[CPMD-list] PBE + NLCC convergence problem
Oleg Yazyev
oleg.yazyev at epfl.ch
Wed Aug 4 17:06:18 CEST 2004
Dear Axel,
AK> and finally, does the same setup work in closed shell cases?
Yes, for closed shell it works fine. At least for water molecule I've
just checked.
AK> also, did you check, how much this is affected by GC-CUTOFF?
Is starts to work fine if GC-CUTOFF >> 1.e-4,
but this is unacceptable for any application.
Probably, at this level no gradient-correction is left at all!
AK> i'm not so sure, if this applies here, but i have seen, that the
AK> line search occasionally gets diverted for some systems in the initial
AK> state of the optimization (too much noise). in those cases, i could get
AK> to convergence, by first using ODIIS until it was 'stuck' and then
AK> continue with PCG MINIMIZE. you should check, however, if the results
AK> are physically reasonable.
Both of the them explodes. The example is isolated CH3 radical, see
below. ODIIS's case even worse!
PGC MINIMIZE:
NFI GEMAX CNORM ETOT DETOT TCPU
1 2.956E-02 3.896E-03 -7.189008 0.000E+00 9.19
LINE SEARCH : LAMBDA=.703E-01 PREDICTED ENERGY = 5.147515178916
2 2.075E+01 3.903E+00 -7.249209 -6.020E-02 8.66
LINE SEARCH : LAMBDA=.211 PREDICTED ENERGY = 3.769833904981
3 1.377E+04 2.676E+03 3.770053 1.102E+01 8.42
LINE SEARCH : LAMBDA=.105 PREDICTED ENERGY = 3.769858361282
4 1.289E+04 2.648E+03 3.769858 -1.947E-04 8.39
LINE SEARCH : LAMBDA=.105 PREDICTED ENERGY = 3.769858574551
5 1.276E+04 2.519E+03 3.769858 1.093E-07 8.42
LINE SEARCH : LAMBDA=.105 PREDICTED ENERGY = 3.769858918988
6 1.292E+04 2.549E+03 3.769859 2.017E-07 8.28
LINE SEARCH : LAMBDA=.105 PREDICTED ENERGY = 3.769859484147
7 1.303E+04 2.530E+03 3.769859 3.286E-07 8.31
LINE SEARCH : LAMBDA=.105 PREDICTED ENERGY = 3.769860363765
8 1.260E+04 2.608E+03 3.769859 5.389E-07 8.30
ODIIS:
NFI GEMAX CNORM ETOT DETOT TCPU
1 2.956E-02 3.896E-03 -7.189008 0.000E+00 3.22
2 5.204E+03 1.049E+03 -7.383763 -1.948E-01 3.25
3 3.489E+03 9.662E+02 -7.383541 2.220E-04 3.22
4 1.876E+03 4.716E+02 -7.375378 8.164E-03 3.24
5 4.387E+01 2.062E+01 -7.363097 1.228E-02 3.25
6 2.883E+02 1.893E+02 -7.352987 1.011E-02 3.25
7 2.128E+01 6.533E+00 -7.344642 8.345E-03 3.25
8 3.753E+01 1.806E+01 -7.337581 7.060E-03 3.25
9 5.459E+00 1.071E+00 -7.331482 6.099E-03 3.25
10 6.486E+01 2.790E+01 -7.326023 5.458E-03 3.28
11 1.321E+01 3.965E+00 -7.321248 4.776E-03 3.25
12 1.340E+05 5.053E+04 21.290431 2.861E+01 3.14
ODIIS| Insufficient progress; reset!
13 1.652E+04 6.124E+03 22.153249 8.628E-01 3.08
14 1.074E+06 1.288E+05 11.617793 -1.054E+01 2.90
15 1.246E+06 1.514E+05 11.626043 8.250E-03 2.88
16 1.044E+06 1.397E+05 20.808698 9.183E+00 2.96
17 4.957E+05 1.125E+05 28.292228 7.484E+00 2.97
18 6.336E+05 1.083E+05 34.496024 6.204E+00 2.97
19 1.452E+05 4.385E+04 39.732968 5.237E+00 2.96
20 2.063E+04 7.521E+03 44.416126 4.683E+00 2.94
AK> could you please post some more information about the
AK> pseudopotentials, you are using.
Sure. For the example above I used BHS pseudos with "typical" cutoffs.
PW cutoff was 60 Ry here. PP headers are:
============================================================
| Pseudopotential Report |
------------------------------------------------------------
| Atomic Symbol : C |
| Atomic Number : 6 |
| Number of core states : 1 |
| Number of valence states : 2 |
| Exchange-Correlation Functional : |
| Slater exchange : 0.6667 |
| LDA correlation : Ceperley-Alder |
| Exchange GC : Perdew-Burke-Ernzerhof |
| Correlation GC : Perdew-Burke-Ernzerhof |
| Electron Configuration : N L Occupation |
| 1 S 2.0000 |
| 2 S 2.0000 |
| 2 P 2.0000 |
| Full Potential Total Energy = -37.748221 |
| Bachelet-Hamann-Schluter normconserving PP |
| n l rc energy |
| 2 S 1.2000 -0.50506 |
| 2 P 1.2000 -0.19451 |
| 3 D 0.7159 -0.19451 |
| Nonlinear core correction |
| Core charge cutoff radius : 0.71590 |
| Number of Mesh Points : 615 |
| Pseudoatom Total Energy = -5.356782 |
============================================================
============================================================
| Pseudopotential Report |
------------------------------------------------------------
| Atomic Symbol : H |
| Atomic Number : 1 |
| Number of core states : 0 |
| Number of valence states : 1 |
| Exchange-Correlation Functional : |
| Slater exchange : 0.6667 |
| LDA correlation : Ceperley-Alder |
| Exchange GC : Perdew-Burke-Ernzerhof |
| Correlation GC : Perdew-Burke-Ernzerhof |
| Electron Configuration : N L Occupation |
| 1 S 0.7000 |
| Full Potential Total Energy = -0.474341 |
| Bachelet-Hamann-Schluter normconserving PP |
| n l rc energy |
| 1 S 0.5000 -0.37203 |
| 2 P 0.3828 -0.37203 |
| Number of Mesh Points : 511 |
| Pseudoatom Total Energy = -0.367687 |
============================================================
--
Best regards,
Oleg
______________________________________________________
Oleg Yazyev
Institute of Molecular and Biological Chemistry
Swiss Federal Institute of Technology in Lausanne (EPFL)
EPFL - BCH
CH-1015 Lausanne (Switzerland)
Tel.: +41 21 693 9881
E-mail: oleg.yazyev at epfl.ch
WWW: http://icmbcu001.epfl.ch/yazyev/index.html
_______________________________________________________
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