[Pw_forum] SCF run not converging

[Paolo Giannozzi]

On Thu, Dec 15, 2016 at 1:20 PM, sayan chaudhuri <csayan895 at gmail.com> wrote:

> ATOMIC_POSITIONS {ANGSTROM}

first two atoms here

> Sn    0.000000    0.000000    0.000000
> Sn    0.000000    0.000000    6.070000

> CELL_PARAMETERS

cell_parameters ... what? default is Bohr radii. Along z:

>    0.00000000000  0.000000000    11.478195655

11.478 Bohr * 0.529177 = 6.074 A . Don't you see that atom 1 and 2 are
almost overlapping?

Paolo

> On Thu, Dec 15, 2016 at 5:41 PM, sayan chaudhuri <csayan895 at gmail.com>
> wrote:
>>
>> Dear QE exparts,
>>
>> Thanks a lot for the replies. I am new to QE and the answers are helping
>> me a lot to learn the program.
>>
>> Sorry. Somehow I skipped the line as Mr. Paolo Giannozzi pointed. But I
>> understand the problem now. I have changed the input code in order to
>> rectify the geometry. And if I check the input in Xcrysden the structure
>> seems fine. Also I am using
>> PBE pseudo-potentials this time.
>>
>> But still it is not converging after ~250 iterations, and the total energy
>> is very high.
>>
>> Please tell what are the mistakes I am doing this time. I am attaching the
>> input and output file herewith.
>>
>> Thanking you,
>>
>>    Sayan Chaudhuri
>>
>>
>> %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
>>
>> &control
>>     prefix='fts',
>>     calculation  = 'scf',
>>     verbosity = 'low',
>>     pseudo_dir   = '/home/ltp/Desktop/espresso-5.4.0/pseudo',
>>     outdir       = './tmp',
>>  /
>>  &system
>>     ibrav=0,
>>     nat=35,
>>     ntyp=3,
>>
>>     nspin=2,
>>     ecutwfc=30.0,
>>     ecutrho = 150,
>>     starting_magnetization(1) =  0.5,
>>     starting_magnetization(2) =  0.5,
>>     starting_magnetization(3) =  0.5,
>>     occupations='tetrahedra',
>>
>>  /
>>  &electrons
>>     electron_maxstep = 300,
>>     diagonalization = 'david',
>>     mixing_mode = 'plain',
>>     conv_thr = 1e-8,
>>     mixing_beta=0.1,
>>  /
>> ATOMIC_SPECIES
>>   Sn   118.71   Sn.pbe-mt_fhi.UPF
>>   Fe   55.845   Fe.pbe-mt_fhi.UPF
>>   Ti   47.867   Ti.pbe-mt_fhi.UPF
>> ATOMIC_POSITIONS {ANGSTROM}
>> Sn    0.000000    0.000000    0.000000
>> Sn    0.000000    0.000000    6.070000
>> Sn    0.000000    6.070000    0.000000
>> Sn    0.000000    6.070000    6.070000
>> Sn    6.070000    0.000000    0.000000
>> Sn    6.070000    0.000000    6.070000
>> Sn    6.070000    6.070000    0.000000
>> Sn    6.070000    6.070000    6.070000
>> Sn    0.000000    3.035000    3.035000
>> Sn    6.070000    3.035000    3.035000
>> Sn    3.035000    0.000000    3.035000
>> Sn    3.035000    6.070000    3.035000
>> Sn    3.035000    3.035000    0.000000
>> Sn    3.035000    3.035000    6.070000
>> Fe    1.517500    1.517500    1.517500
>> Fe    4.552500    4.552500    4.552500
>> Fe    4.552500    4.552500    1.517500
>> Fe    1.517500    1.517500    4.552500
>> Fe    4.552500    1.517500    4.552500
>> Fe    1.517500    4.552500    1.517500
>> Fe    1.517500    4.552500    4.552500
>> Fe    4.552500    1.517500    1.517500
>> Ti    3.035000    3.035000    3.035000
>> Ti    3.035000    0.000000    0.000000
>> Ti    3.035000    0.000000    6.070000
>> Ti    3.035000    6.070000    0.000000
>> Ti    3.035000    6.070000    6.070000
>> Ti    0.000000    3.035000    0.000000
>> Ti    0.000000    3.035000    6.070000
>> Ti    6.070000    3.035000    0.000000
>> Ti    6.070000    3.035000    6.070000
>> Ti    0.000000    0.000000    3.035000
>> Ti    0.000000    6.070000    3.035000
>> Ti    6.070000    0.000000    3.035000
>> Ti    6.070000    6.070000    3.035000
>> CELL_PARAMETERS
>>    11.478195655   0.0000000000    0
>>    0.0000000000   11.478195655    0
>>    0.00000000000  0.000000000    11.478195655
>>  K_POINTS {automatic}
>>    2 2 2 0 0 0
>>
>> On Wed, Dec 14, 2016 at 8:24 PM, Lorenzo Paulatto
>> <lorenzo.paulatto at impmc.upmc.fr> wrote:
>>>
>>> On Wednesday, 14 December 2016 19:49:28 CET sayan chaudhuri wrote:
>>> > It is in the second mail in this thread. Mr. Lorenzo Paulatto said the
>>> > problem may be because the unit cell is too small.
>>>
>>> I cannot say for sure it is too small, for sure it does look quite small
>>> to
>>> me... An its density is 33 g/cm^3 which is 4 times that of Iron or Tin, 5
>>> times that of Antimonium and 7 times that of Titanium. So unless you just
>>> predicted a new super-dense alloy, there is a problem with your input..
>>>
>>> The solution is easy: check you geometry
>>>
>>> hth
>>>
>>> --
>>> Dr. Lorenzo Paulatto
>>> IdR @ IMPMC -- CNRS & Université Paris 6
>>> +33 (0)1 44 275 084 / skype: paulatz
>>> http://www.impmc.upmc.fr/~paulatto/
>>> 23-24/4é16 Boîte courrier 115,
>>> 4 place Jussieu 75252 Paris Cédex 05
>>>
>>> _______________________________________________
>>> Pw_forum mailing list
>>> Pw_forum at pwscf.org
>>> http://pwscf.org/mailman/listinfo/pw_forum
>>
>>
>
>
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-- 
Paolo Giannozzi, Dip. Scienze Matematiche Informatiche e Fisiche,
Univ. Udine, via delle Scienze 208, 33100 Udine, Italy
Phone +39-0432-558216, fax +39-0432-558222