Dear all,
I'm not that new to comp.chem. but the innings of nwchem sometimes dazzle me...
I'm searching for a transition state of some "well-behaved" but somewhat large systems. i managed to find them out at semi-empirical level rather easily, and also at a b3lyp/6-31+g*, which is what i actually need, but using a software i can only use for testing and not for production (money issues involved).
In NWChem I simply cannot find it.
I've tried:
- starting from the semi-empirical TS and simply using "task dft saddle";
- starting from the semi-empirical TS and setting the two relevant bonds equal, optimizing, removing the restrains, and finding the saddle point, as hereafter:
geometry adjust
zcoord
bond 33 20 r1
bond 19 14 r1
end
end
task dft optimize
geometry adjust
zcoord
bond 33 20 ra
bond 19 14 rb
end
end
task dft saddle
- both the previous approaches, starting with 3-21g and then using 6-31+g*;
- both the four previous approaches, starting with "task scf" and moving on to "task dft".
I've tried from 512 to 16384 cores, from 1h to 12h, and it never converges; the best result i got so far is this one, using 409 cores in 3 hours; basically Energy will continue going up and down for hours:
@ Step Energy Delta E Gmax Grms Xrms Xmax Walltime
@ ---- ---------------- -------- -------- -------- -------- -------- --------
@ 0 -1370.07402942 0.0D+00 0.04007 0.00584 0.00000 0.00000 3227.0
@ 1 -1390.09356448 -2.0D+01 0.19141 0.02730 0.18810 0.70698 3621.9
@ 2 -1405.16078729 -1.5D+01 4.41203 0.35142 0.66656 2.33209 3926.9
@ 3 -1395.06021814 1.0D+01 0.46875 0.04920 0.01224 0.03950 4341.4
@ 4 -1391.84280854 3.2D+00 0.20524 0.03234 0.28838 0.96386 4599.3
@ 5 -1390.34902276 1.5D+00 0.41416 0.03152 0.27279 0.80297 4945.5
@ 6 -1391.37084310 -1.0D+00 0.15604 0.02646 0.06094 0.21887 5226.3
@ 7 -1387.37461692 4.0D+00 6.23294 0.75855 0.48296 1.64532 5639.6
@ 8 -1409.51832805 -2.2D+01 3.35162 0.21275 0.31449 1.33895 6082.9
@ 9 -1411.46980249 -2.0D+00 0.80072 0.12469 0.35833 1.04045 6369.8
@ 10 -1418.94320046 -7.5D+00 11.40609 1.65839 0.03230 0.11637 6814.3
@ 11 -1409.56152186 9.4D+00 1.02348 0.11676 0.00497 0.01507 7484.3
@ 12 -1405.06149710 4.5D+00 3.58403 0.21298 0.36337 0.93229 7737.0
@ 13 -1400.18805699 4.9D+00 0.27405 0.03565 0.00261 0.00838 7957.2
@ 14 -1400.90597963 -7.2D-01 0.35446 0.04281 0.00019 0.00068 8168.2
@ 15 -1395.67115410 5.2D+00 0.26135 0.03761 0.00330 0.01143 8385.1
@ 16 -1393.84956516 1.8D+00 0.11285 0.02409 0.12495 0.39939 8606.4
@ 17 -1395.58405244 -1.7D+00 0.52558 0.07931 0.25719 0.86397 9037.0
@ 18 -1399.34965134 -3.8D+00 0.61906 0.04839 0.26580 1.02865 9358.5
@ 19 -1405.85472854 -6.5D+00 6.87758 0.56548 0.85591 2.12683 9591.4
@ 20 -1398.84413270 7.0D+00 3.93401 0.30363 0.54737 1.58926 10032.6
@ 21 -1420.13246889 -2.1D+01 6.50849 0.38982 0.33090 0.99010 10596.9
Are there any approaches I can use to achieve convergence, or is it really a question of time ?
FYI, this same system using the other software converged in 2 weeks with 6 cores on my PC.
I'm attaching in the end the nw file for this example.
Thanks for your time,
E.
memory total 6 gb
start nvp-ts-122
geometry
C 0.00000000 0.00000000 0.00000000
C 1.38819303 0.00000000 0.00000000
C 2.05714020 1.23387879 0.00000000
N 1.41173603 2.40902533 -0.02951515
C 0.05397831 2.40887368 -0.04991691
C -0.69660506 1.21596325 -0.02259409
N -0.60323441 3.65984770 -0.00913331
C -1.47451841 3.90201758 -1.11455132
C -2.68660457 3.16794381 -1.26002907
N -1.12002529 4.89683531 -1.95002306
C -1.96124792 5.25549522 -2.93281358
C -3.20246561 4.64010765 -3.10697993
C -3.58304261 3.59631633 -2.26036756
C -2.15795576 1.15269493 0.09941145
N -3.02397940 2.10488246 -0.40408836
C 0.21218588 4.80508872 0.40414713
C -0.51338105 5.88103623 1.19121266
C 0.43723393 4.94617997 1.89859875
O -2.68230243 0.20385591 0.67467194
C -4.98832124 3.07019628 -2.42541451
H -0.56167060 -0.94126392 0.02806185
H 1.94918329 -0.93011407 0.00896086
H 3.15435684 1.29970786 0.01494971
H -1.61292766 6.06646326 -3.58422168
H -3.86562352 4.98116227 -3.89900363
H 1.00762783 5.07575064 -0.30545644
H -1.58227696 5.78942131 1.36873272
H -0.24547617 6.92096525 1.03140507
H 0.04076995 4.19383901 2.57627965
H 1.39919545 5.30358956 2.25409076
H -5.39131797 3.34567833 -3.42840807
H -5.63997354 3.59240013 -1.67737532
N -5.07147453 1.61478438 -2.17492323
C -6.46994862 1.12381517 -2.17675949
C -6.47563023 -0.35164827 -1.73944610
C -6.13805043 -0.48414174 -0.24929295
C -5.97154116 -1.95718371 0.13736138
C -5.67394366 -2.14025197 1.61035072
C -5.64185034 -3.75396642 1.92039460
N -4.28691725 -1.65088930 1.97436488
O -6.70564138 -4.31336291 1.78348652
O -4.49786285 -4.10281657 2.24359786
H -6.43407699 -1.67904680 2.26165178
H -4.49825692 1.09502708 -2.84013786
H -4.02874978 1.82429252 -0.43150598
H -6.95427999 1.23076646 -3.17088788
H -7.06508397 1.73346399 -1.46199524
H -5.75644924 -0.93415591 -2.34676405
H -7.46985563 -0.79372981 -1.94438982
H -5.20974079 0.08113504 -0.03193829
H -6.93232886 -0.01578371 0.36115442
H -5.19083994 -2.43821664 -0.48593786
H -6.90417272 -2.52480515 -0.09717697
H -4.28929187 -1.14190667 2.85740286
H -3.68704264 -2.53512002 2.09672373
H -3.88297705 -1.04222999 1.24933958
end
driver
loose
maxiter 250
end
basis
* library 6-31+g*
end
scf
maxiter 250
end
dft
xc b3lyp
iterations 250
end
geometry adjust
zcoord
bond 33 20 r1
bond 19 14 r1
end
end
task scf optimize
task dft optimize
geometry adjust
zcoord
bond 33 20 ra
bond 19 14 rb
end
end
basis
* library 6-31+g*
end
task dft saddle
|