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hedge80

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注册: 2018-03-19
专业: 凝聚态物性 II ：电子结构

[求助] too many bands are not converged已有1人参与

刚学qe,在做si的能带和声子计算时没有任何错误，但用si类似的输入文件做ge和gaas时，碰到问题了。
输入文件如下：
+++++++++++++++++++++++++++++++
&control
   calculation = 'vc-relax'
      prefix = 'gaas'
      outdir = './outdir'
   pseudo_dir = '/home/work/pseudos'
etot_conv_thr = 1e-5
forc_conv_thr = 1e-4
/
&system
         ibrav = 2
   celldm(1) = 10.9
         nat = 2
         ntyp = 2
      ecutwfc = 50
      ecutrho = 600
/
&electrons
      conv_thr = 1.0e-14
/
&ions
/
&cell
   cell_dofree = 'ibrav'
/
atomic_species
ga 69.723 ga.pbe-dn-rrkjus_psl.1.0.0.upf
as 74.9216  as.pbe-n-rrkjus_psl.1.0.0.upf

atomic_positions (alat)
ga 0.00  0.00  0.00  0  0  0
as 0.25  0.25  0.25  0  0  0

k_points (automatic)
12  12  12  0  0  0
+++++++++++++++++++++++++++++++
&control
   calculation = 'scf'
      prefix = 'gaas'
      outdir = './outdir'
   pseudo_dir = '/home/work/pseudos'
etot_conv_thr = 1e-5
forc_conv_thr = 1e-4
/
&system
         ibrav = 2
   celldm(1) = 10.8704558116
         nat = 2
         ntyp = 2
      ecutwfc = 50
      ecutrho = 600
/
&electrons
      conv_thr = 1.0e-14
/
&ions
/
&cell
   cell_dofree = 'ibrav'
/
atomic_species
ga 69.723 ga.pbe-dn-rrkjus_psl.1.0.0.upf
as 74.9216  as.pbe-n-rrkjus_psl.1.0.0.upf

atomic_positions (alat)
ga 0.00  0.00  0.00
as 0.25  0.25  0.25

k_points (automatic)
12  12  12  1  1  1
++++++++++++++++++++++++++++++++
&control
   calculation = 'nscf'
      prefix = 'gaas'
      outdir = './outdir'
   pseudo_dir = '/home/work/pseudos'
etot_conv_thr = 1e-5
forc_conv_thr = 1e-4
/
&system
         ibrav = 2
   celldm(1) = 10.8704558116
         nat = 2
         ntyp = 2
      ecutwfc = 50
      ecutrho = 600
         nbnd = 8
      occupations = "tetrahedra'
/
&electrons
      conv_thr = 1.0e-14
/
&ions
/
&cell
   cell_dofree = 'ibrav'
/
atomic_species
ga 69.723 ga.pbe-dn-rrkjus_psl.1.0.0.upf
as 74.9216  as.pbe-n-rrkjus_psl.1.0.0.upf

atomic_positions (alat)
ga 0.00  0.00  0.00
as 0.25  0.25  0.25

k_points (automatic)
12  12  12  1  1  1
++++++++++++++++++++++++++
前面两步计算好像没有问题，但到了nscf计算，就了出现不收敛的问题。"too many bands are not converged"
之前做ge的计算时，也出现一样的问题，把赝势从ge.pbe-dn-rrkjus_psl.1.0.0.upf改成ge.pbe-n-rrkjus_psl.1.0.0.upf就没有问题，
计算结果也可以和教科书一致。这是什么原因呢？
盼高手给以解答。
另外，虽然使用ge.pbe-dn-rrkjus_psl.1.0.0.upf计算vc-relax时没有出现问题，但迭代步数远多于使用ge.pbe-n-rrkjus_psl.1.0.0.upf。这是什么原因呢？

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