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标题: 求助：QE对MgB2(001)/MgO(111)界面算scf时，结果不收敛 [打印本页]

作者
Author: henrenzhenderen 时间: 2022-4-9 18:28
标题: 求助：QE对MgB2(001)/MgO(111)界面算scf时，结果不收敛
老师，
我建了一个MgB2（001）/MgO（111）界面结构，vc-relax之后计算scf一直不收敛，
看了一下scf的out文件，accuracy那一项的数量级好像有些大：

   iteration #100    ecut= 150.00 Ry    beta= 0.30
   Davidson diagonalization with overlap
   ethr =  3.50E-09,  avg # of iterations =  1.0

   negative rho (up, down):  2.505E-07 0.000E+00

   total cpu time spent up to now is    280.3 secs

   total energy             = -907.12963618 Ry
   estimated scf accuracy <    0.00006145 Ry

   End of self-consistent calculation

   convergence NOT achieved after 100 iterations: stopping

scf的in文件：
&CONTROL
  prefix='pwscf', calculation='scf', pseudo_dir='./', outdir='./tmp', verbosity='high',
  tprnfor=.true., tstress=.true., forc_conv_thr=1.0d-4, nstep=100,etot_conv_thr=1.0d-8,
/

&SYSTEM
ibrav = 4, nat = 17, ntyp  = 3, celldm(1)=5.82980435831, celldm(3)=6.48298217179,
  occupations = 'fixed',
  ecutwfc = 150, ecutrho = 500,
/
&ELECTRONS
  mixing_mode = 'local-TF'
  conv_thr = 1.0d-8
  mixing_beta = 0.3d0
/
&IONS
/
&CELL
  press_conv_thr=0.5
/

ATOMIC_SPECIES
Mg    24.30500  Mg.pbe-spnl-rrkjus_psl.1.0.0.UPF
B    10.81100  B.pbe-n-rrkjus_psl.1.0.0.UPF
O    15.99940  O.pbe-rrkjus.UPF

ATOMIC_POSITIONS {angstrom}
Mg    0.000000 0.000000 1.761248
Mg    0.000000 0.000000 5.284466
Mg    0.000000 0.000000 8.807685
Mg    0.000000 0.000000  12.330180
B    -0.000015 1.781134 0.000000
B    -0.000015 1.781134 3.523219
B    -0.000015 1.781134 7.045714
B    -0.000015 1.781134  10.568933
B    1.542515 0.890554 0.000000
B    1.542515 0.890554 3.523219
B    1.542515 0.890554 7.045714
B    1.542515 0.890554  10.568933
Mg    1.490965 0.860792  14.764902
Mg    -0.000015 1.721609  17.199624
O    0.000000 0.000000  15.982183
O    1.490965 0.860792  18.416905
O    -0.000015 1.721609  13.547461

K_POINTS {automatic}
  8 8 1 0 0 0

作者
Author: 丁越 时间: 2022-4-9 22:52
1.D-8的收敛限有点高了，默认才1.D-6，不知道设置多少就采用程序默认算了

另外才跑了100轮，有收敛的趋势，稍增大点SCF圈数应该就收敛了

作者
Author: henrenzhenderen 时间: 2022-4-11 18:39

丁越发表于 2022-4-9 22:52
1.D-8的收敛限有点高了，默认才1.D-6，不知道设置多少就采用程序默认算了

另外才跑了100轮，有收敛的趋 ...

感谢解答。不过后来我发现不收敛的原因是scf的in文件没有用relax之后的结构

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