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saeed_E

Member

Registered: 2019-12-21

Posts: 244

Def2 series in ETS-NOCV

Dear Tian,
If you kindly let me, I am going to ask about Def2 series in ETS-NOCV analysis. Please suppose the presence of iodine atom in the systems studied forces us to use def2-tZVP basis set in ETS-NOCV analysis. If I am not wrong, this basis set includes diffuse functions and, on the other hand, you strongly recommended to avoid diffuse basis sets along ETS-NOCV analysis. Please let me know, in such cases, which basis set you recommend. Is def2-SVP an appropriate choice?

In addition, the message "Note: Calculation of whole system will be conducted in unrestricted way" is always displayed along a sobEDA analysis whether the system considered to be closed-shell or open-shell. Could you please let me know what does it mean?
Sincerely,
Saeed

Last edited by saeed_E (2024-01-01 16:24:38)

sobereva

Tian Lu (Multiwfn developer)

From: Beijing

Registered: 2017-09-11

Posts: 1,830

Website

Re: Def2 series in ETS-NOCV

Dear Saeed,

def2-TZVP doesn't contain diffuse functions. There are variants with diffuse functions: ma-def2-TZVP, def2-TZVPD, aug-def2-TZVP, etc.

If any fragment is open-shell, even though the whole system is closed-shell, sobEDA will still be performed in terms of unrestricted form.

Best,

Tian

saeed_E

Member

Registered: 2019-12-21

Posts: 244

Re: Def2 series in ETS-NOCV

Dear Tian,
Many many thanks for your highly valuable, perfect, and informative comments.

Please, also, let me ask another question. While the "nosymm" keyword prevents any re-orientation of the system considered, which is mandatory for some specific purposes, the total electronic energy is never affected by this keyword (total electronic energy of the given system is quite identical whether or not using nosymm). Is my statement true?

Yours sincerely,
Saeed

Last edited by saeed_E (2024-01-02 10:27:04)

sobereva

Tian Lu (Multiwfn developer)

From: Beijing

Registered: 2017-09-11

Posts: 1,830

Website

Re: Def2 series in ETS-NOCV

Dear Saeed,

In principle it is true. However, in practice, because of the distribution of integration grid for exchange-correlation functional, DFT energy doesn't have exact rotational invariance. But this effect is negligible if quality of integration grid is fine enough.

Best,

Tian

saeed_E

Member

Registered: 2019-12-21

Posts: 244

Re: Def2 series in ETS-NOCV

Dear Tian,
Your very kind attention to provide highly professional and exact comments is extremely appreciated, my nice friend.

In addition, I sent you an email regarding my current study in which some strange results are observed. Indeed, both interaction energy and distortion energy play important role when distortion/interaction model (DIM) analysis was performed on a given reaction. You know much better than me that usually one of these energies control regioselectivity in a given reaction. If possible, please have a brief look at the sent document and let me know your valuable and determining comments regarding the results of the reaction studied.

In advance, your kindness and valuable time are highly appreciated while I well know you are extremely occupied.

Sincerely yours,
Saeed