Posts by AlessioM

AlessioM · Quantum Chemistry

okok

do you know why Gaussian 16 doesn't show me the spin multiplicity in simulated spectra ?

i didn't find anything in literature.

Thanks

AlessioM · Quantum Chemistry

How can i define it the spin multiplicity in Gaussian Input file?

This is the input file: i have checked with Gaussian 16 User Manual and i think it's correct.

This is the experimental spectrum of ethyl acetate and the one simulated with Gaussian, for which I cannot see the spin multiplicity is shown above.

Thanks a lot

Alessio M.

AlessioM · Quantum Chemistry

Thank you so in your opinion with MULTIWFN i wil be able to see SPIN MULTIPLICITY?

thanks a lot

Alessio Macorano

AlessioM · Quantum Chemistry

Dear Prof Tian Lu,

yes i have used the net charge and multiplicity 0 1. here i attached two picture: one of the molecular structure and the NMR simulated spectra with Gaussian 16. level of theory: B3LYP/ 6-31+G(2d,p)

Thank you so much

Alessio M.

AlessioM · Quantum Chemistry

Dear Prof Tian lu.

i'm a PhD student in medicinal chemistry at University of Milan, IT.
As a collaboration with other organic chemistry i'm trying to simulate NMR spectra with Gaussian 16, and i'm reaching you out because i'm facing with a problem on this topic.

I'd like to Ask you if you ever have any problem to see spin multiplicity in NMR spectra from Gaussian16.

Because for a simple molecule like Ethyl Acetate Gaussian doesn't show me the multiplicity spin. (The ppm are rescaleted by TMS reference and they are correct respect to sperimental spectra).

I mean it doesn't show me Doublet, triplet and so on... I have used many DFT functionals and different basis set.

I'm very courious about It. If you want i can share with you .gjf, log, chk files.

Thanks for your suggestion

Alessio Macorano

AlessioM · Multiwfn and wavefunction analysis

Dear Prof Tian Lu,

as far as i know this kier-hall index, also know as connectivity index, is a type of a molecular descriptor that is calculated based on the molecular graph of a chemical compound.Molecular graph is a representation in which the atoms are vertices and bonds are the edges.

I have found in literature that similar index to topological already cited are: Quantum Similarity Related Indices (QSRI).

As reported here: "Quantum similarity topological indices definition, analysis and comparison with classical molecular topological indices"

paper by Emili Besalú (Universitat de Girona) Ramon Carbó-Dorca (Universitat de Girona) january 1995, sorry but i can't find the DOI.

Maybe this can clarify my previous question.

Thanks a lot

Alessio

AlessioM · Multiwfn and wavefunction analysis

Dear Tian Lu,

I'd like to ask you if it is possible to get a topological index similar to the Kier-Hall topological index using MULTIWFN?

If not, could you suggest me a way ? or other descriptors relatively close to the topological index?

I'd like to have such an index because I'd like to use it as molecular descriptors, I have .log and .fchk files of full optimised geometry.

Thanks a lot

My Best

Alessio

AlessioM · Quantum Chemistry

Dear Prof Tian Lu,

I have a question about the energy value obtained from the Gaussian output file.

I've done opt + freq calculation on dichloromethane at B3LYP 6-31+G* as an example and I get an E(B3LYP)=-959.700528 HARTREE/PARTICLE, I know that this energy is related to complete dissociation reaction of the molecule.

If i use a 1 Hartree = 627.5 kcal/mol i get a huge number to be an energy value, is this correct?

Or is there another way to obtain an energy value in kcal/mol more reliable by common sense?

Thanks a lot !

Alessio Macorano

AlessioM · Multiwfn and wavefunction analysis

Dear Prof. Tian Lu

I have calculated condensed fukui function as in the example 4.22 (Phenol molecule) with finite difference method approach.

Is there any way to calculate fukui function with "frozen core approximation" with multiwfn ?
(i.e homo density for electrophilic attacks and lumo density for nucleophilic attacks calculation?)

If not possible, where can i extract those values?

I appreciate a lot !

Best regards !

Alessio

AlessioM · Multiwfn and wavefunction analysis

Dear Multiwfn Users

Regarding to calculation of fukui function following phenol examples in 4.22 section:

is there any way to speed up production of N.wfn, N-1.wfn and N+1.wfn from formatted checkpoint file (.fhck)?

Do you know which features can accellerate this process? maybe use faster pc or with more cores, memory?

I appreciate a lot!

best regards

Alessio

AlessioM · Multiwfn and wavefunction analysis

Good morning to everyone

First of all thanks to the developers of Multiwfn works very well.

I have one question about superdelocalizability index:

As reported in the manual those index can be calculate for closed shell system, for my case i need that also for open shell system (because in our study we would like to compare them with semiempirical calculation) someone can help me?

thank you

bye!

Multiwfn forum

#1 Re: Quantum Chemistry ? NMR Spectra Simulation Gaussian 16 ? 2023-07-18 08:36:00

#2 Re: Quantum Chemistry ? NMR Spectra Simulation Gaussian 16 ? 2023-07-17 12:33:36

#3 Re: Quantum Chemistry ? NMR Spectra Simulation Gaussian 16 ? 2023-07-17 10:56:35

#4 Re: Quantum Chemistry ? NMR Spectra Simulation Gaussian 16 ? 2023-07-17 07:19:07

#5 Quantum Chemistry ? NMR Spectra Simulation Gaussian 16 ? 2023-07-14 10:34:43

#6 Re: Multiwfn and wavefunction analysis ? Topological index ? 2023-06-08 09:55:32

#7 Multiwfn and wavefunction analysis ? Topological index ? 2023-06-08 07:26:51

#8 Quantum Chemistry ? Energy from gaussian output files ? 2023-03-15 13:55:29

#9 Multiwfn and wavefunction analysis ? Fukui function in "frozen core approximation" ? 2022-12-15 14:38:26

#10 Multiwfn and wavefunction analysis ? generation of .wfn files for fukui function calculation ? 2022-10-13 08:32:24

#11 Multiwfn and wavefunction analysis ? Superdelocalizability index ? 2022-10-11 16:45:18

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