Quantifying and understanding errors in molecular geometries

TL;DR

This paper introduces the geometry energy offset (GEO), a new measure to quantify and analyze errors in molecular geometries across various computational methods, providing insights and rankings.

Contribution

The paper presents GEO as a novel, comprehensive metric for assessing geometric errors, enabling better method comparison and understanding of error sources in molecular structures.

Findings

GEO effectively ranks different computational methods.

GEO reveals trends and specific errors in bond lengths and angles.

Using GEO reduces the need for costly high-level geometry optimizations.

Abstract

Electronic structure calculations are ubiquitous in most branches of chemistry, but all have errors in both energies and equilibrium geometries. Quantifying errors in possibly dozens of bond angles and bond lengths is a Herculean task. A single natural measure of geometric error is introduced, the geometry energy offset (GEO). GEO links many disparate aspects of geometry errors: a new ranking of different methods, quantitative insight into errors in specific geometric parameters, and insight into trends with different methods. GEO can also reduce the cost of high-level geometry optimizations and shows when geometric errors distort the overall error of a method. Results, including some surprises, are given for both covalent and weak interactions.