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#1 Re: Multiwfn and wavefunction analysis » XDM method implementation in Multiwfn » 2024-02-16 13:31:06
Dear AxA,
I well know that XDM is a very useful dispersion correction method. In principle it can be implemented in the present framework of Multiwfn, but currently there are many more important functions that closely related to wavefunction analysis to be implemented. I encourage you to implement XDM as a subroutine, and I would like to link it to official release when it is finished. "Modifying source code of Multiwfn" (//www.umsyar.com/multiwfn/res/Modify … ltiwfn.pdf) is a useful guide on modifying and extending source code of Multiwfn. I will provide help as much as possible.
Best,
Tian
Dear Prof. Lu,
This sounds interesting. I would be happy to do so and will share with you the outcome.
Thanks again and best regards,
AxA
#2 Multiwfn and wavefunction analysis » XDM method implementation in Multiwfn » 2024-02-16 12:54:24
- axeljr7
- Replies: 2
Dear Prof. Lu, Dear Multiwfn community,
I am writing to ask if there is an straightforward way to implement XDM method of Becke-Johnson in Multiwfn e.g. according to https://doi.org/10.1063/1.2795701 .
This method will of course be of very high importance and value to the community and it seems, major computations which are needed for that, i.e. computation of exchange-hole for all density grid points and partitioning of the fuzzy space which is also already implemented in module 15 (fuzzy space analysis sub-section 1) are already available in Multiwfn but I couldn’t figure out how to wrap them all together.
I would be thankful for your hint
Best regards,
AxA
#3 Re: Multiwfn and wavefunction analysis » a question about the code » 2024-01-29 20:36:18
I made a mistake. gridatm(ipt)%value is single-center integration weight of point ipt. It is essentially combined from radial weight (second Gauss-Chebyshev) and angular weight of Lebedev method.
The final weight of a integration point is combined of single-center integration weight and Becke's atom weight.
It is strongly adviced to check "subroutine intfunc_silent(ifunc,intval)" in otherfunc.f90, it is a minimal code to integrate a specific real space function over the whole space, it is useful for you to understand the implementation of the integration.
I also have a blog article to detailedly describe the Becke's multi-center integration algorithm: //www.umsyar.com/69, but it was written in Chinese.
Thank you very much for the great details, your prompt support, and the great work
Best,
AxA
#4 Re: Multiwfn and wavefunction analysis » a question about the code » 2024-01-29 16:57:11
fdens is the function used to evaluate electron density for a given Cartesian coordinate.
gridatm(ipt)%x/y/z records X,Y,Z coordinate of integration point ipt
gridatm(ipt)%value records function value at integration point ipt
beckeweigrid(ipt) records weight of point iptThey are not directly relevant to cell volume.
If you are not familiar with Becke's multi-center integration algorithm, please check its original paper J. Chem. Phys. 88, 2547. It is standard algorithm to integrate exchange-correlation functional in quantum chemistry codes.
many thanks, Prof. Lu for the hints. So, I am wondering, what's the difference between fdens and gridatm(ipt)%value as both give the electron density (here they are multiplied together).
And in the mentioned code, the fdens, gridatm(ipt)%value, and beckeweigrid(ipt) are all multiplied together. I would be thankful if you comment what is the idea behind it?
#5 Multiwfn and wavefunction analysis » a question about the code » 2024-01-28 23:28:45
- axeljr7
- Replies: 4
Dear all,
Can anyone help me in the source code, population.f90 file line 4971 and 4972, what these variables mean:
fdens(gridatm(ipt)%x,gridatm(ipt)%y,gridatm(ipt)%z)
gridatm(ipt)%value
beckeweigrid(ipt)
I guess/expect some of them should be the unit cell volume and one of them should be QM electron density but I have no clue about exact meanings and would be super thankful for some hints.
Thanks in advance,
AxA
#6 Re: Multiwfn and wavefunction analysis » sobEDA with Orca » 2023-12-11 14:18:29
axeljr7 wrote:One more thing I would like to add: When I use the method to study interactions between two molecules, it works, but when I use it to study the interaction of a specific atom in molecule 1 and a specific atom in molecule 2 (declared in the fragment.txt), it doesn't seem to work. Are there any solution?
sobEDA is not used to study interatomic interaction, but aims at studying interfragment interaction (like other conventional energy decomposition analysis methods, e.g. SAPT).
thanks for your reply. My question is that, can each one of the fragments be covalently bonded to some other atoms (like what F-SAPT allows)?
#7 Re: Multiwfn and wavefunction analysis » sobEDA with Orca » 2023-12-05 15:16:57
One more thing I would like to add: When I use the method to study interactions between two molecules, it works, but when I use it to study the interaction of a specific atom in molecule 1 and a specific atom in molecule 2 (declared in the fragment.txt), it doesn't seem to work. Are there any solution?
#8 Multiwfn and wavefunction analysis » calculation of atoms in molecules dipole moment and polarizability » 2023-10-04 12:26:51
- axeljr7
- Replies: 1
Dear All,
Does anyone know about the possibility of calculating atoms in molecules dipole moment and polarizability in Multiwfn? I particularly mean dipole moments and polarizability of individual atoms in a molecule based on AIM theory (similar to some implementations e.g. in PolaBer code https://scripts.iucr.org/cgi-bin/paper?to5075) and not the current implementation in Multiwfn which is based on Tkatchenko-Scheffler method.
Thanks in advance and best regards
A.
#9 Re: Quantum Chemistry » computing ESP » 2023-09-12 11:45:02
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.
#10 Quantum Chemistry » computing ESP » 2023-09-10 16:10:07
- axeljr7
- Replies: 2
Dear All,
for computing total electrostatic potential (ESP) based on the equation written in the Multiwfn manual (section 12, page 25), does anyone know for the second integral, how the singular points are treated? For example, electrostatic potential at a point x1,y1,z1 due to electron density in the exact same point will be infinity. Does multiwfn use a damp function or compute only out of a cut-off or other tratment?
Thanks in advance
#11 Re: Multiwfn and wavefunction analysis » population analysis with MBIS partitioning » 2023-08-16 11:59:19
There is no file named no2F2.h.
If you cannot find a way to solve it, you can simply delete definition of "subroutine orbfracderiv" and "function fracderiv" from function.f90, and remove "userfunc=fracderiv(x,y,z)" from this file. Also, remove "use mod_2F2, only: set_alpha_level" from Multiwfn.f90.
I tried it but unfortunately didn't fix the issue. I will try it on another machine and write here the outcome.
Thanks again.
#12 Re: Multiwfn and wavefunction analysis » population analysis with MBIS partitioning » 2023-08-14 09:09:38
axeljr7 wrote:I just tried to modify the code but compilation from the source code raises some errors (as can be seen in the photo attached).
I would be so thankful for a hint to fix it.https://i.postimg.cc/xkyxJXTT/Screenshot-at-2023-08-12-15-36-13.png
I don't find any problem in compiling the latest source code package on Multiwfn website. From the screenshot, mod_2f2.mod cannot be found, however, after compiling ext/2F2.f90 as shown by the following lines in Makefile, mod_2f2.mod should then be produced in current folder. Please check if "ext" subfolder exists in current folder.
2F2.f90.o : ext/2F2.f90 util.o Bspline.o
$(FC) $(OPT) -c ext/2F2.f90 -o 2F2.f90.o
ext subdirectory exists and includes no2F2.c, 2F2.h, 2F2.f90, 2F2.c and no2F2.f90 (but not no2F2.h)
Can it be the reason of the problem?
#13 Re: Multiwfn and wavefunction analysis » population analysis with MBIS partitioning » 2023-08-12 13:40:48
I just tried to modify the code but compilation from the source code raises some errors (as can be seen in the photo attached).
I would be so thankful for a hint to fix it.
#14 Multiwfn and wavefunction analysis » calculation of Hirshfeld weights in Multiwfn » 2023-08-12 11:12:59
- axeljr7
- Replies: 1
Dear all,
Is it possible that the Hirshfeld weights which are computed in several modules of Multiwfn can be somehow printed or stored in Multiwfn? (I am particularly looking for the weights and also corresponding density values on which these weights are applied). I guess it should be possible but I couldn't find much about it in the manual.
Best regards
#15 Re: Multiwfn and wavefunction analysis » population analysis with MBIS partitioning » 2023-08-09 16:19:40
that sounds really exciting. Thanks for that in advance. If might be of help, one can also get the python scripts of the method provided by the main developers at: https://github.com/theochem/denspart
Additionally, one interesting option for the new implementation in Multiwfn would also be also to include it in fuzzy space computations and specially computations of effective and free volumes and atomic polarizability (option 15). That would be highly appreciated.
The MBIS code in Multiwfn currently is in experimental status, and was directly contributed by other people (Frank Jensen). I intend to polish and parallelize this piece of code soon, at that time perhaps I will add an option to export the intermediate quantities. Currently you have to manually modify the source code to realize this pupose (please search "subroutine MBIS" in population.f90)
#16 Multiwfn and wavefunction analysis » population analysis with MBIS partitioning » 2023-08-09 15:58:20
- axeljr7
- Replies: 8
Dear all,
for the computation of MBIS charges implemented in multiwfn, is there a way to obtain and save the final converged parameters of the gaussian terms (sigm_i and N_i values)?
That would be highly beneficial and useful.
#17 Re: Multiwfn and wavefunction analysis » initial guess for population analysis » 2023-08-01 11:06:27
Hello,
There is no so-called initial guess for calculating partial charges. Partial charges only depend on the wavefunction loaded into Multiwfn.
Assume we want to fit partial charges in a way to get the best fit to ESP (as usual e.g. in ChelpG and MK methods). There should be some initial guesses to be improved in each iteration of fitting or I am missing something?
Similarly, for Hirshfeld partitioning approaches that work iteratively, (e.g. Hirhfeld-I), if we start from a good guess of initial partial charges, I suppose we can reduce the number of iterations. Is that correct?
#18 Multiwfn and wavefunction analysis » initial guess for population analysis » 2023-07-31 17:56:36
- axeljr7
- Replies: 3
Dear all,
is it possible that in calculating partial charges, we can provide some user-defined initial guesses for partial charges?
That would be so useful and helpful.
Kind regards
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