I am attempting to do a optimization of the 3C polytype of bulk SiC. When I setup the structure with the lattice constant of 8.9, I only get one SCF loop and no others. If I change the lattice constant to 8.184 I get a lower value for the energy in the TOTENERGY.OUT file. I am not sure if I am getting exciting to perform an optimization. Below is my exciting.in file:
Hi!
To relax the structure you should modify the task flag as follows:
task
2
in exciting.in
However I run with such modification the code and it did only 1 iteration since the forces are already zero, i.e the structure is already relaxed.
You can check the forces in the file INFO.OUT
As a test if you start from the following structure in exciting.in:
With the flag epsforce you can decide the degree of convergence of the forces.
I would also recommend to use the following modified species file C.in and Si.in . In these I removed some of the local orbitals that were not useful, f and d orbitals in C (that are far unoccupied), and same Si. This will reduce your basis set and then speed up your calculation.
Hope this will help!
Best
Francesco Cricchio
'C' : spsymb
'carbon' : spname
-6.00000 : spzn
21894.16673 : spmass
0.816497E-06 1.4500 39.0411 300 : sprmin, rmt, sprmax, nrmt
4 : spnst
1 0 1 2.00000 T : spn, spl, spk, spocc, spcore
2 0 1 2.00000 F
2 1 1 1.00000 F
2 1 2 1.00000 F
1 : apword
0.1500 0 F : apwe0, apwdm, apwve
0 : nlx
3 : nlorb
0 2 : lorbl, lorbord
0.1500 0 F : lorbe0, lorbdm, lorbve
0.1500 1 F
1 2 : lorbl, lorbord
0.1500 0 F : lorbe0, lorbdm, lorbve
0.1500 1 F
0 3 : lorbl, lorbord
0.1500 0 F : lorbe0, lorbdm, lorbve
0.1500 1 F
-0.3512 0 T
'Si' : spsymb
'silicon' : spname
-14.0000 : spzn
51196.73454 : spmass
0.534522E-06 2.0000 46.0509 400 : sprmin, rmt, sprmax, nrmt
7 : spnst
1 0 1 2.00000 T : spn, spl, spk, spocc, spcore
2 0 1 2.00000 T
2 1 1 2.00000 T
2 1 2 4.00000 T
3 0 1 2.00000 F
3 1 1 1.00000 F
3 1 2 1.00000 F
1 : apword
0.1500 0 F : apwe0, apwdm, apwve
0 : nlx
2 : nlorb
0 2 : lorbl, lorbord
0.1500 0 F : lorbe0, lorbdm, lorbve
0.1500 1 F
1 2 : lorbl, lorbord
0.1500 0 F : lorbe0, lorbdm, lorbve
0.1500 1 F
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I am attempting to do a optimization of the 3C polytype of bulk SiC. When I setup the structure with the lattice constant of 8.9, I only get one SCF loop and no others. If I change the lattice constant to 8.184 I get a lower value for the energy in the TOTENERGY.OUT file. I am not sure if I am getting exciting to perform an optimization. Below is my exciting.in file:
tasks
0
20
avec
0.00 0.50 0.50
0.50 0.00 0.50
0.50 0.50 0.00
sppath
'/home/adp/exciting/species/'
atoms
2 : nspecies
ngridk
4 4 4
!vkloff
! 0.5 0.5 0.5
scale
8.751
autormt
.true.
'Si.in' : spfname
1 : natoms
0.0 0.0 0.0 0.0 0.0 0.0 : atposl, bfcmt
'C.in' : spfname
1 : natoms
0.25 0.25 0.25 0.0 0.0 0.0
On another note, I would like to increase the number of k-points that are being produced when I perform a plot1d for bandplots. How can I do that?
Thank you
ADP
Hi!
To relax the structure you should modify the task flag as follows:
task
2
in exciting.in
However I run with such modification the code and it did only 1 iteration since the forces are already zero, i.e the structure is already relaxed.
You can check the forces in the file INFO.OUT
As a test if you start from the following structure in exciting.in:
tasks
2
epsforce
1.d-4
avec
0.00 0.50 0.50
0.50 0.00 0.50
0.50 0.50 0.00
sppath
'./'
ngridk
4 4 4
scale
8.751
autormt
.true.
atoms
2 : nspecies
'Si.in' : spfname
1 : natoms
0.0 0.0 0.0 0.0 0.0 0.0 : atposl, bfcmt
'C.in' : spfname
1 : natoms
0.27 0.27 0.27 0.0 0.0 0.0
The system will relax to
Species : 1 (Si)
atomic positions (lattice) :
1 0.01023356 0.01023356 0.01023356
Species : 2 (C)
atomic positions (lattice) :
1 0.25976644 0.25976644 0.25976644
equivalent to
Si 0 0 0
C 0.25 0.25 0.25
after few relaxation steps.
With the flag epsforce you can decide the degree of convergence of the forces.
I would also recommend to use the following modified species file C.in and Si.in . In these I removed some of the local orbitals that were not useful, f and d orbitals in C (that are far unoccupied), and same Si. This will reduce your basis set and then speed up your calculation.
Hope this will help!
Best
Francesco Cricchio
'C' : spsymb
'carbon' : spname
-6.00000 : spzn
21894.16673 : spmass
0.816497E-06 1.4500 39.0411 300 : sprmin, rmt, sprmax, nrmt
4 : spnst
1 0 1 2.00000 T : spn, spl, spk, spocc, spcore
2 0 1 2.00000 F
2 1 1 1.00000 F
2 1 2 1.00000 F
1 : apword
0.1500 0 F : apwe0, apwdm, apwve
0 : nlx
3 : nlorb
0 2 : lorbl, lorbord
0.1500 0 F : lorbe0, lorbdm, lorbve
0.1500 1 F
1 2 : lorbl, lorbord
0.1500 0 F : lorbe0, lorbdm, lorbve
0.1500 1 F
0 3 : lorbl, lorbord
0.1500 0 F : lorbe0, lorbdm, lorbve
0.1500 1 F
-0.3512 0 T
'Si' : spsymb
'silicon' : spname
-14.0000 : spzn
51196.73454 : spmass
0.534522E-06 2.0000 46.0509 400 : sprmin, rmt, sprmax, nrmt
7 : spnst
1 0 1 2.00000 T : spn, spl, spk, spocc, spcore
2 0 1 2.00000 T
2 1 1 2.00000 T
2 1 2 4.00000 T
3 0 1 2.00000 F
3 1 1 1.00000 F
3 1 2 1.00000 F
1 : apword
0.1500 0 F : apwe0, apwdm, apwve
0 : nlx
2 : nlorb
0 2 : lorbl, lorbord
0.1500 0 F : lorbe0, lorbdm, lorbve
0.1500 1 F
1 2 : lorbl, lorbord
0.1500 0 F : lorbe0, lorbdm, lorbve
0.1500 1 F