Fukui Functions and the Dual Descriptor
***************************************

ADF Catalysis Fukui function Dual descriptor

Chemical reactivity can be analyzed using Fukui Functions and the Dual
Descriptor. ADF provides the tools to perform this analysis. The local
chemical reactivity can be described per atom via a condensed Fukui
Function. Subsequently, the local softness can be determined as well.
The Fukui Functions and the Dual Descriptor can be visualized in the
GUI with AMSview.


Step 1: Setting up the calculation
==================================

   Start AMSinput with the [image: ADFPanel][image] panel active.
   Build the carbon monoxide molecule using the search function [image: Search][image]
   Set the **XC** functional to **GGA BP86**
   Set **Relativity → None** (not all options of QTAIM analysis can be performed in combination with relativistic effects)
   Open the Conceptual DFT tab in **Properties → Conceptual DFT**
   Check both **Conceptual DFT (FDL)** options at the bottom of the panel (electrophilic and nucleophilic attack)

Here you can specify which Fukui functions you want to calculate. Both
can be calculated at the same time, and is also required for the Dual
Descriptor. The default way to calculate the Fukui functions is to add
or subtract a whole electron. However, it is possible to use
fractional charges by modifying the Charge change parameter.

[image]

   Open the Bader tab in **Properties → QTAIM**
   Check the **Perform QTAIM analysis** button
   Set the **Analysis** level to **Full**

The condensed Fukui Functions and local softness are calculated using
atomic charges. By default the Hirshfeld, Voronoi and Mulliken charges
are used. The Bader charges can be used as well if they are
calculated.

   Use **File → Save As** to save the file as "CO_Fukui"
   Run the calculation


Step 2: The output
==================

The condensed Fukui Functions and the local softness can be found in
the output file of the main calculation.

   Open the output file with AMSoutput: **SCM → Output**
   Go to the Condensed Fukui section by **Properties → Conceptual DFT (FDL)**

   Hirshfeld Partitioning


   MAIN ATOMIC DESCRIPTORS: CANONICAL ENSEMBLE
   ===========================================

   Atom   f+     f-     f0     f(2)
   C(1)   0.670  0.674  0.672  -0.004
   O(2)   0.330  0.326  0.328  0.004
   -------------------------------------
   Total  1.000  1.000  1.000  -0.000

The condensed Fukui functions are given per atom, with the various
atomic charge methods.  The above results are for the Hirshfeld
partitioning.


Step 3: Visualizing the Fukui functions and Dual Descriptor
===========================================================

The Fukui functions can be visualized in AMSview, using the electron
density.

   **SCM → View**
   Set the grid size to medium **Fields → Grid → Medium**
   Add an isosurface with phase **Add → Isosurface: With Phase**
   At the right side of the screen (in Select Field...) choose the Properties → Fukui Plus
   The instruction on the screen asks for the result file of the Fukui Plus calculation
   Choose "adf.plus.rkf"
   Enable the **Wireframe** checkbox for the field to use the wireframe model
 [image]

AMSview will create some calculated fields to combine the spin
densities for the unrestricted calculations, and calculates the Fukui
plus function. The wireframe model allows us to see any hidden
isosurface. Another way to do this is by lowering the opacity in the
field details.

   Hide the previous field by unchecking the **Show** checkbox in the right panel
   Create a new isosurface with phase
   At the right side of the screen (in the new "Select Field...") choose Properties → Dual Descriptor (FDL)
   The fukui plus function is already loaded, the instruction now asks for the missing Fukui Minus calculation
   Choose "adf.minus.rkf"
   Enable the **Wireframe** checkbox for the field to use the wireframe model
 [image]
