Multiwfn forum / Quantum Chemistry

Calculate the one-particle and two-particle density matrix

dummy@example.com (prasanta13) — Mon, 09 Oct 2023 11:44:08 +0000

Sorry for the late reply, I am incredibly sorry.
I have asked the PSI4 community to extract 2PDM at CCSD(T) level. However, I got nothing yet. Could you tell me how to obtain the 2PDM from the CCSD(T) calculation from PSI4 (preferred since I can access it) or Molpro.

Thanking You
Prasanta

computing ESP

dummy@example.com (axeljr7) — Tue, 12 Sep 2023 11:45:02 +0000

sobereva wrote:

Please check Phys. Chem. Chem. Phys., 2021, 23, 20323, which describes the algorithm of evaluating ESP used by current version of Multiwfn.

many thanks. Very interesting and helpful work.

Energy value using Gaussian

dummy@example.com (Zubair Sadiq) — Fri, 01 Sep 2023 01:16:05 +0000

Alright. I get it. Thank You!

Question about spin contamination in Gaussian16

dummy@example.com (sobereva) — Sun, 30 Jul 2023 14:21:16 +0000

The larger the deviation of printed to ideal , the larger the spin contamination. However, there is no widely accepted definition of percentage spin contamination.

NMR Spectra Simulation Gaussian 16

dummy@example.com (sobereva) — Wed, 19 Jul 2023 00:48:28 +0000

Spin multiplicity is not directly shown in spectrum, it is only indirectly reflected in the simulated spectrum (spin multiplicity affects position of NMR chemical shifts).

Theoretical antioxidant activity

dummy@example.com (sobereva) — Tue, 18 Jul 2023 05:11:44 +0000

Just perform a regular frequency analysis task for them, you will obtain enthalpy.

Second Order Perturbation Theory Analysis using Gaussian Software

dummy@example.com (Anjali Ganai) — Fri, 16 Jun 2023 05:48:14 +0000

Thanks a lot.

Regards,
Anjali

doubt about programing algorithm called "on grid method"

dummy@example.com (choconostle123) — Wed, 26 Apr 2023 17:57:59 +0000

sorry is basin, I corrected it, oooo now I understand, thanks for your support i will train use a smaller grid spacing

MP2 frequency with G16 (very very short question)

dummy@example.com (saeed_E) — Tue, 25 Apr 2023 18:09:35 +0000

Dear Tian,

Too many thanks for your highest kindness, my nice friend.
Please be aware that, based on my experience, it seems when the Gaussian staff is asked about a problem, the personal licence is firstly checked by them and if one does not have a valid licence, the question is never answered.

On the other hand, please be aware that I did not employ any value for "%mem" and only used "%nproc=8" but, during link 906, I found that only one CPU is used. Taking your very valuable comment, I would employ a large number of "%mem" together with "%nproc=8" to see if link 906 is executed in a parallel manner.

Once again, thank you very much.

Yours sincerely,
Saeed

How were temperature and pressure controlled in MD calculations?

dummy@example.com (Ahmed Wahba) — Sat, 22 Apr 2023 00:51:04 +0000

I learn a lot from you
Thank you very much, Dr. Tian Lu

IR for metal organic framework

dummy@example.com (sobereva) — Mon, 03 Apr 2023 21:16:55 +0000

There is no any problem. Please always carefully check the prompt on screen. Multiwfn just asks you to input the path of input file.

Please follow tutorials in Chapter 4 of Multiwfn manual, all commands needed for wide variety of analyses are given very clearly.

IRC calculation in gaussian 16 ends abnormally!

dummy@example.com (sobereva) — Sat, 01 Apr 2023 20:58:31 +0000

There is no adequate information to figure out the reason. It is best to provide downloading link of the output file.

By the way, using recorrect=never is highly deprecated. Using LQA instead is recommended.

A question about the linear response theory?

dummy@example.com (choconostle123) — Wed, 15 Mar 2023 20:59:06 +0000

I am studying linear response theory and i have a dub :S

if i have <Ψ(0)|O(interaction)|Ψ(0)> ?can i say that is the same that? <Ψ(0)|O|Ψ(0)>

where Ψ(0) is the wave fuction in t=0 and O is and operator, O(interaction) is the operator in the interaction picture and O is the operator in the schrodinger picture

Energy from gaussian output files

dummy@example.com (sobereva) — Wed, 15 Mar 2023 16:23:26 +0000

Dear Alessio Macorano,

What you calculated is electronic energy, rather than energy of complete dissociation reaction of the molecule.

The concept in quantum chemistry field closest to the so-called "energy of complete dissociation reaction of a molecule" is atomization energy. For example, for H2O molecule you should calculate 2*E(H) + E(O) - E(H2O).

Best,

Tian

MP2 or dispersion-corrected DFT-functionals?

dummy@example.com (saeed_E) — Wed, 01 Mar 2023 15:08:53 +0000

Dear Tian,
My highest and warmest gratitude is presented to you for your valuable and nice comments; thank you very very much.

Sincerely yours,
Saeed