Currently wavefunction outputted by CRYSTAL is not supported, sorry!

Best regards,

Tian

]]>The ESP fitting charges based on wavefunction (including MK, CHELPG and RESP) can be calculated via main function 18 of Multiwfn. There is an example of calculating CHELPG charges in Section 4.7.1 of Multiwfn manual.

I just updated Multiwfn on official website today (the 3.6(dev) updated on 2018-Sep-18), this version is able to measure ESP reproducibility of given atomic charges at MK or CHELPG type of ESP fitting points in terms of RMSE and RRMSE. Please check Section 4.7.2 of the latest version of manual for example.

Regards,

Tian Lu

]]>Q:RESP charge by ORCA output

I am trying to get the RESP charges from ORCA calculations in a way similar than in the antechamber, but I am not finding any software that is able to do the fitting in the ORCA outputs. I have tried Multiwfn but the options are CHELPG, AIM, MK and HI.

My problem with the Multiwfn is the lack of equivalence on the atoms charges. I am using a dimer to get the charges, but one of the molecules is symmetrical and when I get the charges by CHELPG in Multiwfn there isn't a equivalence on the atoms. The atoms with the same atom type have different charges.Is there a way to restrain or constraint the charges to force all the atoms with the same atom type have the same atomic charge?

Does anyone know how to procedure?

A:

Fortunately, calculation of RESP charge has been *perfectly* supported by Multiwfn in its latest version. Please go to http://sobereva.com/multiwfn to download the latest version (the current latest version is the 3.6(dev) updated on 2018-Sep-12), and follow the examples given in Section 4.7.7 of the latest version of manual. Multiwfn makes calculation of RESP charge extemely easy. The .molden file outputted by ORCA can be directly used as input file. The RESP module of Multiwfn can not only calculate standard RESP charges, but can also calculate normal ESP fitting charges with customized penalty function, equivalence constraints, charge constraints and multi-conformation consideration.

The underlying reason that spatially equivalent atoms do not have equivalent charges is that the fitting points of CHELPG method are not distributed in accordance with molecular symmetry. If you do not intend to use the new RESP module of Multiwfn to manually impose equivalent constraint on that atoms, you can try to change the CHELPG method to MK method (subfunction 13 of main function 7), if the symmetry of atomic charges is still not satisifed well, you can then try to increase the density of fitting points (there are options used to set parameters of fitting points in the MK and CHELPG interfaces), this problem should be alleviated.

faiz1972 wrote:Thanks Prof Tian Lu, but I am not used Gaussian.

How if use Orca?Any mainstream quantun chemistry code can easily calculate that quantities.

There are many examples in Orca manual, please just follow them.

Okay Prof, Thanks very much.

]]>Q:

I saw that your program Multiwfn has a function to calculate the extent of the spatial overlap between two molecular orbitals (3.100.11 in your manual). I am currently looking into some organic polyradicals in which the overlap between the SOMOs is very important to determine the ground state multiplicity, using Gaussian 09 program, and I was wondering if you could guide me on how to use your program. Also, from a more technical point of view, I wonder how you actually perform the integral and how the phase of the orbitals is taken into account. Do you expand the MO in the basis of the atomic orbitals (expressed as gaussian orbitals) and then take the sum of each of the individual overlap?

A:

Proper way of choice of input file format for Multiwfn is described in Section 2.5 of the manual. As mentioned in Section 3.100.11, the needed information is GTF and atom coordinate, therefore according to the Table in Section 2.5, you can immediately know that you can use .wfn, .wfx or .fch generated by Gaussian as input file. Of course, the easiest way is directly using .fch file. After loading this file, enter main function 100 and select option 11, then input indices of the two orbitals you want to study, the overlap will be immediately outputted.

Technically, the overlap of absolutes of two orbitals is calculated in terms of Becke's multi-center integration method, detail can be found in JCP, 88, 2547 (1988). This is a numerical integration method, at each integration point, the program calculates psi_i and psi_j, and then get |psi_i|*|psi_j|, where psi is orbital wavefunction value and can be easily evaluated according to definition of basis functions and LCAO coefficients.

This works beautifully. Thanks very much.

Best wishes,

Maz.

]]>Thank you for your answer.

The problem with option 1, is that the rotating the image is easy. The problem is the numbers, text, etc.

regarding the second option, I will look for this, maybe changing the order of the points, change the final orientation.

Regards,

Camps

Dear Camps:

For the reply of Tian Lu, I want to add some suggestions of mine.

The first, "Use external image editor", the PS program can be used for it. It may be easy for you. The second, if you can output the file of points of the plotting plane, the sigmaplot program can be used.

You can have a try to do it. hope you can do it well.

Regrads

wawa

I'm pretty new to TD-DFT and I'm currently working on silicon quantum dots passivated with hydrogen (ranging from 40 to 250 atoms), trying to determine the transition dipole moments between electronically excited states. I didn't find any information about how to proceed in order to obtain them (I just got the absorption spectrum, which only shows the transition between the ground state and each individual excited state). Is this feasible or did I miss something ?

Unfortunately, current ORCA doesn't have this feature. However, using Multiwfn, this can be easily done. Below is my reply, I copy it here since some other Multiwfn/ORCA users may have the same problem.

Current latest version, namely version 3.6(dev) of Multiwfn is able to calculate transition dipole moment between excited states based on ORCA output.

First, conduct a CIS or TDA-DFT calculation using keywords like below, assume that file name is test.inp

! PBE0 def2-SVP nopop pal4

%tddft

nroots 4

tprint 1E-8

endThen use such as "orca_2mkl test -molden" command to convert test.gbw to test.molden.input

Finally, boot up Multiwfn and input

test.molden.input // The .molden input file

18 // Electronic excitation analyses

5 // Calculate transition electric dipole moments between all excited states

test.out // The ORCA output file

1 // Output transition dipole moments to screen

Now you will find below result on screen.Ground state dipole moment in X,Y,Z: -0.271701 -0.314645 0.344277 a,u,

Transition dipole moment between excited states (a.u.):

i j X Y Z Diff.(eV) Oscil.str

1 1 -1.7862676 -0.2640772 0.2405912 0.00000 0.00000

1 2 0.1976941 0.0854227 0.0346682 0.70800 0.00083

1 3 2.1779748 -0.1165127 0.1223195 1.38100 0.16146

1 4 -0.4226960 0.0657206 -0.0047136 1.73500 0.00778

2 2 -2.6132918 -0.1285522 0.0996265 0.00000 0.00000

2 3 0.0625351 0.3407469 -0.0481496 0.67300 0.00202

2 4 0.2904364 -0.1027734 -0.2020122 1.02700 0.00341

3 3 -2.9400691 -0.2538387 0.1676538 0.00000 0.00000

3 4 0.4640359 0.0322024 -0.0096710 0.35400 0.00188

4 4 2.3204590 1.0665381 -0.2011480 0.00000 0.00000The i and j are excited state indices, the line such as i=2 and j=2 corresponds to electronic dipole moment of excited state 2.

This feature of Multiwfn should work perfectly for CIS and TDA-DFT. However, for the TDHF or TDDFT, the result may be not always reliable, since in this case, current version of ORCA does not output excitation configuration coefficients and de-excitation configuration coefficients separately, which are needed for strictly evaluating transition dipole moments.

I will look at this github project.

Yuri

]]>1.wfn

The analysis result is identical to .fch file. Probably your .wfn file is problematic.

BTW: Using .fch is always preferred. In the latest 3.6(dev) version, if you have Gaussian installed on your machine and .fch is used as input file, and meantime "cubegenpath" in settings.ini has been set to actual path of cubegen, then Multiwfn can automatically invoke cubegen utility in Gaussian package to significantly accelerate ESP analysis, see Section 5.7 of the latest version of manual.

]]>I am familiar with SIESTA, if cube file of electron density could be exported by SIESTA, then you can load the cube file into Multiwfn and carry out some kinds of analysis about electron density (e.g. plotting plane map, basin analysis based on electron density ...)

Best regards,

Tian

]]>Apologies if this is a naive question but I haven't had much success after finding solution

over internet. I want to generate electrostatic potential grid cube file using point charge

model for small molecules. Any suggestion for is highly appreciated. Thank you in advance.

Considering my reply may be useful for some Multiwfn users, I copy my reply here:

You can use Multiwfn (http://sobereva.com/multiwfn) to easily generate electrostatic potential cube file based on atomic charge.

Below is an example of generating such cube file for water:

Write a plain text file named "water.chg" with below content

O -1.68940800 0.00002500 0.00194100 -0.728713

H -1.08142400 -0.01012400 -0.78063300 0.364427

H -1.06246900 0.00994900 0.76945700 0.364286

The 2,3,4 columns correspond to XYZ coordinates in Angstrom, and the last column corresponds to atomic charges.Then boot up Multiwfn and input

water.chg

5 // Generate grid data

8 // ESP based on atomic charges

2 // Medium quality grid

Then you can use option -1 to visualize isosurface of the grid data, or use option 2 to export the grid data to .cub file.

2 // Topology analysis module

2 // Search CPs from nuclear positions

3 // Search CPs from midpoint of atom pairs

6 // Search CPs from a batch of points within a sphere

-1 // Start the search using each nucleus as sphere center in turn

-9 // Return to topology analysis interface

Now use option 0, you will see below graph

As can be seen, PH relationship has been satisfied, all (3,-3) CPs and all related BCPs and RCPs have been found.

ECP is a very important technique for studying very heavy atoms. In quantum chemistry calculation, ECP is often employed for the elements later than the fourth rows in the periodic table.

More information about ECP can be found in DOI: 10.1002/wcms.28.

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