Intrinsic atomic orbitals: An unbiased bridge between quantum theory and chemical concepts

TL;DR

This paper introduces a simple algebraic method to define atomic orbitals that accurately represent molecular wave functions, bridging quantum theory and chemical concepts for better interpretation of quantum chemistry predictions.

Contribution

It presents an unbiased, algebraic construction of atomic orbitals polarized by the molecular environment, linking quantum calculations directly to chemical concepts.

Findings

Exact representation of SCF wave functions by atomic orbitals

Provides a direct connection between quantum chemistry and chemical bonding

Enables chemical interpretation from first principles

Abstract

Modern quantum chemistry can make quantitative predictions on an immense array of chemical systems. However, the interpretation of those predictions is often complicated by the complex wave function expansions used. Here we show that an exceptionally simple algebraic construction allows for defining atomic core and valence orbitals, polarized by the molecular environment, which can exactly represent self-consistent field wave functions. This construction provides an unbiased and direct connection between quantum chemistry and empirical chemical concepts, and can be used, for example, to calculate the nature of bonding in molecules, in chemical terms, from first principles.