Multiwfn forum / Calculation of rho, grad(rho) and lap(rho)

Re: Calculation of rho, grad(rho) and lap(rho)

dummy@example.com (prasanta13) — Sun, 10 Nov 2024 08:58:26 +0000

Thank you Tian,
I will do as you said and get back to you if I face any problems.

Thanks again
Prasanta

Re: Calculation of rho, grad(rho) and lap(rho)

dummy@example.com (sobereva) — Sat, 09 Nov 2024 09:47:21 +0000

Dear Prasanta,

You can use Multiwfn to easily calculate these function values and compare between different functionals.
You need to use a quantum chemistry or first-principle code to generate wavefunction files first, such as Gaussian, ORCA, NWChem, GAMESS-US, xtb, CP2K and so on, see Section 2.5 of Multiwfn manual for full list of supported wavefunction file format.
You can perform convergence test of the quantity of interest with respect to number of integration points, and thus to determine the least acceptable quality of integration grid.

Best,

Tian

Calculation of rho, grad(rho) and lap(rho)

dummy@example.com (prasanta13) — Fri, 08 Nov 2024 18:33:21 +0000

Dear Tian,
I was looking at this paper, by Medvedev et al (Science 355, 49-52 (2017)) where they have compared the differences of rho, gradient and laplacian of rho for many atoms between CCSD(full), MP2, MP3 etc with many xc functionals. I was wondering if I can test the accuracy of some of the functionals suggested by them (B3LYP, PBE0 etc) by means of rho, grad and lap of rho for some molecules. I think I can calculate those values with Multiwfn, right?

Do I need any particular software, as ORCA, Gaussian for them.
How large integration grids in multiwfn is necessary?

Thank you very much
Prasanta