Can Dalton calculate oscillator strength

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xiongyan21
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Re: Can Dalton calculate oscillator strength

Post by xiongyan21 » 27 Jul 2020, 07:02

One functional in GAMESS modified for ionization potential calculation, contributed last year by Dr. Gerasimov, in A.N.Nesmeyanov Institute of Organoelement Compounds of Russian Academy of Sciences, can give the third one in water, with multiconfigurational and charge transfer characters according to the calculation, 0.12eV deviating from the detection wavelength in reference mentioned above. Perhaps it is not the maximum absorption wavelength.
Previously, the second excited state of gaseous uracil, also a hard one, can be described by this functional.
The other functional gives less than 0.3eV error of the third one, also of charge transfer character, when compared with the detection wavelength in the reference, whereas the oscillator strengths of the first two are also very small.

The optimization using Dalton2018 with b3lyp and 6-31+G* has been finished, and 6-31++G(d,p) optimization with that also has been completed.

Very Best Regards!
Last edited by xiongyan21 on 12 Aug 2020, 10:46, edited 6 times in total.

xiongyan21
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Re: Can Dalton calculate oscillator strength

Post by xiongyan21 » 28 Jul 2020, 09:09

During the aug-cc-pvdz and b3lyp calculation of the above using 6-311++G(d,p) with b3lyp optimized geometry, at the beginnning of the DFT response employing Dalton2018, there is a warning
********* WARNING ORBDIA ***********
DIAGONAL ORBITAL HESSIAN HAS 1 NEGATIVE ELEMENTS
...
Perhaps .INA setting is not very suitable.

The result is completely wrong
...
@ Excited state no: 1 in symmetry 1 ( A ) - singlet excitation
-------------------------------------------------------------------

@ Excitation energy : 4.54909991E-02 au
@ 1.2378731 eV; 9984.1202 cm-1; 119.43660 kJ / mol

@ Total energy : -679.67677 au

@ Operator type: XDIPLEN
@ Oscillator strength (LENGTH) : 0.24231228 (Transition moment : 2.8266406 )

@ Operator type: YDIPLEN
@ Oscillator strength (LENGTH) : 2.23750730E-02 (Transition moment : 0.85894454 )

@ Operator type: ZDIPLEN
@ Oscillator strength (LENGTH) : 2.78751923E-03 (Transition moment : -0.30317391 )

...

Very Best Regards!

xiongyan21
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Re: Can Dalton calculate oscillator strength

Post by xiongyan21 » 29 Jul 2020, 06:01

An article in China suggested that it has two maximum wavelengths at 204 and 265 nm in 70% hexane, and said the area of the first one is very large, using Shimadzu LC-20AD.
According to the GAMESS calculations, the second functional can give an excitation energy of charge transfer in water with 0.18eV deviating from that, and b3lyp can give two weak peaks deviating from the other by 0.13 and 0.24 eVs, respectively, whose oscillator strengths ranging from around 0.08 to 0.05 and whose transition moments cannot be called small, perhaps together giving the wide, not high peak.
The calculation of the first excited state of this compound is a little hard for lots of common functionals because of charge transfer naturer.


The small imainary frequency during b3lyp Hessian analysis should be eliminated and perhaps the employment of 6-311++G(2d,2p) will do especially considering 6-311++G(2d,2p) b3lyp optimized oxirane exhibits the first frequency of around 58 cm-1, not an imaginary one. I will try.

Very Best Regards!
Last edited by xiongyan21 on 14 Aug 2020, 06:40, edited 3 times in total.

xiongyan21
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Re: Can Dalton calculate oscillator strength

Post by xiongyan21 » 01 Aug 2020, 00:27

The 6-311++G(2d,2p) B3lyp frequency analysis with GAMESS has no imaginary frequency and no warning, meaning a true minimum obtained on the PES, which was first through Monte Carlo search. That is good because it seems the optimization is not easy.
I have used RHF and 6-31++G** to calculate ECD by Dalton2018 , but the third one, with oscillator strength around 0.45, is significant deviating form the experimental value, and velocity, length and London of rotational strength are all negative values ranging from around -47 to -50.

Has Dalton evolved to surpass the calculation of pi-pi* and sigma-pi* for ECD, or are the lengths and velocities correct even if the excitation energies have large discrepencies when compared with experimental ones?


Very Best Regards!

xiongyan21
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Re: Can Dalton calculate oscillator strength

Post by xiongyan21 » 03 Aug 2020, 10:53

CAS 864237-81-0, a pesticide, is difficult to optimize, because it requires a lot of Monte Carlo search steps, and the final geometry is obtained using 6-311++G(2d,2p) and B3lyp, all with GAMESS. The excitation energies calculated in water using B3lyp, despite the default grids are questionable, which does not significantly affect final results, can reasonably be compared with the UV spectra obtained by Shimadzu-SPD, etc. in an article published in China, except for the maximum absorption of 200 nm, which is also of perhaps charge transfer nature. There is a terrace in the spectra, and the calculation shows three peaks around there where two of them are very weak. In the spectra, the oscillator strength of the first peak is small but one direction transition moment is not tiny. The Hessian shows no imaginary frequency of the geometry found with 6-311++G(2d,2p) at RHF level. These should be carefully further studied. If possible, I will also use Dalton2018 to study whether the two softwares can agree.

Very Best Regards!
Last edited by xiongyan21 on 14 Aug 2020, 06:42, edited 3 times in total.

xiongyan21
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Re: Can Dalton calculate oscillator strength

Post by xiongyan21 » 07 Aug 2020, 10:37

I find that for 6-311++G(2d,2p) optimized CAS 1185987-44-3, the discrepancies between excitation energies calculated with aug-cc-pvdz and 6-31+G(d,p), characterized by the two functionals mentioned properly, respectively, are within 0.10eVs, accompanying small oscillator strengths alterations.

It seems that 6-31+G(d,p) excitation energies calculated based on b3lyp 6-31+G(d,p) optimized geometry are within 0.1 eVs from the aug-cc-pvdz
calculated, respectively.

It should be noted that if the small basis set is used, the excited energies calculated near 200 nms may not be compared with experimental data in terms of eV., and perhaps even using aug-cc-pvdz and any functional, TDDFT results may also fail in the VUV and other regions in terms of eV.

Using the functional and 6-31+G(d,p) and the increase of the radial point to 75, now out of the question, the excitation energy near 200 nms calculated for CAS 864237-81-0 is 0.62 eVs deviating from the experimental data, because of charge transfer not being able to be tackled with the functional, making the calculation fail.

Fortunately, except for small pesticides. e.g., hymexazole, usually longer wavelength UV absoprtion peaks appear which can be used as the detection wavelength.

Very Best Regards!
Last edited by xiongyan21 on 14 Aug 2020, 06:44, edited 5 times in total.

xiongyan21
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Re: Can Dalton calculate oscillator strength

Post by xiongyan21 » 12 Aug 2020, 10:49

Are there methods in Dalton 2018 to treat double excitations and above in the existence of solvation?

I donnot know whether Prof. Truhlar's new method, the combination of MCSCF and DFT together, which may always overcome the difficulties of KS-DFT in multiconfigurational problems, transition metal chemistry, charge transfer, etc., or MCSCF in GAMESS can include solvation, because I haven't tried this.
Prof. Truhlar's group has demonstrated its abilities in several pubilished articles, e.g,, excitation spectra of retinal in vacuum, which has experimental data.

Very Best regards!

xiongyan21
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Re: Can Dalton calculate oscillator strength

Post by xiongyan21 » 13 Aug 2020, 12:11

There is something perhaps unusual in GAMESS, i.e., Tamm-Dancoff approximation in TDDFT in water can give peaks agreeing with the experimental data not greater than 240 nm of CAS 864237-81-0,meaning the two peaks caused by charge transfer at 200nm and below can be tackled with TD-CIS according to the experiment, and spin-flip TDDFT in TDA of thiabendazole in ethanol can give gaps between T1-D1(?)(the negative root found not being S0) deviating from the middle of the three phosphorescence emission wavelengths published in J. Phys. Chem. from near 0.24 eVs. It seems spin contamination here is very serious, making the spin-flip calculation unreliable, but the original gradient test has no such problems.
The gas phase spin-flip TDDFT in the Tamm-Dancoff approximation of thiabendazole and spin-flip CIS, which perhaps is based on Prof. A. Krylov's spin-flip CISD, according to her published article, have the same excitation energies of the negative root, both possibly being seriously spin contaminated. Spin-flip TDDFT using b3lyp overestimates the T1-S0 gap of solvated thiabendazole. when compared with experimental phosphorescence data.

GAMESS also has spin-flip FCI methods perhaps not including solvation.

I wonder whether Dalton2018 can do TD-CISD.

Very Best Regards!

hjaaj
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Re: Can Dalton calculate oscillator strength

Post by hjaaj » 14 Aug 2020, 14:21

As long as you can specify the desired CISD with the RAS specifications, and it fits in memory and does not exceed some internal limits, then you can do a TD-CISD.

To do that you ask for .CI in the wavefunction part, and then under **RESPONSE the keywords for excitation calculation and oscillator strengths.

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