Corresponding Active Orbital Spaces along Chemical Reaction Paths

Area of Science:

• Computational chemistry
• Quantum chemistry
• Theoretical chemistry

Background:

• Accurate reaction energy profiles are essential for understanding chemical reactions.
• Selecting consistent active orbital spaces in multiconfigurational electronic structure methods is challenging.
• Existing methods often require manual intervention or structure interpolation.

Purpose of the Study:

• To develop a fully automated method for selecting consistent active orbital spaces along reaction coordinates.
• To improve the accuracy and efficiency of calculating reaction energy profiles.
• To enable reliable theoretical studies of chemical reactions and excited states.

Main Methods:

• Synergy of the Direct Orbital Selection (DOS) orbital mapping ansatz.
• Integration with the fully automated active space selection algorithm autoCAS.
• Application to potential energy profiles of C-C bond dissociation and double bond rotation in 1-pentene.
• Demonstration for both electronic ground and excited states.

Main Results:

• A fully automated approach for consistent active orbital space selection was successfully demonstrated.
• The method eliminates the need for structure interpolation between reactants and products.
• Accurate reaction energy profiles can be obtained without manual orbital selection.
• The algorithm is applicable to both ground and excited electronic states.

Conclusions:

• The developed automated method significantly advances the reliability of theoretical reaction energy profile calculations.
• This approach simplifies and enhances the study of complex chemical processes.
• The algorithm provides a robust tool for computational chemists studying reaction mechanisms and excited states.