[DFTB-Plus-User] Unreasonably large number of steps in simultaneous geometry and cell optimization
Alexander Maryewski
A.Maryewski at skoltech.ru
Sat Dec 4 23:11:01 CET 2021
Dear DFTB+ users and developers,
I'm experiencing a problem with unreasonably slow convergence for simultaneous geometry & cell optimization. The initial structure for optimization (organic molecular crystal) is obtained from PBE relaxation with MBD correction in FHI-aims, so it is supposed to be in proximity of DFTB minimum; the system itself is quite simple, with no flexible dihedral angles. The final structure is essentially identical to the initial one, the volume change is very small. However, the relaxation takes 3448 geometry steps and 91 lattice steps, which is, in my opinion, too much for such negligible change.
I'm attaching the initial and final structures, as well as the input specification. I must note that changing the relaxation driver to BFGS or CG led to even bigger number of steps, while increasing the max step size had virtually no effect on number of steps. The problem also persists for all other types of dispersion corrections (D3, D4, and MBD), as well as for DFTB1, DFTB2, and xTB Hamiltonian. I'm using a development version of DFTB+ (commit 65b0275).
Thank you in advance for you help!
Input:
Geometry = VaspFormat {
<<< "POSCAR"
}
Driver = FIRE {
MovedAtoms = 1:-1
MaxForceComponent = 1e-4
LatticeOpt = Yes
MaxSteps = -1
MaxAtomStep = 0.94486
MaxLatticeStep = 0.94486
}
Hamiltonian = DFTB {
SCC = Yes
SCCTolerance = 1e-08
MaxSCCIterations = 2000
SlaterKosterFiles = Type2FileNames{
Prefix = /home/amarjewski/Downloads/3ob-3-1/
Separator = "-"
Suffix = ".skf"
}
HCorrection = Damping {
Exponent = 4.2
}
HubbardDerivs {
C = -0.1492
S = -0.11
N = -0.1535
}
MaxAngularMomentum = {
C = p
S = d
N = p
}
KPointsAndWeights = SupercellFolding {
2. 0. 0.
0. 2. 0.
0. 0. 1.
0.5 0.5 0.5
}
Dispersion = TS {
RangeSeparation = 1.05
}
}
Options {
WriteResultsTag = Yes
TimingVerbosity = -1
}
ParserOptions {
IgnoreUnprocessedNodes = Yes
}
Initial structure:
EA0
1.0000000000000000
0.000000 0.000000 -7.055000
-0.000000 -10.130900 -0.000000
-13.452700 0.000000 -0.000000
C N S
32 16 12
Direct
0.020520 0.692620 0.600950
0.042030 0.587050 0.180350
0.542030 0.412950 0.819650
0.042030 0.912950 0.680350
0.030900 0.137560 0.263670
0.530900 0.862440 0.736330
0.530900 0.637560 0.236330
0.030900 0.362440 0.763670
0.928500 0.241210 0.079410
0.428500 0.758790 0.920590
0.428500 0.741210 0.420590
0.928500 0.258790 0.579410
0.997970 0.671140 0.100580
0.497970 0.328860 0.899420
0.497970 0.171140 0.399420
0.997970 0.828860 0.600580
0.542030 0.087050 0.319650
0.531340 0.943920 0.822090
0.031340 0.056080 0.177910
0.520520 0.307380 0.399050
0.020520 0.807380 0.100950
0.972070 0.640130 0.506290
0.472070 0.359870 0.493710
0.472070 0.140130 0.993710
0.520520 0.192620 0.899050
0.983790 0.392900 0.586900
0.483790 0.607100 0.413100
0.483790 0.892900 0.913100
0.983790 0.107100 0.086900
0.031340 0.443920 0.677910
0.972070 0.859870 0.006290
0.531340 0.556080 0.322090
0.913600 0.774530 0.938670
0.884360 0.148230 0.570310
0.384360 0.851770 0.429690
0.384360 0.648230 0.929690
0.884360 0.351770 0.070310
0.534960 0.798690 0.663870
0.534960 0.701310 0.163870
0.034960 0.201310 0.336130
0.085280 0.976920 0.749030
0.413600 0.225470 0.061330
0.585280 0.023080 0.250970
0.034960 0.298690 0.836130
0.413600 0.274530 0.561330
0.085280 0.523080 0.249030
0.585280 0.476920 0.750970
0.913600 0.725470 0.438670
0.990480 0.028080 0.969370
0.490480 0.971920 0.030630
0.490480 0.528080 0.530630
0.990480 0.471920 0.469370
0.916110 0.621430 0.983970
0.416110 0.121430 0.516030
0.916110 0.878570 0.483970
0.101330 0.893130 0.206480
0.601330 0.106870 0.793520
0.601330 0.393130 0.293520
0.101330 0.606870 0.706480
0.416110 0.378570 0.016030
Final structure:
60 F
C N S
1 1 0.1618820919E-01 0.6953035972E+00 0.6028292686E+00
2 1 0.6054080320E-01 0.5816253594E+00 0.1889168374E+00
3 1 0.5605408032E+00 0.4183746406E+00 0.8110831626E+00
4 1 0.6054080212E-01 0.9183746373E+00 0.6889168379E+00
5 1 0.3894586478E-01 0.1463696753E+00 0.2863807959E+00
6 1 0.5389458648E+00 0.8536303247E+00 0.7136192041E+00
7 1 0.5389458626E+00 0.6463696788E+00 0.2136192044E+00
8 1 0.3894586258E-01 0.3536303212E+00 0.7863807956E+00
9 1 0.9194815724E+00 0.2560876082E+00 0.9025739993E-01
10 1 0.4194815724E+00 0.7439123918E+00 0.9097426001E+00
11 1 0.4194815742E+00 0.7560876117E+00 0.4097426009E+00
12 1 0.9194815742E+00 0.2439123883E+00 0.5902573991E+00
13 1 0.1005024217E+01 0.6667714686E+00 0.1023961561E+00
14 1 0.5050242166E+00 0.3332285314E+00 0.8976038439E+00
15 1 0.5050242175E+00 0.1667714722E+00 0.3976038438E+00
16 1 0.1005024218E+01 0.8332285278E+00 0.6023961562E+00
17 1 0.5605408021E+00 0.8162536268E-01 0.3110831621E+00
18 1 0.5307570847E+00 0.9362083091E+00 0.8076337958E+00
19 1 0.3075708471E-01 0.6379169088E-01 0.1923662042E+00
20 1 0.5161882092E+00 0.3046964028E+00 0.3971707314E+00
21 1 0.1618820762E-01 0.8046963992E+00 0.1028292686E+00
22 1 0.9622657415E+00 0.6386852028E+00 0.5001196801E+00
23 1 0.4622657415E+00 0.3613147972E+00 0.4998803199E+00
24 1 0.4622657378E+00 0.1386852066E+00 0.9998803195E+00
25 1 0.5161882076E+00 0.1953036008E+00 0.8971707314E+00
26 1 0.9767711350E+00 0.3817261045E+00 0.5960237041E+00
27 1 0.4767711350E+00 0.6182738955E+00 0.4039762959E+00
28 1 0.4767711330E+00 0.8817261080E+00 0.9039762953E+00
29 1 0.9767711330E+00 0.1182738920E+00 0.9602370469E-01
30 1 0.3075708476E-01 0.4362083057E+00 0.6923662040E+00
31 1 0.9622657378E+00 0.8613147934E+00 0.1196804560E-03
32 1 0.5307570848E+00 0.5637916943E+00 0.3076337960E+00
33 2 0.9108197374E+00 0.7815481119E+00 0.9219522648E+00
34 2 0.8628543644E+00 0.1347135404E+00 0.5859737071E+00
35 2 0.3628543644E+00 0.8652864596E+00 0.4140262929E+00
36 2 0.3628543630E+00 0.6347135438E+00 0.9140262920E+00
37 2 0.8628543630E+00 0.3652864562E+00 0.8597370800E-01
38 2 0.5489472848E+00 0.7895246992E+00 0.6367080419E+00
39 2 0.5489472805E+00 0.7104753046E+00 0.1367080424E+00
40 2 0.4894728477E-01 0.2104753008E+00 0.3632919581E+00
41 2 0.1132682966E+00 0.9872521695E+00 0.7577586812E+00
42 2 0.4108197374E+00 0.2184518881E+00 0.7804773523E-01
43 2 0.6132682966E+00 0.1274783045E-01 0.2422413188E+00
44 2 0.4894728050E-01 0.2895246954E+00 0.8632919576E+00
45 2 0.4108197421E+00 0.2815481158E+00 0.5780477357E+00
46 2 0.1132682994E+00 0.5127478277E+00 0.2577586806E+00
47 2 0.6132682994E+00 0.4872521723E+00 0.7422413194E+00
48 2 0.9108197421E+00 0.7184518842E+00 0.4219522643E+00
49 3 0.9682605312E+00 0.3602122790E-01 0.9694575748E+00
50 3 0.4682605312E+00 0.9639787721E+00 0.3054242521E-01
51 3 0.4682605362E+00 0.5360212317E+00 0.5305424258E+00
52 3 0.9682605362E+00 0.4639787683E+00 0.4694575742E+00
53 3 0.9256425787E+00 0.6018522640E+00 0.9799177228E+00
54 3 0.4256425811E+00 0.1018522679E+00 0.5200822773E+00
55 3 0.9256425811E+00 0.8981477321E+00 0.4799177227E+00
56 3 0.9347257894E-01 0.8945740691E+00 0.2184145744E+00
57 3 0.5934725789E+00 0.1054259309E+00 0.7815854256E+00
58 3 0.5934725786E+00 0.3945740725E+00 0.2815854253E+00
59 3 0.9347257856E-01 0.6054259275E+00 0.7184145747E+00
60 3 0.4256425786E+00 0.3981477360E+00 0.2008227717E-01
0.0000000000E+00 0.0000000000E+00 0.0000000000E+00
0.3796409345E-10 -0.2823521794E-10 -0.6775993499E+01
0.4331511054E-08 -0.1000091620E+02 -0.3952259833E-11
-0.1248479890E+02 0.7282280671E-08 0.2555546997E-10
Best regards,
Alexander A. Maryewski
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