From NWChem
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Posts 6
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| 12:07:01 PM PDT - Tue, Jul 23rd 2013 |
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Hello Community,
I am attempting to optimize the geometry of several molecules that contain one aromatic ring. Additionally I am optimizing the cations and radicals that result from hydride and hydrogen atom extraction, respectively.
I am experiencing a relatively pervasive problem (about 20 of 50 molecules, give or take), that come back with many, many imaginary vibrational modes. Below is one such case for the ortho-xylenyl cation. The output geometry looks fine, however, there are 26 imaginary modes upwards of -4600 wavenumbers!
Does anyone have any thoughts or suggestions on what the problem may be?
Many thanks in advance!
Input Deck:
start molecule
charge +1
geometry noautosym
C 0.72691046 1.45284526 0.11091742
C -0.63210123 0.76104776 0.13737944
C -0.45116581 -0.78455354 -0.02661775
C 0.67417868 -1.30621629 -0.21286591
C 1.90505572 -0.56823016 -0.23654556
C 1.86346161 0.85642305 -0.07043133
H 2.82627848 1.40454991 -0.09469476
H 0.63615184 2.56001755 0.26219448
H 0.80063075 -2.41913892 -0.37516601
H 2.81868313 -1.06939078 -0.37201259
C -1.69675663 1.39138580 0.21239212
H -1.70695829 2.49124768 0.30020564
H -2.68461262 0.92621640 0.19099999
C -1.78247648 -1.56431749 0.06218713
H -2.50513672 -1.23943447 -0.68946057
H -2.24333518 -1.44725528 1.04698327
H -1.56210081 -2.62497023 -0.09746686
end
basis spherical
C library 6-31G*
H library 6-31G*
O library 6-31G*
END
stepper
maxiter 200
end
dft
xc b3lyp
iterations 200
end
cosmo
dielec 78.4
rsolv 1.30
iscren 0
ificos 1
lineq 0
do_gasphase false
end
task dft optimize
task dft freq
Output geometry:
17
C 0.68376808 1.46742475 0.11473114
C -0.54820826 0.71391884 0.12509824
C -0.51886043 -0.73510232 -0.02138848
C 0.71771712 -1.32932903 -0.21902506
C 1.89583837 -0.56414055 -0.24021652
C 1.88854500 0.83631656 -0.06865335
H 2.81818986 1.39499151 -0.08823833
H 0.62709959 2.54293796 0.24839030
H 0.78428485 -2.40350795 -0.35380689
H 2.84577474 -1.07204553 -0.38596917
C -1.72183025 1.40881544 0.22039110
H -1.71968991 2.49114462 0.30650385
H -2.69407128 0.92857296 0.19436920
C -1.77216931 -1.55486255 0.05749062
H -2.50930255 -1.24529074 -0.69353053
H -2.24475246 -1.45032173 1.04274186
H -1.55225773 -2.61291862 -0.09985774
Projected Modes:
----------------------------------------------------------------------------
Normal Eigenvalue || Projected Infra Red Intensities
Mode [cm**-1] || [atomic units] [(debye/angs)**2] [(KM/mol)] [arbitrary]
------ ---------- || -------------- ----------------- ---------- -----------
1 -4608.262 || 0.616187 14.216 600.690 142.199
2 -4479.212 || 0.106889 2.466 104.201 24.667
3 -3776.994 || 0.005477 0.126 5.339 1.264
4 -3528.245 || 0.033900 0.782 33.047 7.823
5 -3320.287 || 0.074962 1.729 73.077 17.299
6 -3242.856 || 0.017225 0.397 16.791 3.975
7 -2994.189 || 0.144678 3.338 141.039 33.388
8 -2683.759 || 0.001751 0.040 1.707 0.404
9 -2251.862 || 0.000787 0.018 0.767 0.182
10 -2062.414 || 0.047604 1.098 46.407 10.986
11 -1989.765 || 0.000197 0.005 0.192 0.045
12 -1883.087 || 0.082451 1.902 80.377 19.027
13 -1817.149 || 0.041938 0.968 40.883 9.678
14 -1732.541 || 0.002387 0.055 2.327 0.551
15 -1613.296 || 0.010820 0.250 10.548 2.497
16 -1477.257 || 0.073749 1.701 71.895 17.019
17 -1317.031 || 0.000716 0.017 0.698 0.165
18 -1258.820 || 0.000077 0.002 0.076 0.018
19 -1215.598 || 0.010600 0.245 10.334 2.446
20 -1043.645 || 0.020820 0.480 20.296 4.805
21 -877.968 || 0.003398 0.078 3.313 0.784
22 -867.706 || 0.004100 0.095 3.997 0.946
23 -746.045 || 0.000384 0.009 0.374 0.089
24 -553.902 || 0.007930 0.183 7.731 1.830
25 -439.702 || 0.002706 0.062 2.638 0.625
26 -271.939 || 0.000889 0.021 0.867 0.205
27 -0.000 || 0.008560 0.197 8.344 1.975
28 -0.000 || 0.008501 0.196 8.287 1.962
29 0.000 || 0.001993 0.046 1.943 0.460
30 0.000 || 0.009355 0.216 9.120 2.159
31 0.000 || 0.001270 0.029 1.238 0.293
32 0.000 || 0.000862 0.020 0.840 0.199
33 165.222 || 0.019156 0.442 18.674 4.421
34 693.684 || 0.015361 0.354 14.975 3.545
35 808.930 || 0.004877 0.113 4.754 1.125
36 1017.108 || 0.001360 0.031 1.326 0.314
37 1149.865 || 0.005525 0.127 5.386 1.275
38 1220.105 || 0.002900 0.067 2.827 0.669
39 1424.112 || 0.004540 0.105 4.426 1.048
40 1545.903 || 0.017548 0.405 17.107 4.050
41 1671.980 || 0.016708 0.385 16.287 3.856
42 1705.374 || 0.005813 0.134 5.666 1.341
43 2532.736 || 0.002194 0.051 2.139 0.506
44 2627.224 || 0.025924 0.598 25.272 5.983
45 2690.238 || 0.015748 0.363 15.352 3.634
46 2754.035 || 0.125015 2.884 121.871 28.850
47 2762.858 || 0.149932 3.459 146.161 34.600
48 2773.665 || 0.066604 1.537 64.929 15.370
49 2806.405 || 0.168478 3.887 164.241 38.880
50 2863.544 || 0.149385 3.446 145.628 34.474
51 2882.665 || 0.069728 1.609 67.974 16.091
----------------------------------------------------------------------------
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Huub Forum:Admin, Forum:Mod, NWChemDeveloper, bureaucrat, sysop
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Forum Regular
Threads 1
Posts 185
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| 12:06:43 PM PDT - Thu, Aug 1st 2013 |
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Hi,
There seems to be an oversight in the code. NWChem-6.3 does not have analytical COSMO frequencies. The code should have detected that and switched to numerical frequencies but it does not do that. I have fixed this in the development version now but for the NWChem-6.3 release please use
task dft freq numerical
That should fix this issue.
Best wishes, Huub
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Clicked A Few Times
Threads 6
Posts 15
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| 8:11:59 AM PDT - Wed, Apr 29th 2015 |
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many negative frequencies
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Hello Huub
I am also facing similar issues with many negative frequencies but no COSMO ....just simple ground state optimization within the latest NWChem-6.5
I tried rerunning with 'task dft freq numerical'
still the same problem persisted
Any other suggestions??
Pansy
Quote:Huub Aug 1st 12:06 pmHi,
There seems to be an oversight in the code. NWChem-6.3 does not have analytical COSMO frequencies. The code should have detected that and switched to numerical frequencies but it does not do that. I have fixed this in the development version now but for the NWChem-6.3 release please use
task dft freq numerical
That should fix this issue.
Best wishes, Huub |
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