Multiwfn forum

sobereva

Tian Lu (Multiwfn developer)

From: Beijing

Registered: 2017-09-11

Posts: 1,954

Website

Studying H atom in the formation of H-bond

My reply to four questions raised by a user is given below, which may also be useful for other users

He/She asked

Is it possible to deduce the parameters, after on H-bond formation,  i) loss of charge of hydrogen atom, ii) energetic destabilization of hydrogen atom, iii) decrease of dipolar polarization of the hydrogen atom, and iv) decrease of the hydrogen atom's volume
using multiwfn?

My reply

1 You can calculate atomic charge of the H atom before and after H-bond formation, and take their difference.

2 There is no unique definition of "energetic destabilization of hydrogen atom". If want to calculate H-bond energy, you can use the prediction equation fitted in my previous work J. Comput. Chem., 40, 2868 (2019) based on AIM topology analysis, there is an example in Section 4.2.1 of Multiwfn manual ("Evaluate H-bond binding energy"). Multiwfn can also calculate atomic energy by integrating electron energy density in AIM atomic space, see Section 4.17.9 of Multiwfn manual.

3 Perhaps you want to calculate atomic dipole moment for the H atom. Both fuzzy analysis module (main function 15, which employ fuzzy partition of atomic spaces like Becke, Hirshfeld, Hirshfeld-I, etc.) and basin analysis module (main function 17, which can employ AIM partition of atomic spaces) of Multiwfn can do this.

4 You can use basin analysis module to calculate AIM atomic volume for the H atom in the two statuses. See Section 4.17.1 of Multiwfn manual on how to obtain atomic volumes.