When I tried to optimize the internal coordinate of a system with spin-orbit interaction (LSORBIT = .True.),
the atomic forces became very large with VASP 6.1.0. This phenomenon was not observed in VASP 5.4.4.
Before running an optimization with SOI, I relaxed the internal coordinate without SOI by VASP 6.1.0 and copied CONTCAR as POSCAR.
Therefore, the structure in POSCAR should be reasonable.
Below are the excerpts from the OUTCAR files.
VASP 5.4.4
Code: Select all
POSITION TOTAL-FORCE (eV/Angst)
-----------------------------------------------------------------------------------
1.33368 1.07700 0.29010 0.041951 0.000000 0.033320
7.12718 1.07700 1.86290 0.041943 -0.000002 -0.033316
4.35030 3.23100 2.52640 0.013505 0.000001 -0.002236
10.14380 3.23100 3.93260 0.013508 0.000000 0.002235
10.03160 1.07700 2.07089 -0.032839 0.000001 0.004507
1.66492 3.23100 2.29925 -0.022614 0.000000 -0.027963
7.45842 3.23100 4.15975 -0.022615 0.000000 0.027961
4.23810 1.07700 0.08211 -0.032839 -0.000000 -0.004509
-----------------------------------------------------------------------------------
total drift: -0.003161 -0.000003 0.000006
Code: Select all
POSITION TOTAL-FORCE (eV/Angst)
-----------------------------------------------------------------------------------
1.33368 1.07700 0.29010 12.832589 1.333413 -24.539761
7.12718 1.07700 1.86290 111.850117 -24.971320 129.926731
4.35030 3.23100 2.52640 -121.755018 -1.718684 -67.081141
10.14380 3.23100 3.93260 -121.078815 -2.751189 -35.697358
10.03160 1.07700 2.07089 -11.748897 0.129917 -120.542707
1.66492 3.23100 2.29925 -92.867240 -1.443072 -40.272766
7.45842 3.23100 4.15975 52.805601 30.196516 280.629710
4.23810 1.07700 0.08211 169.961663 -0.775582 -122.422708
-----------------------------------------------------------------------------------
total drift: 841.945960 9.049849 410.561481
The large difference was observed only for atomic forces, particularly in the non-local components.
I have attached the relevant input and output files for your consideration.
Any help or comments would be highly appreciated.
Best regards,
Terumasa