Computing Fukui functions without differentiating with respect to electron number. I. Fundamentals

Area of Science:

• Computational Chemistry
• Quantum Chemistry
• Theoretical Chemistry

Background:

• The Fukui function is a crucial indicator of molecular reactivity in chemical systems.
• Calculating the Fukui function traditionally involves differentiating electron density, which can be computationally challenging.
• Accurate computation of reactivity indicators is essential for understanding chemical reactions and designing new molecules.

Purpose of the Study:

• To introduce a novel method for deducing the Fukui function.
• To avoid the difficulties associated with differentiating electron density with respect to electron number.
• To demonstrate the applicability of the method for calculating the Fukui function of specific atoms and molecules.

Main Methods:

• The study utilizes perturbations in the molecular external potential.
• The Fukui function is derived from the resulting changes in Kohn-Sham orbital energies.
• This technique offers a more direct computational pathway compared to traditional methods.

Main Results:

• The proposed method successfully computes the Fukui function for the beryllium atom.
• The Fukui function for the formaldehyde molecule was also accurately determined using this approach.
• The general technique is shown to be adaptable for computing functional derivatives of other observables.

Conclusions:

• The new method provides an effective alternative for calculating the Fukui function.
• This approach simplifies the computation of chemical reactivity indicators.
• The methodology lays the groundwork for further advancements in calculating condensed reactivity indicators in subsequent research.