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本帖最后由 Boble 于 2025-7-8 17:11 编辑
老师同学们大家好,我在使用VASP计算铼单原子掺杂氧化铟111面的模型(参考ACS Catal. 2022, 12, 12658−12669,DOI: 10.1021/acscatal.2c03709)上二氧化碳分子吸附时,首先结构优化一切正常,但是计算二氧化碳分子振动频率时失败,出现了BRMIX: very serious problems the old and the new charge density differ这个问题,log中的信息如下:
N E dE d eps ncg rms rms(c)
Total vdW correction in eV: 186.1347274
DAV: 1 0.137868434813E+05 0.13787E+05 -0.41988E+05 6840 0.157E+03
DAV: 2 0.226898685264E+04 -0.11518E+05 -0.11082E+05 9360 0.475E+02
DAV: 3 -0.395566357679E+03 -0.26646E+04 -0.26086E+04 9160 0.249E+02
DAV: 4 -0.574800796150E+03 -0.17923E+03 -0.17700E+03 8600 0.724E+01
DAV: 5 -0.579905363869E+03 -0.51046E+01 -0.50830E+01 9680 0.129E+01 0.972E+01
Total vdW correction in eV: 194.8274384
DAV: 6 -0.422018035346E+03 0.15789E+03 -0.85722E+02 12160 0.681E+01 0.921E+01
Total vdW correction in eV: 194.9980286
DAV: 7 -0.158793847425E+06 -0.15837E+06 -0.15653E+06 11120 0.402E+01BRMIX: very serious problems
the old and the new charge density differ
old charge density: 1060.00006 new 1060.11509
可见,几个电子步之后就无法继续,然后接下来log中继续出现
WARNING: Sub-Space-Matrix is not hermitian in DAV 99
1.328643722223757E-005
WARNING: Sub-Space-Matrix is not hermitian in DAV 99
1.328643722223757E-005
的无限循环,我尝试了网上的一些解决方法,如下:
1.关闭系统的对称性,即设ISYM=0
2.增强k网格密度
3.设置ADDGRID = TRUE
4.使用10的倍数的核数
5.在INCAR中添加 LSCALAPACK = .FALSE.
6. 添加ALGO = FAST
但是均告失败,依旧报错;
而且神奇的是,只有铼单原子掺杂氧化铟的模型出现这个问题,其他过渡金属元素(铱,钯,钌,铑,铂,镍等)掺杂的模型都没出现过这个问题;
我的计算INCAR如下,Gama点取331,且在POSCAR中仅放开CO2分子,其他的slab原子都是固定的:
INCAR:
ENCUT = 400.000000
SIGMA = 0.1
EDIFF = 1.00e-06
PREC = Normal
ISMEAR = 0
NSW = 1
IBRION = 5
LCHARG = .FALSE.
LWAVE = .FALSE.
LREAL = .FALSE.
POTIM = 0.02
NELM = 1000
NFREE = 2
vdW Calculation
GGA = BF
LUSE_VDW = .TRUE.
Zab_vdW = -1.8867
AGGAC = 0.0000
请问一下各位大佬,有人遇到过这个问题吗,从什么方向去考虑解决?感激不尽!
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