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The function introduced in Section 3.100.15 and exemplified in Section 4.100.15 of Multiwfn manual can calculate overlap integral between orbitals of two different wavefunction files.
Hello,
First there is a big error: If you select "1 Electron density (rho)" in "1 Select real space function", then electron density will be calculated by Multiwfn based on wavefunction, however, cube file cannot provide wavefunction to Multiwfn (it can only provide grid data to Multiwfn. Please carefully check Section 2.5 of Multiwfn manual for details).
Please solve this issue first.
By the way, when you hope to use an external grid data to define the function to be studied/plotted, you should set "iuserfunc" in settings.ini to -1 (linear interpolation) or -3 (B-spline interpolation), then load cube file to Multiwfn after launching it, and then select "100 User-defined function" as the function to be studied/plotted in the real space function selection interface.
Best,
Tian
If you include "dG_solv + 1.89" into "E=" in settings.ini, then you do not need to manually add it to G_gas, otherwise you need to manually add them up.
The 3D isosurface map you illustrated corresponds to orbital wavefunction, green and blue parts correspond to positive and negative phases, respectively. The contour line map of "4 -> 4 (Value of Orbital wave-function)" directly corresponds to the 2D-map on the slice plane of this isosurface map."Orbital probability density" is square of "Value of Orbital wave-function" (according to the well-known Born's probability interpretation of wave function).
The option "5 Use built-in contour values suitable for special purpose" is designed for quickly setting contour values for plotting specific kind of real space function. You can use it for convenience but it is never always needed.
1 If you want to obtain G in solvent phase, you should put E_gas + dG_solv into settings.ini of Shermo, otherwise solvent effect will be missing.
2 The default grid (int=ultrafine for G16) is completely adequate.
3 When two energetic results will be compared with each other, or taking their difference, integration grid setting must be exactly the same.
4 It is true (at least for present purpose).
5 calc5 is meaningless. opt and freq tasks must be conducted at the same computational level (including the use of solvation model, which affects potential energy surface).
1 You can try to calculate a ground-state single point energy using both of them, and see if their results are the same. If not the same, use B3LYP/G keyword in ORCA and check.
2 libxc(B3LYP) is required because functional derivative of native B3LYP is not implemented. It can be used for both ground and excited state calculations, but its speed may be slightly slower than the native code, you can perform test to confirm.
3 Both of them are acceptable.
Section 3.5 describes plotting plane map (realized by main function 4 of Multiwfn), including contour line map. LUMO (or other orbitals) wavefunction is a 3D real space function, in order to plot it as a contour line map, you need to specify one or more contour values (Note that "isosurface value" or "isovalue" is only involved in 3D isosurface map, which can be plotted by main function 5).
Hope this clarifies enough.
You only mentioned you need to evaluate excitation energy. If you also need to calculate interaction energy, then diffuse functions will be needed for 2- or 3-zeta basis sets.
1 This does not constitute a necessity for adding diffusion functions.
2 When diffuse functions are added, LUMO and/or other unoccupied MOs may be quite diffuse, in this case they do not have clear chemical meaning (this phenomenon may be more obvious when HF composition of the employed DFT functional is relatively high).
Hi,
Dispersion effect of sobEDA is considered based on DFT-D3 dispersion correction, which doesn't affect electron density but only affects potential energy surface.
Classic electrostatic interaction doesn't affect electron density, it is a energetic term calculated based on existing charge distribution.
In the process of occurrence of interfragment interaction, it is well-known that only steric effect (mostly corresponding to repulsion and exchange terms) and polarization effect (corresponding to orbital interactions) notably change electron density, the two parts can be separatedly characterized in ETS-NOCV analysis, which can be easily realized by Multiwfn. Please check Section 3.26 of Multiwfn manual for theoretical background and Section 4.23 for abundant examples.
Best regards,
Tian Lu
Development of Multiwfn 3.8 starts from 2020-Aug, during the last 5 years it was very actively developed, now it is the right time to release its formal version, it has been very stable and no bug is known. Now it can be downloaded from "download" page of Multiwfn website. All new functions, improvements and bug fixes with respect to Multiwfn 3.7 can be found in "Update History" page on the Multiwfn website.
From 2026, new naming convention of Multiwfn will be applied. For example, Multiwfn released on Jun-4, 2026 will be named as Multiwfn 2026.6.4, and binary package of Windows version will be Multiwfn_2026.6.4_bin_Win64.rar. The new convention will make users clearly recognize the date of update. No developement version will be released in the future, there will only be formal versions, fully distinguished by version names (directly corresponding to release date).
Thanks all users for supporting Multiwfn and citing Multiwfn original papers in their publications!
Dear Sid,
Cube files of hole and electron are exported separatedly by the hole-electron analysis module of Multiwfn. You should load both of them into VMD, and make them visible as isosurface style, but with different colors (e.g. green for electron and blue for hole).
Best,
Tian
Thank you for the reply,
If you don’t mind, could you help me understand this in a little more detail? Because I thought that in a charge-transfer state where certain atoms (that received charge) are significantly negatively charged, at least those atoms should need to be treated with diffuse functions.
CT excitation doesn't necessarily lead to heavily negatively charged atoms. However, when it is indeed true, adding diffuse functions for those atoms may improve result.
How can I plot the potential energy curves and dipole moment curves and know the transition of dipole moment of excited states in Gaussian 16 software?
If you perform potential energy surface scan with an excited state calculation method (for example, using "scan" together with "TD(root=x)" keyword), you will be able to obtain energy and transition dipole moment of state x for every point of the scan coordinate. If you also need dipole moment of the excited state, also try to add "pop=always".
You do not need to add diffuse functions for common CT states. Only Rydberg states, and excitation state calculations for negatively charged system, need diffuse functions.
Hello,
This is completely beyond the scope of wavefunction analysis, I don't have intention to implement these features in Multiwfn. There have been many available codes to print Huang-Rhys factor for electronic transition, including Gaussian (please search "HuangRhys" in manual), ESD module of ORCA, Dushin, FCclasses.
Dear Saeed,
Happy new year
This observation implies that the automatically determined bonding doesn't fulfill your expectation. You need to use $CHOOSE keyword to customize bonding relationship, please check NBO manual. All atoms directly or indirectly connected by "BD" will be regarded as a single fragment.
Best,
Tian
If the output file was obtained under Powershell, you need to change the encoding of this file from Unicode (default) to ASCII/ANSI, or run the command like D:\orca611\orca test.inp | out-file test.out -encoding ascii. If it is not the case, please open the ORCA output file via text editor, and check if excited state information has been normally printed.
Example:
# MP2/cc-pVTZ density out=wfx
...
D:\test.wfx
Then you can use the test.wfx as input file of Multiwfn to perform various wavefunction analyses.
If you are using Gaussian >=G09 C.01, then "density" can be omitted, because "density" is the default setting in the case of "out=wfx".
Multiwfn doesn't directly provide a function to calculate EET, and I don't know what is the coefitions (coefficients?) you referred to. PS: Frankly speaking, I am not familiar with EET calculation.
There is an update of Multiwfn in 2025-Dec-7, important for ORCA users:
Now the electronic excitation analyses that rely on orbital wavefunctions and configuration coefficients, such as hole-electron, IFCT, CTS, NTO analysis, etc. can be exactly carried out in combination with TDDFT calculation of ORCA since version 6.1.1. See Section 3.21.A.2 of Multiwfn manual for details, and it is suggested to check blog article "Method of performing hole-electron and relevant analyses via Multiwfn in combination with TDDFT calculation of ORCA" (http://sobereva.com/758).
Note: Previously, TDDFT of ORCA could not be exactly combined with Multiwfn for hole-electron analysis, IFCT, CTS, NTO, etc., because ORCA cannot separately output excitation and deexcitation configuration coefficients. This update of Multiwfn, which, combined with json file of ORCA 6.1.1, completely solves this long-standing problem!
I would like to suggest using CASSCF to perform geometry optimization when some likely reliable DFT functionals gave very different geometries. Note that spin density cannot be evaluated for CASSCF wavefunction, but you can use Multiwfn to calculate odd electron density (OED) based on CASSCF wavefunction to characterize distribution of unpaired electrons, and you may compare it with |spin density| calculated by different functionals.
To anyone else who wants to do something similar, plotting electrostatic potential over the electron density surface:
Take a molden, .wfn, or .fchk file, load, and use
5 Ouput and plot specific property within a spatial region (calc. grid data)
1 Electron density (rho)
11 Select a set of atoms, set extension distance around them and grid spacing2.3 A around a central atom of the NO3 ligand worked well.
Density saved to a cube file as density.cub
Repeated with option 5 -> 12 Total electrostatic potential (ESP), saved as totesp.cub
Loaded density.cube into VMD, and totesp.cub isolated just the NO3 atoms I wanted, then colored the isosurface according to volume of totesp.cub.
Color scale set to RGB to have red be the negatively charged areas and blue be positive.
Right, your steps are correct. Thanks for sharing it with other people.
I don't quite understand your question. But I would like to mention it is possible to obtain volume of a fragment (e.g. a ligand in coordinate) via AIM basin analysis. Please check Section 4.17.1 of Multiwfn manual, as you can see via basin analysis, one can obtain volume of each atom enclosed by 0.001 a.u. electron density isosurface.
I don't understand your question.
Excitation energies are dependent of geometry. For example, the excitation energies calculated at S0 minimum and S1 minimum geometries are different.
This is not necessarily emission wavelength.
It is emission wavelength only if the two conditions are satisfied:
(1) The current geometry is the minimum of potential energy surface of actual emission state.
(2) The calculated 1st excited state indeed corresponds to the actual emission state.
For fluorescene, usually the emission state corresponds to S1.
Please enter main function 0 and carefully check your atom coordinates. If the function on the line is zero everywhere, or the line is outside the spatial range of provided grid data, then the map cannot be generated.
Dear Jonghwan Lee,
I did a test, and my input file is attached: benzene_S1.wfn. I didn't find the same issue on both Windows and Linux versions. Perhaps "ulimit -s unlimited" didn't take effect, please check.
Best,
Tian
You should set "iuserfunc" in settings.ini to -1 (linear interpolation) or -3 (B-spline interpolation), then when plotting line map in main function, select "100 User-defined function". In this case the function to be plotted corresponds to interpolated function from the loaded grid data.
Unfortunately there is no relevant options to tune the text size in GUI of Multiwfn.
However, if the graphical window is too small, you can enlarge "plotwinsize3D" in settings.ini.