Multiwfn forum

michaelp

Member

Registered: 2018-02-06

Posts: 21

Why not NBO?

Dear Tian,

MultiWFN is user friendly and full of options. It is almost a complete package for density and wave-function analysis. Thank you for the work and effort you put into this code. My question is, would it be possible to also include the NBO analysis? There is no obvious reason, why this should not be included and would make the code even more useful.

Best wishes,
Michael

sobereva

Tian Lu (Multiwfn developer)

From: Beijing

Registered: 2017-09-11

Posts: 1,773

Website

Re: Why not NBO?

Dear Michael,

There are some reasons why I didn't implement NBO into Multiwfn:

1 The NBO program written by weinhold et al. is already very nice, fast and easy-to-use. Most important analyses in the NBO framework can be realized in the freely available NBO 3.0/3.1. Although the later versions of NBO are no longer free-of-charge, the price is inexpensive (100 USD).

2 NBO consists of a bunch of analysis methods, many technique details are not published, therefore some methods are uneasy to be implemented, and even if they are supported by Multiwfn, the results may be clearly different to NBO program.

3 Lots of things that NBO can do in fact can also be done by Multiwfn via different ways (sometimes better ways). For example, NBO orbital analysis can be largely replaced by localized molecular orbital analysis in Multiwfn, the NBCP analysis can be essentially equivalently realized by Multiwfn in topology analysis module (In Multiwfn, properties at CPs can be decomposed to contribution of orbitals, including NLMOs).

The most valuable and irreplaceable component of NBO framework I think is generation of natural atomic orbital, the NAOs are also utilized by some functions of Multiwfn, such as decomposition of Wiberg bond order to atomic orbital pair contributions. Due to its absolute importance, generating NAO is the only component in NBO framework that I intend to add to Multiwfn in future versions.

Best wishes,

Tian Lu