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#1 Re: Multiwfn and wavefunction analysis » Question about comparasion in electron-hole analysis » Today 02:46:01

According to Kasha's rule, fluorescence of most molecules (except for very few anti-Kasha molecules, see Chem. Rev. 2017, 117, 13353-13381 and Chem. Rev. 2012, 112, 4541−4568 for reviews) corresponds to emission from S1. It is very common that S1 has a very small or negligible oscillator strength; despite of this, after considering vibronic effect, and/or after long enough time, the emission from S1 is still viable. Before emission from S1, there is usually long enough time to occur sufficient interconversions from high-lying excited states to S1. So, unless you can demonstrate that your molecule doesn't satisfy Kasha's rule, S1 should always be analyzed by Multiwfn to study nature of fluorescence.

#2 Re: Multiwfn and wavefunction analysis » CDA error on CO/Pt » 2024-03-01 20:21:51

mudit wrote:

Respected Sir, I am facing an issue with the fragment numbering while performing Charge decomposition analysis. I use gauss view and Chem craft software. Whenever i try to provide the input for the fragments, the interface says that the fragment has different numbering. So please help me in this issue. Thank you.

I don't exactly understand your description. I suggest carefully checking Section 3.19.2 of Multiwfn manual, which described the correct way of preparing CDA input file. Also it is suggested to look at example input files in "examples\CDA" folder

#3 Re: Quantum Chemistry » Activation energy shows unexpected trend » 2024-02-29 10:59:49

Dear Saeed,

I suggest to calculate solvation free energy for each reactant and TS, so that you can make clear about the role of solvation energy in E_act.

Best,

Tian

#4 Re: Multiwfn and wavefunction analysis » How to conduct a stress tensor analysis? » 2024-02-28 22:33:50

One-electron density matrix in real space:
γ(r,r')=∑{i}∑{j} χ_i(r) * P_i,j * χ_j(r')
Where i and j loop over all primitive GTFs. P stands for density matrix in primitive GTF basis. χ_i stands for primitive GTF i

To evaluate the equation in your screenshot, you need P (in primitive GTF basis), as well as first and second derivatives of primitive GTFs.

The density matrix in primitive GTF basis can be constructed by "call genPprim", then the global array "Ptot_prim" will be available.

First and second derivatives of primitive GTFs can be easily evaluated, please check "subroutine orbderv". You can find this subroutine loops over all primitive GTFs, and in each loop, the GTFdx, GTFdy, GTFdz evaluated by this subroutine are the three components of first derivative of the present primitive GTF, and GTFdxx, GTFdyy, GTFdzz, GTFdxy, GTFdxz, GTFdyz are components of second derivative. You can properly extract useful piece of code from this subroutine.

#5 Re: Multiwfn and wavefunction analysis » EDA convergence issue » 2024-02-28 17:29:28

Dear Kang,

Thank you for your feedback

Best,

Tian

#6 Re: Multiwfn and wavefunction analysis » Question about IBSIW values from IGMH analysis » 2024-02-28 11:57:41

You version is too old. Multiwfn 3.8(dev) has been updated several hundereds of times since 2020 (you may check "update history" in Multiwfn website). Please update your Multiwfn to the latest version, you will find that option.

#7 Re: Multiwfn and wavefunction analysis » EDA convergence issue » 2024-02-27 11:36:13

Dear Kang,

I do not easily suggest using scf=dm/xqc, because they are not tested with sobEDA.sh and it is well-known they often converge to unstable wavefunction. You may try to use other ways to solve the unconvergence, such as scf=vshift=xxx, scf=novaracc, other basis sets or theoretical methods, and so on.

Frankly speaking, cleavage of F2 is fairly challenging for sobEDA, the main reason is that when nosymm is used, the orientation of all p orbitals of doublet F (involved in homolytic cleavage) and singlet F+ (involved in heterolytic cleavage) is fully random, however their wavefunctions are needed to construct initial wavefunction of promolecular state, which introduces randomness in physical components given by sobEDA.

The only workaround in the framework of sobEDA is adding a very slightly external perturbation in the calculation of doublet F and singlet F+, the most easiest way I think is adding a very small external field, namely adding "field=z+1" keyword in the F and F+ calculations (I've checked orbital isosurface map using Multiwfn, this treatment indeed removes arbitrariness of orientation of pz orbital for doublet F), this treatment should have negligible impact on total energy, but may make the energy component curves much smoother. I am not sure if this trick really works, but it is worth to try.

Best,

Tian

#8 Re: Quantum Chemistry » Solvation Energy or Solvation Gibbs free energy? » 2024-02-27 11:18:56

I don't know, I have no experience in using these keywords.

#9 Re: Quantum Chemistry » Solvation Energy or Solvation Gibbs free energy? » 2024-02-26 23:21:33

I never use SC,DoVacuum. The most reasonable way of calculating solvation free energy is taking the difference between the electronic energies with and without implicit solvation model.

#10 Re: Multiwfn and wavefunction analysis » sobEDA promol.gjf coordinate issue » 2024-02-26 19:48:10

Hello,

Your system.xyz is problematic. This file actually contains four atoms, however the first line is 2, it should be replaced with 4.

#11 Re: Multiwfn and wavefunction analysis » Question about IBSIW values from IGMH analysis » 2024-02-26 19:47:02

"10 Intrinsic bond strength index (IBSI)" is in main function 9

#12 Re: Multiwfn and wavefunction analysis » ¿How can I export all the orbitals to cube? » 2024-02-26 19:45:26

You can use subfunction 3 in main function 200 of Multiwfn to export cube file(s) for specific range of orbitals, it is extremely convenient.

#13 Re: Multiwfn and wavefunction analysis » Intramolecular H-bonds analysis » 2024-02-26 19:44:44

Dear Mostafa,

It is suggested to use IRI analysis, see Chemistry—Methods 2021, 1, 231–239 DOI: 10.1002/cmtd.202100007
Tutorial of performing IRI analysis using Multiwfn: http://sobereva.com/multiwfn/res/IRI_tutorial.zip

Best,

Tian

#14 Re: Multiwfn and wavefunction analysis » NCI analysis » 2024-02-26 10:09:29

1 Try to use another version of VMD. VMD 1.9.3 always works normally
2 Try to use another machine, or upgrade GPU driver of present machine
3 If your .cub file is very large, then 32bit VMD may be unable to load it, try to use 64bit VMD

#15 Re: Multiwfn and wavefunction analysis » Charge Transfer Spectrum » 2024-02-24 13:47:44

In this case, you should put "CT_multiple" folder into the same folder as Multiwfn.exe, because in this case the folder where you can find Multiwfn.exe is "current folder"

#16 Re: Multiwfn and wavefunction analysis » Charge Transfer Spectrum » 2024-02-23 20:36:02

The position of fchk file is not directly relevant.
Please let me know which operation system are you using? And how did you boot up Multiwfn?

If you are using linux version, please note that in the CT_multiple.txt, all "\" symbol should be replaced with "/" according to linux file path rules.

#17 Re: Multiwfn and wavefunction analysis » Charge Transfer Spectrum » 2024-02-23 18:35:42

Dear Louis-Charl

Please note that "CT_multiple" must be a subfolder of current folder, because "CT_multiple\total_spectrum.txt" is relative path to the current folder. The meaning of "current folder" is mentioned in the page 2 of Multiwfn manual:

8. The so-called “current folder” in this manual and in prompts of Multiwfn refers to the path where you are invoking Multiwfn. If you boot up Multiwfn by clicking the icon of executable file in Windows platform, the “current folder” is the folder containing Multiwfn executable file. In the case of command-line mode, if you are in “D:\study\” directory when invoking Multiwfn, then “D:\study\” is “current directory”.

Please confirm that you have put "CT_multiple" in a correct place.

Best,

Tian

#18 Re: Multiwfn and wavefunction analysis » CDA of aromatic organic compounds » 2024-02-23 14:40:06

1 Yes
3 Correct. Note that it is def2TZVP rather than def2-TZVP, the bar should be removed when writing Gaussian keyword.
If you use .fch file as input file for CDA analysis, then this IOp is fully redundant.

#19 Re: Multiwfn and wavefunction analysis » CDA of aromatic organic compounds » 2024-02-23 10:34:04

1、2 Please check the CH3NH2 CDA example in Section 4.16.2 of Multiwfn manual, your situation is very similar with this case, namely there are two open-shell fragments to be defined while the whole system is closed shell.

3 There is no reason to add diffuse function in this case, also the diffuse functions will greatly break the physical meaning of CDA. Please use 6-311G* or the better def2-TZVP instead.

4 You just use DFT, in this case pop=NO or NOAB and "density" are fully redundant. Please check input files in Section 4.16.2.

#20 Re: Quantum Chemistry » Analysis of ETS-NOCV results » 2024-02-20 13:44:39

NOCV orbitals are obtained as eigenvectors of delta-P matrix (see Section 3.26 of Multiwfn manual for underlying theory), there is no directly relationship between NOCVs and fragment orbitals.

The only way of deriving the relationship between the two kinds of orbitals is using subfunction 6 of main function 200 of Multiwfn, see Section 3.200.6 of Multiwfn manual for detail. This function is able to calculate contribution of an orbital to another orbital.

#21 Re: Quantum Chemistry » Analysis of ETS-NOCV results » 2024-02-19 13:15:13

I cannot view you figures. Please use "Add image to post" button to upload images.

#22 Re: Quantum Chemistry » Analysis of ETS-NOCV results » 2024-02-19 09:21:35

Without figures of a practical system I can hardly answer this question

#24 Re: Quantum Chemistry » A scale factor is needed » 2024-02-16 13:21:54

This difference (0.003) is completely negligible. Even the scale factors fitted by different researchers differ with each other much more than this magnitude. The negligible difference just demonstrated "Diffuse function do not affect scale factor".

#25 Re: Multiwfn and wavefunction analysis » XDM method implementation in Multiwfn » 2024-02-16 13:18:02

Dear AxA,

I well know that XDM is a very useful dispersion correction method. In principle it can be implemented in the present framework of Multiwfn, but currently there are many more important functions that closely related to wavefunction analysis to be implemented. I encourage you to implement XDM as a subroutine, and I would like to link it to official release when it is finished. "Modifying source code of Multiwfn" (http://sobereva.com/multiwfn/res/Modify … ltiwfn.pdf) is a useful guide on modifying and extending source code of Multiwfn. I will provide help as much as possible.

Best,

Tian

#26 Re: Quantum Chemistry » A scale factor is needed » 2024-02-15 13:27:48

Use scale factor of M06-2X/6-31G(d,p) level, which should be able to be found. Diffuse function and dispersion correction do not affect scale factor.

#28 Re: Multiwfn and wavefunction analysis » How to conduct a stress tensor analysis? » 2024-02-11 00:58:54

Perhaps you need to write a code to implement a new real space function. You can extend user-defined function by modifying "function userfunc" in function.f90. Then in topology analysis module, you can obtain value of the function at critical points via option 7, or plot it along a topology path.

#29 Re: Multiwfn and wavefunction analysis » How to conduct a stress tensor analysis? » 2024-02-10 23:31:24

Its is Multiwfn not Multiwnf.

Currently Multiwfn doesn't formally support stress tensor analysis, you may need to extend source code.

#30 Re: Quantum Chemistry » How to properly treat low vibrational frequencies? » 2024-02-09 00:33:07

U_T-U_0=CV(T-0) is incorrect. CV is dependent of temperature, U_T'-U_0 should be expressed as integral of CV(T) over T from 0 to T'. See appendix of Shermo manual.

Minenkov's QRRHO is added to Shermo since version 2.4, see update history in Shermo website.

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