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VERY BAD NEWS! internal error in subroutine IBZKPT:

已有 9909 次阅读 2019-8-8 20:53 |系统分类:科研笔记|文章来源:转载

计算弹性常数时INCAR如下:

SYSTEM=SiP
ENCUT=650
ISYM=0

ISTART=0;ICHARG=2
ISMEAR=0;SIGMA=0.1

ISIF=3
IBRION=6
NFREE=4
NSW=1

EDIFF=1E-6
EDIFFG=-0.01
#NPAR=8

LWAVE=FALSE
LCHG=FALSE

IVDW=1
LVDW=.TRUE.

IALGO=48
NELMIN=4
POTIM=0.1

计算过程报警如下: 

VERY BAD NEWS! internal error in subroutine IBZKPT:
 Reciprocal lattice and k-lattice belong to different class of lattices. Often results are still useful...     168

解决办法:

The message does not mean an error.
The procedure doing the evaluation of symmetry uses a numerical criterion (SYMPREC=1E-5)
to determine which atoms are symmetrically equivalent. When this criterion is too soft
the programm can find "false" symmetry and reports that "reciprocal lattice and k-lattice belong
to different class of lattices." To get rid of this message you can:
1) Switch off the symmetry (ISYM=0)
2) Make the treshold for detecting the symmetry more severe (SYMPREC=1E-8)

注:系统有一定的对称性但不太好,但程序的判定条件较低 (SYMPREC=1E-5,缺省?)而认为有对称,

如果设置上面两项,则需要的k点增多!

在INCAR中添加了SYMPREC=1E-8问题得到解决。




http://blog.sciencenet.cn/blog-3306559-1192944.html

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