Quantification of Geometric Errors Made Simple: Application to Main-Group Molecular Structures

Nearly all electronic structure simulations
begin with obtaining
approximate geometries, making a systematic quantification of errors
in approximate molecular structures of key importance. Recently, the
geometric energy offset (GEO) framework based on a single and natural
measure for quantifying and analyzing these errors has been proposed
(J. Phys. Chem. Lett. 2020, 11, 99579964). An accurate and far less costly approximation to GEO is utilized
here to readily quantify errors in main-group structures and analyze
them in a chemically intuitive way. The use of semiexperimental geometries
as a reference further simplifies the analysis. The analysis reveals
new insights into the geometric performance of methods, their rankings,
as well as patterns across different classes of methods and basis
sets that arise from the analysis.