Stepwise basis set selection.

Area of Science:

• Computational chemistry
• Quantum chemistry methods
• Molecular modeling

Background:

• Computational cost of quantum chemical methods increases with level of theory and basis set size.
• A compromise between computational cost and accuracy is often necessary for molecular systems.
• Heats of reaction are primarily influenced by atoms undergoing significant chemical changes.

Purpose of the Study:

• Introduce the Stepwise Basis Builder (SBB) algorithm.
• Develop a method to selectively optimize basis set size for computational efficiency.
• Achieve target accuracy levels in quantum chemical calculations with reduced computational cost.

Main Methods:

• The Stepwise Basis Builder (SBB) algorithm selectively adds basis functions to reactive atoms.
• Spectator atoms are assigned smaller basis sets.
• The algorithm predicts calculation errors to guide basis set selection.
• SBB aims to reach specific target accuracy levels.

Main Results:

• Benchmarks demonstrate that SBB-calculated heats of reaction and activation barriers converge to high-quality results.
• The SBB algorithm achieves this convergence using a substantially reduced number of basis functions.
• This indicates a significant reduction in computational cost without sacrificing accuracy.

Conclusions:

• The SBB algorithm offers an efficient approach to quantum chemical calculations.
• It effectively balances computational cost and accuracy by focusing basis set expansion on critical atomic regions.
• SBB provides a pathway to achieving reliable computational results with significantly reduced resource requirements.