Prof. Blaha and wien users.<br> <br> I am running wien version 11.1 on a intel core i7 machine with Mandriva 2010 operating system, fortran compiler ifort 11.1 and math<br> libraries mkl 10.<br> The purpose of my calculations is to get forces to perfom surface structure relaxation.<br>
I am calculating tungsten slab with the following initial structure<br><br>W_surface <br>CXY LATTICE,NONEQUIV.ATOMS: 765_Cmmm <br>
MODE OF CALC=RELA unit=bohr <br> 5.981401 8.458979 84.589790 90.000000 90.000000 90.000000 <br>ATOM -1: X=0.00000000 Y=0.00000000 Z=0.00000000<br> MULT= 1 ISPLIT= 8<br>
W 1 NPT= 781 R0=0.00000500 RMT= 2.2000 Z: 74.0 <br>LOCAL ROT MATRIX: 1.0000000 0.0000000 0.0000000<br> 0.0000000 1.0000000 0.0000000<br> 0.0000000 0.0000000 1.0000000<br>
ATOM -2: X=0.50000000 Y=0.00000000 Z=0.05000000<br> MULT= 2 ISPLIT= 8<br> -2: X=0.50000000 Y=0.00000000 Z=0.95000000<br>W 2 NPT= 781 R0=0.00000500 RMT= 2.2000 Z: 74.0 <br>
LOCAL ROT MATRIX: 1.0000000 0.0000000 0.0000000<br> 0.0000000 1.0000000 0.0000000<br> 0.0000000 0.0000000 1.0000000<br>ATOM -3: X=0.00000000 Y=0.00000000 Z=0.10000000<br> MULT= 2 ISPLIT= 8<br>
-3: X=0.00000000 Y=0.00000000 Z=0.90000000<br>W 3 NPT= 781 R0=0.00000500 RMT= 2.2000 Z: 74.0 <br>LOCAL ROT MATRIX: 1.0000000 0.0000000 0.0000000<br> 0.0000000 1.0000000 0.0000000<br>
0.0000000 0.0000000 1.0000000<br>ATOM -4: X=0.50000000 Y=0.00000000 Z=0.15000000<br> MULT= 2 ISPLIT= 8<br> -4: X=0.50000000 Y=0.00000000 Z=0.85000000<br>W 4 NPT= 781 R0=0.00000500 RMT= 2.2000 Z: 74.0 <br>
LOCAL ROT MATRIX: 1.0000000 0.0000000 0.0000000<br> 0.0000000 1.0000000 0.0000000<br> 0.0000000 0.0000000 1.0000000<br>ATOM -5: X=0.00000000 Y=0.00000000 Z=0.20000000<br> MULT= 2 ISPLIT= 8<br>
-5: X=0.00000000 Y=0.00000000 Z=0.80000000<br>W 5 NPT= 781 R0=0.00000500 RMT= 2.2000 Z: 74.0 <br>LOCAL ROT MATRIX: 1.0000000 0.0000000 0.0000000<br> 0.0000000 1.0000000 0.0000000<br>
0.0000000 0.0000000 1.0000000<br>ATOM -6: X=0.50000000 Y=0.00000000 Z=0.25000000<br> MULT= 2 ISPLIT= 8<br> -6: X=0.50000000 Y=0.00000000 Z=0.75000000<br>W 6 NPT= 781 R0=0.00000500 RMT= 2.2000 Z: 74.0 <br>
LOCAL ROT MATRIX: 1.0000000 0.0000000 0.0000000<br> 0.0000000 1.0000000 0.0000000<br> 0.0000000 0.0000000 1.0000000<br>ATOM -7: X=0.00000000 Y=0.00000000 Z=0.30000000<br> MULT= 2 ISPLIT= 8<br>
-7: X=0.00000000 Y=0.00000000 Z=0.70000000<br>W 7 NPT= 781 R0=0.00000500 RMT= 2.2000 Z: 74.0 <br>LOCAL ROT MATRIX: 1.0000000 0.0000000 0.0000000<br> 0.0000000 1.0000000 0.0000000<br>
0.0000000 0.0000000 1.0000000<br> 8 NUMBER OF SYMMETRY OPERATIONS<br><br>using GGA PBE XC potential, spin-orbit interaction without spin polarization, RKmax=7, k-mesh=2000.<br>The commandline is run_lapw -p -so -cc 0.00001 -ec 0.0001 -fc 1.0 -i 120 -r 20.<br>
There is the force result of last two iterations:<br><br>:ITE069: 69. ITERATION TOTAL FORCE WITH RESPECT TO THE GLOBAL COORDINATE SYSTEM:<br>:FGL001: 1.ATOM 0.000000000 0.000000000 0.000000000 partial forces<br>
:FGL002: 2.ATOM 0.000000000 0.000000000 3.035000000 partial forces<br>:FGL003: 3.ATOM 0.000000000 0.000000000 2.956000000 partial forces<br>:FGL004: 4.ATOM 0.000000000 0.000000000 16.247000000 partial forces<br>
:FGL005: 5.ATOM 0.000000000 0.000000000 79.306000000 partial forces<br>:FGL006: 6.ATOM 0.000000000 0.000000000 5.081000000 partial forces<br>:FGL007: 7.ATOM 0.000000000 0.000000000 828.277000000 partial forces<br>
<br>:ITE070: 70. ITERATION TOTAL FORCE WITH RESPECT TO THE GLOBAL COORDINATE SYSTEM:<br>:FGL001: 1.ATOM 0.000000000 0.000000000 0.000000000 total forces<br>:FGL002: 2.ATOM 0.000000000 0.000000000 289.947000000 total forces<br>
:FGL003: 3.ATOM 0.000000000 0.000000000 123.015000000 total forces<br>:FGL004: 4.ATOM 0.000000000 0.000000000 72.397000000 total forces<br>:FGL005: 5.ATOM 0.000000000 0.000000000 33.811000000 total forces<br>
:FGL006: 6.ATOM 0.000000000 0.000000000 25.803000000 total forces<br>:FGL007: 7.ATOM 0.000000000 0.000000000 -56.857000000 total forces <br><br>The difference is because of appearance of huge valence forces in last iteration:<br>
<br> VALENCE-FORCE IN mRy/a.u. = |F| Fx Fy Fz<br>:FVA001: 1.ATOM 0.000 0.000 0.000 0.000<br> VALENCE-FORCE IN mRy/a.u. = |F| Fx Fy Fz<br>
:FVA002: 2.ATOM 287.029 0.000 0.000 287.029<br> VALENCE-FORCE IN mRy/a.u. = |F| Fx Fy Fz<br>:FVA003: 3.ATOM 119.172 0.000 0.000 119.172<br>
VALENCE-FORCE IN mRy/a.u. = |F| Fx Fy Fz<br>:FVA004: 4.ATOM 55.430 0.000 0.000 55.430<br> VALENCE-FORCE IN mRy/a.u. = |F| Fx Fy Fz<br>
:FVA005: 5.ATOM 51.852 0.000 0.000 -51.852<br> VALENCE-FORCE IN mRy/a.u. = |F| Fx Fy Fz<br>:FVA006: 6.ATOM 29.373 0.000 0.000 29.373<br>
VALENCE-FORCE IN mRy/a.u. = |F| Fx Fy Fz<br>:FVA007: 7.ATOM 684.540 0.000 0.000 -684.540 <br><br>The total forces in the 70-th iteration look unphysical. A very high force has appeared on the next to the internal layer of the slab <br>
(it is the 6-th layer from the surface).<br>This leads to an icrease of interlayer distance between internal monolayers. On the other hand, the total forces in the 69-th iteration are<br>rather realistic. However, they do not contain the valence-force corrections. <br>
This effect appears only in the spin-orbit mode.<br><br>The questions are: <br>1. Is it possible to use the forces without valence-force corrections, e.g. pure HELLMAN-FEYMAN forces, for the relaxation?<br><br>2. Can the spin-orbit mode lead to the wrong forces?<br>
<br>Sincerely, Korshunov Alexey, Sarov State Physical Tecnical Institute, Russia. <br><a href="mailto:al.korshunof@gmail.com" target="_blank">al.korshunof@gmail.com</a><br>