Multiwfn forum

shenaya

Member

Registered: 2019-10-16

Posts: 34

Critical points with different basis sets

Dear All,

I have used three different basis sets to obtain critical points.

These are two Ru(II) complexes. I have obtained critical points and contour plots using above-mentioned basis sets. I'm interested in Ru-F bond
I have a few questions to ask.
1. Although Cationic and Neutral compounds have very similar contour plots,

Neutral Cation
6-311g(d,p) no bond path and bond critical point have a bond path and bond critical point
6-311g(2d,p) no bond path and bond critical point have a bond path and bond critical point
cc-pvtz no bond path and bond critical point no bond path and bond critical point

Is there a threshold value that use multiwin program to define a bond path and critical points?
I'm struggling to explain these results.
Can you refer me further analysis or explain this matter if possible
Thanks and regards,
Shen

sobereva

Tian Lu (Multiwfn developer)

From: Beijing

Registered: 2017-09-11

Posts: 1,768

Website

Re: Critical points with different basis sets

There are two possible reasons why in the case of cation with cc-pVTZ there is no bond critical point corresponding to Ru-F can be found:

(1) The cc-pVTZ is not quite suitable for representing electron density of present system. Please change to def2-TZVPP, which has similar quality and cost with cc-pVTZ but works better than cc-pVTZ for DFT methods. If then you can find the missing BCP between Ru and F, that means cc-pVTZ is indeed not a good choice.

(2) The procedure and searching setting of critical points you have used are not suitable for present case, you should try other searching strategy or setting. Please carefully read "What should I do if some CPs of electron density are missing?" in Section 4.2.1 of Multiwfn manual.

Best regards,

Tian

shenaya

Member

Registered: 2019-10-16

Posts: 34

Re: Critical points with different basis sets

Than you very much for your suggestion
I have performed the calculation using def2-TZVPP basis set.
In the neutral Ru complex no bond path and bond critical point between Ru and F. But in the cationic compound, we can see. The main concern is contour lines are very similar between Ru and F atoms in both of the cases. What are the other parameters that I can use to explain this behaviour?

regards,
Shen

sobereva

Tian Lu (Multiwfn developer)

From: Beijing

Registered: 2017-09-11

Posts: 1,768

Website

Re: Critical points with different basis sets

It is more likely that the BCPs in the left map actually exist but you didn't successfully make Multiwfn locate it. You can upload wavefunction file and corresponding input file of quantum chemistry code (alternatively, you can send them to my E-mail privately), I will check and give you a definitive answer.

shenaya

Member

Registered: 2019-10-16

Posts: 34

Re: Critical points with different basis sets

Hi Tian,

I've just emailed relevant files to sobereva@sina.com ;
Please take a look.

best regards,
Shenaya

sobereva

Tian Lu (Multiwfn developer)

From: Beijing

Registered: 2017-09-11

Posts: 1,768

Website

Re: Critical points with different basis sets

I have checked your file. The reason that the expected CPs are missing is that their positions are relatively unusual, while you didn't properly use CP searching options.

After enter main function 2, you should use option 2, 3, 4, 5 in turn, then all CPs can be found, the molecular graph is shown as follows, you can see all CPs have presented (the Poincare-Hopf relationship has also been satisfied).

shenaya

Member

Registered: 2019-10-16

Posts: 34

Re: Critical points with different basis sets

Thank you very much for your quick reply.
Problem solved !!!

regards,
Shen

shenaya

Member

Registered: 2019-10-16

Posts: 34

Re: Critical points with different basis sets

Hi Tian,

I have analysed another complex which has Rh(III) which gives more than one bond critical point between Rh and N atoms.
I'm not sure what it really means?
If possible please explain this.

sobereva

Tian Lu (Multiwfn developer)

From: Beijing

Registered: 2017-09-11

Posts: 1,768

Website

Re: Critical points with different basis sets

https://i.postimg.cc/qtPsz2gg/rhcomples.png

Hi Tian,

I have analysed another complex which has Rh(III) which gives more than one bond critical point between Rh and N atoms.
I'm not sure what it really means?
If possible please explain this.

The reason is unclear, please send the input file of your quantum chemistry code as well as the input file of Multiwfn to my E-mail.
It seems that the several CPs are nearly degenerate, this is a very rare case.

shenaya

Member

Registered: 2019-10-16

Posts: 34

Re: Critical points with different basis sets

Hi Tian,

I'm performing further analysis of this system. I have calculated MO (HOMO,HOMO-1,LUMO,LUMO+). To discuss the results I need to find which type of orbitals of the LIGAND (sigma, sigma*, pi, pi*) contributed to HOMOs and Lumos. I have already calculated MO % contribution from each atom.
I already went through section 4 and couldn't find it.

Can you please direct me on how to find this information.
Calcuation were done using Gaussian.
Thanks,
Shen

sobereva

Tian Lu (Multiwfn developer)

From: Beijing

Registered: 2017-09-11

Posts: 1,768

Website

Re: Critical points with different basis sets

In common situation, you can perform charge decomposition analysis (CDA) analysis, see Section 4.16 of manual for example. In this module, you can obtain contribution of various MOs of fragments (ligands and metal) to MOs of the whole coordinate.

shenaya

Member

Registered: 2019-10-16

Posts: 34

Re: Critical points with different basis sets

Is it possible to generate this type of MO diagram

sobereva

Tian Lu (Multiwfn developer)

From: Beijing

Registered: 2017-09-11

Posts: 1,768

Website

Re: Critical points with different basis sets

https://i.postimg.cc/1fXL71ZL/MOdiagram.jpg

Is it possible to generate this type of MO diagram

Multiwfn cannot directly generate this type of map, however, you can manually plot it via this procedure:
1. Use Multiwfn to load fch file. Then enter main function 6, select subfunction 3, then copy all orbital energies from screen to Origin program as column B
2. Set value of column A to 1.0
3. Plot scatter map with column A as X-data and column B as Y-data, then change the symbol of the points to "-" and properly adjust size of the symbol, you will obtain similar plot. The labels should be manually added.