I used DFTB2 to optimize C2H5SH with GAMESS, but the following vibrational analysis told me it was not a stationary point on PES. Yestoday, Dr. Schmidt told me why here there was a warning like this. I used NWCHEM6.8 to do the vibrational analysis by DFT and RHF, the inputs were
echo
start molecule
memory total 12000 stack 4000 heap 500 global 7500 mb
title "Title"
charge 0
geometry units angstroms print xyz autosym
...
end
basis
* library 6-31G
end
dft
xc b3lyp
mult 1
end
task dft freq
and
echo
start molecule
memory total 12000 stack 4000 heap 500 global 7500 mb
title "Title"
charge 0
geometry units angstroms print xyz autosym
...
end
basis
* library 6-31G
end
SCF
RHF
END
task scf freq
I got in the DFT case:
Normal Eigenvalue || Projected Derivative Dipole Moments (debye/angs)
Mode [cm**-1] || [d/dqX] [d/dqY] [d/dqZ]
------ ---------- || ------------------ ------------------ -----------------
1 -0.000 || 0.001 -0.000 0.211
2 -0.000 || -0.089 -0.121 0.005
3 -0.000 || 0.070 0.094 0.001
4 -0.000 || -0.001 0.000 -0.163
5 0.000 || -0.020 -0.027 0.001
6 0.000 || 0.003 0.002 0.298
7 251.813 || -0.001 -0.001 -0.036
8 327.340 || -0.049 0.277 -0.000
9 455.218 || -0.002 -0.001 -0.758
10 717.307 || -0.034 0.188 0.000
11 859.934 || -0.004 0.001 0.365
12 904.596 || -0.333 -0.063 -0.005
13 1070.980 || 0.105 -0.371 0.000
14 1109.831 || 0.011 -0.014 -0.030
15 1168.240 || 0.203 0.203 -0.002
16 1328.353 || 0.015 -0.033 -0.170
17 1392.799 || 0.483 -0.868 0.011
18 1481.538 || 0.275 0.377 -0.002
19 1542.006 || -0.002 0.010 0.490
20 1552.169 || -0.173 0.287 -0.013
21 1568.989 || 0.200 0.247 -0.019
22 2120.546 || 0.906 0.775 -0.001
23 2892.624 || 0.738 -0.294 0.399
24 2965.138 || 0.438 -0.171 -0.595
25 3033.997 || -0.354 -0.643 -0.003
26 3104.707 || 0.595 -0.449 0.002
27 3116.689 || 0.016 -0.009 -0.799
----------------------------------------------------------------------------
----------------------------------------------------------------------------
Normal Eigenvalue || Projected Infra Red Intensities
Mode [cm**-1] || [atomic units] [(debye/angs)**2] [(KM/mol)] [arbitrary]
------ ---------- || -------------- ----------------- ---------- -----------
1 -0.000 || 0.001924 0.044 1.876 1.582
2 -0.000 || 0.000982 0.023 0.957 0.807
3 -0.000 || 0.000596 0.014 0.581 0.490
4 -0.000 || 0.001157 0.027 1.128 0.951
5 0.000 || 0.000049 0.001 0.048 0.041
6 0.000 || 0.003839 0.089 3.743 3.156
7 251.813 || 0.000057 0.001 0.055 0.046
8 327.340 || 0.003427 0.079 3.341 2.817
9 455.218 || 0.024917 0.575 24.291 20.480
10 717.307 || 0.001583 0.037 1.543 1.301
11 859.934 || 0.005771 0.133 5.626 4.743
12 904.596 || 0.004993 0.115 4.867 4.104
13 1070.980 || 0.006461 0.149 6.299 5.311
14 1109.831 || 0.000052 0.001 0.051 0.043
15 1168.240 || 0.003564 0.082 3.474 2.929
16 1328.353 || 0.001311 0.030 1.278 1.078
17 1392.799 || 0.042811 0.988 41.734 35.187
18 1481.538 || 0.009436 0.218 9.199 7.756
19 1542.006 || 0.010398 0.240 10.136 8.546
20 1552.169 || 0.004863 0.112 4.740 3.997
21 1568.989 || 0.004410 0.102 4.299 3.625
22 2120.546 || 0.061632 1.422 60.082 50.657
23 2892.624 || 0.034234 0.790 33.373 28.138
24 2965.138 || 0.024935 0.575 24.308 20.495
25 3033.997 || 0.023362 0.539 22.774 19.202
26 3104.707 || 0.024058 0.555 23.453 19.774
27 3116.689 || 0.027675 0.638 26.979 22.746
----------------------------------------------------------------------------
in the RHF case
Normal Eigenvalue || Projected Derivative Dipole Moments (debye/angs)
Mode [cm**-1] || [d/dqX] [d/dqY] [d/dqZ]
------ ---------- || ------------------ ------------------ -----------------
1 -0.000 || 0.003 0.002 0.346
2 -0.000 || -0.024 -0.032 -0.002
3 -0.000 || -0.096 -0.126 0.005
4 -0.000 || 0.001 0.000 0.173
5 0.000 || 0.076 0.100 -0.001
6 0.000 || -0.000 -0.001 0.166
7 362.271 || -0.001 0.005 -0.008
8 367.001 || -0.034 0.275 0.000
9 568.596 || -0.001 -0.002 -0.782
10 751.215 || -0.089 0.276 -0.000
11 962.902 || -0.005 -0.001 0.291
12 997.976 || -0.370 -0.179 -0.004
13 1131.567 || 0.225 -0.275 -0.001
14 1219.019 || 0.012 -0.007 0.008
15 1265.285 || 0.216 0.303 -0.002
16 1440.273 || 0.009 -0.022 -0.146
17 1518.070 || 0.525 -0.888 0.008
18 1617.833 || 0.271 0.336 -0.002
19 1662.843 || -0.002 0.009 0.469
20 1670.485 || -0.184 0.222 -0.011
21 1689.357 || 0.229 0.309 -0.018
22 2127.666 || 0.801 0.811 -0.002
23 2932.493 || 0.714 -0.325 0.414
24 3002.990 || 0.459 -0.202 -0.570
25 3073.851 || -0.342 -0.759 -0.006
26 3132.781 || 0.649 -0.531 0.003
27 3145.187 || 0.018 -0.012 -0.877
----------------------------------------------------------------------------
----------------------------------------------------------------------------
Normal Eigenvalue || Projected Infra Red Intensities
Mode [cm**-1] || [atomic units] [(debye/angs)**2] [(KM/mol)] [arbitrary]
------ ---------- || -------------- ----------------- ---------- -----------
1 -0.000 || 0.005175 0.119 5.045 3.999
2 -0.000 || 0.000068 0.002 0.066 0.053
3 -0.000 || 0.001090 0.025 1.063 0.842
4 -0.000 || 0.001305 0.030 1.272 1.008
5 0.000 || 0.000679 0.016 0.662 0.525
6 0.000 || 0.001194 0.028 1.164 0.923
7 362.271 || 0.000004 0.000 0.004 0.003
8 367.001 || 0.003334 0.077 3.250 2.576
9 568.596 || 0.026523 0.612 25.856 20.496
10 751.215 || 0.003640 0.084 3.549 2.813
11 962.902 || 0.003664 0.085 3.572 2.831
12 997.976 || 0.007306 0.169 7.123 5.646
13 1131.567 || 0.005482 0.126 5.344 4.236
14 1219.019 || 0.000011 0.000 0.011 0.008
15 1265.285 || 0.006003 0.139 5.852 4.639
16 1440.273 || 0.000952 0.022 0.928 0.736
17 1518.070 || 0.046084 1.063 44.925 35.612
18 1617.833 || 0.008057 0.186 7.854 6.226
19 1662.843 || 0.009525 0.220 9.286 7.361
20 1670.485 || 0.003608 0.083 3.517 2.788
21 1689.357 || 0.006425 0.148 6.263 4.965
22 2127.666 || 0.056353 1.300 54.936 43.547
23 2932.493 || 0.034098 0.787 33.240 26.349
24 3002.990 || 0.024977 0.576 24.349 19.301
25 3073.851 || 0.030016 0.692 29.261 23.195
26 3132.781 || 0.030497 0.704 29.730 23.567
27 3145.187 || 0.033326 0.769 32.488 25.753
----------------------------------------------------------------------------
Can this be accepted as a stationary point for geometry optimization.
I know this requires rich group knowledge, structural intuition and art, just as indicated in the GAMESS test for [Ni(NH3)6]2+, etc.
Very Best Regards!
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