请问这种SCF不收敛问题如何解决？

yiranfengbai

使用CASTEP模块优化氧化物晶面时，无论是调整精度（fine到medium）还是增大SCF循环（150到250）或者减小charge（0.5到0.2）都会出现这样的问题，氧化物的磁性设置是正确的，K点和Cutoff也测试过了，应该不会有问题的，请问各位是否遇到这样的问题，是怎么解决的？
  *Warning* max. SCF cycles performed but system has not reached the groundstate.
  
Current total energy, E     =  -18236.11027804     eV
Current free energy (E-TS)  =  -18236.13927387     eV
(energies not corrected for finite basis set)

NB est. 0K energy (E-0.5TS)      =  -18236.12477595     eV

  ****************************************************************************
  Warning: electronic minimisation did not converge when finding ground state.
  ****************************************************************************

Writing analysis data to Fe2O3_001_.castep_bin

Writing model to Fe2O3_001_.check
Error in geom_get_forces - electronic_minimisation of current_cell failed
Current trace stack:
geom_get_forces
geom_BFGS
geometry_optimise
castep
application called MPI_Abort(MPI_COMM_WORLD, 1) - process 14
application called MPI_Abort(MPI_COMM_WORLD, 1) - process 16
application called MPI_Abort(MPI_COMM_WORLD, 1) - process 17
application called MPI_Abort(MPI_COMM_WORLD, 1) - process 20
application called MPI_Abort(MPI_COMM_WORLD, 1) - process 5
application called MPI_Abort(MPI_COMM_WORLD, 1) - process 12
application called MPI_Abort(MPI_COMM_WORLD, 1) - process 13
application called MPI_Abort(MPI_COMM_WORLD, 1) - process 15
application called MPI_Abort(MPI_COMM_WORLD, 1) - process 18
application called MPI_Abort(MPI_COMM_WORLD, 1) - process 19
application called MPI_Abort(MPI_COMM_WORLD, 1) - process 6
application called MPI_Abort(MPI_COMM_WORLD, 1) - process 10
application called MPI_Abort(MPI_COMM_WORLD, 1) - process 2
application called MPI_Abort(MPI_COMM_WORLD, 1) - process 3
application called MPI_Abort(MPI_COMM_WORLD, 1) - process 7
application called MPI_Abort(MPI_COMM_WORLD, 1) - process 8
application called MPI_Abort(MPI_COMM_WORLD, 1) - process 1
application called MPI_Abort(MPI_COMM_WORLD, 1) - process 4
application called MPI_Abort(MPI_COMM_WORLD, 1) - process 9
application called MPI_Abort(MPI_COMM_WORLD, 1) - process 11
application called MPI_Abort(MPI_COMM_WORLD, 1) - process 0

Last known process information:
===============================
Name:        castepexe.exe
Umask:        0002
State:        D (disk sleep)
Tgid:        9582
Ngid:        0
Pid:        9582
PPid:        9578
TracerPid:        0
Uid:        1002        1002        1002        1002
Gid:        1003        1003        1003        1003
FDSize:        64
Groups:        1002 1003
VmPeak:          715652 kB
VmSize:          671232 kB
VmLck:               0 kB
VmPin:               0 kB
VmHWM:          382408 kB
VmRSS:          338328 kB
RssAnon:          315988 kB
RssFile:           12432 kB
RssShmem:            9908 kB
VmData:          322928 kB
VmStk:             768 kB
VmExe:           96728 kB
VmLib:           10124 kB
VmPTE:            1092 kB
VmSwap:               0 kB
Threads:        1
SigQ:        0/256454
SigPnd:        0000000000000000
ShdPnd:        0000000000000000
SigBlk:        0000000000000000
SigIgn:        0000000000000000
SigCgt:        00000001800046ae
CapInh:        0000000000000000
CapPrm:        0000000000000000
CapEff:        0000000000000000
CapBnd:        0000001fffffffff
CapAmb:        0000000000000000
Seccomp:        0
Speculation_Store_Bypass:        thread vulnerable
Cpus_allowed:        0000,01000001
Cpus_allowed_list:        0,24
Mems_allowed:        00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000003
Mems_allowed_list:        0-1
voluntary_ctxt_switches:        778
nonvoluntary_ctxt_switches:        6514

yiranfengbai

这个问题解决了，方法是：首先使用最低精度Coarse进行优化，然后在使用高精度进行优化。说到底还是结构不太好优化，该问题应该会常见于磁性氧化物种。

BBH

yiranfengbai 发表于 2019-6-29 16:06
这个问题解决了，方法是：首先使用最低精度Coarse进行优化，然后在使用高精度进行优化。说到底还是结构不太 ...

您好，我想问一下这个首先使用Coarse进行优化是指先把SCF tolerance的精度设置成Coarse吗