Posts by mbergami

mbergami · Multiwfn and wavefunction analysis

Hi all,

I need to calculate Coulomb and four-center integrals between specific orbitals from different molden files.

1- The Coulomb integrals are different from the usual Coulomb integrals between electronic orbitals, in this case the integrals are:
(ii'|jj') = int ( phi_i(r1) phi_i'(r2) r12 phi_j(r1) phi_j'(r_2) )dr1 dr2

the molecular orbitals phi_i(r1) and phi_j(r1) are from the same molden file, while both orbitals phi_i'(r2) and phi_j'(r2) are saved in other molden file.

2- The four-center integrals are a specific case of overlap integrals, in this case the integrals are:

S_(iji'j') = int ( phi_i(r) phi_j(r) phi_i'(r) phi_j'(r) )dr

phi_i and phi_j are molecular orbitals from the same molden file, phi_i' and phi_j' are molecular orbitals from other molden file as in the case of Coulomb integrals.

I am sending in this message also the equations of Coulomb integral (coulomb_integral.jpeg) and four-center integral (four_center_integral.jpeg) attached.

Is there any way to calculate this special cases of coulomb and four-center integrals with Multiwfn code?

mbergami · Multiwfn and wavefunction analysis

Hi all,

I am getting a strange result with function 3.200.6 when I perform the overlap calculation between the densities (density1 and density2) from some orbitals obtained with two different schemes (case1 and case2).

The radial profiles of the densities from cases 1 and 2 indicate that the overlap should be greater in case 2, but I find a higher result in case 1.

The .wfn files used to calculate the overlaps were taken from converting .molden files.

The wave functions used in these calculations were obtained with ghost centers positioned in different positions in cases 1 and 2. In case 2, more ghost centers are used than in case 1.

I don't understand if the .wfn files are wrong, or if there is some other problem. Can the use of ghost centers affect the density overlap calculation obtained with function 3.200.6?

Thanks for the attention

Mateus

mbergami · Quantum Chemistry

Hi all,

Does anyone know how to computationally calculate the Fourier transform of the product of two molecular orbitals? I have molecular orbitals at position space obtained from quantum calculations, and I need the Fourier transform of product of orbitals.

Thanks,

Mateus

mbergami · Multiwfn and wavefunction analysis

Hi Tian, thanks for your help as usual!

I used the subfunction 6 of main function 200 and the result for overlap integrals between square of orbitals are too high, for my system the overlap is 0.91 and the overlap of square is 0.93. I think there is something wrong...

I did other test with two .wfn files of alpha and beta orbitals respectively, and the overlap of square calculated with subfunction 6 of main function 200 is different than the result obtained with the subfunction 11 of main function 100 using just one file with alpha and beta electrons.

mbergami · Multiwfn and wavefunction analysis

Dear Tian,

I am trying to obtain overlap integral of square of the two orbitals from two wavefunctions files. I just know to calculate this overlap integral using function 3.100.11, in this case I can't use two wavefunctions files with this function.

In this case, is there some way to calculate the overlap integral of square of the two orbitals without to merge the two wavefunctions files?

Thanks for the attention,

Mateus Bergami

mbergami · Multiwfn and wavefunction analysis

In this case, I modify the molden file of alpha electrons including the positron orbital and output the .wfn for this modified molden file.

mbergami · Multiwfn and wavefunction analysis

Hi all,

I need to calculate the overlap between two specific orbitals obtained with UHF calculation for a system compused by 10 water molecules,
one additional electron and one positron. In this calculation, I positioned GTF's for electrons on atom coordinates, and also a extra expansion center on origin (center of cavity). The GTF's positioned on atom coordinates (6-31G+(d,p)) and on origin (aug-cc-pVTZ) are different.

For the positron I positioned just one expansion center on origin with the same GTF (aug-cc-pVTZ) used for extra center of electrons. Therefore, the electronic wave function has different GTF's (6-31G+(d,p) and aug-cc-pVTZ) than positronic wave function (aug-cc-pVTZ). I have separate molden files for beta electrons, alpha electrons and the positron.

My question is:

Is there some problem to create just one .wfn file for alpha electrons and positron, and use this file to calculate overlap between alpha orbital with positron orbital using the function "3.200.10 Output various kind of integral between orbitals"? Is this function use the information of GTF's to calculate the overlap?

Thanks for the attention,

Mateus Bergami

mbergami · Multiwfn and wavefunction analysis

Hi all,

I would like to know what is the difference between Radial Distribuction Function (RDF) of spin density and spherically averaged spin density.

When I calculate RDF of spin density the program give me the option "7 Export the spherically averaged function", and it isn't clear to me what is this because the RDF function already give me the integral on angular coordinates.

Thanks for the attention,

Mateus Bergami

mbergami · Multiwfn and wavefunction analysis

Hi everyone,

My question is how could I convert two .molden files from alpha and beta orbitals into just one .wfn file? I know how to convert just one .molden file into a .wfn with Multiwfn program.

I need this .wfn to calculate the spin density of electrons, because actually I have a .molden of alpha electrons and other for beta electrons.

Thanks,

Mateus Bergami

Multiwfn forum

#1 Multiwfn and wavefunction analysis » Coulomb and four-center integrals with specific orbitals » 2022-08-19 00:30:46

#2 Multiwfn and wavefunction analysis » Problem with 3.200.6 function » 2021-07-14 19:23:04

#3 Quantum Chemistry » Fourier transform of molecular orbitals » 2020-06-28 21:44:37

#4 Re: Multiwfn and wavefunction analysis » Overlap between specific orbitals » 2020-05-29 21:33:25

#5 Re: Multiwfn and wavefunction analysis » Overlap between specific orbitals » 2020-05-27 16:46:13

#6 Re: Multiwfn and wavefunction analysis » Overlap between specific orbitals » 2020-03-19 19:48:43

#7 Multiwfn and wavefunction analysis » Overlap between specific orbitals » 2020-03-19 19:40:02

#8 Multiwfn and wavefunction analysis » Spherically averaged function for spin density » 2020-02-04 14:22:54

#9 Multiwfn and wavefunction analysis » How to convert two .molden files (alpha and beta orbitals)? » 2020-01-12 22:14:38

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