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Does the warning in Test Raman-h2co matter #56
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This also can be caused by numerical issues when using finite differencing.
…On Thu, Jul 22, 2021 at 11:36 PM xiongyan21 ***@***.***> wrote:
Test-h2co has a warning at the end
MODE FREQ(CM**-1) SYMMETRY RED. MASS IR INTENS. RAMAN ACT. DEPOLARIZ.
1 86.452 B2 3.821881 0.672525 2.946837 0.750000
2 19.148 B1 2.879470 0.617671 0.877410 0.750000
3 0.071 B2 7.511561 0.000000 0.000001 0.750000
4 0.079 A1 7.502507 0.000000 0.000000 0.636416
5 0.151 B1 7.602040 0.000038 0.000055 0.750000
6 230.307 A2 1.007825 0.000000 3.876159 0.750000
7 1305.770 B2 1.345334 0.156786 0.047834 0.750000
8 1331.556 B1 1.318633 0.410328 0.972588 0.750000
9 1614.810 A1 1.131278 0.627055 10.953659 0.346079
10 1891.815 A1 6.215292 2.649156 14.930165 0.155271
11 3014.277 A1 1.050215 1.105944 142.451658 0.112713
12 3101.547 B1 1.119653 1.611123 63.308669 0.750000
-------------------------------
THERMOCHEMISTRY AT T= 298.15 K
-------------------------------
USING IDEAL GAS, RIGID ROTOR, HARMONIC NORMAL MODE APPROXIMATIONS.
P= 1.01325E+05 PASCAL.
ALL FREQUENCIES ARE SCALED BY 1.00000
THE MOMENTS OF INERTIA ARE (IN AMU*BOHR
*2) 6.28646 46.18916 52.47562 THE ROTATIONAL SYMMETRY NUMBER IS 2.0 THE
ROTATIONAL CONSTANTS ARE (IN GHZ) 286.82110 39.03704 34.36050 7 - 12
VIBRATIONAL MODES ARE USED IN THERMOCHEMISTRY. THE HARMONIC ZERO POINT
ENERGY IS (SCALED BY 1.000) 0.027930 HARTREE/MOLECULE 6129.887380 CM*
-1/MOLECULE
17.526245 KCAL/MOL 73.329809 KJ/MOL
Q LN Q
ELEC. 1.00000E+00 0.000000
TRANS. 6.46197E+06 15.681445
ROT. 6.98656E+02 6.549158
VIB. 1.00399E+00 0.003978
TOT. 4.53269E+09 22.234581
E H G CV CP S
KJ/MOL KJ/MOL KJ/MOL J/MOL-K J/MOL-K J/MOL-K
ELEC. 0.000 0.000 0.000 0.000 0.000 0.000
TRANS. 3.718 6.197 -38.873 12.472 20.786 151.168
ROT. 3.718 3.718 -16.235 12.472 12.472 66.924
VIB. 73.395 73.395 73.320 1.451 1.451 0.251
TOTAL 80.832 83.311 18.212 26.394 34.708 218.343
VIB. THERMAL CORRECTION E(T)-E(0) = H(T)-H(0) = 64.998 J/MOL
E H G CV CP S
KCAL/MOL KCAL/MOL KCAL/MOL CAL/MOL-K CAL/MOL-K CAL/MOL-K
ELEC. 0.000 0.000 0.000 0.000 0.000 0.000
TRANS. 0.889 1.481 -9.291 2.981 4.968 36.130
ROT. 0.889 0.889 -3.880 2.981 2.981 15.995
VIB. 17.542 17.542 17.524 0.347 0.347 0.060
TOTAL 19.319 19.912 4.353 6.308 8.295 52.185
VIB. THERMAL CORRECTION E(T)-E(0) = H(T)-H(0) = 15.535 CAL/MOL
------------------------------
* THIS IS NOT A STATIONARY POINT ON THE MOLECULAR PES *
* THE VIBRATIONAL ANALYSIS IS NOT VALID !!! *
*******************************************************
This may caused by Hessian calculated with another kind of method, e.g.,
DFT or another kind of basis set.
Does it matter? If it does, how can we eliminate it?
Very Best Regards!
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I have used 6-31G to try TDHF Raman calculation of imidacloprid, and will try larger basis sets. It seems NWCHEM gives questionable strengths if I haven't misunderstood the strength expressions. of frequencies : 9freq [ 1/cm] S [Ang**4/amu]1 ... 4.6943E+06 Dalton2018 6-311++G** numerical Hessian( gives the second highest peak at around 3200 cm-1(three lines) for 6-311++G** mp2 geometry optimized with itself. Mode Freq. Alpha**2 Beta(a)**2 Pol.Int. DepolInt. 180/0Int. DepRatio 1 ... 151.3303 ... Isotope effects are not considered in all of the above. Very Best Regards! |
According to the article High-Resolution Raman Spectroscopy of Gases "" Methane (CH,) has four fundamental vibrations: v1 = 2916.7 cm-1 1 (T 2 ) 1431 cm ⫺1 Can GAMESS give a criterion of degeneracy in TDHF package? Very Best Regards! |
Actually, DFT , HF and mp2 each have a well-known scaled factor for vibrational frequencies and zero-point energy, from Prof. Pople, respectively, but it seems if it is applied, it will underestimated the frequencies(different basis sets here). I have found in an reference the scaled factor for SCC-DFTB is 0.9933. Here, DFTB underestimates the frequencies except the one over 3000 cm-1, but the absolute relative errors are all smaller than about 4%. It is a common practice to adopt adaptive scaled factors in order to make the calculated match the experimental. Very Best Regards |
By the way, I do not include LIBBCHEM (this needs another software to equip my computer), and CCSD3 and CCT3( several of these will fail on my computer), and NEO( which I am not interested in). Very Best Regards! |
There is another thing baffling, i.e., the Raman experimental spectra of pesticides are gereally obtained with SERS. For imidacloprid, the three detection lines calculated by DFTB (perhaps not the strongest nearby) are within 2.4% deviances when compared with reproted experimental SERS peaks, and for thiamethoxam(strongest nearby, four detection lines), those become within 3.6%, whereas for nitenpyram, those become within 4.6% if the strongest nearby are chosen of the three detection lines. It seems the deviances are large without scaled factors for pyruvic acid. I am searching experimental data. There are no warnings now in the DFTB calcualtions, and previously for DFTB Raman calculation of thiameoxam not using DFTB geometry, not a stationary point warning appears. Very Best Regards! |
Unfortunately, there is no parametrization of Ag in 3ob-3-1and there are onl;y C-C|C-N|C-O in 3ob:freq, but there are no obvious changes of the chief static Raman peaks from the calculations of indigo and indigo-Ag2 complex(with small peaks might being eliminated), according to The Raman and SERS spectra of indigo and indigo-Ag 2 complex: DFT calculation and comparison with experiment. Very Best Regards! |
According to An Ab Initio Study of Pyruvic, experimental IR should be fitted to the mp2 6-311++G** calculated frequencies. With DFTB and C1 symmetry, the first can be as low as 47 cm-1, over 70 cm-1 when compared with the experimental data indexed, and for some peaks, the frequencies calculated can be accepted. I cann't use MacMolplt to make a planar pyruvic acid drawn by Avogadra. Very Best Regards! |
It is OK if B3lyp and 6-31G** geometry and Raman calculations of methane run successively with one input like QA test h2o-raman_3.nw in terms of projected IR by NWCHEM7.0.2
Excitation wavelength 514.50 nm
|
Test-h2co has a warning at the end
MODE FREQ(CM**-1) SYMMETRY RED. MASS IR INTENS. RAMAN ACT. DEPOLARIZ.
1 86.452 B2 3.821881 0.672525 2.946837 0.750000
2 19.148 B1 2.879470 0.617671 0.877410 0.750000
3 0.071 B2 7.511561 0.000000 0.000001 0.750000
4 0.079 A1 7.502507 0.000000 0.000000 0.636416
5 0.151 B1 7.602040 0.000038 0.000055 0.750000
6 230.307 A2 1.007825 0.000000 3.876159 0.750000
7 1305.770 B2 1.345334 0.156786 0.047834 0.750000
8 1331.556 B1 1.318633 0.410328 0.972588 0.750000
9 1614.810 A1 1.131278 0.627055 10.953659 0.346079
10 1891.815 A1 6.215292 2.649156 14.930165 0.155271
11 3014.277 A1 1.050215 1.105944 142.451658 0.112713
12 3101.547 B1 1.119653 1.611123 63.308669 0.750000
USING IDEAL GAS, RIGID ROTOR, HARMONIC NORMAL MODE APPROXIMATIONS.
P= 1.01325E+05 PASCAL.
ALL FREQUENCIES ARE SCALED BY 1.00000
THE MOMENTS OF INERTIA ARE (IN AMU*BOHR2)
6.28646 46.18916 52.47562
THE ROTATIONAL SYMMETRY NUMBER IS 2.0
THE ROTATIONAL CONSTANTS ARE (IN GHZ)
286.82110 39.03704 34.36050
7 - 12 VIBRATIONAL MODES ARE USED IN THERMOCHEMISTRY.
THE HARMONIC ZERO POINT ENERGY IS (SCALED BY 1.000)
0.027930 HARTREE/MOLECULE 6129.887380 CM-1/MOLECULE
17.526245 KCAL/MOL 73.329809 KJ/MOL
ELEC. 1.00000E+00 0.000000
TRANS. 6.46197E+06 15.681445
ROT. 6.98656E+02 6.549158
VIB. 1.00399E+00 0.003978
TOT. 4.53269E+09 22.234581
ELEC. 0.000 0.000 0.000 0.000 0.000 0.000
TRANS. 3.718 6.197 -38.873 12.472 20.786 151.168
ROT. 3.718 3.718 -16.235 12.472 12.472 66.924
VIB. 73.395 73.395 73.320 1.451 1.451 0.251
TOTAL 80.832 83.311 18.212 26.394 34.708 218.343
VIB. THERMAL CORRECTION E(T)-E(0) = H(T)-H(0) = 64.998 J/MOL
ELEC. 0.000 0.000 0.000 0.000 0.000 0.000
TRANS. 0.889 1.481 -9.291 2.981 4.968 36.130
ROT. 0.889 0.889 -3.880 2.981 2.981 15.995
VIB. 17.542 17.542 17.524 0.347 0.347 0.060
TOTAL 19.319 19.912 4.353 6.308 8.295 52.185
VIB. THERMAL CORRECTION E(T)-E(0) = H(T)-H(0) = 15.535 CAL/MOL
This may be caused by Hessian calculated with another kind of method, e.g., DFT or another kind of basis set.
Does it matter? If it does, how can we eliminate it?
I have used DFTB3 with conv=10d-12 and 3ob-3-1 parameters to calculate Raman for three pesticides(why no $Hess? ) , Nitenpyram, Thiamethoxam and Imidacloprid, and found no such a warning.
I also have tried RHF Raman calculatation for one of them(optimized with B3lyp), and found such a warning appears either using RHF or DFT Hessian.
TDHF calculation of Raman also gives the warning.
Very Best Regards!
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