listinfo/users
>
> _______________________________________________
> Quantum ESPRESSO is supported by MaX (www.max-centre.eu/quantum-espresso)
> users mailing list users at lists.quantum-espresso.org
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