BOPT < 0,no correction made

[Kun Tao]

Dear all,

I am using the vasp.5.4.4. When I try to do some relaxations, I encountered some warning message in the STDOUT file as following "BOPT < 0, no correction made". After this the total energy keeps constant until the end as following:

209 SDA: 1 -0.112679044652E+04 -0.23283E-09 0.00000E+00 768 0.357E-08 0.000E+00
210 CGA: 2 -0.112679044652E+04 0.21828E-09 -0.20072E-09 768 0.204E-08 0.167E-08
211 CGA: 3 -0.112679044651E+04 0.45839E-08 -0.27078E-08 768 0.472E-07-0.590E-08
212 CGA: 4 -0.112679044652E+04 -0.58062E-08 -0.42431E-08 768 0.379E-07-0.946E-08
213 CGA: 5 -0.112679044652E+04 -0.49913E-08 -0.41926E-08 768 0.654E-08-0.989E-08
214 CGA: 6 -0.112679044652E+04 -0.14552E-10 -0.26449E-09 768 0.358E-08 0.270E-08
215 CGA: 7 -0.112679044652E+04 0.78580E-09 -0.19056E-09 768 0.275E-08 0.387E-08
216 CGA: 8 -0.112679044652E+04 0.00000E+00 -0.12039E-09 768 0.196E-08 0.223E-08
217 10 F= -.11267904E+04 E0= -.11267757E+04 d E =-.295269E-01 mag= 0.0310
... ...
... ...
2109 SDA: 1 -0.112679044650E+04 -0.45111E-09 0.00000E+00 768 0.337E-07 0.000E+00
2110 CGA: 2 -0.112679044650E+04 -0.32014E-09 -0.81599E-42 768 0.337E-07 0.337E-07
2111 CGA: 3 -0.112679044650E+04 0.00000E+00 -0.56646E-43 768 0.337E-07 0.337E-07
2112 CGA: 4 -0.112679044650E+04 0.49477E-09 -0.16614E-42 768 0.337E-07 0.337E-07
2113 CGA: 5 -0.112679044650E+04 -0.46566E-09 0.18742E-43 768 0.337E-07 0.337E-07
2114 CGA: 6 -0.112679044650E+04 0.43656E-10 -0.21419E-43 768 0.337E-07 0.337E-07
2115 CGA: 7 -0.112679044650E+04 0.16007E-09 -0.13878E-43 768 0.337E-07 0.337E-07
2116 CGA: 8 -0.112679044650E+04 0.00000E+00 -0.40705E-43 768 0.337E-07 0.337E-07
2117 200 F= -.11267904E+04 E0= -.11267757E+04 d E =-.295269E-01 mag= 0.0310

The INCAR file as following:

1 System
2
3 ISTART = 0
4 NWRITE = 2 : verbosity
5
13
14 ENCUT = 520
15 ADDGRID = .TRUE.
16
17 PREC = accurate : accuracy
18 NELM = 300 : maximum number of SCF iterations
19 NELMIN = 8 : minimal number of SCF iterations
20 NELMDL = -6 : number of non-SCF iterations
21 EDIFF = 1E-6 : criterion for SCF convergence
22 ISMEAR = 0 : Methfessel-Paxton smearing
23 SIGMA = 0.05 : sigma for smearing
24
25 NPAR = 8
26
27 GGA = PS
28 GGA_COMPAT = .FALSE.
29 VOSKOWN = 1
30
32 ALGO = All
33
34 ISPIN = 2
35 MAGMOM = 112*0 24*0 38*0 1 1 2
36
39 LORBIT = 11
40
41 AMIX = 0.002
42 BMIX = 0.0001
43 AMIX_MAG = 0.005
44 BMIX_MAG = 0.0001
45
46 LWAVE = .FALSE.
49 LREAL = Auto
50
51 ####################################
52 # Parameters for SOC
53 ISYM = -1
68 # LDA+U
69 LDAU=.TRUE. # AFLOW LSDA+U
70 # LDAU_SPECIES=B Lu # LDAU species
71 LDAUL=-1 -1 -1 2 0 # l-quantum number for which the on site interaction is added (Default 2)
72 LDAUU=0 0 0 73 LDAUJ=0 0 0 0.7 0 # J parameter (if used). Automatic LDAUJ table
74 LDAUTYPE=2 # Type of LDA+U.
75 LDAUPRINT=0 # Controls verbosity of the L(S)DA+U module. (Default 0) # AFLOW LSDA+U
76
77 ####################################
78 # Ionic Relaxation
79 NSW = 200 : maximum number of ionic steps
80 EDIFFG = -1.0E-2 : maximal residual force in eV/Ang
81 IBRION = -1 : quasi-Newton optimization
82 ISIF = 3 : optimize ions, cell shape and volume7.0 0

The KPOINTS file as following:

1 K-Spacing Value to Generate K-Mesh: 0.040
2 0
3 Gamma
4 1 1 1
5 0.0 0.0 0.0

Could you give me any suggestions?

Best wishes,
Kun Tao

[svijay]

Dear Kun Tao,

Please supply VASP input and output files in accordance with the forum guidelines here: https://www.vasp.at/forum/viewtopic.php?t=17928. Additionally, please make sure to supply a minimal working example in case of specific queries: https://www.vasp.at/wiki/index.php/Mini ... le_example

That being said, from the output - it does appear that the calculation converges to the required accuracy. Is that correct?

Sudarshan

[Kun Tao]

Dear Sudarshan,

I am trying to optimize ions, cell shape and volume using ISIF. But, after 200 iterations, there is no any difference between the POSCAR and the CONTCAR. Attached below are the input and the output files. Could you give me any suggestions?

With regards,
Kun Tao

[svijay]

Dear Kun Tao,

There are a couple of things you could try:
- I see that you do not set an EDIFFG, it may be a good idea to decide what (for example) force convergence threshold you would like to reach
- I see that you set IBRION=-1, which translates to no update to the ion positions (see here: https://www.vasp.at/wiki/index.php/IBRION). Perhaps switching to IBRION=1,2 is a better choice.

Sudarshan