A paradigm system for strong correlation and charge transfer competition

TL;DR

This paper introduces a new paradigm system based on the H2 molecule with fractional nuclear charges to study the interplay between strong electron correlation and charge transfer, aiding the development of better electronic structure methods.

Contribution

It extends the classic H2 system by incorporating fractional nuclear charges, enabling detailed analysis of correlation and charge transfer competition in materials.

Findings

Enables controlled study of correlation and charge transfer dynamics.

Provides a versatile platform for testing electronic structure theories.

Lays groundwork for improved computational methods.

Abstract

In chemistry and condensed matter physics the solution of simple paradigm systems, such as the hydrogen atom and the uniform electron gas, plays a critical role in understanding electron behaviors and developing electronic structure methods. The H$_2$ molecule is a paradigm system for strong correlation with a spin-singlet ground state that localizes the two electrons onto opposite protons at dissociation. We extend H$_2$ to a new paradigm system by using fractional nuclear charges to break the left-right nuclear symmetry, thereby enabling the competition between strong correlation and charge transfer that drives the exotic properties of many materials. This modification lays a foundation for improving practical electronic structure theories and provides an extendable playground for analyzing how the competition appears and evolves.