Multiwfn forum

saeed_E

Member

Registered: 2019-12-21

Posts: 328

IGM and QTAIM

Dear Tian,
It is well known that, in the some case of molecular systems, QTAIM is not able to correctly show the bond path and BCP regarding an interaction between two sites. That is, while there is an interaction between atoms A and B, QTAIM analysis does not show corresponding bond path and BCP between A and B. On the other hand, in such cases, IGM is nicely able to provide corresponding spike regarding interaction between A and B, resolving the QTAIM drawback.
Please, if possible, introduce me a decisive and valuable reference for such cases so that I can cite that in my manuscript (while I am sure such references are present on my PC, I could not find them!).

Best regards,
Saeed

Last edited by saeed_E (2025-09-21 23:54:11)

sobereva

Tian Lu (Multiwfn developer)

From: Beijing

Registered: 2017-09-11

Posts: 2,081

Website

Re: IGM and QTAIM

Please look at my reviews:

Tian Lu, Visualization Analysis of Covalent and Noncovalent Interactions in Real Space, Angew. Chem. Int. Ed., 137, e202504895 (2025) DOI: 10.1002/anie.202504895
Tian Lu, Qinxue Chen, Visualization Analysis of Weak Interactions in Chemical Systems (2023), in Comprehensive Computational Chemistry, Vol. 2 pp. 240-264. Oxford: Elsevier. DOI: 10.1016/B978-0-12-821978-2.00076-3

Also, in my IRI original paper (Chemistry—Methods, 1, 231-239 (2021) DOI: 10.1002/cmtd.202100007), I presented an example clearly showing QTAIM cannot exhibit intramolecular H-bond while IRI can, and I carefully discussed the underlying reason.

PS: I recommend IGMH instead of IGM, the former has evidently better isosurface.

saeed_E

Member

Registered: 2019-12-21

Posts: 328

Re: IGM and QTAIM

Your kind attention, together with introducing highly valuable references, is deeply appreciated.
Saeed