Quantum walks in polycyclic aromatic hydrocarbons

TL;DR

This paper proposes a quantum walk model to explain electron delocalization in polycyclic aromatic hydrocarbons, successfully predicting reactive sites and stability, offering a novel quantum perspective on aromaticity.

Contribution

It introduces a quantum walk framework to model electron delocalization in aromatic molecules, linking quantum dynamics to chemical structure and stability.

Findings

Quantum walk accurately predicts reactive sites.

Model reproduces stability order of molecules.

Provides a quantum-based explanation for aromaticity.

Abstract

Aromaticity is a well-known phenomenon in both physics and chemistry, and is responsible for many unique chemical and physical properties of aromatic molecules. The primary feature contributing to the stability of polycyclic aromatic hydrocarbons is the delocalised $\pi$-electron clouds in the $2p_z$ orbitals of each of the $N$ carbon atoms. While it is known that electrons delocalize among the hybridized $sp^2$ orbitals, this paper proposes quantum walk as the mechanism by which the delocalization occurs, and also obtains how the functional chemical structures of these molecules arise naturally out of such a construction. We present results of computations performed for some benzoid polycyclic aromatic hydrocarbons in this regard, and show that the quantum walk-based approach does correctly predict the reactive sites and stability order of the molecules considered.