Molecular theory of graphene

TL;DR

This paper presents a molecular theory of graphene based on the behavior of odd electrons and discusses how single-determinant computational methods like UHF and UDFT can reliably model electron correlation in graphene.

Contribution

It introduces a molecular theory of graphene emphasizing odd electron behavior and demonstrates the reliability of single-determinant computational schemes for studying electron correlation.

Findings

Single-determinant methods can effectively model electron correlation in graphene.

The molecular theory provides a new perspective on graphene's electronic structure.

Computational techniques like UHF and UDFT are validated for large polyatomic systems.

Abstract

Odd electrons of benzenoid units and correlation of these electrons having different spins are the main concepts of the molecular theory of graphene. In contrast to the theory of aromaticity, the molecular theory is based on the fact that odd electrons with different spins occupy different places in the space so that the configuration interaction becomes the central point of the theory. Consequently, a multi-determinant presentation of the wave function of the system of weakly interacting odd electrons is absolutely mandatory on the way of the theory realization at the computational level. However, the efficacy of the available CI computational techniques is quite restricted in regards large polyatomic systems, which does not allow performing extensive computational experiments. Facing the problem, computationists have addressed to standard single-determinant ones albeit not often being aware of how correct are the obtained results. The current chapter presents the molecular theory of graphene in terms of single-determinant computational schemes and discloses how reliable information about electron-correlated system can be obtained by using either UHF or UDFT computational schemes.