Optimizing Molecular Geometries in Strong Magnetic Fields.

Area of Science:

• Computational Chemistry
• Quantum Chemistry
• Theoretical Chemistry

Background:

• Studying molecular structure in strong magnetic fields is crucial for understanding exotic chemical phenomena.
• Existing computational methods face challenges in accurately describing systems under intense magnetic fields.

Purpose of the Study:

• To develop and implement an efficient computational method for calculating geometrical derivatives at Hartree-Fock and current-density functional theory levels for molecules in strong magnetic fields.
• To enable accurate molecular structure optimization and electronic structure analysis for systems under extreme magnetic conditions.

Main Methods:

• Implementation of geometrical derivatives using a hybrid McMurchie-Davidson and Rys quadrature approach for integral derivatives.
• Application of the resolution-of-the-identity approximation for efficient gradient calculations.
• Inclusion of current-density functional theory contributions for various density functionals, including meta-GGA, and hybrids.

Main Results:

• Demonstrated efficient optimization of molecular structure for many-electron systems in strong magnetic fields.
• Revealed complex chemical behavior induced by external magnetic fields in illustrative applications to OH and benzene molecules.
• Highlighted challenges in geometry optimization and the necessity of careful electronic structure analysis.

Conclusions:

• The developed method provides a cost-effective approach for studying molecular structure in strong magnetic fields.
• This implementation opens new avenues for exploring chemistry in regimes previously inaccessible.
• Comparison between Hartree-Fock and current-density functional theory highlights the importance of correlation effects.