Multiwfn forum

sobereva

Tian Lu (Multiwfn developer)

From: Beijing

Registered: 2017-09-11

Posts: 1,773

Website

Analysis of Fukui function

A user send me a mail to ask how to carry out Fukui function analysis, in fact there are many different ways to do that, below is my reply:

In Multiwfn, Fukui function can be characterized in many different ways:
(1) Fukui function can be plotted as isosurface map, see Section 4.5.4 of Multiwfn manual for example, this is the most commonly used way of analyzing Fukui function
(2) Fukui function can also be studied in terms of "condensed Fukui function", which is a quantitative indicator of total amount of Fukui function on each atom site, please check Section 4.7.3 of the manual for example.
(3) The "quantitative molecular surface analysis " module of Multiwfn can map Fukui function on molecular surface to investigate its distribution character (e.g. average value) on local molecular surface corresponding to various atoms, this method is not popular currently but undoubtedly useful, see Section 4.12.4 of the manual for example.

These kinds of analyses can also be applied to dual descriptor.

prasanta13

Member

Registered: 2018-12-30

Posts: 39

Re: Analysis of Fukui function

I was going through the manual of Multiwfn 3.7 on Fukui function section. I need to calculate local electrophilicity index of OH radical. Could anyone provide a step by step guide to do so? Thanks in Advance.

sobereva

Tian Lu (Multiwfn developer)

From: Beijing

Registered: 2017-09-11

Posts: 1,773

Website

Re: Analysis of Fukui function

I was going through the manual of Multiwfn 3.7 on Fukui function section. I need to calculate local electrophilicity index of OH radical. Could anyone provide a step by step guide to do so? Thanks in Advance.

The easiest way is using subfunction 16 of main function 100, this function is able to directly calculate almost all quantities defined in conceptual density functional theory framework, including local electrophilicity index. Please check Section 4.100.6 for example of using this function.

When the program asks you to set net charge and spin multiplicity, for N electrons state, you should input 0 2 ; for N-1 state, you should input 1 1 ; for N+1 state, you should input -1 1.

prasanta13

Member

Registered: 2018-12-30

Posts: 39

Re: Analysis of Fukui function

Thank You Sir, I was testing this for CH4 molecule, and it worked fine with 6-311++G**, with 0 1 for N electron state. However, when it stops functioning with OH radical. Let me detail the procedure.
I load OH.fchk > 100 > 16 > 1
I input ub3lyp/6-311++G**
I input 0 2
Program hangs, it do not output the wfn files it did for previous time.

Thanks in Advance

prasanta13

Member

Registered: 2018-12-30

Posts: 39

Re: Analysis of Fukui function

One more small question. It does analyze the CDFT parameters using Hirshfeld charges. As these parameters are very much dependent upon atomic charge, DFT methods and basis sets, I just ask, Can I use mulliken and ChelPG or natural charge to calculate them? Can I use cam-b3lyp, m062x and wb97xd method and aug-cc-pvtz basis set?

sobereva

Tian Lu (Multiwfn developer)

From: Beijing

Registered: 2017-09-11

Posts: 1,773

Website

Re: Analysis of Fukui function

One more small question. It does analyze the CDFT parameters using Hirshfeld charges. As these parameters are very much dependent upon atomic charge, DFT methods and basis sets, I just ask, Can I use mulliken and ChelPG or natural charge to calculate them? Can I use cam-b3lyp, m062x and wb97xd method and aug-cc-pvtz basis set?

Because Hirshfeld charge is best for calculating these CDFT quantities, therefore Hirshfeld charge is the only choice of this module. Using CHELPG or Mulliken charge may result in very worse result.

Use these functionals in combination with aug-cc-pVTZ are completely OK.

sobereva

Tian Lu (Multiwfn developer)

From: Beijing

Registered: 2017-09-11

Posts: 1,773

Website

Re: Analysis of Fukui function

Thank You Sir, I was testing this for CH4 molecule, and it worked fine with 6-311++G**, with 0 1 for N electron state. However, when it stops functioning with OH radical. Let me detail the procedure.
I load OH.fchk > 100 > 16 > 1
I input ub3lyp/6-311++G**
I input 0 2
Program hangs, it do not output the wfn files it did for previous time.

Thanks in Advance

It is a bug, sorry for inconvenicen. I have fixed it, please re-download the 3.7(dev) version from Multiwfn website.