Multiwfn forum

monthem

Member

Registered: 2025-03-29

Posts: 7

Different results obtained with Multiwfn and NCIPLOT

Hello.

I want to do NCI analysis. I ran a job with Multiwfn 3.8 dev and NCIPLOT 4.0 on a same .wfn file, using same grid density. The results differ a lot.

- For Multiwfn: i am using the following input: 20 1 4 0.05 -1 1 2

- For NCIPLOT (i know its a different independent program, but here is the input) : 1 filename.wfn ULTRAFINE (this specifies that there will be 1 wawefunction file used and ULTRAFINE grid, which is 0.025 Angstrom spacing)

The RDG vs sign(lambda_2)rho scatter maps generated by the two are completely different. I am aware that NCIPLOT outputs 100 * sign(lambda_2)rho. Still, there is quite a mismatch.

May I kindly ask to take a look at the two scatter data files provided and ask for what may be causing the difference? I assume that both programs should yield essentially identical results.

The wfn file: Be2F6_dianion_vacuum.wfn

I apologize but both the scatter data and the images are too large to upload via the forum. Here is a google drive link to those:

https://drive.google.com/drive/folders/ … sp=sharing

Multiwfn output.txt is significantly larger. May I also use the chance to ask what are each of the columns in the output.txt produced by multiwfn here?

Kind regards

sobereva

Tian Lu (Multiwfn developer)

From: Beijing

Registered: 2017-09-11

Posts: 1,965

Website

Re: Different results obtained with Multiwfn and NCIPLOT

I am not a NCIplot user. The NCI data exported by Multiwfn are exactly in line with the standard definition, see equations in Multiwfn manual (Section 3.23.1 of Multiwfn manual) and my reviews:
Tian Lu, Qinxue Chen, Visualization Analysis of Weak Interactions in Chemical Systems (2023), Comprehensive Computational Chemistry, Vol. 2 pp. 240-264. Oxford: Elsevier. DOI: 10.1016/B978-0-12-821978-2.00076-3  (preprint: //www.umsyar.com/attach/Visualizatio … ystems.pdf)
Tian Lu, Visualization Analysis of Covalent and Noncovalent Interactions in Real Space, ChemRxiv (2025) DOI: 10.26434/chemrxiv-2025-9t442

I also strongly suggest you reproducing the NCI examples given in Multiwfn manual, and then apply the analysis to your own system.

There is no any special prefactor like "100" in the outputted data of Multiwfn.

When you ask Multiwfn to export a text file, including the file exported by option "2 Output scatter points to output.txt in current folder", meaning of each column in the exported file is always very clearly shown on screen. Please carefully check these information on screen.