[Pw_forum] Convergence NOT achieved for Sr2MnMoO6 using PAW pp

[stefano de gironcoli]

I would give a shot to local-TF, mixing-beta not too small (~ 0.3).

is it a metal ? does increasing degauss help ?
is this an instability related to the occupation of the U-projectors ?
does it converge if you if you remove U ?
does the fcc cell with 10 atoms converge ?

stefano

On 09/10/2015 09:03, 庞瑞(PANG Rui) wrote:
> Dear Zhao
> The most efficient way is reducing the mixing_beta, you may try 0.1 
> -0.01 or even smaller if you can afford the CPU time. Is 50 enough for 
> O? You may check it, the smallest value usually is given in the PP 
> file. A personal experience is that do not use semi-core PP. I do not 
> understand the reason but I seldom get convergence when using 
> semi-core PPs in periodical cases with PWSCF.
> Good luck
>
>
>
>
> ------------------
>
>
>         庞瑞 (PANG Rui)
>
> South University of Science and Technology of China/Department of Physics
>
> No.1088,Xueyuan Road, Shenzhen,Guangdong
>
> ------------------ Original ------------------
> *From: * "Shuai"<zhao-shuai at edu.life.kyutech.ac.jp>;
> *Date: * Fri, Oct 9, 2015 12:00 PM
> *To: * "PWSCF Forum"<pw_forum at pwscf.org>;
> *Subject: * [Pw_forum] Convergence NOT achieved for Sr2MnMoO6 using PAW pp
> Dear User:
>
> I am doing the SCF calculation of Sr2MnMoO6 using PAW Potentials but it
> cannot converged.
>
> I checked different Ecut (30Ry, 40Ry or 50Ry), mixing mode (TF or
> plain), diagonalization (david or cg) and mixing_beta (0.3, 0.7), but it
> always not converged.
>
> The SCF input is:
>
>   &control
>    calculation   = 'scf'
>    prefix           = 'Sr2MnMoO6'
>    restart_mode  = 'from_scratch'
>    pseudo_dir    = '/'
>    outdir           = '/'
>   /
>   &system
>    ibrav            = 1
>    celldm(1)     = 15.27295
>    nat               = 40
>    ntyp             = 4
>    ecutwfc        = 50
>    ecutrho        = 600
>    occupations   = 'smearing'
>    smearing      = 'mp'
>    degauss        = 0.01
>    lda_plus_u     = .true.
>    Hubbard_U(2)  = 4.0
>   /
>   &electrons
>    conv_thr         = 1e-8
>    mixing_mode   = 'TF'
>    mixing_beta   = 0.7
>    diagonalization = 'david'
>   /
> ATOMIC_SPECIES
>    Sr    87.620   Sr.pbe-spn-kjpaw_psl.1.0.0.UPF
>    Mn   54.938   Mn.pbe-spn-kjpaw_psl.1.0.0.UPF
>    Mo   95.960   Mo.pbe-spn-kjpaw_psl.1.0.0.UPF
>    O     15.999   O.pbe-n-kjpaw_psl.1.0.0.UPF
> ATOMIC_POSITIONS (crystal)
>    Sr    0.0000   0.0000   0.0000
>    Sr    0.5000   0.0000   0.0000
>    Sr    0.0000   0.5000   0.0000
>    Sr    0.5000   0.5000   0.0000
>    Sr    0.0000   0.0000   0.5000
>    Sr    0.5000   0.0000   0.5000
>    Sr    0.0000   0.5000   0.5000
>    Sr    0.5000   0.5000   0.5000
>    Mn   0.2500   0.2500   0.2500
>    Mo   0.7500   0.2500   0.2500
>    Mo   0.2500   0.7500   0.2500
>    Mn   0.7500   0.7500   0.2500
>    Mo   0.2500   0.2500   0.7500
>    Mn   0.7500   0.2500   0.7500
>    Mn   0.2500   0.7500   0.7500
>    Mo   0.7500   0.7500   0.7500
>    O     0.2500  -0.0140   0.2500
>    O    -0.0140   0.2500   0.2500
>    O     0.2500   0.2500  -0.0140
>    O     0.7500   0.0140   0.2500
>    O     0.5140   0.2500   0.2500
>    O     0.7500   0.2500   0.0140
>    O     0.2500   0.5140   0.2500
>    O     0.0140   0.7500   0.2500
>    O     0.2500   0.7500   0.0140
>    O     0.7500   0.4860   0.2500
>    O     0.4860   0.7500   0.2500
>    O     0.7500   0.7500  -0.0140
>    O     0.2500   0.0140   0.7500
>    O     0.0140   0.2500   0.7500
>    O     0.2500   0.2500   0.5140
>    O     0.7500  -0.0140   0.7500
>    O     0.4860   0.2500   0.7500
>    O     0.7500   0.2500   0.4860
>    O     0.2500   0.4860   0.7500
>    O    -0.0140   0.7500   0.7500
>    O     0.2500   0.7500   0.4860
>    O     0.7500   0.5140   0.7500
>    O     0.5140   0.7500   0.7500
>    O     0.7500   0.7500   0.5140
> K_POINTS (automatic)
>    4 4 4 1 1 1
>
> Thanks in advance for your suggestions.
>
> Best regards,
>
> Shuai Zhao
>
> -- 
> PhD candidate
> Graduate School of Life Science and Systems Engineering
> Kyushu Institute of Technology, Japan
>
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