Dear Ajmalghan
Sorry for asking a possibly stupid question, but you are focusing on
the calculation of isolated Ti, and the error might be contained in
the calculation of hcp metal Ti... Are you sure that everything is
correct in that case?
HTH
Giuseppe
Quoting Ajmal Ghan <[email protected]>:
Thanks all for the reply,
With all the inputs provided here and mail archives, I made some
significant changes ( fixed magnetization, increased the size of the cell,
Gamma point calculation, Mixing beta etc...).
*Input of isolated Ti atom*:
&control
calculation = 'scf'
restart_mode = 'from_scratch'
pseudo_dir = '/work/shared/s-tih/pseudo/'
prefix = 'Tifree_deg1_40_gk_1'
wf_collect = .true.
forc_conv_thr = 1.0d-5
verbosity = 'high'
/
&system
ibrav = 1
celldm(1) = 30
nat = 1
ntyp = 1
ecutwfc = 40
ecutrho = 320
nspin = 2
tot_magnetization = 2
nosym = .true
nbnd = 100
occupations = 'fixed'
/
&electrons
diagonalization = 'cg'
mixing_beta = 0.3d00
conv_thr = 1.0d-7
/
ATOMIC_SPECIES
Ti 47.8670 Ti.pbe-spn-rrkjus_psl.1.0.0.UPF
ATOMIC_POSITIONS (crystal)
Ti 0.5 0.5 0.5
K_POINTS GAMMA
And for bulk calculations, i used same forc_conv_thr, ecutwfc, &electrons
parameters. *But I am still getting 5.23 eV as cohesive energy for Ti*. is
it possible to get the experimental ( 4.85 eV) using DFT calculations as
reported in some of the journals?
The output of isolated Ti atom calculation looks like,
bravais-lattice index = 1
lattice parameter (alat) = 30.0000 a.u.
unit-cell volume = 27000.0000 (a.u.)^3
number of atoms/cell = 1
number of atomic types = 1
number of electrons = 12.00 (up: 7.00, down: 5.00)
number of Kohn-Sham states= 100
kinetic-energy cutoff = 40.0000 Ry
charge density cutoff = 320.0000 Ry
convergence threshold = 1.0E-07
mixing beta = 0.3000
number of iterations used = 8 plain mixing
Exchange-correlation = PBE ( 1 4 3 4 0 0)
celldm(1)= 30.000000 celldm(2)= 0.000000 celldm(3)= 0.000000
celldm(4)= 0.000000 celldm(5)= 0.000000 celldm(6)= 0.000000
etc..............................................................................................................
Starting magnetic structure
atomic species magnetization
Ti 0.000
No symmetry found
etc..............................................................................................................
..................................................................................................................
iteration # 23 ecut= 40.00 Ry beta= 0.30
CG style diagonalization
ethr = 1.01E-09, avg # of iterations = 3.1
negative rho (up, down): 1.660E-02 1.306E-01
Magnetic moment per site:
atom: 1 charge: 11.9999 magn: 2.0000 constr: 0.0000
total cpu time spent up to now is 108.5 secs
End of self-consistent calculation
------ SPIN UP ------------
k = 0.0000 0.0000 0.0000 ( 57657 PWs) bands (ev):
-62.1874 -38.4854 -38.4348 -38.4332 -4.4517 -4.4503 -4.4048 -3.5611
-3.5610 -3.5153 -1.4572 -1.4565 -1.1485 -0.4725 0.0828 0.0992
0.1709 0.1890 0.1914 0.2168 0.5306 0.5437 0.6058 0.6689
0.6794 0.6917 0.7097 0.7127 0.8758 0.8811 0.9122 0.9174
1.1513 1.1544 1.1806 1.2368 1.4025 1.4198 1.4417 1.4878
1.5485 1.5709 1.9392 1.9444 1.9629 2.0040 2.0535 2.0683
2.1492 2.1983 2.2084 2.3100 2.3235 2.3454 2.3845 2.4064
2.4189 2.4639 2.4693 2.4865 2.4880 2.5054 2.5055 2.5179
2.5188 2.5215 2.7061 2.7211 2.7420 2.7869 2.7963 2.8090
2.8145 2.8304 2.9938 3.0003 3.0113 3.0175 3.0230 3.0259
3.0280 3.0332 3.0529 3.0580 3.0645 3.0690 3.0757 3.0785
3.0808 3.0898 3.5616 3.5684 3.6347 3.8452 3.9717 3.9774
4.0381 4.0472 4.0540 4.0617
occupation numbers
1.0000 1.0000 1.0000 1.0000 1.0000 1.0000 1.0000 0.0000
0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000
0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000
0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000
0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000
0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000
0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000
0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000
0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000
0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000
0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000
0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000
0.0000 0.0000 0.0000 0.0000
------ SPIN DOWN ----------
k = 0.0000 0.0000 0.0000 ( 57657 PWs) bands (ev):
-60.5692 -37.0219 -36.7521 -36.7481 -3.9282 -2.9464 -2.8480 -2.8461
-2.0737 -2.0734 -1.3881 -0.9733 -0.9724 -0.4455 0.0983 0.1054
0.2139 0.2301 0.2409 0.2476 0.5776 0.5939 0.6083 0.6823
0.6922 0.7172 0.7202 0.7223 0.9007 0.9617 0.9637 0.9653
1.1886 1.2019 1.2109 1.2572 1.4214 1.4579 1.4604 1.5175
1.5802 1.6023 1.9618 1.9874 1.9882 2.0402 2.1348 2.1844
2.2059 2.2275 2.2450 2.3219 2.3301 2.3507 2.4059 2.4124
2.4170 2.4823 2.4877 2.4881 2.5037 2.5077 2.5266 2.5297
2.5305 2.5376 2.7444 2.7669 2.7706 2.8302 2.8379 2.8443
2.8558 2.8670 3.0199 3.0266 3.0335 3.0380 3.0397 3.0427
3.0462 3.0493 3.0781 3.0795 3.0805 3.0813 3.0847 3.0869
3.1009 3.1038 3.6043 3.6940 3.6955 3.9171 4.0363 4.0648
4.0726 4.0791 4.0896 4.0980
occupation numbers
1.0000 1.0000 1.0000 1.0000 1.0000 0.0000 0.0000 0.0000
0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000
0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000
0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000
0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000
0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000
0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000
0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000
0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000
0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000
0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000
0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000
0.0000 0.0000 0.0000 0.0000
highest occupied, lowest unoccupied level (ev): -3.9282 -3.5611
! total energy = -119.34098597 Ry
Harris-Foulkes estimate = -119.34098367 Ry
estimated scf accuracy < 0.00000010 Ry
The total energy is the sum of the following terms:
one-electron contribution = -167.22501663 Ry
hartree contribution = 79.78699354 Ry
xc contribution = -18.28393498 Ry
ewald contribution = -13.61902790 Ry
total magnetization = 2.00 Bohr mag/cell
absolute magnetization = 2.44 Bohr mag/cell
convergence has been achieved in 23 iterations
Waiting for reply. Thanks for all the inputs.
Thanks & Regards,
*------------------------------------------------------------------------------------------------------*
Ajmalghan MUTHALI
Post doctorate researcher
Laboratoire ICB
UMR 6303 CNRS-Université de Bourgogne
9 Avenue Alain Savary, BP 47870
F-21078 DIJON Cedex, France
Tel: +33-(0)7.69.28.19.91
Email : [email protected]
On Sun, Nov 10, 2019 at 3:52 PM Ari P Seitsonen <[email protected]>
wrote:
Dear Ajmalghan,
Some quick comments:
- Why do you use k point in the case of an isolated atom?? Well, that
should not matter, just that you are wasting computing time
- I guess that the spherical symmetry of the atom is broken; thus I
would
use a non-cube cell, preferably the orthorhombic cell, with slightly
different lengths of the basis vectors of the unit cell. Then to break the
symmetry, you can use some randomisation of the initial wave functions.
And still, the convergence is probably going to be very difficult... You
can indeed try to fix the magnetisation; and I would reduce the
'mixing_beta' to something (very) small - in principle already at the
first step the electron density should be close to the self-consistent
one, bar the loss of sphericality and the randomised wave function
- Please remember that the scale of 'starting_magnetisation' is from -1
to +1, meaning that all the electrons are spin-polarised either up or
down, whereas in your case you only want to polarise the two valence
electrons out of the valence of the pseudo potential that seems to be 12
electrons
Well, Good Luck. :)
Greetings from Paris,
apsi
-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-
Ari Paavo Seitsonen / [email protected] / http://www.iki.fi/~apsi/
Ecole Normale Supérieure (ENS), Département de Chimie, Paris
Mobile (F) : +33 789 37 24 25 (CH) : +41 79 71 90 935
On Sat, 9 Nov 2019, Ajmal Ghan wrote:
> Hello all,
>
> I have gone through all the archived discussion about cohesive energy
calculation.
>
> I am trying to calculate the cohesive energy of Ti which is 4.85eV. But
I am getting 5.23 eV which is closer. But I have found from a previous
discussion
> here (
https://www.mail-archive.com/[email protected]/msg11410.html
) that, the final magnetization should be 2 Bohr mag/ cell at the end
> of calculation for Ti and smearing contribution of energy should be
0.0Ry.
> But I am getting to get 3.83 Bohr mag/cell and a significant smearing
contribution = -0.03295688 Ry.
>
> Anyone help me to sort this. what should I change in the input?
>
>
> here is my input,
>
> &control
> calculation = 'scf'
> restart_mode = 'from_scratch'
> pseudo_dir = '/work/shared/s-tih/pseudo/'
> prefix = 'Tifree_deg1_50_8k_1'
> wf_collect = .true.
> tstress = .true.
> tprnfor = .true.
> forc_conv_thr = 1.0d-6
> verbosity = 'high'
> /
> &system
> ibrav = 1
> celldm(1) = 20
> nat = 1
> ntyp = 1
> ecutwfc = 50 //( I have performed convergence study. But
since degauss is reduced to 0.01, i increased ecut)
> ecutrho = 400
> nspin = 2
> starting_magnetization(1) = 1 // I think, the final
magnetisation should be 2 bohr mag/ cell at the end of calculation.
> nosym = .true /// I hope this is enough
to break the symmetry
> nbnd = 100
> occupations = 'smearing', smearing='mp', degauss=0.01D0
> /
> &electrons
> diagonalization = 'cg'
> mixing_beta = 0.7d00
> conv_thr = 1.0d-8 // I used even higher convergence since
smearing is reduced.
> /
> ATOMIC_SPECIES
> Ti 47.8670 Ti.pbe-spn-rrkjus_psl.1.0.0.UPF
>
>
> ATOMIC_POSITIONS (crystal)
> Ti 0.5 0.5 0.5
>
> K_POINTS {automatic}
> 8 8 5 0 0 0
>
>
> I don't really know this is the correct way to post a reply. All input
is welcome.
>
> Thanks & Regards,
>
------------------------------------------------------------------------------------------------------
> Ajmalghan MUTHALI
>
> Post doctorate researcher
> Laboratoire ICB
> UMR 6303 CNRS-Université de Bourgogne
> 9 Avenue Alain Savary, BP 47870
> F-21078 DIJON Cedex, France
> Tel: +33-(0)7.69.28.19.91
> Email : [email protected]
>
>_______________________________________________
Quantum ESPRESSO is supported by MaX (www.max-centre.eu/quantum-espresso)
users mailing list [email protected]
https://lists.quantum-espresso.org/mailman/listinfo/users
GIUSEPPE MATTIOLI
CNR - ISTITUTO DI STRUTTURA DELLA MATERIA
Via Salaria Km 29,300 - C.P. 10
I-00015 - Monterotondo Scalo (RM)
Mob (*preferred*) +39 373 7305625
Tel + 39 06 90672342 - Fax +39 06 90672316
E-mail: <[email protected]>
_______________________________________________
Quantum ESPRESSO is supported by MaX (www.max-centre.eu/quantum-espresso)
users mailing list [email protected]
https://lists.quantum-espresso.org/mailman/listinfo/users
