New accurate reference energies for the G2/97 test set

Area of Science:

• Computational Chemistry
• Quantum Chemistry
• Theoretical Chemistry

Background:

• The G2/97 test set is widely used for evaluating computational chemistry methods.
• Experimental heats of formation are often used as benchmarks, but can have limitations.

Purpose of the Study:

• To compute highly accurate atomization energies for the G2/97 test set.
• To provide a more reliable reference dataset for assessing new computational methods.

Main Methods:

• Employed an explicitly correlated coupled-cluster method (CCSD(T)) with quadruple-ζ basis sets.
• Included corrections for higher excitations and core/core-valence correlation effects.
• Utilized a recently proposed computational protocol for high accuracy.

Main Results:

• Achieved highly accurate atomization energies for 148 diverse molecules.
• Obtained a mean deviation of -0.75 kJ/mol and a standard deviation of 1.06 kJ/mol against active thermochemical tables.
• Demonstrated the superior accuracy of the computed values compared to experimental data.

Conclusions:

• The proposed computational protocol yields highly accurate atomization energies.
• These computed values serve as improved reference data for approximate methods like density functional theory.
• This work enhances the reliability of computational chemistry benchmarks.